Effect of Pulsatile and Non-pulsatile Left Ventricular Assist Devices on the Renin-Angiotensin System in Patients with End-Stage Heart Failure

Introduction: Left ventricular assist devices have been successfully used as a bridge to cardiac transplantation. Because many patients exhibit marked clinical improvement of their heart failure after LVAD implantation, we studied the physiological effect of pulsatile and non-pulsatile devices on the neurohormonal axis and exercise capacity. Methods: We prospectively included 20 patients (17 men, 3 women) undergoing LVAD implantation between November 2001 and January 2004. Ten patients (1 woman and 9 men) were treated with the non-pulsatile INCOR-LVAD (Berlin Heart c) and ten patients received the pulsatile EXCOR LVAD (Berlin Heart c). Blood samples for plasma renin activity (PRA) were taken once a week over a period of ten weeks. All blood samples were collected in the morning before mobilization. Blood pressure, body weight, fluid intake and urine production were measured once a day. All patients received standard hospital diet with no limitation in fluid intake. Results: Body weight remained constant in both groups throughout the ten weeks' examination, and fluid intake and urine production were balanced in all patients. Although there was no significant difference in mean blood pressure (INCOR: 70 +/- 10 mmHg; EXCOR: 73 +/- 10 mmHg), plasma renin activity was substantially elevated in patients with non-pulsatile left ventricular support (INCOR: 94.68 +/- 33.97 mu U/ml; EXCOR: 17.06 +/- 15.94 mu U/ml; p < 0.05). Furthermore plasma aldosterone levels were significantly higher in patients supported by non-pulsatile INCOR LVAD (INCOR: 73.4 +/- 9.6 mu g/ml; EXCOR: 20.6 +/- 4.6 mu g/ml; p < 0.05). Conclusions: Our data suggest that pulsatile as well as non-pulsatile left ventricular assist devices are equally able to treat chronic heart failure. However pulsatile devices seem to have a greater impact on reversing the changes in plasma renin activity and might thus offer a greater advantage when recovery of left ventricular function is expected.