Nathaen S. Weitzel, S. Adil Husain, and Laurie K. Davies
1. In adult CHD, a clinically relevant classification of lesions into three categories is useful: (1) Complete surgical correction, (2) partial surgical correction or palliation, and (iii) uncorrected CHD.
2. Over 1 million patients with congenital heart disease have reached adulthood in the United States.
3. Improvements in surgical techniques have allowed 90% of children with CHD to survive to adulthood with relatively normal functionality.
4. Ventricular and atrial arrhythmias are extremely common in adult CHD, accounting for nearly 50% of emergency hospitalizations.
5. Adult CHD patients have an incidence of pulmonary artery hypertension (PAH) as high as 10%.
6. Patients with PAH have a high surgical mortality rate (4% to 24%).
7. For both cyanotic (right-to-left shunts) and left-to-right shunts, there are general principles that impact anesthetic management.
8. Patients with complicated residual lesions requiring medium- to high-risk surgery should be managed at centers of excellence with physicians and staff trained in adult congenital disease.
In 1938, Robert Gross performed the first ligation of a patent ductus arteriosus (PDA), thus initiating a major advance in congenital heart surgery and paving the way for development of modern surgical techniques . Major improvements followed, with significant improvements in mortality throughout the 70s and 80s, leading to a greater survival. In 2000, the 32nd Bethesda Conference report generated from the American College of Cardiology indicated that approximately 85% of patients operated on with congenital heart disease (CHD) survive to adulthood . It was estimated that 800,000 patients with adult congenital heart disease (ACHD) were in the United States in 2000. This report highlighted the importance of an emerging problem in our health care system. The issue is how to develop a model for seamless transition of care of patients presently cared for at pediatric heart centers who now must move into the adult population and adult hospitals. There has been a widespread call for an increased number of physicians capable of providing continuity of care for these patients in an outpatient setting, as well as during the perioperative period. This section will focus on the specific issues facing the patient with ACHD as they enter the perioperative period as it relates to the anesthesiologist.
A. Defining ACHD: Attempts to establish prevalence and even mortality data for ACHD depend on the defining characteristics of which patients to include. A strict definition of ACHD was proposed by Mitchell et al., “a gross structural abnormality of the heart or intrathoracic great vessels that is actually or possibly of functional significance” . This definition excludes persistent left-sided vena cava, abnormalities of major arteries, and in addition excludes bicuspid aortic valve (AV) disease, mitral valve prolapse, and the like .
B. Classification: A pathologic categorization scheme divides patients into categories of great complexity, moderate complexity, and simple CHD [5,6] (Table 15.1). These categories are particularly helpful in neonatal disease, as well as to establish prevalence data. In ACHD, a different categorization approach may be more clinically relevant and will be utilized later in this section. These three categories are listed below :
1. Complete surgical correction
a. Examples include repaired atrial septal defect (ASD), ventricular septal defect (VSD), and PDA without hemodynamic sequelae.
2. Partial surgical correction or palliation
a. Examples include palliative repairs such as Fontan, tetrology of Fallot (ToF), and transposition of great arteries (TGA) (Mustard repair), leaving hemodynamic or physiologic compromise.
Table 15.1 Adult congenital heart disease classification 
3. Uncorrected CHD
a. Examples include minor ASD, minor VSD, Ebstein’s anomaly, or undiagnosed ACHD due to limited health care access as child.
1. The actual number of adult patients with congenital heart defects is difficult to obtain; however, recent estimates suggest that over 1 million patients have reached adulthood in the United States, with an additional 8,500 corrected each year [4,8]. Significant improvements in surgical techniques have allowed many patients (>90% of children with CHD) to survive to adulthood, and maintain relatively normal function [2,4,8].
2. Select populations
a. A recent estimate from Canada reported 11.89 cases per 1,000 children and 4.09 cases per 1,000 adults with CHD. Selecting out patients with complex ACHD (Table 15.1) reduces these estimates to 1.45 per 1,000 children and 0.38 per 1,000 adult cases.
b. ACHD becomes a significant issue in certain populations such as obstetrics where patients with CHD now represent the majority (60% to 80%) of obstetric patients with cardiac disease. This population is in general young and healthy, so it makes sense that as patients with CHD reach childbearing age, they begin to represent a higher proportion of patients in this group with cardiac disease.
3. Survival data
a. It is estimated that 96% of newborns who survive the first year will reach the age of 16 .
b. Median expected survival has increased significantly since 2000, with current estimates placing the median age of death for ACHD at 57 yrs .
D. Health care system considerations
1. The ACC/AHA 2008 guidelines for ACHD highlight the fact that the pediatric cardiology centers have significant infrastructure to support patients with CHD, but that this is largely lacking in the adult health care system. This includes access to physicians with training in ACHD, as well as advanced practice nursing, case management, and social workers familiar with the needs of these patients . These guidelines echo the recommendations made by the Bethesda Conference, as well as the Canadian Cardiovascular Society Consensus Conference statements from 2010 [2,10–15].
2. Overall recommendations taken from these reports suggest a focus on improvement in ACHD health care delivery through the following:
a. Improved transition clinics for adolescents approaching adulthood
b. Outreach programs to educate patients and families of key issues related to their disease
c. Enhanced education of adult caregivers trained in ACHD management
d. Coordination of health care delivery through regional centers of excellence
e. Development of primary-care physicians with ready referral access to these regional centers of excellence
3. Centers of excellence
a. The services and provider requirements for such centers are summarized in Table 15.2, taken from the 2008 ACC/AHA guidelines. Key areas with physicians specializing in ACHD are indicated.
Table 15.2 Summary of qualifications for regional centers of excellence in adult congenital heart disease
III. What are the key anesthetic considerations in ACHD?
To evaluate the ACHD patient prior to surgery, the anesthesiologist must gain an understanding of the patient’s medical history, current functional status, state of surgical repair, and overall health. Key items are discussed below.
A. History: Obtaining a thorough and accurate surgical and medical history is critical, however challenging, as only half of patients with ACHD are able to correctly describe their diagnosis . Patients with ACHD have varying functional capacities which may make evaluation of true cardiac capacity more challenging.
B. Signs and symptoms of ACHD: Some generalized exam findings that may indicate ACHD include the following :
1. Continuous heart murmurs: There are relatively few acquired cardiac diseases producing a continuous type of murmur.
2. Right bundle branch block (RBBB): This can occur in the general population; however, if found in conjunction with a continuous murmur, this may indicate a congenital defect.
3. Evidence of cyanosis without existing pulmonary disease
4. The above findings should trigger an echocardiographic study prior to surgical care.
C. How can you assess the perioperative risk for ACHD patients?
Anesthetic evaluation should focus on predicting risk of surgery in this patient population. Some key prognostic indicators for outcomes in ACHD surgery (both cardiac and noncardiac) include the presence of the below-listed factors [7,9,16,18] (Table 15.3):
Table 15.3 Common medical concerns in patients with ACHD 
1. Pulmonary arterial hypertension (PAH)
2. Cyanosis or residual VSD
3. Need for reoperation (cardiac surgery)
5. Ventricular dysfunction
6. Single ventricle physiology or a systemic right ventricle
IV. What common sequelae are associated with ACHD?
In contrast to the neonate with CHD, ACHD patients begin to acquire additional medical comorbidities that should be considered in management planning. Common comorbidities in this patient population are listed in Table 15.3, and preoperative evaluation should take these into account. Cardiac arrhythmias, pulmonary hypertension, ventricular dysfunction, cyanosis (or residual VSD), valve abnormalities, and aneurysms represent some of the key comorbid conditions commonly associated with ACHD that have serious management considerations and result in overall increased perioperative risk . Obtaining a detailed history on the degree of involvement of these issues will enable adequate planning in management. Two of the most common and critical areas (arrhythmias and pulmonary hypertension) will be addressed here.
A. Arrhythmias: Ventricular and atrial arrhythmias are extremely common in ACHD patients accounting for nearly 50% of emergency hospitalizations . The type of rhythm disturbance depends primarily on the lesion and method of surgical repair. Tables 15.4 and 15.5 divide the bradyarrhythmias from tachyarrhythmias by lesion type.
Table 15.4 Tachyarrhythmias associated with ACHD [4,7,20]
Table 15.5 Bradyarrhythmias associated with ACHD [4,7,20]
1. In general, patients who fall in the moderate to complex categories are at higher risk for arrhythmias. Tetralogy of Fallot (Fig. 15.1) and Fontan lesions carry an extremely high arrhythmia burden [19,20]. In addition, any patient with a ventricular repair or patch is at high risk for ventricular rhythm disturbances, while those patients with atrial repairs, atrial baffles, etc., are likely to develop atrial arrhythmias .
Figure 15.1 Macro–re-entrant VT in tetralogy of Fallot. A: An autopsy specimen of repaired tetralogy with the anterior RV surface opened to reveal the VSD patch and the patch-augmented RVOT (the outflow patch in this case is transannular). A hypothetical re-entry circuit is traced onto this image (black arrows), with the superior portion of the loop traveling through the conal septum (upper rim of the VSD). B: Actual electroanatomic map of sustained VT from an adult tetralogy patient, showing a nearly identical circuit. The propagation pattern is shown by the black arrows and is reflected by the color scheme (red > yellow > green > blue > purple). A narrow conduction channel was found between the rightward edge of the outflow patch scar (gray area) and the superior rim of the tricuspid valve. A cluster of radiofrequency applications at this site (pink dots) closed off the channel and permanently eliminated this VT circuit. LV, left ventricle; MPA, main pulmonary artery; TV, tricuspid valve. (Reused with permission from Walsh EP, Cecchin F. Congenital heart disease for the adult cardiologist: Arrhythmias in adult patients with congenital heart disease. Circulation. 2007;115:534–545.)
2. Patients with right-sided lesions have a higher likelihood of developing arrhythmias, although the morbidity/mortality results are similar between right- and left-sided lesions .
3. Patients with either ASD or VSD can have interruption in the normal conduction pathways or abnormal variants such as duplicate AV nodes (Fig. 15.2), leading to re-entrant arrhythmias .
Figure 15.2 Representation of twin AV nodes with a Mönckeberg sling. The cardiac anatomy in this sketch includes a large septal defect in the AV canal region, shown in a right anterior oblique projection. Both an anterior and a posterior AV node are depicted (each with its own His bundle) along with a connecting “sling” between the two systems. This conduction arrangement can produce two distinct non–pre-excited QRS morphologies (depending on which AV node is engaged earliest by the atrial activation wave front), and a variety of re-entrant tachycardias. (Redrawn from Walsh EP, Cecchin F. Congenital heart disease for the adult cardiologist: Arrhythmias in adult patients with congenital heart disease. Circulation. 2007;115:534–545.)
a. Antiarrhythmic medical therapy remains the mainstay for most patients, although results are often suboptimal in many cases such as intra-atrial re-entrant tachycardia (IART), despite the use of potent agents such as amiodarone .
b. Ablative procedures: Recent advances in electrophysiology have allowed significant improvements in management of these rhythm disturbances. Electrophysiologists are able to map out the conduction pathways in the heart, and ablate malignant tracts (Figs. 15.1 and 15.3). This is most useful for atrial arrhythmias, with short-term success rates nearing 90% . Long-term outcomes following ablation are less promising and not widely reported. de Groot et al. reported a 59% recurrence after the initial ablation, with the location of the recurrent pathway being different for all but one patient. At 5 yrs, 58% of patients were in sinus rhythm and 33% of the initial population were maintained on antiarrhythmic drug therapy . Electrophysiologic testing and ablative procedures are considered a Class I recommendation for patients with known rhythm disturbances .
Figure 15.3 Electroanatomic map of an IART circuit involving the anterolateral surface of the right atrium in a patient with a previous Fontan operation (cavopulmonary connection). A detailed anatomic shell was generated for the ablation procedure by merging high-resolution computed tomography data with real-time data gathered from the 3D mapping catheter. The propagation pattern for the IART circuit is shown by black arrows and is also reflected by the color scheme (red > yellow > green > blue > purple). The critical component of the circuit appeared to be a narrow conduction channel through a region of scar (central gray area). A cluster of radiofrequency applications (maroon dots) was placed at the entrance zone to this narrow channel and permanently eliminated this IART circuit. LPA, left pulmonary artery; RPA, right pulmonary artery; RA, right atrium; JXN, junction; LAT, lateral. (Reused with permission from Walsh EP, Cecchin F. Congenital heart disease for the adult cardiologist: Arrhythmias in adult patients with congenital heart disease. Circulation. 2007;115:534–545.)
c. Implantable devices: For patients at risk for ventricular arrhythmias, automatic implantable cardiac defibrillators (AICD) can offer a life-saving modality and are a class II recommendation for ACHD patients . While ventricular tachycardia (VT) is rare in the first and second decades, it becomes increasingly prevalent as the patient ages, with those patients with a history of ventricular intervention being at highest risk . VT circuits can develop a macro–re-entrant characteristic similar to the atrial IART (Fig. 15.3). ToF patients have a high risk, and a careful history should be obtained, inquiring about symptoms and any outpatient studies. Patients at risk for bradyarrhythmias often will have a pacemaker in place, which should be interrogated and sensitivity limits adjusted for the surgical procedure .
(1) Anesthetic management: The most recent practice advisory (2011) for patients with implanted cardiac devices recommends that AICD’s be disabled prior to surgery to prevent inadvertent defibrillation due to electrocautery; however, this is specific to procedures where electromagnetic interference is likely . If the AICD is disabled, it is imperative that the patient be placed on continuous monitoring, with external defibrillation pads in place, and that the device be enabled again in the PACU.
(2) Complex patients: Actual placement of AICD leads into the heart in patients with complex lesions is often difficult, if not impossible . Presence of abnormal venous return, surgically created shunts or baffles, as well as scarring from previous surgery can make adequate placement challenging. Occasionally, patients will require an open surgical approach to place epicardial pacing/defibrillation leads, although this procedure often carries risk as well due to scarring and reoperative concerns (see Section IX below).
B. Pulmonary Arterial Hypertension (PAH): PAH is defined as a mean pulmonary pressure greater than 25 mm Hg at rest or 30 during exercise . ACHD patients have an incidence of PAH in up to 10% of patients, with Eisenmenger’s syndrome (ES) being present in approximately 1% . The etiology of the PAH typically falls in the World Health Organization category I or II. Group I is PAH due to primary PAH but includes congenital shunts, and group II is due to pulmonary venous hypertension (i.e., disease due to valve disorders, volume excess, and LV dysfunction).
1. Surgical risk: PAH patients are high-risk surgical candidates. Published series demonstrate a range of surgical mortalities from a low of 4% to a high of 24% depending on disease severity and surgical procedure. Surgical and anesthetic risk should be clearly stated to the patient, especially for an elective case. Patients with ES should be considered higher-risk candidates and extreme care should be taken in managing these cases. See Section XII.B.2.
a. Hemodynamic spiral: Acute deterioration is possible as RV failure causes reduced pulmonary blood flow, leading to hypoxia which subsequently increases the pulmonary vascular resistance (PVR). The elevated PVR ultimately leads to increased strain on the RV. This initiates a catastrophic hemodynamic chain of events where the decreased RV stroke volume decreases LV output, and coronary blood flow to both the LV and RV decreases. The already failing RV may not be able to recover from this insult, resulting in cardiac arrest. This “death spiral” is always a potential in PAH patients; the anesthesia provider should be aware of it and take steps to prevent it .
2. How do you treat RV failure in the setting of PAH? Treatment of acute RV failure should focus on reducing PVR (see Section IV.B.3 below), while utilizing b-stimulating inotropic agents such as dobutamine and/or phosphodiesterase-inhibiting agents such as milrinone, as these provide inotropic support with moderate reductions in PVR (and systemic vascular resistance [SVR]). Consider using a vasopressor such as norepinephrine in the setting of systemic hypotension to increase the coronary perfusion pressure. In severe scenarios, an intra-aortic balloon pump can also be used to increase coronary perfusion pressure, thus supporting the RV .
3. What are some treatment modalities during surgery to reduce PVR acutely ?
a. Consider moderate hyperventilation (PaCO2 ~25 to 30 mm Hg) while administering 100% oxygen.
b. Use low-pressure ventilation if possible as high intrathoracic pressure can mechanically compress extra-alveolar vessels and reduce CO.
c. Utilize nitric oxide for acute reductions in PVR.
d. Consider inhaled prostanoid (iloprost) if available.
e. Intravenous (IV) magnesium sulfate may provide temporary reductions in PVR.
C. What are some general hemodynamic goals for patients with PAH ?
Anesthetic and hemodynamic goals for pulmonary hypertension
1. Avoid elevations in PVR: Prevent hypoxemia, acidosis, hypercarbia, and pain. Provide supplemental oxygen at all times. Consider inhaled nitric oxide (iNO) to acutely decrease PVR.
2. Maintain SVR: Decreased SVR dramatically reduces CO due to “fixed” PVR.
3. Avoid myocardial depressants and maintain myocardial contractility.
4. Maintain chronic prostaglandin therapy without altering dosage.
5. Utilize low-pressure mechanical ventilation when possible.
V. What laboratory and imaging studies are needed?
The overall goal in preoperative laboratory and imaging studies is to assist the physicians in understanding the degree of involvement of any comorbid disease.
A. Preoperative laboratory and imaging testing should be guided by degree of severity of disease. Patients with normal functional status can be treated as any adult presenting for surgery, whereas the patient with severe functional limitation due to cardiac disease warrants additional evaluation. Lab evaluation may include complete blood count, coagulation studies, and basic metabolic studies.
B. Cardiac catheterization and/or echocardiography studies are particularly helpful in symptomatic patients by providing information on structural status of the heart, functional status of the ventricles, and degree of PAH. Many patients will also have either magnetic resonance imaging (MRI) or computed tomography (CT) reconstructive imaging as part of standard surveillance, and these can add tremendous information to the history.
C. EKG should be obtained at baseline as there are often abnormalities present. This can also alert the practitioner to the presence of a pacemaker or other abnormal rhythm disturbances.
D. Chest radiography: It can be helpful to determine degree of heart and lung disease at baseline.
VI. What monitors should be used in ACHD surgery?
A. Standard ASA monitors should be employed for every case. In addition, most cases involving moderate to complex ACHD patients will utilize some degree of invasive monitoring. Some key considerations here include the following :
1. Location of arterial line, if needed, should consider previous surgical procedures such as Blalock–Taussig shunts using the subclavian artery, which compromise blood flow to the ipsilateral upper extremity.
2. Central venous catheters should be reserved for the most symptomatic patients as risk of thrombus and stroke is higher.
3. Pulmonary artery (PA) catheters are often anatomically difficult or impossible to place and are seldom helpful in patients with cyanotic cardiac lesions.
4. Transesophageal echocardiography (TEE) may be the most useful real-time monitor of cardiovascular status, especially when using general anesthesia, and should strongly be considered for patients with reduced functional status for all medium- and high-risk procedures.
5. Near-infrared spectroscopy (NIRS) has been suggested as a tool to monitor both cerebral and peripheral oxygenation. The concept is that this technology helps identify changes in oxygen delivery and may be more sensitive to changes in cardiac output. See the discussion in the previous chapter on pediatric CHD.
VII. What are some general intraoperative anesthetic considerations for patients with ACHD?
While the pathologic categorization (simple, moderate, and complex) of CHD is useful, a more clinically based approach may be more useful in intraoperative planning. One scheme would be to consider patients based on surgical correction such as the following:
A. Complete surgical correction (i.e., repaired ASD, VSD, and PDA). Patients with surgically corrected lesions, as well as palliated lesions with good functional results, typically demonstrate hemodynamic stability and normal physiology. As such, these can be assumed to be very low-risk patients and managed as an otherwise healthy adult patient.
B. Partial surgical correction or palliation (i.e., Fontan, ToF, and TGA [Mustard or Senning repair]). Palliated patients with complex disease and reduced functional capacity due to the type of lesion should be managed with more concern and will be the main focus below.
C. Uncorrected lesions (i.e., minor ASD, minor VSD, and Ebstein’s anomaly). Uncorrected patients warrant thorough examination into type of lesion and current functional state, as often these are minor lesions if they have not caused any medical or functional issues into adulthood.
D. General approach: For both cyanotic lesions (right-to-left shunts) and left-to-right shunts, there are general concepts that will aid in careful anesthetic planning.
1. Cyanotic lesions 
a. Cyanotic lesions have some element of right-to-left shunt, often even after surgical repair. The degree of this shunt determines the level of cyanosis present. Caution should be taken with sedative medicines, as lowering ventilation can increase PVR and exacerbate cyanosis by increasing right-to-left shunt.
b. Right-to-left shunting reduces the uptake of inhalational anesthetics and can prolong inhalation induction. Conversely, the onset of IV induction may be hastened.
c. Nitrous oxide may elevate PA pressure and should be used cautiously.
d. Air embolus: Take extreme care to avoid an air embolus. All IV lines should be aggressively deaired and monitored during medication administration. Epidural catheter placement should use saline for loss of resistance, not air, because air into an epidural vein can cross into the systemic circulation.
e. SVR: Changes in SVR disrupt the balance between pulmonary and systemic circulations to change the shunt. All anesthetic medications should be slowly titrated to prevent rapid changes. This holds true for both regional and general anesthetics.
f. Single-shot spinal anesthetic techniques are generally contraindicated, as quick onset of spinal sympathectomy is poorly tolerated.
g. Administration of antibiotics (vancomycin), if given quickly, may reduce SVR and become clinically relevant.
h. Choice of anesthetic induction drug is not as important as the manner and vigilance used by the anesthesiologist in managing hemodynamics.
i. Clinical endpoints that might decrease PVR, such as increases in mixed venous O2 (typically via high FiO2) and modest degrees of respiratory alkalosis, are encouraged.
2. Chronic left-to-right shunting: Balance between SVR and PVR determines the shunt fraction and the direction of shunting. Chronic left-to-right shunting causes the following:
a. Excessive pulmonary blood flow leading to pulmonary edema or pulmonary hypertension. The increased pulmonary flow causes PVR increases over time, reducing left-to-right shunting, and eventually equilibration of left and right ventricular pressures. Eventually, this process results in conversion of the left-to-right shunt into a right-to-left shunt, the so-called Eisenmenger’s physiology or syndrome.
b. Once ES develops, cyanosis ensues along with variable degrees of heart failure which places patients in the highest-risk category for surgical procedures.
c. Even without Eisenmenger’s complex, these patients may experience heart failure as a result of the high RV and pulmonary blood flow, which may be as much as four times systemic blood flow.
d. SVR: Acute changes in SVR from anesthetic administration or pain can result in alteration or reversal of the shunt, leading to heart failure or cyanosis, depending upon where the patient is in her evolution from large left-to-right shunt into the right-to-left shunting of Eisenmenger’s physiology. Overall anesthetic goals should be to maintain the balance that the patient has and avoid abrupt alterations.
e. High levels of supplemental oxygen may allow for reduced PVR and worsening of the left-to-right shunt. On the other hand, hypoxemia should be prevented as this may shift the shunt to right-to-left and result in cyanosis. A fine balance must be struck when managing oxygenation for these patients.
f. Air embolus: As in cyanotic lesions, take extreme care to avoid an air embolus. Even predominant left-to-right shunts can become bidirectional, putting the patient at risk for a systemic air embolus.
g. Single-shot spinal anesthesia is contraindicated for patients who have or are approaching Eisenmenger’s physiology. Spinal anesthesia is theoretically beneficial for patients with large left-to-right shunts and normal or only slightly elevated PVR that remains far below SVR.
h. Inhalational agents: Uptake should not be affected by left-to-right shunting. Right-to-left shunting prolongs inhalation inductions, but this is rarely clinically relevant.
VIII. What is the ideal approach to postoperative management for ACHD patients?
Postoperative management should take into account all the risk factors described above in the anesthetic planning, and one should attempt to maintain the patient in the hemodynamic state to which he/she has adapted.
A. Pain management: Patients with palliated lesions often have some degree of residual shunt, or even single ventricle physiology. As such, overall cardiac performance depends to a large degree on the PVR. Attempts should be made to minimize impairment of ventilation in these patients as hypercarbia will increase PVR and potentially worsen cyanosis or increase ventricular failure in susceptible patients.
1. Regional anesthesia may be ideal for patients with significant anticipated postoperative pain as this can greatly reduce the level of systemic opioid use, thus reducing risk of respiratory complications. Laboratory evaluation of coagulation status should be obtained in any patient with a history of anticoagulant therapy prior to neuraxial interventions.
B. Arrhythmias: For patients at elevated risk (Tables 15.4 and 15.5), perioperative monitoring in a telemetry bed may be indicated if there is not an AICD in place. For patients with AICDs or pacemakers, consider postoperative interrogation of the device if there was significant electrical interference during the surgery, or if the device had a magnet applied. Additionally, if the AICD was disabled for the procedure, it is imperative that defibrillation equipment be immediately available until the device is turned back on.
C. Volume considerations: Many ACHD patients with palliated lesions have a narrow margin of error in fluid management. They can easily be pushed into heart failure with too aggressive fluid management, and conversely may develop significant reductions in cardiac output with a minimalist approach. There is not an ideal volume strategy that fits all patients, but management must be closely tailored to each patient’s physiologic status. As discussed above, invasive monitoring may not be possible in many of these patients or may not accurately reflect actual volume status, so management can be complicated. TEE use intraoperatively along with close monitoring of urine output may be the best approach in complex patients.
IX. What is the approach for patients presenting for repeat sternotomy?
A. What are the key surgical considerations in preparation for repeat sternotomy?
In patients with ACHD, the need for repeat sternotomy is often encountered as the initial challenge regarding surgical intervention. Often these patients have had multiple prior chest surgeries, increasing the degree of scarring in the pericardial space and thus making the surgical approach more demanding. Overall mortality increases with repeat sternotomy and is reported to be in the range of 3% to 6%. Re-entrant injury has been reported to greatly increase the risk in certain series and may approach 18% to 25%. However, other reports indicate no increase in mortality but a significant increase in duration of surgery [26–29]. The risk appears to correlate to increased number of sternotomies, presence of single ventricle diagnosis, and presence of an RV–PA conduit.
1. Preoperative preparation: Several preoperative variables are of importance and can prove to be quite valuable in planning a repeat sternotomy. A PA and lateral chest radiograph can be quite helpful and should always be examined prior to operative intervention. The radiographs can supply important information regarding number of sternal wires in place and their condition as well as the lateral film in particular providing clues as to the degree of distance between the posterior sternal table and the heart itself. In addition, many patients have had preoperative cardiac catheterization studies. It is always quite helpful to assess this study and the lateral images in particular to obtain an anatomic roadmap as to areas of concern regarding the repeat sternotomy. These pictures can provide much data as to what portion of the sternum may be more impacted by adhesions to cardiac structures and which sternal wires are in closest approximation to these areas of concern.
2. Cannulation options: Should there be any significant concern regarding repeat sternotomy and a high index of suspicion for injury, femoral cannulation should be considered. Preoperative discussions with the perfusion and anesthesia teams is critical to planning alternative strategies for cannulation and the decision to begin use of the CPB circuit before completing the repeat sternotomy.
3. Specifics of repeat sternotomy: Several techniques are of importance when pursuing a repeat sternotomy. Manipulation of the surgical table with anesthesia assistance can be critical in obtaining better visualization of the posterior table of the sternum as one pursues the repeat entry from below. In addition, use of specified retractors can also be of great assistance (mammary retractor) to allow for slow and sequential separation and elevation of the sternum. The goal of this portion of re-entry should be to obtain safe removal of previously placed sternal wires and separation of the sternum.
4. Lysis of adhesions: Once the repeat sternotomy is accomplished, significant lysis of adhesions is undertaken. Good communication with the team is critical during this process. The surgical goals should be to define and separate from scar tissue areas of cannulation (assuming the patient was not cannulated via femoral access before initiating the repeat sternotomy). These areas include the ascending aorta, right atrium (in single venous cannulation), and/or the superior vena cava (SVC) and inferior vena cava (IVC) (in cases of bicaval cannulation). Further dissection of the heart and possible previously placed shunts may be more safely accomplished once cannulae are in place for initiation of CPB.
5. Initiation of CPB: It is important to have all systemic to PA conduits/shunts adequately isolated and secured prior to initiation of CPB. Once bypass is begun, these connections must be ligated so that the circuit will not induce pulmonary overcirculation and systemic undercirculation.
B. What are the key anesthetic considerations in preparation for repeat sternotomy?
The majority of ACHD patients requiring cardiac intervention will require repeat sternotomy. Often these patients have had multiple prior chest surgeries, increasing the degree of scarring in the pericardial space, thus making the surgical approach more demanding. Key anesthetic considerations for repeat sternotomy revolve around preparation for possible re-entrant injury as well as increased transfusion requirements.
1. Large-bore IV access is critical in the event of re-entrant injury. Consider the patient’s vascular anatomy and evaluate any possible central venous clots/strictures as these patients may have had multiple central lines in the past. Ultrasound guidance is recommended during line placement to help evaluate vasculature. A large-bore central venous catheter (8.5 Fr introducer) in addition to one to two large-bore peripheral IV’s attached to a high-flow fluid warmer may be prudent.
2. Placement of external defibrillator patches since access to an open chest for internal defibrillation may be delayed.
3. Type-specific blood products should be available and double-checked in a cooler in the OR at incision. Many patients will have had multiple transfusions in the past, and thus may have unique antibody profiles, which can delay the type and cross process. Typically, one should have 6 to 10 units of PRBCs available.
4. Ventilation management during re-entry should be discussed with the surgical team. There is suggestion that slight hyperinflation of the lungs, using a recruitment maneuver during sternal spreading, can actually minimize re-entrant injury as it reduces venous return through the increased intrathoracic pressure, decreasing the size of the RV and reducing the risk of re-entrant injury .
5. Full discussion of risk should be undertaken with the surgical team before surgery. On the basis of this discussion, the surgical team may elect to cannulate the femoral vessels or perform axillary cannulation to enable emergent institution of cardiopulmonary bypass in the event of re-entrant injury.
C. What is the role of antifibrinolytic therapy?
Fibrinolysis is known to occur during cardiopulmonary bypass and is associated with increased blood loss and need for transfusions in cardiac surgery. Due to this, antifibrinolytics have been recommended in the Society of Thoracic Surgeons and Society of Cardiovascular Anesthesiologists (STS/SCA) guidelines recently updated for 2011 . Aprotinin was withdrawn from the world market in 2008 due to concerns for increased mortality despite reduction in blood loss which was demonstrated in various trials [31,32]. Current STS/SCA recommendations include routine use of either aminocaproic acid or tranexamic acid for all cardiac surgeries with a typical regimen being to initiate the infusion prior to skin incision and continue throughout the operation [32–36].
X. When should ACHD patients be listed for transplantation and what are the outcomes?
A. Heart and lung transplant can be a life-saving measure for the patient who has developed severe heart failure. ACHD patients most commonly listed for transplant include patients with uncorrectable or partially palliated lesions such as those listed below :
1. Single ventricle physiology with pulmonary vascular disease (heart/lung transplant)
2. Lesions associated with LV dysfunction due to pulmonary vascular disease (heart/lung or isolated lung transplant)
3. Isolated heart failure without significant pulmonary vascular disease (more common in single ventricle physiology, or transposition of the great vessels [TGV] patients treated by atrial switch procedures) (heart transplant).
4. Patients who clinically meet the metrics for transplant should have a thorough pretransplant evaluation assessing the anatomy of the patient, as well as PVR. Longstanding elevations in PVR can easily lead to right heart failure in the donor heart and must be anticipated in these patients.
a. For cases involving elevated PVR, it is recommended to take steps to avoid acute right heart failure in the transplanted donor heart. This often involves a combination of iNO and vasoactive infusions (dobutamine, milrinone) to provide inotropic support along with pulmonary vasodilation. See chapter on heart transplantation for full discussion.
B. What are the outcomes of transplant? ACHD patients make up nearly 3% of the total number of patients listed for cardiac transplantation . Davies et al. investigated patients listed for transplant from 1995 to 2009. This study indicated that the ACHD patients who went on to obtain a heart transplant had a higher early mortality, possibly due to increased repeat sternotomy incidence in this group, but an equivalent long-term mortality as non-CHD patients (53% 10-yr survival in both groups).
XI. What are the specific details for managing patients with partially corrected or palliative repairs?
A. Fontan repair: Fontan palliation has been the primary surgical approach for complex lesions such as tricuspid atresia (TA), hypoplastic left heart, double inlet LV, double-outlet RV, severe AV defects, and heterotaxy syndrome . Management of these lesions in both the neonate, and the adult patient, is one of the biggest challenges in anesthetic practice . Survival rates are now approximately 90% at 10 yrs following palliation; thus, more and more Fontan patients may present for adult surgery . This lesion is described in detail for the neonate previously, but key aspects pertaining to adult management are presented below.
1. Pathophysiology: TA creates a situation where blood must pass from the right atrium to the left atrium via an ASD, where it mixes with pulmonary venous return. Blood flow is then directed to both the PA and the aorta by various routes. Regardless of type of repair, blood flow depends entirely on the left ventricle for cardiac output [25,38]. For a more detailed review, please see the extensive discussion of adult Fontan physiology provided by Drs. Eagle and Daves in 2011 .
2. Surgical correction. The Fontan procedure is the definitive palliative surgical approach that creates a univentricular circulation via a cavopulmonary anastamosis. The Fontan procedure consists of creation of a classical or bidirectional Glenn shunt (SVC to PA connection), closure of the ASD, ligation of the proximal PA, and creation of a right atrial or IVC to PA connection. Multiple variations to the Fontan procedure exist (Fig. 15.4); however, the same general physiologic principles apply to most situations .
Figure 15.4 Fontan surgical techniques: Classical atriopulmonary connection (A), lateral tunnel (B), and extracardiac conduit (C). (Redrawn from d’Udekem, Iyengar AJ, Cochrane AD, et al. The Fontan procedure: Contemporary techniques have improved long-term outcomes. Circulation. 2007;116:I-157–I-164.)
3. What are the key physiologic and anesthetic management considerations?
a. Blood flow to the PAs is passive. Elevations in PVR will therefore reduce pulmonary flow, and hence decrease cardiac output, by reducing the gradient between the vena cava and the PA.
b. Hemodynamic stability is highly dependent upon maintaining appropriately high systemic venous pressures and right atrial preload. Decreased right atrial preload causes dramatic declines in pulmonary blood flow and cardiac output. Peripheral edema often results from the high systemic venous pressures.
c. Spontaneous respiration assists forward flow by keeping PVR low. Any compromise in pulmonary function can be detrimental by increasing PVR. Preoperative sedation should be used carefully due to risk of increasing hypercapnia and elevation in PVR. If positive pressure ventilation is necessary, use the lowest pressure possible to achieve adequate ventilation.
d. The single ventricle is prone to failure leading to pulmonary edema. The atrial contribution to flow is significant, but arrhythmias are common and poorly tolerated.
e. Progressive hepatic failure is widely prevalent due to altered hepatic circulation from increased systemic venous pressures. This can present as a bleeding tendency, a clotting tendency, or as a mixed picture. Pulmonary embolism and stroke are common late complications.
f. Invasive monitoring can be problematic and may be unnecessary except for hemodynamically unstable patients.
(1) Central venous catheter placement probably carries a higher risk of thromboembolic events but may nevertheless be appropriate for short-term use. CVPs as high as 25 to 30 mm Hg are not unexpected and may be essential to drive blood through the pulmonary circulation. Attempts to place PA catheters are not advised.
(2) Arterial line monitoring is advised, but must take into account surgical shunts regarding location of arterial access.
(3) TEE should be strongly considered for intraoperative monitoring during general anesthesia.
g. General anesthesia: A careful selection of induction agents that will provide a smooth hemodynamic profile is preferred.
(1) Etomidate and ketamine are excellent induction agents, and moderate doses of an opioid such as fentanyl, sufentanil, or remifentanil will reduce the stress response.
(2) A muscle relaxant with minimal hemodynamic effects (e.g., succinylcholine or rocuronium) is desirable.
h. Regional anesthesia may be employed for appropriate surgical cases. However, titrated epidural anesthesia may be preferable to single-shot spinal as abrupt reductions in sympathetic tone may not be well tolerated.
Anesthetic and hemodynamic goals for patients with Fontan physiology
1. Maintain preload. Avoid aortocaval compression.
2. Avoid elevation in PVR by preventing acidosis, hypoxemia, and hypercarbia.
3. Maintain sinus rhythm.
4. Maintain spontaneous respiration when possible.
5. Avoid myocardial depressants.
B. ToF—“Blue baby syndrome”: ToF is characterized by existence of a VSD, pulmonic stenosis/right ventricular outflow tract obstruction (RVOTO), over-riding aorta, and right ventricular hypertrophy. There is great variability in the extent of these defects ranging from small VSD and over-riding aorta with minimal pulmonary stenosis (PS) to severe PS and large VSD. Outcomes with current surgical repair techniques are excellent and there is a 36-yr survival of nearly 86% .
1. Palliative shunts (Blalock–Taussig, Waterston, or Potts) were the initial solution, which involve systemic arterial (aorta or subclavian artery) to PA anastomoses. They provided temporary relief of symptoms, but often had long-term sequelae .
2. Definitive surgical repair involves closure of the VSD and relief of RVOTO using resection and reconstruction with Gore-Tex patch grafting across the RVOTO or conduits to bypass the RVOTO (Fig. 15.5).
Figure 15.5 Transesophageal echocardiographic image of the VSD patch repair typically visualized in adult patients with previous ToF repair. This is the midesophageal long-axis view demonstrating the over-riding aorta with the in situ patch. Image provided by Bryan Ahlgren DO, University of Colorado Denver.
3. Common reasons for reoperation include residual VSD or recurrence of the VSD (10% to 20%), residual RVOTO or stenosis (10%) leading to right heart failure, and rarely RV failure caused by pulmonic insufficiency (PI) from the RVOT patch.
4. Additional concerns include a higher risk of sudden cardiac death compared with age-matched controls, elevated risk of arrhythmias (especially atrial fibrillation), right bundle branch block, pulmonary regurgitation, and right ventricular aneurysms.
5. Patients with PS or significant pulmonic valvular regurgitation are more likely to develop right heart failure. Avoidance of elevated PVR and maintenance of high-normal filling pressures are critical in patients with pulmonic valvular regurgitation . See discussion for RV–PA conduits below.
6. General anesthesia: Choice of induction agents should be tailored to achieve the hemodynamic goals below and based on the underlying cardiac function.
a. If an arterial catheter is placed, patients with Blalock–Taussig shunts will require cannulation in the contralateral arm, or in either leg.
b. TEE should be considered during general anesthesia.
7. Regional anesthesia may be employed for appropriate surgical cases. However, titrated epidural anesthesia may be preferable to single-shot spinal for certain ToF patients depending on the degree of palliation and current symptoms.
Anesthetic and Hemodynamic goals in ToF
1. Avoid changes (especially decreases) in SVR to prevent altering existing shunt.
2. Avoid increases in PVR by preventing hypoxia, hypercarbia, acidosis, and providing supplemental oxygen.
3. Maintain normal to elevated cardiac filling pressures, especially in patients with right ventricular impairment. Avoid aortocaval compression.
4. Continuous EKG monitoring is advisable due to high incidence of both atrial and ventricular arrhythmias.
5. Tachycardia and increases in myocardial contractility should be avoided in situations where there is residual RVOTO, as this may exacerbate the obstruction and cause right-to-left shunting.
C. Right (pulmonary) ventricle to pulmonary artery conduits: The RV–PA conduit is a surgical technique used in the palliation of multiple lesions including pulmonary atresia, ToF, truncus arteriosus, TGA, PS, and forms of double-outlet RV . Various types of conduits have been employed for initial repair ranging from aortic homografts (Ross procedure), pulmonary homografts, pericardial patches/reconstructions, to a variety of valved or nonvalved artificial conduits (Dacron, Gore-Tex, etc.). For this section, it is useful to discuss the ventricle as either the pulmonary ventricle or the systemic ventricle.
1. Risk factors leading to reoperation: Conduit failure is thought to occur in roughly 50% of patients at 10 yrs and 70% of patients at 20 yrs. Conduit failure, typically, is due to patient growth, thus resulting in a functionally “small” conduit, development of pulmonary valve (PV) insufficiency, and/or various degrees of calcification. Conduit failure is defined by a variety of methods depending on the type of conduit, but in general include the following [41–44]:
a. Symptomatic patients (dyspnea, fatigue, chest pain, palpitations, presyncope, and decreased exercise tolerance) demonstrating signs of RV failure with elevated PV peak gradients >40 mm Hg.
b. Asymptomatic patients with pulmonary ventricular pressures approaching systemic pressures, increasing pulmonary ventricular size with increasing PV insufficiency and/or tricuspid insufficiency.
c. Patients with severe PI and NYHA functional class II or III symptoms should be considered for PV replacement ± conduit repair .
d. Deterioration in exercise testing or functional capacity.
e. Patients who are very young at the time of conduit placement, those with small-diameter conduits, those with diagnosis of truncus arteriosis or TGA, and those receiving homografts are at elevated risk of failure.
2. What are the key anesthetic concerns for pulmonary ventricle–pulmonary artery conduit replacements?
a. These are repeat sternotomy procedures, so all the considerations outlined in Section IX should be followed. The pulmonary ventricle–PA conduit is an anterior structure, so has greater risk of injury on re-entry sternotomy.
b. Hemodynamic considerations should take into account current physiologic and functional status of the patient. The majority of these patients will be suffering from degrees of right heart failure, so careful control of the PVR should be of utmost concern. In addition, PI is common and often in the moderate to severe range. This leads to overdistension of the RV with the potential to worsen RV failure.
c. Patients with residual VSD are at risk for alterations in the shunt fraction if there are significant changes to either PVR or SVR, which can worsen right heart function or create cyanosis.
d. As with PAH, the right ventricle is susceptible to failure which leads to reduced pulmonary blood flow, hypoxia, and subsequent increases in PVR. This in turn initiates a catastrophic hemodynamic chain of events where the decreased RV stroke volume decreases LV output and coronary blood flow to both the LV and RV decreases.
3. What are the hemodynamic goals for patients with RV–conduit failure?
Management should be based on the etiology of the conduit failure, which generally falls into two basic categories: stenosis versus insufficiency. Stenotic lesions are discussed in the next section (XI.D) on PV stenosis. PI is frequently caused by balloon valvuloplasty to treat pulmonic stenosis. It is also common after successful repair of the RVOTO associated with ToF . For patients with PI, there are some basic hemodynamic suggestions that will assist in developing the anesthetic plan.
a. Overall goals for management are a relative tachycardia (heart rate 80 to 90), with overall reduction in PVR. This will help reduce the regurgitant fraction and promote increased forward flow.
b. In patients with elements of RV failure, avoid agents with direct myocardial depressant effects such as propofol. Etomidate may be an ideal choice.
c. Consider early inotropic support for patients with RV failure. Dobutamine is a good option given the relative tachycardia coupled with reduction in PVR/SVR associated with this b-adrenergic agent. Guidelines provided for PAH also apply to these patients (see Section IV.C) regarding management of PVR.
D. Pulmonary Valve abnormalities: PV abnormalities are associated with approximately 12% of ACHD lesions . The causes of PS range from valve-specific abnormalities to problems with the development of the RV itself (see Table 15.6), and are almost exclusively due to congenital lesions. These lesions may be found in patients with palliated disease (i.e., ToF following repair), or may represent an unrepaired lesion, but are discussed here due to association with RV–conduit abnormalities.
Table 15.6 Causes of RV outflow tract obstruction in adult patients
1. How is PS diagnosed and what are typical symptoms? Clinical symptoms for patients with severe PS are generally related to shortness of breath and functional limitation to exercise. Diagnosis is generally made following echocardiographic exam, and in isolated PV disease, cardiac catheterization is rarely needed.
2. How is PS categorized?
a. Trivial PS = peak gradient < 25 mm Hg.
b. Mild PS = peak gradient of 25 to 49 mm Hg.
c. Moderate PS = peak gradient of 50 to 79 mm Hg.
d. Severe PS = peak gradient > 80 mm Hg.
3. What are the available therapeutic options for PS? Patients with trivial or mild PS can expect a 96% and 77% 10-yr surgery-free survival, respectively, based on existing outcome studies. These patients are typically followed by echocardiography every 5 to 10 yrs for progression, or more frequently based on symptom development .
a. Balloon valvuloplasty is the treatment of choice (Class I recommendation) for patients with PS with gradients >50 mm Hg and less than that of mild PI, or any patient with exertional dyspnea and gradients in the 30 to 40 mm Hg range. It is not recommended for patients with dysplastic valve disease (characterized by poorly mobile valve without commissural fusion), for gradients <30 mm Hg or in patients with moderate to severe PI. Both short- and long-term results are quite good with balloon valvuloplasty with restenosis rates <5% [46,47], and these results are essentially equivalent to surgical management with commissurotomy.
b. Surgical intervention is also effective and carried out under direct visualization for patients deemed poor candidates for balloon valvuloplasty. There is typically some residual PI following surgical commissurotomy, and depending on the valve morphology, occasionally PV replacement is required. Bioprosthetic valves carry a long life span in the pulmonic position and are the replacement valve of choice [44,45].
4. What are the key anesthetic management concerns for patients with PS? Patients with PS tend to follow a similar course as a patient with aortic stenosis. Over time, the increased RV systolic pressure required to overcome the obstructive lesion leads to RV hypertrophy, and, if left untreated, to RV failure. Ideally, these lesions should be treated before the onset of RV failure for best outcomes. Hemodynamic considerations during anesthetic management should follow the guidelines for any stenotic lesion.
a. Relative bradycardia (heart rate in the 60 to 80 range) is preferred to allow time for complete ventricular ejection. Slower heart rates will also allow for increased coronary perfusion time.
b. PS represents a fixed obstruction to outflow, so alterations in PVR will not change the obstruction. Preload should be maintained to promote forward flow.
c. SVR should be maintained in the patient’s normal range, as reductions in diastolic pressure will decrease coronary perfusion pressure, leading to RV ischemia. Normally, the RV receives blood flow during both diastole and systole; however, with RV hypertrophy this is shifted primarily to the diastolic phase.
E. Transposition of great vessels
TGV is relatively rare, representing 1% to 5% of congenital heart defects. Two main types are congenitally corrected TGV (L-TGV) and complete TGV (D-TGV). Without surgical intervention, survival to 6 mos in D-TGV is less than 10% [7,9,25]. L-TGV allows survival, albeit typically at the cost of early adult heart failure.
1. How is D-TGV palliated and what are the physiologic sequelae?
D-TGV is described as blood flow in a parallel system, such that systemic venous return flows to the right atrium and right ventricle, which then ejects blood into the aorta [8,25]. Pulmonary venous blood flow proceeds to the left atrium, left ventricle, and then into the PA. Without additional communication from septal defects or a PDA, there is no connection between blood oxygenated in the lungs and systemic arteries, and therefore survival is impossible.
a. Atrial switch operations such as the Mustard or Senning procedure create an atrial baffle that causes venous blood to cross at the atrial level into the appropriate ventricle. Since the morphologic right ventricle then continues to eject blood into the aorta, these patients experience a higher risk of heart failure as a result of that ventricle’s impaired capacity to chronically pump against systemic arterial pressures .
b. The arterial switch, known as the Jatene procedure, switches the PA and aorta with re-implantation of the coronary vessels. This requires the left ventricle of sufficient size to provide systemic flows. These patients often have relatively normal physiology following surgical repair and should be considered in the surgically corrected category . There are two long-term complications to be aware of, which include development of aortic insufficiency on the neoaortic valve (occurring in 25% of patients), and coronary ostial lesions leading to increased risk of myocardial ischemia .
2. What are the key anesthetic considerations for patients with TGV?
a. Patients with D-TGV who have been treated with the arterial switch (Jatene) will typically have normal cardiac function, so management should focus on any coexisting medical issues. Contrary to this, those patients managed with the Mustard or Senning approach (atrial switch) are at higher risk of developing heart failure due to the systemic right ventricle, as well as the atrial baffle which occasionally results in obstructive flow.
b. As mentioned above, L-TGV patients are also at increased risk of heart failure, so evaluation should focus on determining functional status and symptoms of heart failure.
c. Arrhythmias are very common in patients treated with Mustard or Senning repairs. Ventricular tachycardia and IART are the most common (Table 15.3).
d. Invasive monitors should be used selectively. Central venous catheters may be useful for vascular access and monitoring in patients with heart failure, but PA catheters are probably ill-advised in patients who have undergone atrial switch procedures. Preoperative information from recent echocardiograms can be invaluable for symptomatic patients.
3. How should induction of general anesthesia be managed?
Induction should focus on the degree of heart failure present in the patient. Choose induction agents with minimal myocardial depressant effects; etomidate, midazolam, or fentanyl may be ideal choices. Additional effects of inhaled agents in moderate doses are generally well tolerated as the afterload reduction improves forward flow.
Anesthetic and hemodynamic goals for TGV
1. Consider an arterial catheter and/or CVP catheter and avoid excessive fluids in patients with evidence of heart failure.
2. Avoid negative inotropic agents.
3. Monitor for arrhythmias and treat as indicated.
4. Should regional anesthesia be utilized in patients with TGV? As with general anesthesia, the afterload reduction following the sympathetic blockade from neuraxial anesthesia will improve forward flow in patients with mild to moderate degrees of heart failure. Care should be taken for patients with severe heart failure symptoms and single-shot spinal techniques may not be tolerated due to the rapid changes in hemodynamics. Consider using epidural techniques with a slow titration of local anesthetic agents.
XII. What are the key details for patients with uncorrected CHD?
Uncorrected lesions presenting in the adult patient represent a group of diagnoses that are typically on the mild end of the spectrum, given that these patients remain largely symptom-free into adulthood. Examples include ASD, VSD, Ebstein’s anomaly, or undiagnosed ACHD due to limited health care access as child. Those patients with more complex disease states that are unrepaired due to health care access should be managed according to the existing lesion, and will represent a more complex situation. This section will focus primarily on the septal defects presenting in the adult patient.
A. Adult Atrial Septal Defect (ASD)
ASDs account for nearly one-third of adult congenital heart defects and are found in women more commonly than in men . Small defects (less than 5 mm) are hemodynamically insignificant, but large defects (greater than 20 mm) can lead to significant shunting and eventual RV overload or failure [25,49]. ASDs do not typically close spontaneously and are commonly associated with additional cardiac defects. The anatomy of septal defects in the adult is typically the same as described for the child (Fig. 15.6). Common defects include ostium primum, ostium secundum, sinus venosus, and patent foramen ovale. These defects are often linked to more complex CHD, which should be considered during initial workup. Ostium primum defects are frequently associated with a mitral cleft or other atrioventricular valve abnormalities, while sinus venosus defects are associated with partial anomalous pulmonary venous return. Hemodynamic consequences of ASD follows that of a left-to-right shunt as described above, the severity of which depends on the shunt fraction (Qp:Qs ratio).
Figure 15.6 Location of ASDs. (Reproduced from Rouine-Rapp K, Miller–Hance WC. Transesophageal echocardiography for congenital heart disease in the adult. In: Perrino AC Jr, Reeves ST, eds. A Practical Approach to Transesophageal Echocardiography. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2008: 372, with permission.)
1. What are the clinical symptoms for adult ASDs?
The natural course of unrepaired ASD is that as the patient ages and LV diastolic dysfunction develops, the increased LV end-diastolic pressure tends to worsen the left-to-right shunt. This leads to increased shunt fraction, RV dilation, and development of clinical symptoms, often in the fourth or fifth decade of life . Typical clinical symptoms include the following:
a. Dyspnea with exertion, possibly due to chronic preload reduction of the LV along with overloaded pulmonary system. This symptom typically is improved with ASD closure.
b. Cardiac arrhythmias (atrial fibrillation) due to atrial enlargement and stretching of conduction system. Atrial volumes tend to remain elevated in the adult following repair, and thus arrhythmias tend to persist after repair.
c. Embolic stroke—typically due to paradoxical embolism.
2. What are the indications for repair [48,49]? A combination of echocardiographic and catheterization-based diagnostic testing is generally used to determine eligibility for repair. Outcomes with repair (either surgical or transcatheter) seem to indicate a benefit in overall survival as 10-yr survival rates for adult patients following repair exceed 95%, while those treated with medical management alone have a 10-yr survival of 84% . Outcomes appear to be better for patients repaired at earlier ages (before fourth decade) and medical management may be better later in life [50,51]. Indications for repair include the following:
a. Adult patients with a pulmonary-to-systemic shunt (Qp:Qs) ratio >1.5:1.0
b. Echocardiographic evidence of RV volume overload
c. Development of arrhythmia due to atrial enlargement
d. Exercise-induced cyanosis without existing pulmonary hypertension
3. How does pulmonary hypertension relate to ASD? PAH is rarely caused by an ASD, is found in less than 10% of patients with ASD, and if PAH is not diagnosed by adulthood in the presence of an ASD, it rarely develops. In addition, Eisenmenger’s physiology rarely develops due to ASD. There is debate regarding the mechanism of PAH associated with ASD, but many consider ASD a marker of PAH, and not a causative agent [49,50]. Regardless, there are important considerations for patients with ASD and moderate to severe PAH. The presence of an ASD allows for blood to flow from right to left, bypassing the high-resistance pulmonary bed in PAH, and thus decompressing the RV. This reduces the classic heart failure symptoms, at the cost of cyanosis, and these patients should not have the ASD closed. Occasionally, creation of an ASD is a temporary measure used to bridge patients with severe PAH to transplant. In fact, presence of PAH with PVR >14 Woods units is a contraindication for ASD closure.
4. Should surgical repair or transcatheter closure be used to repair the ASD? Surgical closure of ASD is a safe and effective operation, with mortality rates at surgery below 1.5%, and long-term survival >95% as mentioned above . Recent advances in transcatheter approaches have shown excellent outcomes, equivalent to surgical repair, with the obvious avoidance of the morbidity associated with sternotomy [50–54]. Typically, transcatheter closure is associated with shorter hospital stays, less overall complications, and reduced cost.
5. What characteristics of the lesion increase difficulty with transcatheter repair? Once the indications for closure listed previously are established, certain anatomic characteristics must be considered for adequate transcatheter closure. Key anatomic features include the following:
a. Size of defect: ASD <26 mm is considered normal size, with >26 mm considered a large defect. Large ASD is not a contraindication for device closure, but there is an elevated risk of dislodgement or erosion when using large devices .
b. Central lesions, i.e., ostium secundum defects, are the most amenable to treatment. Ostium primum and sinus venosus lesions are often not anatomically suited to transcatheter techniques and are recommended to be repaired surgically .
(1) Lesions with deficient anterior-superior rim: This deficiency is common in large ASDs, and makes placement of the device more technically challenging. Despite this, complications such as dislodgement or erosion are well below 1% in multiple studies , and seem to be most related to oversizing of devices. As such, device sizing should be limited to 1.5× the diameter of the ASD by TEE.
(2) Lesions with deficient posterior-inferior rim: This lesion is even more technically challenging than deficient anterior-superior rim. However, the incidence is also lower and thus there are insufficient data to determine overall complications in these lesions.
c. Multiple lesions/fenestrated defects: This type of abnormality is also a technical challenge. Approaches vary between balloon atrial septostomy to create a single ASD versus placement of multiple smaller occlusion devices.
d. Atrial septal aneurysms: The aneurysmal septal wall creates difficulty with device closure using standard devices that rely to some degree on the septal structure. Patch or double disc devices are more appropriate, and again this type of lesion is more technically challenging.
6. What are the typical devices used in the catheterization laboratory?
Currently, two main devices have become the standard following multiple studies using many different devices. In the United States, Amplatzer (AGA Medical Corp) and Helex (W.L. Gore) are the two devices with current FDA approval. Three-dimensional (3D) TEE imaging of an Amplatzer device in place is seen in Figure 15.7.
Figure 15.7 Three-dimensional TEE view of an Amplatzer device placed in a large centrally located ASD. Image by Nathaen Weitzel, MD, University of Colorado Denver.
7. What are the anesthetic considerations for device closure in ASD? General considerations for patients with shunts are discussed in Section VII.D, which all apply to these patients. Typically, adult patients presenting for ASD closure are hemodynamically stable even in the setting of the clinical symptoms discussed above. On the basis of preoperative evaluation, specifically current functional status, the anesthesiologist can anticipate a relatively normal induction plan aiming for overall smooth hemodynamics. Some key aspects of this procedure to anticipate in anesthetic planning are listed below.
a. Discuss the procedure plans with the cardiology team, as many times the interventional cardiologist will want to place right heart catheters while the patient is spontaneously ventilating to obtain catheter-based measurements of RA, RV, and PA pressures. Typically, this portion of the procedure will be carried out under mild sedation and on room air to avoid any changes to the PVR due to oxygen supplementation.
b. Device closure is typically carried out using both echocardiography and X-ray imaging in the catheterization suite. Total procedural time can range in duration, but typically will take 1 to 4 h. Due to the length of the procedure along with need for prolonged TEE evaluation, general anesthesia is typically employed. Standard ASA monitors are usually all that is needed. However, for patients with severe hemodynamic compromise, invasive blood pressure monitoring may be utilized.
c. General anesthesia can be safely induced with various approaches in nearly all patients and agents such as propofol or etomidate are acceptable. Heparin is typically given during the procedure to maintain an ACT >250 s.
d. Key point: Patients with septal defects are at risk for embolic events to the brain. All IV lines should be aggressively deaired, and extreme care should be taken to avoid any injection of air through IV lines.
B. Ventricular Septal Defects: VSD is the most common congenital heart lesion in children, although nearly 90% close spontaneously by age 10 [48,49]. Those patients with large lesions who are symptomatic at birth will usually be surgically corrected, while asymptomatic patients will often be closely monitored for evidence of spontaneous closure. Surgical closure often involves a right atriotomy or ventricular incision, and this carries a significant risk of interventricular and even atrioventricular conduction abnormalities. VSDs can present in multiple areas of the septum, with 80% being in the perimembranous region (Fig. 15.8), the muscular septum the next highest frequency, and the subarterial or double committed outlet being rather rare. In contrast to ASD, unrepaired VSDs can have significant consequences and may lead to development of Eisenmenger’s physiology if left untreated.
Figure 15.8 Common locations for VSDs. (Reproduced from Rouine-Rapp K, Miller-Hance WC. Transesophageal echocardiography for congenital heart disease in the adult. In: Perrino AC Jr, Reeves ST, eds. A Practical Approach to Transesophageal Echocardiography. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2008: 377, with permission.)
1. Can transcatheter closure be utilized to treat VSD? This question is not as clearly answered as for ASD closure. However, advances over the past decade have led to significant improvements in device closure for VSD. Outcome data seem to favor this approach, with the most common associated complication being arrhythmias. Placement success is more than 95% in multiple studies, and 6-yr follow-up demonstrates more than 85% freedom from event rates [55–60]. The considerations for device closure in ASD will apply here as well, with the biggest issue being establishing good communication with the cardiology team before the procedure to discuss specific diagnostic planning that may impact anesthetic planning.
2. What if ES is present? ES represents the most common cyanotic cardiac defect in adults . Chronic left-to-right shunting results in right ventricular hypertrophy, elevated PVR, and significant ventricular and arterial remodeling on the right side. ES carries a maternal mortality ranging from 30% to 70% along with high incidence of fetal demise, so patients are usually counseled against pregnancy , and considered extremely high risk for surgery. Sudden death is common and may be due to stroke, arrhythmia, abscess, or heart failure. Twenty-five–yr survival after diagnosis of ES is reported to be 42% in the absence of pregnancy .
a. Pathophysiology: ES is defined by a PVR greater than 800 dyn·s/cm5 along with right-to-left or bidirectional shunt flow. Correction of the shunt may resolve the pulmonary hypertension, but once pulmonary arteriolar remodeling (i.e., medial hypertrophy) develops, the elevated PVR is irreversible, differentiating ES from primary pulmonary hypertension.
b. Symptoms: Fatigue, dyspnea, cyanosis, edema, clubbing, and polycythemia.
c. The underlying right-to-left shunt, hyperviscosity from polycythemia, and the development of heart failure promote thrombus formation and may elevate stroke risk.
3. Anesthetic management in ES: Historically, regional anesthesia was thought to be contraindicated and general anesthesia was the standard. A review of cases of noncardiac surgery including labor and cesarean section in ES indicates that regional anesthesia is indeed safe for these patients . Martin and colleagues state that mortality is related to type of surgical procedure, independent of choice of anesthetic. Despite this, anesthetic delivery requires utmost vigilance to maintain the above hemodynamic goals with any type of anesthesia.
a. Regional anesthesia: Slow titration of local anesthetic with aggressive treatment for any reduction in SVR (i.e., systemic hypotension) using phenylephrine is effective. Maintenance of intravascular volume status using careful fluid boluses along with the use of phenylephrine for decreased SVR should be used to prevent onset or exacerbation of cyanosis. Single-shot spinal anesthesia should not be used and is considered contraindicated. Avoidance of elevations in PVR is critical; thus, additional sedative medications should be used cautiously as reductions in ventilation will lead to hypercarbia and elevation of PVR.
b. For general anesthesia, slow titration of induction agents is preferred as rapid sequence inductions carry high risk of SVR alterations and subsequent hemodynamic collapse. This places the patient at increased risk of aspiration, so strict NPO guidelines, use of pharmacologic prophylaxis against aspiration (sodium citrate, H2 blockade, etc.), and mask ventilation using cricoid pressure should be considered. Ketamine and etomidate are probably the best options for induction agents, whereas propofol and thiopental should be avoided due to marked reductions in SVR or cardiac output. Inhalational agents should be used with caution because of their propensity to decrease SVR. Nitrous oxide should be avoided because of its propensity to increase PVR. Maintenance of anesthesia may be accomplished using careful titration of IV agents such as nondepolarizing neuromuscular blockers, opioids, and sedative-hypnotic agents such as midazolam or ketamine, “topping off” with potent inhalational agents being used at concentrations of less than 0.5 MAC.
c. Monitors: Pulse oximetry may be the most important monitor as changes in saturation directly correlate with alterations in shunt flow . Intra-arterial monitoring is generally employed to closely follow blood pressure. Central venous catheters are controversial. CVP catheter placement carries a risk of air embolus, thrombus, and pneumothorax, which can be devastating in these patients, although information regarding cardiac filling pressures can be useful. PA catheters are relatively contraindicated in patients with ES for a number of reasons . The anatomic abnormality causing ES typically renders flow-directed flotation of PA catheters difficult or impossible, and the risk of arrhythmia, PA rupture, and thromboembolism are elevated. Cardiac output measurements will be inaccurate due to the large shunt. TEE may provide the best real-time monitor of cardiac preload and of the status of right-to-left shunting.
Anesthetic and hemodynamic goals for ES
1. Avoid elevations in PVR: Prevent hypoxemia, acidosis, hypercarbia, and pain. Provide supplemental oxygen at all times.
2. Maintain SVR: Reductions in SVR will increase right-to-left shunting.
3. Avoid myocardial depressants and maintain myocardial contractility.
4. Maintain preload and sinus rhythm.
4. Can iNO be employed in ES? iNO is a direct-acting pulmonary vasodilator that avoids systemic vasodilation, thus reducing shunt flow and hypoxia. Evidence for the use of iNO for labor in Eisenmenger patients is limited, but several case reports indicate improvement in oxygenation and reduced pulmonary pressures . Therapy with IV pulmonary vasodilators may be required postoperatively to prevent rebound elevation in pulmonary pressures.
XIII. What are the antibiotic prophylactic considerations for patients with ACHD?
Infective endocarditis carries high morbidity and mortality, and as such has led to previous recommendations regarding antibiotic prophylaxis regimens for patients with heart defects. Current recommendations center around the concept that most exposures to infectious agents occur during daily activities, and suggest maintaining a high index of suspicion for signs of endocarditis in susceptible patients . Good oral hygiene is critical for these patients to help prevent infection and antibiotic prophylaxis is recommended only in select lesions listed in Table 15.7.
ACHD encompasses a wide range of patients with variable presentations, symptoms, and degree of illness. Some of the key and most common presentations have been addressed in this chapter; however, due to the huge range of presentations, variations in all of these lesions are likely to be found, and many other diagnoses have not been covered. The underlying concept found throughout management of ACHD is to obtain as much information as possible about the patient’s medical and surgical history, along with current functional capacity as this will give the greatest information about current level of heart failure. On the basis of this information, consider the lesion based on the classifications discussed above, and develop an anesthetic management plan based on individualized physiology for your patient. Consultation with congenital cardiologists or cardiothoracic surgeons can be invaluable. Patients with complicated residual lesions requiring medium- to high-risk surgery should be handled at centers of excellence with physicians and nursing staff trained in adult congenital disease.
Table 15.7 Cardiac conditions associated with highest risk of adverse outcomes from endocarditis for which prophylaxis with dental procedures is reasonable
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