Effect of pulsatile and nonpulsatile left ventricular assist devices on plasma renin activity

Objectives: Left ventricular assist devices (LVAD) are a well-known therapeutic option for patients with end-stage heart failure. It leads to an improvement of cardiac function and is sometimes accompanied with arterial hypertension. The aim of this study was to determine the effect of nonpulsatile LVADs on neurohormonal stimulation.

Methods: We prospectively studied 9 patients undergoing LVAD implantation between 09–2001 and 01–2004. Five patients were treated with the nonpulsatile INCOR-LVAD, 4 patients received the pulsatile EXCOR-LVAD. Patients were included after at least 60 days of left ventricular support (mean 98 days) and after being taken off inotropic medications and mechanical ventilation.

Results: Although there was no significant difference in mean blood pressure, plasma renin activity was substantially elevated in patient with non-pulsatile LV support (INCOR: 94.68±33.97µU/ml; EXCOR: 17.06±15.94µU/ml; p<0.05). Plasma aldosteron levels were also significantly higher in patients supported with the nonpulsatile LVAD (INCOR: 73.4±9.6µg/ml; EXCOR: 20.6±4.6µg/ml, p<0.05). Plasma sodium and potassium levels were not significantly different, but INCOR-LVAD patients required significantly more potassium substitution to maintain normal blood levels (INCOR: 42±8 mmol/l/d; EXCOR: 23±7.0 mmol/l/d). There were no statistically significant differences between the two groups with regard to plasma ADH levels.

Conclusion: Our data suggest that nonpulsatile left ventricular support results in an activation of the renin-angiotensin-aldosteron-cascade or at least prevents the decline in plasma renin activity observed under pulsatile left ventricular support.