Vasodilator properties of prostacyclin after coronary artery bypass surgery

The vasodilatory properties of prostacyclin were studied in 12 intubated patients who underwent coronary artery bypass surgery. When infused in doses of 2.5, 5, 10, and 20 ng/kg/min, prostacyclin produced a dose-dependent decrease in systemic vascular resistance from 2,702 +/- 143 to 1,654 +/- 106 dynes/cm5/m2 (p less than 0.05). Heart rate, right atrial pressure, and pulmonary arterial and capillary wedge pressures did not change. Cardiac function was improved, since stroke volume index increased from 29.5 +/- 1.4 to 35.5 +/- 2.0 ml/min/m2 (p less than 0.05) and the rate pressure product decreased from 13.3 +/- 1.3 to 10.9 +/- 0.9 X 10(3) mm Hg/beats/min (p less than 0.05), while stroke work index remained unchanged. These hemodynamic changes were associated with a dose-dependent decrease in arterial oxygen tension which occurred from 278 +/- 25 to 133 +/- 22 mm Hg; however, oxygen transport increased as a result of the prostacyclin-induced increase in cardiac index. This study demonstrates that prostacyclin is a potent arterial vasodilator that may be of interest in the treatment of postoperative vasoconstriction occurring after coronary artery bypass surgery.