Correlation between plasma neurohormone levels and left ventricular functional and morphological improvement in LVAD patients

Abstract

Objective: Certain neurohormones (e.g., brain natriuretic peptide (BNP), endothelin-1 (ET-1)) have demonstrated reliability as clinical markers of left ventricular (LV) function. The aim of this study was to examine the relationship between plasma levels of these neurohormones, LV function and histological evidence of morphological improvement in left ventricular assist device (LVAD) recipients to determine whether serial hormonal expression may be used to assess cardiac status in the LVAD setting. Methods: Plasma levels of BNP and ET-1 were measured in 19 end-stage congestive heart failure patients directly before and up to 18 weeks after implantation with various devices (DeBakeyVAD, Novacor, TCI HeartMate). Echocardiographic indices corresponding to the time-points of serial hormonal measurement were evaluated. Immunohistochemical collagen staining of LV tissue samples derived from LVAD patients at the time of device insertion and removal were then contrasted. Patients were grouped according to device employed and etiology (ischemic/dilated cardiomyopathy, ICMP/DCMP). Results: LVAD therapy significantly enhanced LV ejection fraction (EF%: 21% ± 3.8% to 37% ± 11.39%) and cardiac output (CO: 3.49 ± 1.3 to 7.3 ± 0.2 l/m) in all patients; other parameters were not appreciably altered. Absolute BNP and ET-1 plasma levels remained significantly lower in all patients after LVAD implantation (both: p < 0.001). The NOV group exhibited the most BNP reduction and EF% increase (p < 0.0004 and p < 0.038, respectively), whereas ET-1 was lower in the DVAD group (p < 0.06). In all categories, the ICMP group experienced more significant change when compared to those in the DCMP grouping. Collagen levels were sharply reduced in all patients (p < 0.0005); however, while those in the DVAD demonstrated the most evident change (p < 0.0036), there was little difference between the DCMP/ICMP groups (p < 0.012 vs p < 0.022). Both BNP and ET-1 manifested bi-phasic tendencies and an inverse proportionality to EF% measurements. Conclusions: Plasma BNP and ET-1 levels appear to correlate both with device-related LV functional and myocardial morphological improvement and may be of potential use as therapeutic indicators.