Hemodynamics and patient safety during pump-off studies of an axial-flow left ventricular assist device

Abstract

Background: Axial-flow left ventricular assist devices (LVADs), when inactivated, may result in regurgitant blood flow. We assessed the effects of regurgitant pump flow with the intraventricular Jarvik 2000 Heart LVAD (Jarvik Heart, Inc., New York, NY) on hemodynamics and patient safety under pump-off conditions.

Methods: Thirty patients being supported by a Jarvik 2000 as a bridge to heart transplantation underwent pump-off studies. Hemodynamics, vital signs and cognitive function were monitored; Doppler echocardiographic studies were done with the pump turned off for 5 minutes if tolerated. Regurgitant flow was assessed in terms of the difference between left ventricular and right ventricular outflow tract cardiac output (LVOT CO - RVOT CO).

Results: During pump-off periods, the mean regurgitant flow was 0.42 +/- 0.41 liter/min, and the mean arterial blood pressure was 63.1 +/- 11.6 mm Hg. There was no regurgitant flow when the pump was on. Three patients did not tolerate the pump being off for periods of 5 minutes; in these tests, the mean regurgitant flow rate was 0.54 +/- 0.50 liter/min, the mean arterial blood pressure was 52.8 +/- 9.8 mm Hg, and the mean pump-off time was 3.1 +/- 1.1 minutes. All patients remained conscious during the pump-off period, and none showed lasting adverse effects.

Conclusions: Our findings suggest that patients being supported with the axial-flow Jarvik 2000 Heart LVAD can generally tolerate pump-off times of 5 minutes.