Clinical correlates of B-type natriuretic peptide monitoring in outpatients with left ventricular assist device.

Background: B-type natriuretic peptide (BNP) is a strong predictor of prognosis in chronic heart failure. We aimed to evaluate the clinical correlates and interpretation of BNP monitoring in LVAD out-patient recipients.
Methods: We performed a prospective study in 136 individuals after HeartMate II LVAD implantation. During follow-up they were divided into group A (severe adverse events requiring hospitalisation), group B (mild to moderate adverse events) and group C (an uneventful course). BNP was measured pre-implant, at the first out-patient visit, and then every 2 months. We identified the lowest level, and the level at the clinical event and/or the highest value in patients without clinical events (BNP peak).
Results: During a median follow-up of 298 days, 8 patients (6%) died, 21 patients (15%) experienced a severe adverse event (group A) and 38 patients (28%) had other adverse event (group B). Both the absolute value of BNP peak and its percentage values relative to pre-implant, first visit and minimum BNP had similar areas under the curve (AUC) to identify individuals with adverse events (group A and B) from group C. The performance of BNP peak rose from detection of infection to diagnosis of heart failure and culminated in individuals with pump thrombosis (AUC 0.68 vs. 0.75 vs. 0.93).
Conclusions: Serial measurement of BNP in outpatients with LVAD correlates with the occurrence of adverse events. Assessment of absolute values of BNP peak seems to have a similar accuracy to analysis of intra-individual variation of BNP and it is more practical.