Background: Nesiritide, a synthetic B-type natriuretic peptide, is used for the treatment of patients with acutely decompensated heart failure. Although nesiritide has been reported to worsen renal function, as reflected by significant elevations in serum creatinine (SCr), the impact of infusion duration on renal function has not been evaluated. Objective: To investigate the effect of nesiritide infusion duration (<24 h vs ≥24 h) on worsening renal function in patients with acutely decompensated heart failure. Methods: Medical records of hospitalized patients receiving nesiritide were retrospectively reviewed, and 84 consecutive charts of patients with acute decompensated heart failure and available renal function tests were identified for the study. SCr and blood urea nitrogen (BUN) were documented at baseline and during infusion. Worsening renal function was defined as an increase in SCr of 0.5 mg/dL or more or BUN 10 mg/dL or more from baseline. Results: Univariate analysis showed a significant association between nesiritide infusion duration of 24 hours or more (26.1% vs 2.6%; p = 0.003), high diuretic doses (61.5% vs 32.4%; p = 0.045), and baseline SCr (2.0 ± 0.8 vs 1.5 ± 0.7 mg/dL; p = 0.04) with increases in SCr of 0.5 mg/dL or more. However, only infusion duration of 24 hours or more was statistically significant on multivariate analysis, after adjusting for baseline SCr (OR 10.46; 95% CI 1.26 to 86.72; p = 0.03). Longer duration of infusion was also a consistent variable in both univariate and multivariate analysis when elevated BUN was evaluated (34.8 vs 2.6%; p < 0.001 and OR 19.73; 95% CI 2.47 to 157.46; p = 0.005, respectively). Conclusions: Nesiritide infusion of 24 hours or more appears to be significantly associated with elevated markers of worsening renal function in patients with acutely decompensated heart failure compared with infusion of less than 24 hours; however, prospective studies are needed to corroborate this finding.

Background: Previous studies have shown that long-term oral daily PDE 5 inhibitors (PDE5i) counteract fibrosis, cell loss, and the resulting dysfunction in tissues of various rat organs and that implantation of skeletal muscle-derived stem cells (MDSC) exerts some of these effects. PDE5i and stem cells in combination were found to be more effective in non-MI cardiac repair than each treatment separately. We have now investigated whether sildenafil at lower doses and MDSC, alone or in combination are effective to attenuate LV remodeling after MI in rats.Methods: MI was induced in rats by ligature of the left anterior descending coronary artery. Treatment groups were: “Series A”: 1) untreated; 2) oral sildenafil 3 mg/kg/day from day 1; and “Series B”: intracardiac injection at day 7 of: 3) saline; 4) rat MDSC (10⁶cells); 5) as #4, with sildenafil as in #2. Before surgery, and at 1 and 4 weeks, the left ventricle ejection fraction(LVEF)was measured. LV sections were stained for collagen,myofibroblasts, apoptosis, cardiomyocytes, and iNOS, followed by quantitative image analysis.Western blots estimated angiogenesis and myofibroblast accumulation, as well as potential sildenafil tachyphylaxis by PDE 5 expression. Zymography estimated MMPs 2 and 9 in serum.Results: As compared to untreated MI rats, sildenafil improved LVEF, reduced collagen, myofibroblasts, and circulating MMPs, and increased cardiac troponin T. MDSC replicated most of these effects and stimulated cardiac angiogenesis. Concurrent MDSC/sildenafil counteracted cardiomyocyte and endothelial cells loss, but did not improve LVEF or angiogenesis, and upregulated PDE 5.Conclusions: Long-term oral sildenafil, or MDSC given separately, reduce the MI fibrotic scar and improve left ventricular function in this rat model. The failure of the treatment combination may be due to inducing overexpression of PDE5.

Nesiritide, a recombinant form of B-type natriuretic peptide, is a vasodilator and currently recommended as an additive therapy for patients with acute decompensated heart failure (ADHF) who have been optimized on loop diuretics. With hospitalizations for ADHF rising, appropriate selection of therapy becomes even more important to optimize efficacy and reduce adverse events. Nesiritide has many properties that antagonize the pathophysiologic processes of heart failure and has demonstrated a comparative benefit in previous reports; however, controversy still remains with respect to its efficacy and safety. Based on results from recent clinical trials, nesiritide has been shown to be safe at currently approved doses and strongly considered for the treatment of ADHF in patients who remain symptomatic despite optimal doses of intravenous loop divertics.