Central and regional hemodynamic effects of intravenous isosorbide dinitrate, nitroglycerin and nitroprusside in patients with congestive heart failure

Abstract

A triple crossover random design was used to compare the central and regional hemodynamic effects of intravenous isosorbide dinitrate, nitroglycerin and nitroprusside in 10 patients with low output congestive heart failure. Isosorbide dinitrate and nitroglycerin were infused in dose increments of 0.8 μg/kg body weight per min up to 4.0 μg/kg per min and nitroprusside in increments of 0.4 μg/kg per min up to 2.0 μg/kg per min. The central and regional hemodynamic responses of isosorbide dinitrate and nitroglycerin were similar;both effected a 10 to 35 percent reduction in pulmonary capillary wedge pressure, systemic blood pressure and vascular resistance and pulmonary arterial pressure and resistance with a 7 to 22 percent increase in stroke volume and cardiac output. Nitroprusside elicited a similar decrease in pulmonary capillary wedge pressure with a greater reduction (15 to 45 percent) in systemic blood pressure and resistance and pulmonary arterial pressure and resistance and greater augmentation of stroke volume and cardiac output (20 to 40 percent). Arterial oxygen saturation remained unchanged with isosorbide dinitrate and nitroglycerin and decreased slightly with nitroprusside. None of the drugs altered total body oxygen consumption. All three drugs decreased limb vascular resistance and elevated limb blood flow proportional to the degree of change in systemic vascular resistance and cardiac output. Isosorbide dinitrate and nitroglycerin did not alter renal vascular resistance, so that a mild reduction in renal blood flow was noted as systemic blood pressure decreased. Nitroprusside decreased renal vascular resistance; however, the concomitant decrease in arterial pressure resulted in no net change in renal blood flow. None of the three drugs altered hepatic blood flow or vascular resistance. In low output congestive heart failure, these three drugs effect similar responses in preload, nitroprusside causing a greater change in afterload. Preferential vasodilation of regional vascular beds was noted with limb flow greater than hepatic and renal flow with isosorbide dinitrate and nitroglycerin and limb flow much greater than renal and greater than hepatic flow with nitroprusside.