Potential Renal Protective Benefits of Intra-Operative BNP Infusion During Cardiac Transplantation

Abstract

Background Recombinant BNP (nesiritide) is known to reduce endothelin levels, cause afferent arteriole vasodilation, and increase natriuresis and diuresis. We hypothesized that intraoperative infusion of BNP may benefit renal function in cardiac transplant patients. Methods From June 2003 to September 2005, 22 consecutive heart transplant patients received BNP at a dose of 0.01 μg/kg/min before initiation of cardiopulmonary bypass (group A). BNP infusion was continued for a mean of 3.3 ± 1.9 days. Hemodynamics, urine output, and serum creatinine levels were prospectively collected and compared with 22 consecutive patients who underwent heart transplantation between May 2002 and June 2003 following the identical transplant protocol, but without BNP infusion (group B). Results At 24 hours postoperatively, mean blood pressure was comparable between groups (87 ± 11 mm Hg vs 89 ± 17 mm Hg, P = .7), but pulmonary artery pressure (18 ± 5 mm Hg vs 24 ± 5 mm Hg, P = .001) and central venous pressure (12 ± 5 mm Hg vs 16 ± 4 mm Hg, P = .01) were lower with BNP infusion, whereas cardiac index was augmented (2.8 ± 0.5 vs 2.4 ± 0.6, P = .03). Requirement of low-dose inotropic and vasopressor support was equally distributed between groups ( P ≥ .72). Postoperative urine output for the initial 24 hours was higher in group A (84 ± 15 vs 55 ± 36 mL/h, P = .01). None of the patients with BNP infusion required additional diuretics or renal replacement therapy during the first week after transplantation. Mean postoperative serum creatinine levels as compared with preoperative values remained unchanged within group A ( P = .12), but increased significantly in group B ( P < .001). Conclusions Intraoperative BNP infusion in heart transplant recipients was associated with favorable postoperative hemodynamics, significantly improved urine output, and stable serum creatinine levels. A prospective, randomized, multicenter trial is warranted to evaluate the potential renal protective benefits of intraoperative BNP infusion in this patient population.