Frequency of acute myocardial infarction in valve repairs versus valve replacement for pure mitral regurgitation

Three hundred thirty-five consecutive isolated mitral valve operations for mitral regurgitation in patients with no significant coronary artery disease were reviewed over a 26-month period for the presence of a perioperative acute myocardial infarction (AMI). Of 224 patients undergoing mitral valve repair 12 (5.4%) had electrocardiographic and cardiac enzyme evidence of perioperative AMI develop. Of 111 patients undergoing mitral valve replacement none had perioperative AMI develop as determined by electrocardiographic and enzyme criteria (p = 0.01). All 12 infarctions after valve repair involved the inferior wall by electrocardiographic or echocardiographic criteria. Although no patient had significant clinical difficulty in recovery, 7 of the 12 patients (58%) were left with Q waves upon hospital discharge. The etiology of the AMI is believed to be air emboli introduced at the time of testing valve competence during left ventricular insufflation under pressure. Changes in surgical technique may reduce or eliminate this complication.