Nesiritide - Dilated Cardiomyopathy

Nesiritide is a rapid vasodilator that mimics the action of an endogenous hormone - human B-type natriuretic peptide (BNP). BNP is produced naturally in the ventricles of the heart in response to stretch.

Nesiritide decreases systemic vascular resistance (SVR), pulmonary capillary wedge pressure (PCWP), right atrial pressure (RAP), and mean pulmonary arterial pressure. Nesiritide does not affect the heart rate, but does increase the stroke volume and consequently cardiac output, resulting in a decrease in the symptoms of decompensated heart failure. It is generally well tolerated, with the major negative side effect being hypotension. When compared to standard therapy consisting of dobutamine and nitroglycerin, nesiritide had similar vasodilatory effects, but showed a lower incidence of arrhythmia.

Nesiritide has been approved for IV treatment of patients with acutely decompensated congestive heart failure. Although studies have tested the effectiveness and safety of nesiritide in adult CHF patients, this has not been done in children.

Subjects enrolled in this study will be pediatric (<21 years) patients carrying a diagnosis of dilated cardiomyopathy with decompensated congestive heart failure. The standard of care for these patients is to undergo cardiac catheterization with placement of a Swan-Ganz catheter for hemodynamic monitoring. Subjects will be randomly assigned to receive either Nesiritide or placebo (5% Dextrose). The infusion will then be continued for a total of twenty-four hours. During this one day period, measurements of systemic blood pressure, central venous pressure (right atrial pressure), pulmonary capillary wedge pressure, cardiac output, mixed venous saturation, pulmonary vascular resistance, and systemic vascular resistance will be measured at regularly scheduled intervals. The Swan-Ganz catheter will remain in place for 2 hours after the discontinuation of study drug, and then removed.

The objectives of this study are:

1. To assess the efficacy of Nesiritide therapy in decreasing the pulmonary capillary wedge pressure, right atrial pressure, and systemic vascular resistance in children with dilated cardiomyopathy. 2. To assess the efficacy of Nesiritide in decreasing pulmonary edema and increasing cardiac index in the above mentioned population. 3. To assess the safety of both bolus administration and continuous infusion of Nesiritide in children with dilated cardiomyopathy. 4. To assess the pharmacokinetics of Nesiritide in this population.