Background: Nesiritide is a recombinant brain-type natriuretic peptide (BNP), which decreases pulmonary arterial (PA) pressures and myocardial oxygen consumption while increasing coronary flow and urine output. Mitral valve (MV) surgery in patients with severe mitral regurgitation (MR), impaired left ventricular function, and pulmonary hypertension is associated with a high operative mortality. We hypothesized that the perioperative use of Nesiritide is safe, and may improve surgical outcomes.
Methods: From May 2003 to August 2004, 14 patients (11 male, 3 female; mean age, 64 years [23-87 years]; mean systolic PA, 63 mm Hg [48-94 mm Hg]; mean ejection fraction, 36% [10-50%]), undergoing MV surgery (10 repairs, 2 replacements, and 2 rereplacements) for severe MR, were treated for a median of 24 hours (13-55 hours) preoperatively with intravenous Nesiritide. Expected mortality by EuroSCORE was 26% (7.8-59%) (5 reoperations). Concomitant procedures included tricuspid valve repair (n = 7), coronary artery bypass grafting (n = 5), and left atrial maze procedure (n = 3). Eleven patients received Nesiritide postoperatively during a mean duration of 22 hours (2-80 hours).
Results: Operative mortality was 0%. Prior to surgery after BNP treatment, mean systolic PA pressure dropped to 39 mm Hg (p = 0.0003), pulmonary capillary wedge pressure to 15 mm Hg (p = 0.001), central venous pressure to 6 mm Hg (p = 0.002), and weight by 3.7 kg (p = 0.006). Postoperative median ventilation time was 14 hours (4-48 hours). All other major hemodynamic parameters (systemic blood pressure, heart rate, and cardiac output) remained constant. The treatment was well-tolerated in all patients.
Conclusions: Perioperative use of Nesiritide is safe, and may contribute to improved early outcomes in high-risk patients undergoing MV surgery. This may be due to improved ventricular loading conditions (decreased PA pressures, more effective diuresis) and/or a direct myocardial effect of BNP. Further prospective evaluation of the role of BNP in cardiac surgery is warranted.