Coronary sinus blood flow and myocardial oxygen consumption after valve replacement for aortic insufficiency

Seven cases are reviewed in which the aortic valve was replaced with a Björk-Shiley tilting disk valve to treat aortic insufficiency. Comparative studies were made to determine coronary sinus blood flow (CSF) and myocardial oxygen consumption (MVO2) by using a continuous thermodilution method both before and after the operation. Additionally, indexes of left ventricular function were obtained by catheterization of the right and left heart and by left ventriculography. Postoperative total CSF decreased significantly compared with the preoperative value (p less than 0.02). However, in all cases, the postoperative CSF per 100 g of left ventricle (LV) increased compared with the preoperative measurement (p less than 0.001). The CSF per beat per 100 g LV also increased postoperatively (p less than 0.001). Total MVO2 decreased postoperatively (p less than 0.02). However, the MVO2 per unit mass tended to increase postoperatively; these increases were not significant. Postoperatively the left ventricular mass and left ventricular wall stress decreased considerably. The left ventricular ejection fraction (EF) and the mean velocity of circumferential fiber shortening (mVCF) remained at normal levels, whereas the left ventricular function improved markedly. In short, the total CSF decreased, along with LVM and left ventricular wall stress. However, because CSF per unit mass increased and EF and mVCF remained at normal values, it is assumed that the increase in CSF is associated with improvement in postoperative contractility.