Images in Cardiovascular Medicine Left Ventricular Assist Device-Related Systolic Aortic Regurgitation

A 39-year-old woman underwent transesophageal echocardiography during heart transplantation after 2.5 years of support with a continuous-flow left ventricular assist device (cf-LVAD). The patient was admitted to the hospital when a donor heart became available, and did not present with any symptoms or signs of heart failure on cf-LVAD support. Color-flow imaging demonstrated pronounced systolic aortic regurgitation (AR) while the LVAD was providing full support. The development of this unusual LVAD-related systolic AR may involve dynamic changes in resistance to flow of the aortic valve of an unknown mechanism. In most cases involving a combination of cf-LVAD support and aortic valve incompetence, AR would manifest as a mild-to-moderate diastolic or continuous valve regurgitation.1 Surprisingly, the patient demonstrated pronounced systolic AR (Figure 1and Movie in the online-only Data Supplement) on support with a Heartmate II LVAD (Thoratec Corp, Pleasanton, CA). At that time, the electrocardiogram showed low voltage and widespread T-top abnormalities, but was not changed in comparison with previous registrations (Figure 2). Furthermore, the chest x-ray showed no signs of heart dilation and decompensation while on LVAD support (Figure 3). Mean arterial pressures were nonpulsatile (mean, 70 mm Hg) at a pump speed setting of 9400 rpm at the time of echocardiography assessment. It is suggested that the development of systolic AR might be related to dynamic changes in the resistance to flow of the aortic valve along with consistent aortic valve closure. The mechanism allowing systolic AR to manifest has yet to be explained. Hence, when the aortic valve would be consistently closed and incompetent at the same time, aortic AR might occur throughout the entire cardiac cycle. It is possible that decrease in resistance to flow of the aortic valve during systole rather than diastole may have caused explicitly systolic AR in this patient to manifest. Accordingly, dynamic movements of the aortic valve annulus and valve leaflets during LVAD support may explain this phenomenon. Similarly, local pressure disturbances around the valve leaflets induced by turbulent flow patterns of the cf-LVAD may be a potential cause as well. Even so, we do not know whether this phenomenon is caused by purely physiological effects of the cf-LVAD, or it involves primarily anatomic factors. Perhaps in association with good-functioning cf-LVAD at the time of heart transplantation, no evidence was found that indicates that the systolic AR carried any hemodynamic significance in this patient. Thus, more detailed assessment strategies are Figure 1. (A) Color Doppler mapping of the parasternal long axis with transesophageal echocardiography of a patient supported by a continuous-flow LVAD during systole. This image shows systolic AR while the aortic valve is closed (arrow) along with coexistence of mitral AR (arrowhead). (B) Through the diastolic phase no AR is observed. This confirms the explicit systolic nature of the AR in this patient. LVAD indicates left ventricular assist device; AR, aortic regurgitation.