Cardiology Intensive Board Review, 3 ed.

Valvular Heart Disease

Dermot Phelan. Maran Thamilarasan

ANSWERS

1.b. Transesophageal echocardiography (TEE). The clinical history is of a patient who had an inferior wall myocardial infarction approximately 1 week ago. He now presents in shock with acute congestive heart failure. Mechanical complication of myocardial infarction is first on the differential. The presence of a ventricular gallop and an apical murmur without a thrill makes papillary muscle rupture the leading diagnosis (as opposed to ventricular septal defect). Transthoracic echocardiography may miss eccentric jets in this setting. TEE should be performed to make the diagnosis. He will certainly need a cardiac catheterization (at which time a saturation run may be performed), but a TEE should be done quickly at the bedside to confirm the diagnosis so that the surgical team can be mobilized.

2.b. Posterior papillary muscle rupture as it has a single blood supply. The 3D reconstruction of the mitral valve shown here is orientated in the “surgeons view,” looking down on the mitral valve from the left atrium with the aortic valve situated on top, the anterior mitral valve leaflet adjacent to it, and the posterior mitral valve leaflet inferiorly. We see a bulky mass (the posterior papillary muscle) protruding into the left atrium in systole. The middle panel (early diastole) clearly shows that the mass is attached to the posterior leaflet. The posterior papillary muscle has a single blood supply (usually the right coronary artery), while the anterior papillary muscle often has dual blood supply. For this reason, post infarction rupture of the posterior papillary muscle is more common.

3.b. She likely has more severe MR than is evident on the echocardiogram. Her examination is suggestive of severe MR. The echo confirms LV dilation and mitral leaflet pathology, which could be consistent. The eccentric nature of the jet suggests that it may have been underestimated by transthoracic imaging. A more definitive imaging procedure such as TEE will be helpful here.

4.b. Mitral valve surgery. The presence of mild LV dysfunction with LV dilation is a class I indication for surgery. TEE would be the next test of choice prior to surgery to confirm the severity and mechanism of MR and assess suitability for surgical repair. While exercise echo is reasonable in asymptomatic patients with severe MR to assess functional capacity the patient already has indications for surgery.

5.c. Stress echocardiogram, to assess for mitral pressures post stress. She has moderate mitral stenosis. The fact that she has stopped exercising may be a clue to the onset of symptoms. An assessment of functional capacity and post-stress mitral pressures would be useful in management There are insufficient data for immediate referral for intervention. Follow-up in a short period of time may not be unreasonable; however, 2 years is too long a period.

6.a. Consideration for percutaneous valvuloplasty. Her functional capacity is below average for her age. Her valve is favorable for percutaneous valvuloplasty (splittability score of 6) and she had a significant rise in PA pressures post stress. Ideally, the splittability index should be 8 or less for optimal results post balloon valvuloplasty. A increase in mean valve gradient of 15 mmHg with exercise is a class I indication by the American College of Cardiology (ACC)/American Heart Association (AHA) guidelines. A β-blocker would not be an unreasonable addition, but she should be followed more frequently than every 2 years. In addition, she does have class I indication for intervention. She has normal LV function and is in sinus rhythm—there is no role for digoxin in this setting. Valve replacement is considered only if the valve is deemed unsuitable for percutaneous valvuloplasty or surgical repair.

7.b. Carcinoid. The history and examination are consistent with tricuspid stenosis and regurgitation. (She has symptoms of fatigability from decreased cardiac output, signs, and symptoms of systemic venous congestion—hepatic distension and right upper quadrant pain, peripheral edema, and ascites. There is a diastolic murmur along the sternal border, which increases with inspiration, along with a prominent awave in the JVP. In addition, she has a pansystolic murmur and a prominent v wave.) However, no evidence for mitral stenosis is noted on examination. Isolated rheumatic tricuspid stenosis is very rare. Thus, other causes for tricuspid stenosis should be considered. The second most common cause of tricuspid stenosis is the carcinoid syndrome. She also has bronchospasm and diarrhea, which go along with this diagnosis. She has a normal P2, making primary pulmonary hypertension unlikely. Liver disease in and of itself would not produce elevation in the JVP.

8.c. Check lower extremity BP. He has a bicuspid aortic valve (an ejection sound is heard, along with a short systolic ejection murmur). There is an association between bicuspid aortic valves and coarctation of the aorta. Therefore, looking for discrepancy between the upper and lower extremity BP would be paramount.

9.c. Dobutamine echocardiogram. This is a patient presenting with low-gradient AS in the setting of LV dysfunction. It may be that the patient has severe AS, but the gradients are now low secondary to decreased stroke volume. However, the degree of AS may not be that significant, but because of decreased cardiac output, the continuity equation overestimates AS severity. In this setting, low-dose dobutamine echocardiography may be useful. With inotropic stimulation, an improvement in stroke volume and cardiac output may help to differentiate true severe AS from what has been labeled pseudo-AS. If true severe AS is not present, then valve area will increase. It would not be prudent to send such a patient to aortic valve surgery without performing such an evaluation. It would be necessary to exclude severe stenosis before proceeding with transplant evaluation. ACEI may be beneficial, but it would be important to proceed with the workup as above first. Afterload reduction would need to be introduced with very careful hemodynamic monitoring if true severe AS were in fact present. The use of dobutamine echocardiographic testing to evaluate low-gradient AS in the setting of LV dysfunction is a class IIa indication by ACC/AHA guidelines.

10.a. AVR. The patient has true, severe AS and although may have a higher potential complication rate with surgery is likely to benefit prognostically and symptomatically from surgery. Balloon aortic valvuloplasty has not been shown to improve survival without the addition of a more definitive procedure such as aortic valve surgery. It is only indicated for palliation or as a bridge to a more definitive procedure such as transcatheter aortic valve replacement (TAVR) or surgery.

11.d. Patient has a lack of contractile reserve but should still be considered for AVR. There are three possible outcomes to a low-dose dobutamine test in this situation: true AS, pseudo-AS, and absence of contractile reserve. As was the case in Question 10, there may be an increase in stroke volume (defined as ≤20% increase from baseline) associated with an increase in transvalvular gradients (mean gradient >40 mmHg) without a significant increase in aortic valve area (AVA) (AVA increase <0.2 cm2) indicative of true AS. Conversely, in pseudo-AS the increase in stroke volume is associated with an increase in AVA without a significant change in gradients. Finally, absence of contractile reserve is defined as failure to increase the stroke volume by ≤20% from baseline. In this case, dobutamine does not help to differentiate between the former two scenarios. While there is a significantly higher mortality during the perioperative period in those with the absence of contractile reserve compared with true AS, for those that survive surgery their 5-year survival is significantly better than those treated with medical therapy alone. Therefore, surgery should be considered on an individual basis.

12.b. Addition of vasodilator therapy. The patient is asymptomatic with good functional capacity. He has a normal ejection fraction with a mildly dilated LV. Surgery is a class III indication (harmful) in this setting. Vasodilator therapy may have some benefit in this asymptomatic population with preserved ejection fraction and LV dilation, although this is not definite. This is a class IIb indication. However, he has systolic hypertension which is likely at least in part related to his aortic regurgitation, and vasodilator therapy is an optimal therapy for this. Observation alone would be reasonable, but such a patient should be followed at 6-month intervals initially and not every 3 years. There is no role for cardiac catheterization at this juncture.

13.a. <1%. From the available published literature, as summarized in the ACC/AHA consensus guidelines, the risk is about 0.2% per year in those asymptomatic patients with preserved LV function.

14.d. Referral for surgical intervention to repair or replace his aortic valve and to replace his ascending aorta. An aortic dimension >5.0 cm (or growth >0.5 cm per year) in a patient with a bicuspid aortic valve is a class I indication for surgery. The valve is often repairable in bicuspid valve associated with predominant aortic regurgitation assuming the mechanism is due to prolapse of the conjoint cusp, and there is no significant stenosis or calcification of the valve.

15.d. AVR with tricuspid valve repair if feasible. The mitral valve appears morphologically normal. After relief of the outflow tract obstruction, the MR will likely improve; therefore, mitral valve repair is not indicated. Tricuspid valve repair for moderate TR at the time of left-sided valve surgery is reasonable in the context of annular dilation and elevated PA pressures. This is a class IIb indication from the ACC/AHA guidelines but receives a class IIa recommendation from the European Society of Cardiology (2012). Tricuspid valve repair is favored over replacement.

16.a. 0.4 cm2. The EROA based on the assumptions above is 0.4 cm2 consistent with severe MR. The EROA is calculated using the abbreviated proximal isovelocity surface area (PISA) method as r2/2 (r = radius of the PFCR). In this case, the radius is 0.9 cm; therefore, the EROA can be estimated as 0.4 cm2.

17.b. 2+, moderate. Using the complete PISA method and calculating the regurgitant volume, the MR is determined to be only moderate in severity which is consistent with the brief duration of MR heard on physical examination. The complete method for calculating the EROA is (2πr2 × AV)/Vmax (AV: aliasing velocity; Vmax: maximum velocity across the mitral valve); therefore, in this case the EROA = (2π(0.9)2× 38.5)/600 = 0.33 cm2. However, as we see from the continuous-wave Doppler signal, the MR only occurs in late systole consistent with mitral valve prolapse. The regurgitant volume is equal to EROA × VTIMR (VTIMR = velocity time integral of the mitral regurgitation), which in this case is = 0.33 × 100 = 33 mL consistent with 2+ MR. If we used the EROA from the abbreviated PISA method (0.4 cm2), the regurgitant volume is 40 mL, which is still consistent with moderate MR.

18.a. Transesophageal echocardiogram. Left atrial and appendage thrombus should be excluded prior to proceeding with percutaneous valvuloplasty and is recommended by ACC/AHA guidelines to be performed prior to the procedure. Transthoracic echocardiography does not have sufficient sensitivity for this purpose. Documentation of atrial fibrillation by ambulatory monitoring may make the likelihood of finding a thrombus higher, but the transesophageal echocardiogram should be performed regardless. Routine surveillance for aortic calcification has no role in this setting. A nuclear perfusion study would not be necessary here (angiography can be performed if needed at the time of the procedure).

19.a. It is absolutely indicated. Given LV dysfunction (EF < 50%), this is a class I indication for surgery. There is no question as to the severity of the AS given the gradients and the aortic valve area; thus dobutamine echocardiography is not of value here.

20.d. The rate of mortality, for a patient with these findings, is higher compared with patients with severe AS and high gradients across the aortic valve but aortic valve surgery has resulted in better outcomes in these patients. This woman has paradoxical low-gradient, severe AS with preserved ejection fraction. Her clinical history, examination, and 2D imaging of the aortic valve are consistent with severe AS. She has a low indexed stroke volume (<35 mL/m2), resulting in low gradients across the AV but the dimensionless index and AVA both are consistent with severe AS. When there is discordant echocardiographic data the accuracy of measurements should always be looked at again; however, in this case, the low gradients are consistent with low-stroke volume. There are currently no guidelines from the ACC or AHA on how to manage these patients; however, the recent 2012 European Society of Cardiology guidelines for valvular heart disease provide a class IIa recommendation for AVR in symptomatic patients with paradoxical low-gradient, severe AS with preserved ejection fraction. A number of studies have confirmed that the rate of mortality is higher in this cohort when compared with patients with severe AS and high gradients but surgery on the aortic valve is associated with significantly better outcomes.

21.c. Aortic root dimension. The patient clinically has severe AI. The murmur is loudest at the right sternal border, suggesting aortic root dilation as a potential cause of his AI. The presence of root dilation (≤5.5 cm) may lead to earlier surgery, hence is vital to know. The diastolic rumble is most likely an Austin Flint murmur and not concomitant mitral stenosis (no opening snap, S1 not loud).

22.a. Cardiac catheterization with aortography. Clinically, the patient has severe aortic regurgitation. He is symptomatic. Consistent with this, the echocardiogram reveals a dilated LV with low normal systolic function. The degree of aortic regurgitation must be underestimated by this study. When there is such discrepancy, proceed with aortography to confirm aortic regurgitation severity and to assess coronaries prior to surgical referral. As he is symptomatic, continued observation and/or medical therapy is not the preferred treatment approach. β-Blockers, by prolonging the diastolic filling period, could actually increase regurgitant volume.

23.a. Transesophageal echocardiogram, emergent cardiac surgical consultation. The patient has a clinical presentation of severe acute AI (short diastolic murmur, soft S1 from premature mitral valve closure, low output state, and pulmonary edema). In the context of chest pain, this scenario suggests aortic dissection until proven otherwise. The dissection flap likely involves the ostium of the right coronary artery, producing the inferior ST-segment elevation. Thrombolytics should not be used until dissection is ruled out. Even if there is no dissection, an intra-aortic balloon pump should not be used with severe AI. The augmented diastolic pressure worsens the severity of the insufficiency. MRI would also provide the diagnosis, but given the hemodynamic instability of the patient, a bedside TEE would be a safer and quicker option to arrive at the diagnosis.

24.b. No evidence for dysfunction. The physical examination does not suggest either stenosis or insufficiency. He appears to be in a high-output state, secondary to his febrile illness. As a result, the gradients are increased. The LVOT VTI is also increased, secondary to the increased cardiac output. The LVOT/aortic valve VTI ratio is the same in the two echocardiograms, which would speak against any significant obstruction.

25.a. TEE with surgical consultation. The clinical scenario, with a new first-degree AV block and acute aortic regurgitation, is highly suspicious for prosthetic valve abscess and possibly even partial dehiscence. A transesophageal echocardiogram should be performed, but prompt surgical consultation should also be requested given the high suspicion for aortic root abscess and the onset of heart failure symptoms.

26.c. Repeat echocardiogram with planimetry of mitral valve area. With acute changes in atrial and ventricular compliance (as with valvuloplasty), the half-time is unreliable. Usually 72 hours or more is required after the procedure before the half-time can be used with reasonable reliability. Planimetry, if performed correctly, would provide a more reliable estimate of stenosis severity. Clinically, the patient seems to have had a good result (longer S2–OS interval, shorter murmur). TEE rarely provides incremental data on mitral stenosis if the transthoracic images are reasonable.

27.a. Observation. The shunt is secondary to the valvuloplasty procedure where the interventionalist must perform an interatrial septal puncture in order to access the mitral valve. Most of these small shunts will close over the next 6 months without any intervention. The shunt is left to right by color. He has good O2 saturation on room air, making any significant right-to-left shunting unlikely. Anticoagulation with an atrial septal defect/patent foramen ovale may be recommended in certain settings, however not indefinitely, given the good chance that the defect will close.

28.b. Antibiotic prophylaxis, with yearly office visits. He requires antibiotic prophylaxis with a prosthetic valve (by 2007 guidelines, prosthetic cardiac valves are an indication for subacute bacterial endocarditis prophylaxis prior to dental procedures). These patients still require close follow-up with complete evaluation on a yearly basis. Some advocate a 3-month period of warfarin therapy after bioprosthetic valve placement. He is now 4 months out, and has no other indications or a high-risk profile (LV dysfunction, prior embolic event, and atrial fibrillation); thus warfarin is no longer needed at this time. Similarly, there is no specific indication in this man for clopidogrel therapy.

29.e. No therapy at present but follow carefully with serial clinical and echo evaluation. Antibiotics are not recommended routinely for prophylaxis at the time of delivery for patients with valvular heart disease unless infection is suspected. If there is evidence of pulmonary congestion treatment with diuretics and afterload reduction with hydralazine is recommended but ACEIs are teratogenic and are absolutely contraindicated in pregnancy. Your patient is clinically euvolemic and therefore medical therapy need not be initiated. Surgery should only be performed if the mother’s life is threatened due to the associated high fetal mortality rate (20% to 30%). Management will involve close follow-up and monitoring by her cardiologist and obstetrician and treatment only if her clinical situation deteriorates.

30.a. TEE. The echocardiogram reveals a normal-appearing aortic valve. Yet, the profile of the continuous-wave Doppler jet is more consistent with a fixed obstruction, as opposed to the dagger shape of dynamic obstruction. These findings are suggestive of the presence of a subvalvular membrane. TEE would be useful to better delineate this area and identify the membrane. The patient already has a 5-m jet in the absence of systolic anterior motion; therefore, it would not be prudent to use provocation with amyl nitrate. A stress echocardiogram would have no diagnostic value and may have some risk in the setting of symptomatic LVOT obstruction. One should always consider contamination with an MR signal; however, the physical examination is consistent with outflow tract obstruction and the continuous-wave Doppler signal begins after the QRS (after isovolumetric relaxation) consistent with outflow tract obstruction. The MR signal will begin earlier relative to the QRS (through isovolumetric contraction).

31.c. There is no clear role for aspirin therapy in such patients. If there is echocardiographic evidence for high-risk mitral valve prolapse (leaflet thickening, elongated chordae, left atrial enlargement, and LV dilation), aspirin therapy is considered a class IIb indication. Therapy is clearly recommended if there have been documented stroke or transient ischemic events.

32.b. Continue with vasodilator therapy and reassess in 6 months. By ACC/AHA guidelines, decline in ejection fraction following stress echocardiography by itself is not an accepted indication for referral to surgical intervention. Owing to the high afterload and the increase in afterload on exercise, a small-to-modest decline in ejection fraction (<10%) may still be consistent with well-compensated AI. This patient has normal resting ejection fraction and mildly dilated LV with excellent functional capacity.

33.b. Repeat the echocardiogram with amyl nitrate (Fig. 2.11). The physical examination is highly suggestive of hypertrophic cardiomyopathy (brisk, bisferiens carotid pulse, normal S2, and murmur increasing with Valsalva and decreasing with handgrip). The patient may not have a significant resting gradient, but may have a significant provocable gradient. Generally, a transesophageal echocardiogram is not needed to make the diagnosis. Invasive hemodynamics with provocation would be useful, but angiography alone would not be sufficient.

Figure 2.11

34.c. She will probably not need surgery on her mitral valve. MR secondary to systolic anterior motion of the mitral valve is related to hydrodynamic drag and Venturi effects on the anterior mitral valve. Often there are intrinsic mitral valve abnormalities that, in combination with septal hypertrophy, predispose to systolic anterior motion. Abnormal chordal attachments or hypermobile papillary muscles seen best on cardiac MRI may mandate chordae remodeling or papillary muscle reorientation; however, in this case the mitral valve apparatus is noted to be structurally normal. Relief of the hydrodynamic effects of a narrowed LVOT after myectomy will usually result in significant improvement in MR without further surgery. Before chest closure, careful assessment of MR should be done after the myectomy, usually with isoproterenol infusion, to ensure resolution.

35.b. Transesophageal echocardiogram. By examination, the patient has mitral insufficiency. The echocardiogram is consistent with this, with an elevated peak transmitral gradient. Pressure half-time is not prolonged; thus there does not appear to be any significant stenosis (gradients elevated owing to increased flow from regurgitant volume). A TEE would be the most useful to confirm the diagnosis. Fluoroscopy may identify partial dehiscence, but would not be helpful if there were a leak in the setting of a well-seated valve. There is no evidence for stenosis, where fluoroscopic evaluation of leaflet motion could be diagnostic. There is no clinical evidence for endocarditis.

36.a. Prominent closing click, soft and brief diastolic rumble. The bileaflet mechanical valves do not typically produce a loud opening sound, but do have prominent closing sounds. A brief diastolic rumble may be heard in a normally functioning prosthetic valve in the mitral position.

37.b. Prominent opening and closing clicks, soft and brief diastolic rumble. With the ball-and-cage valves, one would expect to hear the opening click as well.

38.e. Warfarin therapy with a target INR of 2.5 to 3.5 plus aspirin 75 to 100 mg. All patients with a mechanical valve require warfarin. The risk of thromboembolic events is higher for prosthetic valves in the mitral position; therefore, the recommended therapeutic range is higher than that for mechanical valves in the aortic position. The addition of low-dose aspirin (75 to 100 mg) further reduces the risk of thromboembolic event and reduces mortality from cardiovascular disease. Therefore, aspirin is recommended for all patients with valvular prostheses. Higher doses of aspirin have not been shown to be beneficial and increase the bleeding risk.

39.a. <2%. In the absence of symptoms, natural history studies would suggest a relatively low risk of sudden death.

40.d. >50%. He has a velocity across the aortic valve of >4 m/s. Observational studies would suggest a high likelihood of symptom development in the next 3 years.

41.d. Start ASA, 81 mg/day, and increase warfarin to achieve an INR of 2.5 to 3.5. ACC/AHA guidelines recommended an INR of 2.5 to 3.5 for patients with bileaflet tilting disk mechanical valves in the aortic position who have had a thromboembolic event, and who have atrial fibrillation, LV dysfunction, or a hypercoagulable state. Addition of low-dose ASA (75 to 100 mg) is a class I indication for all patients with mechanical heart valves, and those with the above risk factors and bioprosthetic valves.

42.a. Intravenous heparin. Since a small clot was present (without any obstruction to valve function) the patient would benefit from increased anticoagulant therapy. If he were to fail this, then the other alternatives could be considered, such as continuous infusion thrombolytic therapy. Such continuous therapy (although not bolus) could also be used as primary treatment. No established indications exist at this time for glycoprotein IIb/IIIa inhibitors in this clinical setting. It would not be advisable to proceed to reoperation just yet, in the absence of a large clot burden or obstruction to inflow. If treatment with heparin leads to clot resolution, then subsequent warfarin dosing should be increased to maintain INR in the 3.0 to 4.0 range.

43.a. Therapy with warfarin. He should be on warfarin. Valvuloplasty in this setting (onset of atrial fibrillation, in an otherwise asymptomatic patient) is a class IIb indication by current guidelines.

44.a. Reassurance, with a repeat physical examination in 6 months. If a thorough physical examination reveals no signs of cardiopulmonary disease and the patient has no symptoms, then reassurance and follow-up are all that are required. Echocardiography should be performed if obesity limits the physical examination or if signs or symptoms are present.

45.b. Consider elective mitral valve repair at a hospital where repair is performed with a high degree of success or if he wishes to defer surgery, follow up at 6 monthly intervals with echo. Referral for surgery is reasonable (class IIa indication) if chance of repair is >95%. There are no data to suggest a beneficial role for the addition of afterload-reducing agents in the absence of systemic hypertension (again by ACC/AHA guidelines). There is absolutely no role for the prophylactic use of amiodarone. Close clinical follow-up is reasonable, but repeat evaluation should not be deferred for 2 years. Guidelines use LV dimensions and ejection fraction to guide surgical intervention, even in the absence of symptoms. As such, these patients should have clinical reevaluation and echo every 6 months.

46.a. Referral for mitral valve repair. He is now symptomatic with depressed ejection fraction and a dilated LV. This is a class I indication for surgery. Valve repair as opposed to replacement is the preferred surgical treatment. Medical therapy may be needed as an adjunct, but is insufficient as the sole treatment.

47.c. Life expectancy <1 year. Life expectancy of <1 year, despite treatment of AS, is an absolute contraindication for TAVR. Severe peripheral artery disease precludes a transfemoral approach; however, the procedure may be done via a transapical approach, a transsubclavian approach, and even a transaortic approach. Severe pulmonary disease and an inaccessible apex preclude a transapical approach but the other approaches remain available. Active endocarditis is a contraindication to the procedure. The available valves are suitable for annular sizes between 19 and 29 mm.

48.c. Mitral and tricuspid stenoses. The loud S1, opening snap, and apical diastolic rumble are features of mitral stenosis. The presence of the diastolic rumble along the sternal border, which increases with inspiration, along with the prominent a wave in the JVP and evidence of systemic venous congestion (hepatomegaly and peripheral edema) suggests that concomitant tricuspid stenosis is present as well.

49.c. Cardiac catheterization. By physical examination, the patient has severe AS (no A2 of second heart sound, late-peaking murmur, and diminished carotid upstrokes). A stress test would not be appropriate in a patient with symptomatic AS. An echocardiogram would usually be the first step, but proceeding directly to catheterization to measure transvalvular gradients and assess coronary anatomy would be reasonable. SL NTG could have disastrous consequences in this setting. By reducing preload, it may precipitate syncope.

50.b. Refer for percutaneous balloon valvuloplasty, followed by gastrectomy. He has symptomatic critical AS. AVR, with concomitant need for anticoagulation while on cardiopulmonary bypass, is not an attractive first option. Proceeding directly to gastric surgery would carry high risk, given the ongoing symptoms. Valvuloplasty would be a reasonable bridge to lower risk from the noncardiac surgery.

51.a. Bovine pericardial valve. He is at an age where there is substantial durability of the bioprosthetic valve. He is at increased risk for anticoagulation; thus, mechanical valves would not be the valve of first choice. By history, he would not appear to need anticoagulation for any other indication. Homograft is not unreasonable, but there would not appear to be any hemodynamic or durability benefits for an 80-year-old patient, and its insertion requires a more difficult operation.

52.c. ∼50% of cases have a bicuspid aortic valve. Coarctation of the aorta is suspected clinically and confirmed on a gated CT angiogram of the thoracic aorta. This lesion is frequently associated with concomitant congenital cardiac anomalies, the most frequent of which is a bicuspid aortic valve (occurs in ∼50% to 85% of cases).

53.a. Stress test. The patient has significant aortic regurgitation with a dilated LV although not yet at the dimension that would be an indication for surgery in the absence of symptoms (his end-systolic dimension is <5.0 cm and end-diastolic dimension is <7.0 cm). He leads a sedentary lifestyle, and although he has no dyspnea, he does relate some equivocal symptom. A stress test would be useful to assess functional capacity and to objectively assess symptoms. If he were to develop symptoms at a low level of exercise, this may be an indication for surgical intervention. A vasodilator may be useful (class IIb indication with dilated LV), but he would need more frequent follow-up, given the LV dilation.

54.b. Surgical intervention. (Refer for surgery.) His ventricle has dilated even further. An end-diastolic dimension of >7.5 cm is a class IIa indication for surgery and is associated with an increased risk of sudden death, even in the absence of symptoms.

55.b. Mean gradient across the mitral prosthesis of 17 mmHg. The clinical presentation and examination are suggestive of prosthetic mitral stenosis (long diastolic rumble, muffled closing click, and clinical heart failure). The PMI is not displaced, so it is unlikely that she has significant LV dysfunction. There are no clinical signs of severe MR. Given the acute onset of symptoms, acute valvular thrombosis leading to valvular obstruction is high on the differential. If this were the case by ACC/AHA guidelines, reoperation would be the preferred treatment approach. If other comorbidities were prohibitive, thrombolytic therapy could be considered.

56.a. Arrhythmias secondary to an accessory pathway. The examination is highly suggestive of Ebstein anomaly (presence of TR, widely split first heart sound). The echocardiogram confirms this. Accessory pathways are frequently associated with this condition.

57.a. Echocardiography with saline contrast study. Ebstein anomaly is frequently associated with cardiac shunts (either patent foramen ovale, or atrial or ventricular septal defect). The setting of a TIA in someone who has been immobilized (such as with a fracture) raises the concern of paradoxical embolism of a venous thrombus to the systemic circulation.

58.b. Vmax across the pulmonic valve of 4 m/s. The physical examination is consistent with pulmonic stenosis (presence of thrill, RV heave, ejection click, and crescendo-decrescendo murmur loudest over the pulmonic area). Normal carotid upstrokes and preserved A2 make significant AS unlikely. The murmur is not consistent with a regurgitant murmur.

59.a. He tells you of an episode of syncope. The presence of exertional dyspnea, angina, syncope, or near-syncope are class I indications for intervention. For gradients between 30 and 39 mmHg, there is some divergence of opinion about the role of intervention (class IIb for gradients 30 to 39). There is no role for intervention in those with gradients <30 mmHg who have no symptoms. A peak-to-peak gradient >40 mmHg by catheterization is a class I indication for intervention, even in an asymptomatic patient.

60.a. Percutaneous valvuloplasty. This is the preferred treatment for young adults with pulmonic stenosis.

61.b. Doppler echocardiography, using the continuity equation. With significant insufficiency, the Gorlin formula becomes less reliable. Pressure half-time is not used to calculate aortic valve area, but does give a clue to the severity of the AI.

62.c. Aortic homograft. Mechanical and bioprosthetic valves have a similar incidence of endocarditis, which is higher than that seen for homografts. In the setting of acute bacterial endocarditis of a prosthetic aortic valve, homografts are the valve of first choice when surgery is indicated.

63.d. Pulmonary hypertension resulting from primary left-sided disease. The most common cause of tricuspid insufficiency is pulmonary hypertension that results from primary pathology on the left side of the heart. This includes aortic and mitral valvular diseases, as well as LV dysfunction from coronary artery disease or other cardiomyopathies.

64.a. Streptococcus viridans accounts for up to 50% of cases. Staphylococcus aureus is the next most common pathogen.

65.c. Staphylococcus epidermidis. This patient presents with early prosthetic valve endocarditis (within 2 months of surgery). This is usually acquired during the operation, and the skin species Staphylococcus epidermidis is the most frequent pathogen encountered. Late prosthetic valve endocarditis is similar to native valve endocarditis in terms of the spectrum of pathogens involved.

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