The preferred approach for mitral valve surgery after CABG: Right thoracotomy, hypothermia and avoidance of LIMA-LAD graft

Background and aim of the study: An alternative to avoid redo sternotomy in patients with patent left internal mammary artery-left anterior descending coronary artery (LIMA-LAD) grafts undergoing mitral valve surgery is right thoracotomy with moderate-deep hypothermia (similar to 20 degreesC) and fi brillatory arrest without aortic cross-clamping. Few reports exist which di rectly compare re-sternotomy and right thoracotomy, Methods: Between July 1992 and February 2000, 47 patients (39 males, eight females; median age 66 years; range: 41-83 years; 41 in NYHA class III or I V) with patent LIMA-LAD grafts underwent mitral valve surgery. Thirty-seven patients were approached through a right thoracotomy with moderate-deep hy pothermia (median similar to 20 degreesC) and fibrillatory arrest (right th oracotomy group), and 10 were approached through a re-sternotomy, with aort ic cross-clamping and cardioplegic arrest. The median ejection fraction was 42% (range: 20-71%). Univariate analysis was used to determine predictors of out-come, as well as to evaluate differences in characteristics between groups. Results: Operative mortality (OM) and perioperative myocardial infarction f or the entire cohort was 11% and 10%, respectively, and there were no inter -group differences. No preoperative characteristics were associated with OM . Two LIMA-LAD graft injuries occurred in the re-sternotomy group compared with none in the right thoracotomy group (20% versus 0%, p = 0.04). Transfu sion requirements were also greater in the redo sternotomy group (median 7 versus 2 packed red blood cell units, p = 0.04). Conclusion: Right thoracotomy with moderate-deep hypothermia and fibrillato ry arrest is the preferred approach for reoperative mitral valve surgery af ter coronary artery bypass grafting in the presence of patent LIMA-LAD graf ts. These data suggest that this approach is associated with decreased inci dence of LIMA-LAD graft injury, as well as reduced transfusion requirements .