Hemodynamic effects of α-human atrial natriuretic polypeptide on patients undergoing open-heart surgery

Abstract

Background. A cardiac hormone, α-human atrial natriuretic polypeptide (α-hANP), acts as a vasodilator and a diuretic by activating cyclic GMP formation. We studied the hemodynamic effects of continuous intravenous infusion of α-hANP on patients undergoing open-heart surgery. Methods. A total of 15 patients, including 7 with CABG, 4 with AVR, 2 with CABG plus AVR, and 2 with AVR plus MVR were involved in the study. They underwent open-heart surgery in our institute between July 1996 and April 1997. The mean age of patients was 68 years, ranging from 63 to 77. A dosage of 0.05 μg/kg/min of α-hANP was administered to all patients on postoperative day 1. Hemodynamics and blood and urine samples were measured at the following times: 2 hours before continuous intravenous infusion of α-hANP, 0, 1, 2, 3, 6, 12 and 24 hours after continuous intravenous infusion. We concomitantly measured urine volume and the plasma concentration of α-hANP. Results. The plasma concentration of α-hANP increased sufficiently after the beginning of continuous intravenous infusion without any side effects, and the urine volume increased too. The administration of α-hANP induced a decrease in central venous pressure, pulmonary capillary wedged pressure and the pulmonary vascular resistance index. Systemic vascular resistance index and cardiac output remained unchanged. Conclusions. It is useful for the management of patients with associated volume overload following open-heart surgery because the administration of α-hANP decreases preload and facilitates satisfactory urination.