Abstract
Of 11 patients who underwent elective aortocoronary bypass operation using nonpulsatile flow with moderate hypothermia (28 degrees C), 8 had hypertension defined as blood pressure of 160/100 mm Hg or greater. The plasma renin level was not elevated during bypass by postoperatively in the intensive care unit it became significant (P < 0.05) elevated. An increase in the release of renin was associated with a rise in systemic vascular resistance and coincided with the onset of hypertension. Although the values of plasma catecholamines were elevated during bypass and in the intensive care unit, they did not appear to contribute appreciably to increases in systemic resistance. The authors conclude that an increase in the release of renin is associated with increased vascular resistance and elevated blood pressure following myocardial revascularization.