Postoperative B-Type Natriuretic Peptide as Predictor for Postoperative Outcomes in Patients Implanted With Left Ventricular Assist Devices.

Abstract

B-type natriuretic peptide (BNP) is a cardiac neurohormone known to correlate with left ventricular (LV) dilation, decreased contractility, and increased stiffness. Consequently, BNP has been used as a prognostic tool to assess the degree of LV unloading for patients supported by continuous-flow LV assist devices (LVADs). We assessed the prognostic value of changes in BNP in the 2 weeks after LVAD implantation. This retrospective study analyzed laboratory findings and outcomes of 189 LVAD patients. Patients were separated into two groups based on whether serum BNP levels had improved from preoperative levels by postoperative day 14. Group 1 had improvement in BNP levels, whereas group 2 had no improvement or worsening in BNP. There were no significant differences between the groups in age, gender, race, body mass index, or comorbidities. Group 1 had preoperative BNP 1,125 ± 1,078.3 pg/dl and postoperative BNP 440.2 ± 267.7 pg/dl (preoperative minus postoperative [ΔBNP] = -693.09 ± 942.4 pg/dl), whereas group 2 had preoperative BNP 346.0 ± 309.1 pg/dl and postoperative BNP 631.57 ± 483.4 pg/dl (ΔBNP = 289.32 ± 329.7 pg/dl). Postoperative survival in group 2 was significantly worse than in group 1. Rates of right ventricular failure (RVF) were significantly higher in group 2 (group 1: 39%, group 2: 52.7%; p = 0.01). In most patients implanted with a LVAD, BNP improves significantly in the postoperative period as the LV is unloaded. Our results indicate that lack of improvement in postoperative BNP is associated with longer length of stay, increased rates of RVF, and is an independent risk factor for reduced postoperative survival.