Evaluation of Acute Ischemic Mitral Regurgitation Following Cardiopulmonary Bypass Assessed by Biplane Transesophageal Echocardiography

The aim of this study was to evaluate pathogenesis and outcome of acute ischemic mitral regurgitation (MR) in patients undergoing coronary artery bypass grafting (CABG) using biplane transesophageal echocardiography (TEE). Biplane TEE was continuously monitored in a total of 96 patients who were scheduled for elective CABG surgery. Of 96 patients, 10 with no MR at stages 1 (after anesthetic induction but before skin incision) and 2 (after cardiopulmonary bypass [CPBJ and decannulation) were excluded. In the remaining 86 patients with MR between stages 1 and 2, 45 (group A) had an increase in MR, and 41 (group B) had a decrease in MR. An increase in MR・ at stage 2 in group A was associated with a significant increase in annular diameter (p < 0.05), and pulmonary capillary wedge pressure (p < 0.01) compared with stage 1. A significant decrease in the left ventricular end-diastolic area (p < 0.01), end-systolic area (p < 0.05) and the mean wall motion abnormality score (WMA score) (p < 0.001) was observed at stage 2 compared with stage 1 in group B. In 16 of 17 patients (94%) with an increased WMA score in group A, a regional wall motion abnormality (RWMA) was detected in the right coronary artery (RCA) and/or left circumflex coronary artery (LCX) areas. In 7 patients in group A, MR increased continuously until stage 3 (after sternal closure) despite treatment. In 2 of these 7 patients, pulmonary venous systolic flow (PVSF) decreased during stage 2 and persisted to stage 3. The post operative course of these 2 patients was complicated with atrial fibrillation (AF). The increase in annular diameter and worsening in RWMA in RCA and/or LCX areas are associated with acute ischemic MR following CPB. The majority of acute ischemic MR cases were resolved by pharmacological intervention. Post operative AF was noted in 2 patients with acute ischemic MR associated with persistently decreased PVSF following CPB despite treatment.This study was presented in part at the 9th Annual Meeting of the European Association of Cardiothoracic Anesthesiologists, held on June 1-4, 1994 in Turku, Finland, at the 5th Annual Scientific Sessions of the American Society of Echocardiography, held on June 13-15, 1994 in San Francisco, CA, and at the 1994 Annual Meeting of the American Society of Anesthesiologists, held on October 15-19, 1994 in San Francisco, CA