Central hemodynamics and right ventricular function after coronary artery bypass surgery. A comparison of prostacyclin, sodium nitroprusside, and nitroglycerin for treatment of postcardiac surgical hypertension

Abstract

The aim of this study was to compare the effects of prostacyclin on central hemodynamics and right ventricular function to the more widely used vasodilators sodium nitroprusside (SNP) and nitroglycerin (NTG), and to investigate whether prostacyclin is more selective to the pulmonary vascular bed compared to SNP and NTG after coronary artery bypass surgery. Twelve patients with two-vessel or three-vessel coronary artery disease and an ejection fraction > 0.5 were included. Hemodynamic measurements were made postoperatively in the intensive care unit using a pulmonary artery fast-response ejection fraction/volumetric thermodilution catheter. The aim was to control and maintain mean arterial blood pressure around 75 to 80 mmHg with each drug. After a 10-minute infusion of each drug at a stable infusion rate, central hemodynamic variables as well as right ventricular end-diastolic volume (RVEDV), end-systolic volume (RVESV) and ejection fraction (RVEF) were measured or derived in triplicate. The average infusion rates of SNP, NTG, and prostacyclin were 2.3 +/- 0.8 micrograms/kg/min, 12.6 +/- 6.0 micrograms/kg/min and 20.0 +/- 0.5 ng/kg/min, respectively. Cardiac output, stroke volume, RVEDV, and central filling pressures were highest for prostacyclin compared to both NTG and SNP. Systemic vascular resistance (SVR) was lowest for prostacyclin but the effects on pulmonary vascular resistance (PVR) were comparable to that of SNP. The PVR/SVR ratio was significantly lower with both SNP and NTG when compared to prostacyclin. RVEF did not differ among the three drugs.(ABSTRACT TRUNCATED AT 250 WORDS)