Cardiology Intensive Board Review, 3 ed.

Aorta

Craig R. Asher • Gian M. Novaro

ANSWERS

1.d. Aortic dilatation with moderate aortic regurgitation and mild aortic stenosis. A bicuspid aortic valve is not likely in a 78-year-old with an initial presentation of aortic valve disease. An aortic ejection click is often present in patients with bicuspid aortic valve disease when the valve is still pliable and is not heard in this patient. Furthermore, the examination is not consistent with severe aortic regurgitation because the diastolic BP is normal (not reduced), the S1 sound is normal in intensity (not reduced as a result of premature closure of the mitral valve), and the carotid pulsations are normal (not bisferiens). The examination is not consistent with severe aortic stenosis because the murmur is early peaking and S2 (A2) is audible and not reduced in intensity. The intensity of a systolic ejection murmur is related in part to the stroke volume and not a good single indicator of severity of stenosis. Therefore, the most likely explanation for the heart murmur is aortic dilatation with nonsevere aortic regurgitation and stenosis. Of note, aortic regurgitant murmurs originating from aortic abnormalities are generally heard best along the right sternal border and those originating from valvular disease heard best along the left sternal border.

2.b. Magnetic resonance angiography (MRA) of the great vessels. The presence of a pericardial effusion and an elevated erythrocyte sedimentation rate in a patient with aortic dilatation suggests an inflammatory etiology. Etiologies of aortic aneurysms are listed in Table 6.1. Inflammatory aortitis includes systemic diseases and primary large-vessel vasculitis. Numerous systemic diseases may involve the aorta, including systemic lupus erythematosus, rheumatoid and psoriatic arthritis, inflammatory bowel disease, ankylosing spondylitis, systemic sclerosis, relapsing polychondritis, Behçet syndrome, and Reiter syndrome. Primary vascular disorders include Takayasu and giant cell arteritis. MRA of the aorta may distinguish characteristic thickening and tissue edema that are diagnostic of aortitis.

3.d. Giant cell arteritis. The presence of systemic symptoms including headaches and myalgias with an elevated sedimentation rate in an elderly woman is suggestive of temporal arteritis. Temporal arteritis affects women twice as often as it does men and is most commonly seen after age 55 years. Temporal artery tenderness may be present with the potential for blindness to occur. Biopsy of the temporal arteries is diagnostic. Associated giant cell arteritis with involvement of the aorta and branch vessels with aneurysm formation may occur. Diagnostic criteria are sensitive and specific for giant cell arteritis if at least three of the following findings are present: (a) >50 years of age, (b) recent onset of localized headaches, (c) temporal artery tenderness or pulse attenuation, (d) erythrocyte sedimentation rate >50 mm/h, and (e) arterial biopsy showing necrotizing vasculitis.

The MRA of this patient shows features of vessel thickening of the ascending aorta and arch with “edema”-weighted characteristics and mural enhancement suggestive of an inflammatory aortitis and consistent with giant cell aortitis. Corticosteroids therapy can be used to reduce inflammation seen with aortitis with guidance from serial MRA imaging. Cardiac MRI. Sagittal delayed enhancement (phase-sensitive inversion recovery) image (A) and axial black-blood (double IR) (B) images demonstrating diffuse mural enhancement (A) and thickening of the ascending aorta and arch (B) consistent with an inflammatory arteritis. This patient has giant cell arteritis of the aorta (see Figure 6.1).

4.d. No additional testing. The revised Ghent criteria are based primarily on clinical criteria although genetic testing for the FBN1 mutation can aid in diagnosis. There are criteria for individuals with and without a family history of Marfan syndrome (see Table 6.2). The patient presented has ectopia lentis and a family history of Marfan syndrome. Therefore, no additional information is required to make a diagnosis. She does additionally have systemic criteria that are consistent with the diagnosis, including pectus carinatum, wrist and thumb sign, high-arched palate, and mitral valve prolapse. An increased arm span-to-height ratio is no longer considered a diagnostic criterion for Marfan syndrome.

5.d. Elective aortic replacement. The timing of surgery for patients with ascending aortic aneurysms caused by Marfan syndrome is addressed in the 2010 guidelines for thoracic aortic diseases. Surgery is recommended for asymptomatic patients with Marfan syndrome or other genetic etiologies for thoracic ascending aortic aneurysms between 4.0 and 5.0 cm (class I) or when the ratio of the maximal ascending aortic or aortic root area (π × radius2) in cm2 divided by the patient’s height in meters exceeds 10 (class IIa). In this patient, the calculation would be as follows: (π × 2.52 = 3.14 × 6.25 = 19.6 cm2/1.70 m = 11.5), well above the 10:1 ratio. For women anticipating pregnancy, elective surgery should be performed when the ascending aortic dimension is >4.0 cm. Additional factors of importance include rate of change of aortic size >0.5 cm/year, presence and severity of aortic regurgitation, family history of dissection or sudden cardiac death, and the extent of aortic involvement. See Table 6.3 for timing of surgery in aortic diseases. An open-label study of adult patients with aortic dilatation and Marfan syndrome who were randomized to propranolol or no treatment showed less aortic dilatation and aortic complications among patients on propranolol. Therefore, β-blockers should be advised for this patient although this is not the most important recommendation.

6.c. Reduction in activity of transforming growth factor (TGF)-β. The ARB losartan has been associated with a reduction in the rate of aortic dilatation and aneurysm growth in both experimental mouse studies and recently an open-label randomized trial of Marfan syndrome patients (COMPARE trial). A larger prospective randomized trial comparing atenolol versus losartan sponsored by the NIH is in progress. The postulated mechanism of action is independent of BP lowering. Because of defective production in fibrillin due to the FBN1 mutation, there is overexpression of TGF-β activity. TGF-β activity leads to an increase in destructive MMPs, which cause aortic wall weakening. Losartan appears to block the overproduction of TGF-β and MMPs so that aortic wall integrity is maintained.

7.c. TTE. A TTE should be performed immediately in this patient since the clinical findings are highly suggestive of a proximal ascending aortic dissection (character of chest pain, differential BPs, and weak pulses) and cardiac tamponade (tachycardia, elevated jugular venous pressure, soft heart sounds, and globular-shaped heart on CXR with interstitial edema). Cardiac enzymes may determine the presence of myocardial injury but not reveal the cause. An acute inferior MI is likely due to the aortic dissection involving the origin of the RCA and not due to occlusive coronary artery disease.

The advantages and disadvantages of CTA, MRA, and TEE for the diagnosis of aortic dissection have been reviewed in detail. Each of these tests has high diagnostic accuracy for diagnosing aortic dissection. The test of choice for a given patient should be determined based on the relative expertise of each institution, the rapid availability of the test and its interpretation, and the specific individual circumstances of a patient. Given the likelihood of an aortic dissection and the possibility of cardiac tamponade in this patient, a TTE or a TEE is best suited for this patient. A limited TTE could assess whether a pericardial effusion and cardiac tamponade are present followed by either a TEE or CTA of the aorta to confirm and determine the location and extent of dissection.

8.b. Emergent aortic surgery. A proximal aortic dissection with hypotension or cardiac tamponade should be treated by emergent aortic surgery. A rapid confirmatory test can be performed on the way to or in the operating room. Small retrospective reviews have raised concerns regarding pericardiocentesis in patients with cardiac tamponade and aortic dissection. Rapid decompensation and death can occur in some patients due to propagation of dissection and increased bleeding into the pericardium. Most importantly, the presence of cardiac tamponade with aortic dissection should mandate immediate surgery. Pericardiocentesis can be performed if the patient is deteriorating rapidly and surgical assistance is not readily available or if the patient is in pulseless electrical activity.

Controversy also exists regarding cardiac catheterization for patients with proximal aortic dissection. Proponents of cardiac catheterization argue that patients with severe obstructive coronary disease require grafting at the time of surgery and that failure to do so will increase the risk of perioperative and postoperative cardiac events. Those who favor not performing cardiac catheterization argue that any delay may increase the risk of death and that an invasive procedure will add further risk of dissection, tamponade, or rupture. One study comparing outcomes of patients undergoing surgery for aortic dissection found that those not undergoing cardiac catheterization had similar mortality than those undergoing the procedure. The 2010 guidelines for thoracic aortic diseases recommend that coronary angiography should be considered if the patient is over 40 years of age, stable, and has either known CAD, significant risk factors for CAD, or an ischemic presentation. Computed tomographic angiography of the chest. Sagittal oblique reconstruction shows an ascending aortic and aortic arch aneurysm with a dual lumen consistent with a type A aortic dissection (see Figure 6.2).

9.c. Cerebral aneurysm rupture. The history of HTN requiring treatment in a young man with a bicuspid aortic valve suggests the likelihood of an aortic coarctation. Given his recent well-controlled BP, aortic dissection, hypertensive crisis, and endocarditis are unlikely. A known association between aortic coarctation and cerebral aneurysms involving the circle of Willis is well established. Testing for this abnormality with MRA or CTA of the brain should be performed for coarctation patients when any neurologic symptoms are present. However, at least a 1 time scan of the brain for intracranial aneurysms is recommended for all patients with coarctation accordingly to the 2008 guidelines for management of congenital heart disease.

10.b. Ventricular septal defect. Several cardiac structural lesions are associated with coarctation of the aorta. The most common is a bicuspid aortic valve occurring in up to 85% of patients. Valvular, subvalvular, or supravalvular stenosis may occur. Aortic ectasia or aneurysm involving the ascending thoracic aorta and arch is often present. Other associated structural abnormalities include patent ductus arteriosus, perimembranous ventricular septal defect, and mitral stenosis (parachute mitral valve) as part of the Shone complex of left heart obstructive lesions.

11.c. CTA of the chest and abdomen. The patient’s history is most suggestive of a thoracic aortic aneurysm or AAA or dissection. He is known to have thoracic aortic dilatation and atherosclerosis, and presents hypertensive with back pain and diminished pulses. Although TEE may be accurate for diagnosis of aortic dissection above the diaphragm, a CT scan may extend imaging to the entire aorta including the abdominal aorta and provide information regarding the involvement of branch vessels. Therefore, CT imaging would be preferable. Aortography is invasive and could cause further injury to the aorta. However, it could provide useful information along with angiography regarding the patency of the patient’s bypass grafts and native circulation.

12.b. MRA of the chest/aorta. The patient is experiencing ongoing pain refractory to medical therapy and the clinical history remains suggestive of an acute aortic syndrome. The types of acute aortic syndromes are listed in Table 6.4. Although CT imaging is highly accurate in diagnosing aortic dissection, there are false-negative readings. In the International Registry of Aortic Dissection (IRAD) registry, many patients with suspected aortic dissection required more than one imaging test. Therefore, additional imaging should be performed in this patient especially since an alternative diagnosis for the patient’s symptoms is not available. An acute coronary syndrome is not likely in view of recent CABG and unremarkable ECG and cardiac enzymes. Biomarkers are emerging as a diagnostic aide in diagnosing acute aortic syndromes. A D-dimer level <500 ng/mL and a low C-reactive protein make aortic dissection unlikely.

13.a. Initiate a β-blocker and repeat ultrasound in 6 months. To determine the stability of an AAA between 4.0 and 4.9 cm (4.2 cm in this patient), it is generally recommended to do an initial follow-up ultrasound in 6 months. However, most patients with AAA size = 4.5 cm should be referred to a vascular surgeon for subsequent follow-up and risk assessment for surgical consideration and have a baseline CT of the aorta to assess for anatomic feasibility for endovascular repair. β-Blockers have been shown to delay the rate of AAA enlargement and would be indicated for this patient with suboptimal control of BP.

14.d. Penetrating aortic ulcer. A penetrating aortic ulcer occurs when aortic atheroma ruptures into the aortic media through the internal elastic lamina. Subsequently, an aneurysm, pseudoaneurysm, localized dissection, hematoma, or aortic rupture may develop. Penetrating ulcers can be diagnosed by aortography, CTA, MRA, or TEE. They more typically occur in the descending aorta. Typical findings include a focal outpouching or ulcer crater in the region of severe, calcified atheroma. Localized flow may be seen by contrast opacification or color Doppler. The aortogram in this patient shows multiple penetrating aortic ulcers, seen as outpouching on the greater curvature of the ascending aortic wall. Contrast aortogram (A) shows several outpouchings on the greater curvature of the ascending aorta consistent with penetrating ulcers. Transesophageal echocardiogram (B) showing a break in the lesser curvature of the aorta in the same patient in the region of diffuse calcific atheroma also consistent with a penetrating aortic ulcer (see Figure 6.3).

15.b. Transfer to the operating room immediately for replacement of the ascending aorta. The patient has an acute aortic syndrome with a symptomatic penetrating ulcer in the ascending aorta. Immediate surgery is indicated to prevent the possibility of aortic rupture. Further confirmatory imaging is not required.

16.d. Angiography. The patient presents with pulse deficits, bruits, and symptoms consistent with arterial insufficiency in multiple distributions, including the upper and lower extremities. Angiography (either CTA/MRA or invasive) of the arterial system would define the site and extent of arterial disease. The appearance of the lesions may also help with determining the etiology of the vascular disease (i.e., atherosclerotic versus vasculitic).

17.d. Takayasu arteritis. Takayasu arteritis (“pulseless disease”) is an inflammatory disease of large sized arteries. Both stenotic lesions and aneurysms may be present with involvement of proximal segments of the aortic arch vessels. Aortic regurgitation is not uncommon due to involvement of the aortic root and aortic valve with inflammatory disease. Although most commonly described in Japanese patients, it has been described throughout the world.

A diagnostic classification proposed by the American College of Rheumatology requires three of six criteria: (a) age at onset younger than 40 years, (b) intermittent claudication, (c) diminished brachial artery pulse, (d) >10 mmHg difference in systolic BP between arms, (e) bruit of the subclavian arteries or the aorta, or (f) angiographic narrowing or occlusion of the aorta or branches.

18.d. Presence of systolic and diastolic flow is consistent with severe coarctation. The peak Doppler pressure gradient as obtained from the simplified Bernoulli often overestimates the gradient obtained across the coarctation as measured by invasive hemodynamics. Since the pre-coarctation velocity is often increased due to abnormality of aortic valve, it must be accounted for in the Bernoulli equation. This requires using the modified Bernoulli equation, where pressure = 4 (V22 – V12), in which V2 is the peak Doppler velocity across the coarctation and V1 is the pre-coarctation velocity. The typical sawtooth pattern of aortic coarctation is shown in this example with an elevated systolic velocity and a lower velocity forward flow in diastole. The presence of a continuous flow across the coarctation is consistent with severe obstruction regardless of the peak pressure gradient. Transthoracic suprasternal notch (SSN) view with continuous Doppler in the upper descending aorta. The Doppler profile shows a high-velocity antegrade velocity of 316 cm/s consistent with a 40-mmHg systolic gradient. There is a lower velocity antegrade flow during diastole. These findings are consistent with coarctation of the aorta (see Figure 6.4).

19.c. The hallmark of coarctation is the presence of persistent antegrade flow in diastole. The image is a pulsed Doppler spectral recording from the abdominal aorta consistent with coarctation of the aorta. The findings consistent with coarctation are a blunted or low-velocity systolic flow and persistent antegrade flow in diastole (absent retrograde flow). The presence of early diastolic reversal excludes significant coarctation. Other findings consistent with coarctation include a low systolic-to-diastolic velocity ratio, decreased pulsatility, and a prolonged pulse delay. Transthoracic subcostal view with pulsed Doppler in the abdominal aorta. A blunted or low-velocity systolic flow and persistent antegrade flow in diastole (absent retrograde flow) are specific features consistent with coarctation of the aorta (see Figure 6.5).

20.c. Balloon angioplasty with or without stents is generally recommended. The patient has severe recoarctation of the aorta after surgical repair. The choice of intervention for coarctation remains controversial and should be made in a center experienced with congenital heart disease among a team of surgical and interventional specialists. However, for recurrent coarctation after surgical repair, catheter intervention with or without stents is generally preferred if the anatomy is suitable. Favorable anatomy is a discrete, nontortuous short segment of narrowing without aneurysms, pseudoaneurysm, or hypoplasia of the aorta. Additional consideration should be given to women considering pregnancy where there is concern regarding the tissue fragility and risk of aortic complications with residual coarctation tissue. In that setting, surgery may be considered. Cardiac MR angiography. Sagittal oblique maximum intensity projection showing a discrete, short region of coarctation in the upper descending aorta without associated dilatation of the adjacent segments (see Figure 6.6).

21.c. Asymptomatic patient with a peak-to-peak gradient across the coarctation site of 15 mmHg with extensive collaterals. According to the American College of Cardiology (ACC)/American Heart Association (AHA) 2008 guidelines for adults with congenital heart disease intervention for coarctation of the aorta is recommended if (a) peak-to-peak gradient across the coarctation is ≤20 mmHg or (b) peak-to-peak gradient across the coarctation is <20 mmHg but there is anatomic evidence of severe obstruction and radiologic evidence of collateral flow. For the patient undergoing aortic valve replacement for bicuspid severe aortic regurgitation, the coarctation of the aorta should be reassessed after surgery to determine whether it is clinically significant.

22.c. Osteogenesis imperfecta. The patient has osteogenesis imperfecta, a heritable disease of the connective tissue with mutations in procollagen that are associated with bone fragility (with multiple fractures), ocular changes (most notably blue sclerae), abnormal dentition, and hearing loss. Cardiovascular manifestations may occur and are similar to Marfan syndrome with aortic root dilatation, aortic regurgitation, and mitral valve prolapse.

23.b. Intravenous diltiazem. The initial management of aortic dissection is aimed at reduction in heart rate, BP, LV wall stress, and the force of LV contraction (dp/dt). The goals are a heart rate less than 60 bpm and BP less than 120 mmHg systolic. β-Blockers are the drug of choice if contraindications are not present. The patient described has severe COPD and therefore if a β-blocker is used it should be short-acting esmolol and not metoprolol. Otherwise, nondihydropyridine calcium-channel blocking agents such as diltiazem and verapamil are alternative options. Vasodilator therapy such as intravenous nitroprusside is contraindicated when initiated prior to atrioventricular blockade because of associated increase in reflex tachycardia, aortic wall stress, and LV force of contraction.

24.d. It is circumferential or crescentic. The CT demonstrates an intramural hematoma involving the descending aorta. The mechanism for intramural hematomas is thought due to rupture of the vasa vasorum in the media or small intimal tears. Typical features as seen by CT include the following: (a) absence of an intimal flap; (b) circumferential, focal, or crescentic appearance; (c) displacement of intimal calcium; and (d) high-attenuation thickening consistent with hematoma. Additional features that are seen by TEE include echolucent regions with flow consistent with intramural blood vessels.

Of note, the 2010 guidelines for thoracic aortic diseases state that intramural hematoma should be treated similar to aortic dissection in the corresponding segment of the aorta. Computed tomographic angiography axial image showing a descending thoracic aortic intramural hematoma. The intramural hematoma is evident given the circumferential appearance of high attenuation density of the aortic wall (see Figure 6.7).

25.d. TEE. A cardioembolic source of stroke is most likely given the territory of a middle cerebral artery event. The patient has a cholesterol level >300 suggestive of a heritable dyslipidemia and premature atherosclerosis and therefore aortic atheroma would be the most likely finding. A patent foramen ovale may be an alternative source of emboli in this young patient and would be the most likely etiology if the patient did not have a lipid disorder. Intracranial small-vessel disease detected by MRA would be less likely despite a dyslipidemic disorder. There is no information to suggest atrial fibrillation and therefore an event recorder would not likely be revealing.

26.a. Statin and aspirin. The TEE shows a large protruding sessile atheroma in the distal descending aorta/distal aortic arch. Treatment for aortic atheroma remains controversial. Antiplatelet therapies such as aspirin and statins are the mainstay of treatment. Systemic anticoagulation with warfarin or warfarin alternatives is unproven due to limited data. However, several observational reports particularly for aortic arch atheroma demonstrate resolution or reduction of large mobile thrombus/atheroma and embolic events in patients on warfarin. Transesophageal echocardiogram with a short-axis view of the upper descending aorta. A large sessile protruding atheromatous plaque is seen (see Figure 6.8).

27.a. 3-mm plaque with severe calcification and no mobile components. Predictors of embolic events in patients with aortic atheroma include (a) plaque thickness >4 mm, (b) mobile components, (c) ulceration, and (d) lack of calcification. Therefore, a smaller atheroma without mobile debris and with calcification is the least likely to be associated with an embolic event.

28.b. Alternative sites for cross-clamping or cannulation may reduce stroke risk. Alternative sites for cross-clamping and cannulation such as femoral and axillary arteries may reduce the risk of stroke in a patient with significant ascending aortic atheroma. Aortic arch endarterectomy has been found to increase the risk of perioperative stroke and is seldom recommended. Replacement of the ascending aorta is not generally recommended as a prophylactic measure to reduce the risk of stroke in patients with severe atheroma of the ascending aorta because of the additive surgical morbidity and mortality. Palpation of the aorta by the surgeon is usually not accurate in finding noncalcified atheroma that may be detected by TEE.

29.d. Williams syndrome. The physical examination findings are classic for supravalvular aortic stenosis, with a left-sided systolic ejection murmur (increase with expiration) heard best in the first right intercostal space, an increased intensity S2/A2 heart sound, increase in right-sided BP and pulses relative to the left side, and thrill in the suprasternal notch. Differential BP and pulses in the upper extremities is due to the Coanda effect with preferential deflection of blood flow toward the right brachiocephalic artery. Patent ductus arteriosus and severe coarctation of the aorta typically have continuous murmurs and would not typically have arm pulse differences. Supravalvular pulmonary stenosis would also not have pulse differences and the ejection murmur would decrease with expiration. Supravalvular aortic stenosis typically occurs in association with the Williams syndrome and associated mental retardation, and hypercalcemia. Supravalvular aortic stenosis is a form of aortopathy where obstruction occurs above the aortic sinuses usually at the sinotubular junction and is due to mutation in the elastin gene. The obstructive aortopathy is due either to a fibrous diaphragm, hour-glass deformity, or diffuse hypoplasia of the aorta.

30.c. Right-sided aortic arch. The CXR (Fig. 6.9) shows a right-sided aortic arch with the aortic knob on the right side and absence of a left-sided aortic knob. A bovine aortic arch is an anatomic variant where the origin of the innominate artery and the left carotid artery arises from a common origin or the left carotid artery arises from the innominate artery. This variant occurs in approximately 13% of individuals and has no clinical significance. A cervical arch refers to the takeoff of the aortic branch vessels above the sternum into the soft tissues of the neck before turning downward to the descending aorta. It may present as a pulsatile mass in the neck or supraclavicular region and be associated with compressive symptoms and other vascular anomalies.

31.a. Tetralogy of Fallot. A right-sided aortic arch is most commonly associated with tetralogy of Fallot, particularly for the mirror image form. There are several types of right-sided aortic arch, but the mirror image and the non-mirror image variety are the most common. With the non-mirror image type, the order of branches from left to right are as follows: left carotid, right carotid, right subclavian, and left subclavian artery. The left (aberrant) subclavian artery arises from the descending aorta. The mirror image type is much more frequently associated with congenital anomalies than the non-mirror image type. Chest X-ray PA projection shows tracheal deviation to the left and round opacity on the right with absence of a distinct aortic knob on the left. This is most consistent with a right-sided arch (see Figure 6.9).

32.a. Aberrant left subclavian artery and diverticulum of Kommerell. Aortic arch anomalies may result in dysphagia, stridor, or wheezing associated with vascular rings that compress the esophagus or trachea. With the non-mirror image right aortic arch, the left subclavian artery arises from the right side and crosses posterior to the esophagus and trachea. This causes a vascular ring that may cause compressive symptoms. Aberrant vessels such as the left subclavian artery may arise from an aneurysmal segment called a diverticulum of Kommerell. An aberrant right subclavian artery may be an isolated anomaly in a normal left-sided aortic arch and is the most common aortic arch abnormality. Although generally asymptomatic, it may also be associated with a vascular ring.

33.d. 24-Hour Holter monitoring. CTA or MRA of the aorta is required to assess postoperative complications of prior coarctation repair. Complications include recoarctation and aneurysms in the ascending aorta, aortic arch, or descending aorta in the region of the repair. In adults, a TTE does not adequately visualize the descending thoracic aorta, although gradients can be obtained to assess hemodynamic significance. Exercise-induced HTN may occur late after coarctation repair even among patients who are normotensive at rest and should be assessed for by exercise stress testing. TTE is important to assess the aortic valve and the possibility of a bicuspid valve, as well as associated structural abnormalities. Arrhythmias are an infrequent consequence of a corrected coarctation in an asymptomatic patient and therefore Holter monitoring is not necessary.

34.a. Generally every 5 years. The ACC/AHA 2008 guidelines for adults with congenital heart disease recommend at least a one-time CT or MR angiogram for repaired or unrepaired coarctation for complete evaluation of the thoracic aorta. In addition, follow-up should be performed at intervals of 5 years or less depending on the prior findings.

35.d. Observation only. Based on examination and echocardiography, the patient has mixed but predominantly severe congenital bicuspid aortic regurgitation. Holodiastolic flow reversal in the descending aorta is the key confirmatory finding supporting severe aortic regurgitation. The three murmurs described include the systolic murmur of bicuspid aortic stenosis and the diastolic murmurs of aortic regurgitation with the associated Austin Flint murmur. There are no clinical or echocardiographic indications for surgery based on aortic valve or aortic disease. β-blockers for aortic root dimensions >4.0 cm should generally be used only if severe aortic regurgitation is not present because of concern of increasing regurgitant volume and fraction with slower heart rates.

36.c. Aortic valve replacement and aortic graft. Surgery is indicated in this patient both for symptomatic aortic regurgitation and because of significant progression in aortic size. ACC/AHA valvular heart disease guidelines for bicuspid aortic valves recommend replacement of the aortic root or ascending aorta if the diameter is greater than 4.5 cm at the time of aortic valve replacement. Aortic valve repair can be performed successfully in select patients with bicuspid aortic regurgitation but is usually not performed when stenosis is present or if there are unfavorable anatomic findings such as calcification. Therefore, aortic valve replacement with either a mechanical or bioprosthetic valve is indicated along with an aortic graft. The aortic graft may incorporate the aortic root or may be in the supracoronary position.

37.b. Screening men >65 years old is associated with a reduction in aneurysm-related deaths compared with unscreened men of similar ages. Guidelines to screen for AAA vary among different governing bodies. The United States Preventive Services Task Force (USPSTF) recommends one-time screening for any male former or present smoker between ages 65 and 75 years. They do not recommend screening in women based on the lower expected prevalence of AAA. Other vascular societies have less restrictive screening recommendations for men and women. However, screening in patients with first-degree relatives with AAA is recommended. Randomized controlled trials of ultrasound screening for AAA in predominantly men aged 65 to 75 years show a reduction in aneurysm-related mortality compared with unscreened age-matched controls. Ultrasound screening of at-risk patients in accredited laboratories is associated with sensitivities and specificities of over 90%, respectively. Repeat screening after a negative study is not recommended.

38.c. Inflammatory or infectious aneurysms should be repaired at any size. Two large trials of predominantly males showed that early elective AAA repair for aneurysms (4.0 to 5.5 cm) resulted in a similar mortality compared with medical therapy. Therefore, repair is generally indicated for asymptomatic AAA if (a) >5.5 cm; (b) increase in size ≤0.5 cm in 1 year; (c) inflammatory, traumatic, or infectious etiology; or (d) there is a family history of rupture. However, since AAAs may rupture at smaller sizes in women and smaller men, repair should be considered at 5.0 cm or even smaller in low-risk candidates for repair.

39.b. Open repair and EVAR are associated with similar long-term mortality. Endovascular repair of AAA is an alternative to open repair. Comparative trials including EVAR and DREAM have demonstrated a lower short-term morbidity and mortality (at 30 days) for EVAR compared with open repair. However, in long-term follow-up mortality was similar for the two procedures. EVAR is associated with more complications including endoleaks and need for repeat interventions and may require conversion to an open procedure.

40.b. Endoleaks may occur as a result of retrograde flow of small arterial branches back into the aneurysm sac. Endoleaks refer to the occurrence of repressurization of the excluded aneurysmal sac after an EVAR procedure. There are four main types: I—proximal or distal stent attachment site bleeding around the graft; II—leaking back into the sac from branch arterial vessels; III—mechanical failure of stent graft components; IV—leakage of blood through the graft material. Type II leaks are most common. Types I and III may require immediate reintervention, whereas type II can be monitored by repeat surveillance but may require repeat intervention if the aneurysm sac continues to expand.

41.d. CTA of the chest and aorta. The patient’s history and examination has several features suggestive of Ehlers-Danlos syndrome. Since she has a low pre- and posttest probability of coronary ischemia, a cardiac catheterization is not advisable. The vascular type of Ehlers-Danlos syndrome (type IV) is associated with spontaneous or iatrogenic arterial or organ rupture (e.g., rupture of gravid uterus or intestines). Aortic complications including dissection and rupture can occur and therefore arterial puncture is generally contraindicated. A CTA of the chest and aorta would exclude pathologies found in Ehlers-Danlos syndrome, including aortic and pulmonary aneurysm and dissection.

42.b. DNA sequencing. Diagnosis of Ehlers-Danlos type IV is generally made based on clinical and family history and DNA sequencing for the COL3A1 gene mutations. However, a negative test does not definitively rule out disease since not all causative mutations are known. A punch biopsy of the skin to obtain fibroblasts for culture and detection of defective type III collagen can also be performed.

43.b. Loeys-Dietz syndrome. Loeys-Dietz is an autosomal dominant genetic aortic aneurysm syndrome. It predominantly involves children and young adults with risk of rapid progression to aneurysms, arterial tortuosity, and dissection. It is associated with a bifid uvula (shown in Fig. 6.10), cleft palate, and hypertelorism. Other clinical findings similar to Marfan syndrome may be present. Cogan syndrome is a rare large-vessel vasculitis that involves the aorta and is associated with vestibular and ocular abnormalities including uveitis and keratitis. Ormond disease is an inflammatory form of aortitis associated with retroperitoneal fibrosis. Behçet disease is an instead of a arteritis associated with oral and genital ulcers and skin lesions. Image of the oropharynx of a young boy with Loeys-Dietz syndrome showing a bifid uvula (see Figure 6.10).

44.b. TGFBR1 or TGFBR2. The genetic defect associated with Loeys-Dietz syndrome is a mutation in transforming growth factor β-receptor, TGFBR1 or TGFBR2. Table 6.5 shows the most common gene mutations associated with aortic diseases.

45.c. Recommend aortic repair. Because of high risk of aortic dissection in patients with Loeys-Dietz, surgery is recommended at smaller aortic sizes. The 2010 guidelines for thoracic aortic diseases recommend aortic repair based on CTA or MRA for a dimension ≤4.4 cm.

46.c. Descending aortic partial transection with pseudoaneurysm. The patient experienced blunt cardiac trauma with injury to the aorta. This type of deceleration MVA as occurs with a head-to-head car collision may result in catastrophic aortic transection, rupture, or pseudoaneurysm. The typical site of injury occurs at the aortic isthmus (level of the ligamentum arteriosum or junction of the aortic arch and descending thoracic aorta) as a result of fixation of the aorta to the spine by intercostal arteries. The favorable hemodynamics in this patient are not suggestive of either aortic transection or cardiac tamponade. The preserved upper extremity BP and reduced perfusion in the lower extremities are suggestive of partial transection of the descending aorta with a pseudoaneurysm. The pseudoaneurysm is suggested by the widening of the mediastinum on CXR.

47.c. Medical therapy is recommended. Medical therapy should be recommended for this patient. The timing of surgery for descending thoracic aneurysms is addressed by the 2010 guidelines for thoracic aortic diseases. Most descending thoracic aneurysms or chronic dissections (not including thoracoabdominal aneurysms) that are of degenerative, traumatic, or connective tissue etiologies should be repaired when the size is >5.5 cm if comorbidity-related risks are acceptable.

48.c. TEVAR is associated with a 30-day risk of endoleaks of 10%. There are no randomized trials comparing TEVAR with open aortic repair. However, nonrandomized comparisons show a lower rate of hospital complications including paraplegia and death relative to open repair. Despite TEVAR patients generally being older with more comorbid conditions, long-term mortality seems similar. The estimated rate of type I endoleaks with TEVAR is approximately 10% due to difficulties achieving an adequate proximal anastomosis.

49.d. Aortic root localized dissection. Localized staining of contrast dye is seen in the region of the right sinus of Valsalva. This finding is consistent with an iatrogenic localized dissection. In this patient, it is likely due to either catheter trauma or retrograde propagation of the RCA dissection into the corresponding sinus of Valsalva. Coronary dissection is commonly associated with fibromuscular dysplasia. Contrast aortogram with staining of contrast seen in the right sinus of Valsalva that occurred post MI and following percutaneous coronary stenting in a young woman with fibromuscular dysplasia and RCA dissection. Contrast aortogram with staining of contrast seen in the right sinus of Valsalva that occurred post MI and following percutaneous coronary stenting in a young woman with fibromuscular dysplasia and RCA dissection (see Figure 6.11).

50.a. Observation and medical therapy. Most localized iatrogenic intramural hematomas or dissections occurring in the cardiac catheterization laboratory can be observed and managed medically even when involving the ascending aorta. In general, the site of tear seals and propagation or expansion does not occur. However, repeat aortic imaging should be performed to confirm stability.

SUGGESTED READINGS

Groenink M, den Hartog AW, Frankin R, et al. Losartan reduces aortic dilatation rate in adults with Marfan syndrome: a randomized controlled trial. Eur Heart J. 2013;34(45):3491–3500.

Hagan PG, Nienaber CA, Isselbacher EM, et al. The International Registry of Acute Aortic Dissection (IRAD): new insights into an old disease. JAMA. 2000;283:897–903.

Hiratzka LF, Bakris GL, Beckman JA, et al. 2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with thoracic aortic disease: executive summary. Circulation. 2010;121:1544–1579.

Isselbacher EM, Cigarroa JE, Eagle KA. Cardiac tamponade complicating proximal aortic dissection: is pericardiocentesis harmful? Circulation. 1994;90:2375–2378.

Loeys BL, Dietz HC, Braverman AC, et al. The revised Ghent nosology for the Marfan syndrome. J Med Genet. 2010;47:476–485.

Loeys BL, Schwarze U, Holm T, et al. Aneurysm syndromes caused by mutations in the TGF-beta receptor. N Engl J Med. 2006;355: 788–798.

Maraj R, Rerkpattanapipat P, Jacobs LE, et al. Meta-analysis of 143 reported cases of aortic intramural hematomas. Am J Cardiol. 2000;86: 664–668.

Penn MS, Smedira N, Lytle B, et al. Does coronary angiography before emergency aortic surgery affect in-hospital mortality? J Am Coll Cardiol. 2000;35:889–894.

Pretre R, Chilcott M. Blunt trauma to the heart and great vessels. N Engl J Med. 1997;336:626–632.

Schermerhorn ML, O’Malley AJ, Jhaveri A, et al. Endovascular vs. open repair of abdominal aortic aneurysms in the medicare population. N Engl J Med. 2008;358:464–474.

Shores J, Berger KR, Murphy EA, et al. Progression of aortic dilatation and the benefit of long-term beta-adrenergic blockage in Marfan’s syndrome. N Engl J Med. 1994;330:1335–1341.

Song JK, Kim HS, Kang DH, et al. Different clinical features of aortic intramural hematoma versus dissection involving the ascending aorta. J Am Coll Cardiol. 2001;37:1604–1610.

Svennson LG, Labib SB, Eisenhauer AC, et al. Intimal tear without hematoma: an important variant of aortic dissection that can elude current imaging techniques. Circulation. 1999;99:1331–1336.

Trimarchi S, Sangiorgi G, Sang X, et al. In search of blood tests for thoracic aortic diseases Ann Thorac Surg. 2010;90:1735–1742.

Tunick PA, Kronzon I. Atheromas of the thoracic aorta: clinical and therapeutic update. J Am Coll Cardiol. 2000;35:545–554.

Vilacosta I, San Roman JA, Aragoncillo P, et al. Penetrating atherosclerotic aortic ulcer: documentation by transesophageal echocardiography. J Am Coll Cardiol. 1998;32:82–89.

Warnes CA, Williams RG, Bashore TM, et al. ACC/AHA 2008 guidelines for the management of adults with congenital heart disease. Circulation. 2008;118:2395–2451.