1. Answer: F. Among the most important aspects of preimplantation TEE are reevaluation of the degree of AR, determination of the presence or absence of a cardiac-level shunt, identification of intracardiac thrombi, assessment of RV function, and evaluation of the degree of TR. These conditions may have been undiagnosed or underappreciated on previous imaging examinations or may have progressed in the intervening time. Their presence may alter the surgical plan or influence the decision for biventricular support.

2. Answer: C. While the LV diastolic dimension and LV end-diastolic volume are moderately to severely increased in most patients considered for an LVAD, limited data suggest that a smaller LV cavity (defined by an LV diastolic dimension of <6.3 cm) is associated with increased 30-day morbidity and mortality after LVAD implantation. Whereas a small LV cavity is not an absolute contraindication to LVAD implantation, the presence of this finding should be communicated to the Heart Failure team. An intracardiac thrombus is not an absolute contraindication for LVAD implantation, but may increase the risk of stroke during the LV cannulation portion of the procedure. Acute endocarditis (or any other active infection) is an absolute contraindication to device implantation because of the risk of bacterial seeding of a newly implanted LVAD. Mitral regurgitation is expected to improve after LVAD implantation and thus is not considered a contraindication.

3. Answer: E. Moderate or severe MS can prevent adequate LVAD cannula inflow and must be corrected before LVAD implantation. In contrast, AS of any severity may be present without affecting LVAD function, because LVADs completely bypass the native LV outflow tract. Significant AR enables a blind loop of flow in which blood enters the LVAD from the left ventricle, is pumped into the ascending aorta, but then flows back into the LV through the aortic valve, and thus must be addressed prior to LVAD implantation. Surgical treatment options for significant native valve AR include replacement with a bioprosthesis, completely oversewing the valve (by suturing along all coaptation zones) or by performing a central coaptation (Park) stitch. It is important to note that patients with significant AS or who undergo surgical aortic valve closure to correct AR will have minimal to zero forward flow in the event of LVAD failure. Mitral regurgitation that is significant preoperatively is often markedly improved after initiation of LVAD support because of reduced LV size, reduced filling pressures, and improved coaptation of the mitral valve leaflets after LVAD implantation. For this reason, any degree of MR is acceptable in LVAD candidates.

4. Answer: D. When present at LVAD implantation, significant AR enables a blind loop of flow in which blood enters the LVAD from the LV, is pumped into the ascending aorta, but then flows back into the LV through the regurgitant aortic valve. The presence of more than mild AR should be communicated to the implanting surgeon, because recent guidelines advise confirmation by perioperative TEE and surgical correction of AR before LVAD implantation. Surgical treatment options for significant native valve AR include replacement with a bioprosthesis, completely oversewing the valve (by suturing along all coaptation zones) or by performing a central coaptation (Park) stitch. Completely oversewing the aortic valve cusps effectively eliminates AR, but leaves the patient with no means of LV ejection in the event of LVAD failure. When the aortic cusp integrity is good, a central coaptation (Park) stitch technique can treat central AR while allowing aortic forward flow through the residual commissural zones during reduced LVAD support or in the event of LVAD pump failure. Aortic valve replacement with a mechanical valve is discouraged due to the prohibitively high risk of valve thrombus formation.

5. Answer: D. MR that is significant preoperatively is often markedly improved after initiation of LVAD support because of reduced filling pressures, reduced LV size, and improved coaptation of the mitral valve leaflets. For this reason, any degree of MR is acceptable in LVAD candidates.

6. Answer: E. Some patients with mild RV dysfunction at preoperative assessment will develop severe RV dysfunction after LVAD implantation. This complication is defined by the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) as the requirement of an RV assist device or >14 consecutive days of IV inotropic support. Right ventricular failure following LVAD occurs in approximately 20% of patients and is associated with significantly increased morbidity and mortality.

7. Answer: E. During LVAD support, AR can be intermittent (depending upon the valve opening duration), predominantly diastolic, nearly continuous (extending into the normal systolic phase of the cardiac cycle), or continuous (holosystolic and holodiastolic). The AR duration, vena contracta width, LVOT jet height, and other evidence of hemodynamically significant AR should guide the need for possible surgical intervention on the aortic valve. The AR pressure half-time and pulsed Doppler in the ascending aorta are unreliable measurements in the setting of an LVAD due to the outflow graft flow in the ascending aorta.

8. Answer: A. The AR duration, vena contracta width, LVOT jet height, and other evidence of hemodynamically significant AR should guide the need for possible surgical intervention on the aortic valve. A vena contracta width of ≥0.3 cm or a jet width/LVOT width of >46% at a Nyquist limit of 50-60 cm/s should be considered to indicate at least moderate AR. Neither the AR pressure half-time method nor pulsed Doppler evaluation of aortic diastolic flow reversal is a reliable method for AR severity assessment after LVAD implantation because the AR duration extends into the systolic ejection period. In addition, both of these methods are highly affected by LV preload, LV afterload, and aortic pulse pressure, which are diminished during LVAD support.

9. Answer: B. In evaluating patients with advanced heart failure for atrial septal defects and PFOs, the use of IV agitated saline combined with an appropriately performed Valsalva maneuver is necessary because elevated left and/or right atrial pressures may reduce interatrial pressure gradients and preclude detection of the defect by color Doppler imaging or agitated saline injection at rest alone.

10. Answer: C. A PFO, present in up to 30% of the general population, increases the risk of hypoxemia and paradoxical embolization in patients receiving LVAD support. Patent foramen ovale or any other interatrial communication should be closed at the time of device implantation.

11. Answer: B. Both the HeartMate II and the Heart-Ware HVAD require coring in the region of the LV apex for inflow cannula insertion. This part of the procedure is inevitably accompanied by some degree of entrained air on the left side of the heart. Subsequent de-airing maneuvers require continuous TEE guidance. The ostium of the RCA is situated anteriorly in the aortic root and is a common destination for air ejected from the left ventricle. Acute RV dysfunction or dilatation and/or an increase in the severity of TR suggest the possibility of air embolization to the RCA. This complication may resolve with watchful waiting. Although acute pulmonary embolism could present with these findings, it is less likely in this setting while the patient is on cardiopulmonary bypass and fully heparinized.

12. Answer: A. After initiation of LVAD support, early imaging of the interatrial septum with color Doppler and with IV injection of agitated saline contrast to confirm the absence of an atrial septal communication is recommended. This is particularly important if initiation of LVAD support results in a sudden decrease in arterial oxygen saturation, the hallmark of an unmasked PFO or other right-to-left shunt.

13. Answer: B. In the absence of significant pulmonary valve regurgitation, the net cardiac output (combined native LV outflow and LVAD conduit flow) is the same as the right-sided cardiac output. The right-sided output is calculated by using the following commonly applied equation: RVOT cardiac output = RVOT pulsed Doppler TVI × [3.14 × (RVOT diameter/2)² × HR] or RVOT TVI × 0.785 × (RVOT diameter)² × HR. When the aortic valve does not open, and there is no significant AR, the RVOT-derived cardiac output is the same as the LVAD cardiac output. When the AV opens significantly and an adequate LVOT TVI can be measured with pulsed Doppler (and in the absence of significant AR), the LVAD cardiac output should equal the RVOT-derived cardiac output minus the LVOT cardiac output.

14. Answer: D. The minimum and maximum speed settings for the HeartMate II LVAD are 6,000 and 15,000 rpm, respectively. The speed can be changed in 200 rpm increments. Although patient dependent, the recommended range of typical operating speeds is 8,800-10,000 rpm. With the HeartMate II pump, speed changes for optimizing device function are usually made in small increments of 200-400 rpm. The minimum and maximum speed settings for the HeartWare HVAD are 1,800 and 4,000 rpm, respectively. The speed can be changed in 20 rpm increments. The recommended range of typical operating speeds is 2,400-3,200 rpm. With this device, speed changes for optimizing device function are usually made in small increments of 20 or 40 rpm.

15. Answer: D. Clinical features associated with pump thrombosis include hemolysis, which is characterized by hemoglobinuria along with elevated lactate dehydrogenase, total bilirubin, and plasma free hemoglobin levels. On echocardiography, primary pump dysfunction secondary to thrombosis may manifest as signs of reduced LV unloading in comparison with the previous surveillance examination. Echocardiographic signs of impaired pump performance (reduced LV unloading) include an increased LVID_d, worsened MR, septal shift toward the RV and increased aortic valve opening duration or frequency in comparison to the prior echocardiogram.

16. Answer: C. During suction events, the LVAD decompresses the LV chamber to an abnormally small size, leading to a right-to-left interventricular septal shift. Interventricular septal contact with the LVAD inflow cannula can induce ventricular arrhythmias and trigger LVAD alarms. Monitoring for possible suction events is an important component of a speed-change echocardiogram. The treatment recommendation for a suction event is typically twofold: (1) decrease the pump speed and (2) identify and treat the underlying cause of the event.

17. Answer: B. After LVAD implantation, the RV begins to receive a significantly increased stroke volume. In some cases, the RV cannot appropriately accommodate this sudden increase in volume and, as a result, fails. Clinicians must maintain a high index of suspicion for RV dysfunction post-LVAD implantation and have a low threshold to perform an echocardiographic examination. Echocardiography findings concerning for RV dysfunction post-LVAD implantation include RV enlargement, reduced RV function, interventricular septal position shifted toward the LV, dilated IVC, and worsening TR with elevated pulmonary pressure. These are critical changes to recognize and diagnose promptly as they will greatly affect patient management.

18. Answer: C. Echocardiographic features associated with impellar thrombosis include reduced LV unloading in comparison with prior examinations. Specifically, these patients have increased LVID_d despite increasing LVAD speed, worsening MR, and increased aortic valve opening. LVAD controller alarms indicating high power and elevated pulsatility index (PI) are also markers of LVAD dysfunction, especially impellar thrombosis.

19. Answer: A. A Doppler ultrasound blood pressure is defined as the cuff pressure at which a Doppler signal is obtained at the brachial or radial artery. In nonpulsatile LVAD patients, it is only appropriate to measure/document a mean arterial pressure.

20. Answer: A. Significant AR may be associated with a high estimated LVAD flow but with normal power. Aortic regurgitant volume can lead to an increased LV preload, which may result in increased native LVOT output and AV opening, with intermittent AR on color Doppler. Alternatively, the AR may be continuous if the contractile force is not sufficient to interrupt the regurgitant flow during systole. Doppler flow across the inflow cannula and outflow graft will be normal or increased due to the aortaleft ventricle-LVAD blind loop.

21. Answer: E. LVAD suction events relate to contact of the inflow cannula and the LV endocardium, which results in reduced inflow cannula flow. During suction events, the LVAD decompresses the LV chamber to an abnormally small size, resulting in a right-to-left ventricular septal shift. Patients with a malpositioned inflow cannula may be predisposed to the development of intermittent inflow cannula obstruction.

22. Answer: A. The LVID_d from the two-dimensional parasternal long-axis image is considered the most reproducible measure of LV size after LVAD implantation. Although LV volumes determined by Simpson biplane or single-plane method reflect the LV size more accurately than do linear measurements, the LV size by volume assessment may be technically challenging to obtain after LVAD implantation because of apical shadowing/dropout associated with the inflow cannula. LV systolic function assessment is difficult to evaluate in the setting of continuous LVAD unloading. When LV recovery is suspected, LVEF by Simpson’s bi-plane or single plane method may be useful.