The timecourse of natriuretic hormones as plasma markers of myocardial recovery in heart-transplant candidates during ventricular assist device support reveals differences between device types

Abstract

The natriuretic hormones ANP and BNP are expressed in the myocardium to a different extent. Both hormones have compensatory diuretic activity during heart failure. The expression of these hormones is mainly induced by mechanical stretch of the myocardial walls. In failing human myocardium both ANP and BNP are transcribed in the ventricular myocardium in high amounts. We have measured the plasma-concentrations of ANP and BNP in patients supported by different ventricular assist devices (VAD) at various times. The time course of ANP and BNP were analysed to determine a) the time scale of their downregulation as a marker of myocardial recovery, b) their steady state levels under VAD-support and c) differences due to different VAD devices, d) changes of their plasma concentrations after exercise training of VAD patients. ANP and BNP were analysed by commercialy available radioimmune assays. The time course of patients supported by Thoratec® [THO] LVAD (8), TCI Heartmate® [TCI] (6), Novacor® [NOV] (7) and Lionheart® [LIO] (3) were analysed. Patients supported by NOV-VAD and some patients with a TCI-VAD show downregulation of BNP to a steady state level on a time scale of ca. 30–50 days, following a single exponential decay. In contrast patients supported by THO- or LIO-VAD do not reveal a determined time course of the natriuretic hormones. Only a few patients reached normal plasma values during VAD support. The time course of ANP & BNP reveals differences in the unloading capapcity of different VAD-types due to construction an/or driving mode, which might be important in patients considered to be weaned from VAD without HTx. The slope of plasma ANP increase after exercise correlates with the clinical situation.