Background and aim of the study: The study aim was to determine the safety and benefits of minimally invasive mitral valve surgery without aortic cross-clamping for mitral valve surgery after previous cardiac surgery.
Methods: Between January 2006 and August 2008, a total of 90 consecutive patients (38 females, 52 males; mean age 66 +/- 9 years) underwent minimally invasive mitral valve surgery after having undergone previous cardiac surgery. Of these patients, 80 (89%) underwent mitral valve replacement and 10 (11%) mitral valve repair utilizing a small (5 cm) right lateral thoracotomy along the 4th or 5th intercostal space under fibrillatory arrest (mean temperature 28 +/- 2 degrees C). The predicted mortality, calculated using the Society of Thoracic Surgeons (STS) algorithm, was compared to the observed mortality.
Results: The mean ejection fraction was 45 +/- 13%, mean NYHA class 3 +/- 1, while 66 patients (73%) had previous coronary artery bypass grafting and 37 (41%) had previous valve surgery. Twenty-six patients (29%) underwent non-elective surgery. Cardiopulmonary bypass was instituted through axillary (n = 19), femoral (n = 70) or direct use aortic (n = 1) cannulation. Operative mortality was 2% (2/90), lower than the STS-predicted mortality of 7%. Three patients (3%) developed acute renal failure postoperatively, one patient (1%) required new-onset hemodialysis, and one (1%) developed postoperative stroke. No patients developed postoperative myocardial infarction. The mean postoperative packed red blood cell transfusion requirement at 48 h was 2 +/- 3 units.
Conclusion: Minimally invasive right thoracotomy without aortic cross-clamping is an excellent alternative to conventional redo-sternotomy for reoperative mitral valve surgery. The present study confirmed that this technique is safe and effective in reducing operative mortality in high-risk patients undergoing reoperative cardiac surgery.