The acute effects of intravenous isosorbide dinitrate during cardiac surgery.

The acute effects of intravenous isosorbide dinitrate during open heart surgery were studied in 15 adult patients. Consistent and significant (p less than 0.001) reductions in pulmonary vascular resistance (25% before, 23% after, cardiopulmonary bypass) and mean pulmonary artery pressure (14% before, 13% after, cardiopulmonary bypass) were observed in the absence of significant changes in cardiac index, mean systemic arterial pressures or right or left atrial filling pressures. These findings indicate that after cardiopulmonary bypass, when right ventricular dysfunction with raised pulmonary vascular resistance may occur, selective reduction of right ventricular afterload with isosorbide dinitrate may prove beneficial.