1. Answer: C. Studies comparing transthoracic echocardiography (TTE) with transesophageal echocardiography (TEE) for the detection of vegetations with TEE as the gold standard have shown that the sensitivity of TTE is dependent on vegetation size. It varies from 0% to 25% for vegetations of <5 mm and from 84% to 100% for vegetations of >10 mm. Therefore, vegetations of <5 mm can easily be missed by TTE even with the application of harmonic imaging. The sensitivity of TTE to detect vegetations is also affected by image quality. A recent meta-analysis showed that the sensitivities of TTE and TEE in detecting vegetations in native valve endocarditis were 62% and 92%, respectively.

2. Answer: A. TEE provides high spatial resolution of cardiac structures due to its close proximity to the heart and the high frequency of the transducer, and can depict a structure as small as 1 mm in diameter.

3. Answer: D. Initially, M-mode was used to detect vegetations. With two-dimensional TTE, better spatial definition of vegetations can now be obtained. An active vegetation is an echogenic mass with an irregular shape. It is usually located at or near the lines of valve closure at the low-pressure end of the jet lesion with high-frequency motion independent of the underlying cardiac structure. The mass can be associated with valve dysfunction. Chronic healed vegetations become echo-dense masses due to fibrin, collagen, and calcium deposition. The echocardiographic identification of vegetation or abscess is considered a major criterion for IE in the widely used Duke criteria (Table 20-1). A definite diagnosis of IE requires the presence of two major criteria, or one major and three minor criteria, or five minor criteria. According to the modified Duke criteria, a vegetation is “an oscillating intracardiac mass on valves or supporting structures, or in the path of regurgitant jets, or on implanted material, in the absence of an alternative anatomical explanation.” Compared with infective vegetations, noninfective vegetations from marantic or Libman-Sacks endocarditis have similar morphologic features and can only be differentiated from infective vegetations on the basis of the clinical findings.

4. Answer: C. Because of its close proximity to the ventricular septal defect (VSD) jet, the septal leaflet of the tricuspid valve is usually affected. However, right ventricular outflow tract (RVOT) and subpulmonic vegetations have also been described in patients with VSD presenting with infective endocarditis.

5. Answer: D. The parasternal long-axis view of the right ventricular inflow tract is obtained by rotating the transducer 15-30 degrees clockwise and tilting the transducer inferiorly and medially. It usually allows the visualization of the anterior and septal leaflets of the tricuspid valve, although the posterior leaflet may be uncommonly seen if the right ventricular posterior wall is visualized.

The apical 4-chamber views allow visualization of the anterior and septal leaflets of the tricuspid valve, but not the posterior leaflet. In many patients, the subcostal window can provide a good short-axis view of the tricuspid valve so that the posterior tricuspid leaflet can be identified with confidence. The parasternal short-axis view at the level of the aortic valve also can visualize the posterior leaflet, but this choice is not offered as an answer.

6. Answer: C. TEE detects vegetation(s) in about a third of all patients with Staphylococcus aureus bacteremia. In patients with insufficient criteria for IE based on the Duke criteria which include the TTE findings, 15% of the patients will be reclassified to have possible or definite IE following TEE.

7. Answer: C. On echocardiography, an abscess is identified as a localized abnormal thickening of the perivalvular tissue or echolucent space within the perivalvular tissue that does not communicate with surrounding cardiac chambers. It is predominantly located at the aortic root and aorto-mitral intervalvular fibrosa. Myocardial abscesses are associated with very high mortality. The development of heart block in this setting is an indication of abscess formation involving the ventricular septum. A pericardial abscess usually represents a fistula formation between an annular abscess and the pericardial space.

8. Answer: A. Caseous calcification of the mitral annulus can present as an echolucent space within the calcification of the mitral annulus, simulating a mitral valve annular abscess. To differentiate from an abscess, other echocardiographic features need to be sought, such as a vegetation, perforation of the leaflet, or valve dysfunction.

A dilated coronary sinus, thoracic descending aorta, and epicardial fat can be easily distinguished from an abscess in the presence of normal mitral valve anatomy and function.

9. Answer: B. On TEE or TTE, the short-axis view of the aortic valve allows better visualization of the location and extent of an aortic root abscess. This view provides a 360-degree spatial orientation of the aortic root and aortic valve leaflets.

10. Answer: C. Abnormal thickness of the aortic wall of >10 mm is suspicious for an aortic root abscess in native aortic valve endocarditis. If present, serial echocardiograms can follow the evolution of this thickening and identify formation of an echolucent space over time. This criterion cannot be used in patients with recent aortic valve or aortic root replacement, as postoperative inflammation can contribute to thickening of the aortic wall. Prosthetic valvular thrombosis and pannus formation can be differentiated from an abscess by their predilection to involve the sewing ring encroaching onto the prosthetic orifice instead of the surrounding annulus. A pseudoaneurysm can be recognized by the presence of an echolucent cavity with communication with a neighboring cardiac chamber.

11. Answer: C. Vegetations evolve during successful antibiotic treatment. Reduction in vegetation size and increase in density are common. Persistence of vegetations alone does not predict a worse outcome. The lack of regression of vegetation size after 4-6 weeks of antibiotic therapy is associated with an increased risk of mortality and complications related to endocarditis. However, this occurs only in patients with progressive valve disruption and dysfunction. In contrast, in patients with endocarditis but without significant valve dysfunction, the mortality and morbidity rate is not increased despite the lack of reduction in the vegetation size.

12. Answer: A. After healing from endocarditis, <10% of affected valves regain their normal structure. The majority of affected valves show nodular changes, thickening, or disruption of the leaflets after healing. No reliable predictors for complete healing have been identified.

13. Answer: A. Right ventricular (RV) inflow and parasternal short-axis views are the best views to appreciate the anatomy of the eustachian valve. Sometimes, the apical 4-chamber view and the subcostal views can also be used to assess the extent of vegetation, but the eustachian valve is usually not well seen because of the increased image depth necessary for these views. The eustachian valve is an embryonic remnant from the incomplete resolution of the membranous partition between the smooth posterior venous chamber and the anterior trabeculated primitive atrium. When the membranous embryonic remnant is extensive and weblike with attachment to multiple sites, it is referred to as Chiari network.

14. Answer: C. The normal eustachian valve is thin with a thickness <3 mm, and it has predictable oscillating motion. Abnormal thickness (>5 mm) of the eustachian valve and an adherent mass with chaotic high-frequency motion are features of a vegetation of the eustachian valve.

15. Answer: E. Multiplane TEE has been reported as a highly diagnostic tool with a negative predictive value varying from 87% to 98% in IE, depending on the clinical setting and the criteria used to define IE (native valve vs. prosthetic valve, modified Duke criteria vs. pathologic confirmation). The negative predictive value of TEE can be further increased if a repeat TEE 7-10 days later remains negative.

16. Answer: B. A mitral valve aneurysm is characterized by a localized bulging of the mitral leaflet toward the left atrium, with systolic expansion and diastolic collapse. Mitral valve aneurysms are usually due to endocarditis. Surgical repair is frequently indicated because of the concomitant presence of perforation involving the aneurysm resulting in significant mitral regurgitation.

17. Answer: A. Mitral valve prolapse can sometimes mimic mitral valve aneurysm because of the systolic bulging of the mitral valve leaflet toward the left atrium. However, the absence of vegetation and valve disruption favor the diagnosis of prolapse. A mitral valve blood cyst is a very rare condition that can present as an immobile echogenic mass on the mitral valve leaflet.

Flail of the mitral valve leaflet is usually associated with ruptured chordae that can be identified by the typical “snake-tongue” appearance of the corresponding mitral leaflet into the LA during systole. Mitral valve repair with an Alfieri stitch presents as a double-orifice mitral valve on the parasternal shortaxis view. On the parasternal long-axis view, the mitral valve leaflets appear thickened and restricted.

18. Answer: A. According to the Appropriate Use Guidelines, TEE is indicated when there is a moderate to high pretest probability of IE such as is the case with a prosthetic heart valve, fungemia or Staphylococcus aureus bacteremia. Despite a negative TTE for IE, about 15% of patients with Staphylococcus aureus bacteremia are diagnosed to have possible or definite IE based on TEE findings. In patients with mechanical heart valves, a false-negative TTE is common and it is reasonable to perform TEE to exclude IE. TEE is inappropriate when the pretest probability is low such as transient fever, a known alternative source of infection and negative blood culture or positive blood culture with an atypical pathogen for IE such as Escherichia coli.

19. Answer: E. There is a wide spectrum of cardiac manifestations of APLA syndrome, ranging from valvular abnormalities to pulmonary hypertension. Large valvular masses can be detected in 10%-40% of patients and may be difficult to differentiate from infective vegetations in IE patients. The valvular masses in APLA syndrome can be mobile, pedunculated, or immobile and broad-based in the setting of leaflet thickening. They may have heterogeneous echogenicity and often can present as multiple lesions (kissing vegetations) at any location on the leaflets (base to tip). However, tissue destruction is usually absent with APLA syndrome and when present should raise the suspicion for IE.

20. Answer: C. According to the current guidelines, patients with IE should undergo early surgery if there is valve dysfunction associated with heart failure, if there is a left-sided IE caused by a resistant organism, including Staphylococcus aureus and fungal organisms, or if periannular complications such as abscesses are present. An early surgery should also be performed if persistent signs of bacteremia are present following 5-7 days of targeted antimicrobial therapy, and in patients with recurrent embolic events and persistent vegetations (Fig. 20-16). This patient does not meet any of these indications for surgery. However, a recent trial showed that patients with a vegetation >10 mm and severe valvular disease benefited from early surgery which was associated with a reduced risk of embolic events, although mortality was not reduced. Thus early surgery within 48 hours of diagnosis is reasonable in this patient.

21. Answer: D. The TEE view shows a vegetation (arrow) at the orifice of the coronary sinus. Isolated coronary sinus IE is a rare occurrence that has not been reported in structurally normal hearts without prosthetic devices. The presence of a coronary sinus lead is associated with the development of a coronary sinus vegetation. Coronary sinus vegetations have also been reported in patients with tunneled hemodialysis catheters or congenital coronary artery fistulas to the coronary sinus, but not in patients with persistent left superior vena cava.

22. Answer: A. Behçet’s disease is a vasculitis affecting multiple organ systems. Cardiac involvement is rare, and pericarditis is the most common finding. Other manifestations include valvular insufficiency (mostly aortic), myocardial infarction, and endomyocardial fibrosis. Intracardiac thrombi account for 19% of cardiac involvement in Behçet’s disease, always in the right-sided cavities. Right atrial thrombus extends into the vena cava in 40% of cases. Renal cell carcinoma involves the right cardiac chambers by extension via the inferior vena cava. In this patient, the large mobile mass (arrows) is attached to the lateral wall of the right atrium. Cardiac tumors are not features of cardiac involvement in Behçet’s disease. IE is rare in Behçet’s disease and would be less likely than a thrombus in this context.

23. Answer: B. A “ghost” is a tubular, mobile mass in the path of an intracardiac lead following lead extraction. It seldom occurs following lead extraction for a noninfective reason. They are believed to consist of fibrous sheaths mixed with vegetations in most cases. They persist in 35% of patients at 3 months but their prognostic significance is uncertain. “Ghosts” have been reported in 8% of all patients following lead removal. The incidence rises to 16% in the setting of cardiac device-related IE, but only 5% if there is only local device pocket infection. Cardiac device-related IE and positive lead cultures, but not positive blood cultures, have been reported to be associated with the presence of a “ghost” after lead removal.

A vegetation is an oscillating intracardiac mass usually attached to a cardiac valve. It may be pedunculated or sessile. Benign cardiac tumors do not arise from an implanted lead. Thrombus can develop on an intracardiac lead, but it is usually dislodged and embolized upon removal of the lead and unlikely to stay in situ.

24. Answer: B. This patient has a pseudoaneurysm of the intervalvular fibrosa which communicates with the left ventricular outflow tract and protrudes into the left atrium. This is a known long-term complication of an aortic annular abscess which this patient had 1 year ago. Annular abscess is much more common in aortic valve IE than in mitral valve IE. Rupture of the pseudoaneurysm is rare and thus urgent surgery is not indicated. The patient needs to be followed for worsening aortic valvular function and progressive enlargement of the pseudoaneurysm.

25. Answer: B. Aortic valve endocarditis usually leads to valve disruption and aortic regurgitation. The regurgitant jet can either be directed anteriorly against the septum or posteriorly against the anterior mitral valve leaflet. If aortic regurgitation is directed posteriorly, a satellite vegetation may form on the anterior mitral valve leaflet. This localized infection destroys the endothelium and fibrosa of the valve. If the infection is not controlled, aneurysm (diverticulum) formation and perforation of the anterior mitral leaflet may ensue.

26. Answer: A. On TEE, the short-axis view of the aortic valve allows the best visualization of the location of a vegetation on its three cusps. This view provides a 360-degree spatial orientation of the aortic root and aortic valve leaflet from the aspect of the aorta. To better assess the LVOT aspect of the aortic valve, realtime three-dimensional imaging may be very helpful.

27. Answer: C. The patient has double valve lesions, multiple mobile aortic vegetations, and severe aortic valve disruption with severe aortic regurgitation. These findings suggest a high risk of embolic events, a strong indication for surgical intervention and a poor outcome.