CORONARY-ARTERY SIZE IN MITRAL REGURGITATION AND ITS REGRESSION AFTERMITRAL-VALVE SURGERY

The relationship between coronary artery size and left ventricular (LV ) muscle mass was studied in 10 control subjects and in 10 patients wi th chronic mitral regurgitation before and 28 +/- 15 months after mitr al valve surgery. Left and right coronary artery size was determined b y quantitative coronary arteriography. Left coronary artery size was s ignificantly increased before surgery (26 mm2) and decreased after ope ration (23 MM2), but was still larger than in control subjects (14 mm2 ). The right coronary artery was also enlarged preoperatively (13 MM2; controls = 9 MM2), but was normalized after surgery (11 MM2). A linea r correlation was found between LV muscle mass and left (r = 0.88, p < 0.001) and right coronary artery size (r = 0.84, p < 0.001) as well a s between right coronary artery size and mean pulmonary artery pressur e (r = 0.56, p < 0.01). Thus in chronic mitral regurgitation the enlar gement of the left and right coronary artery is proportional to the de gree of LV hypertrophy. The increase in right coronary artery size is probably the result of right ventricular pressure overload. Postoperat ively there is only partial regression of left coronary artery size bu t normalization of right coronary artery size.