Minimally Invasive Direct Coronary Artery Bypass Grafting (MIDCAB) and Off-Pump Coronary Artery Bypass Grafting (OPCAB): Two Techniques for Beating Heart Surgery

Abstract

Objective: Coronary bypass surgery can be performed less invasively by avoiding cardiopulmonary bypass (CPB). We present our experiences with beating heart bypass surgery performed through a minithoracotomy or sternotomy.
Methods: From May 1997 to September 1999, 340 patients were included in a prospective study. Of these patients, 111 (group 1) underwent minimally invasive direct coronary artery bypass grafting (MIDCAB) through an antero-lateral minithoracotomy, and 229 (group 2) had off-pump coronary artery bypass grafting (OPCAB) through a full sternotomy. A pressure stabilizer was used for MIDCAB and a suction stabilizer for OPCAB surgery. Early postoperative angiography was performed on 48% of patients in group 1 and 45% of those in group 2. Statistical analysis was applied to compare the variables from both groups and a probability value of less than 0.05 was considered significant.
Results: In all MIDCAB grafts, revascularization was performed by a single left internal mammary artery (LIMA) graft to the left anterior descending coronary artery (LAD). This procedure was completed in 96.4% of patients without CPB. Conversion to sternotomy was necessary for one patient (0.9%). In the OPCAB group, an average of 1.7 grafts per patient were revascularized, of which 98 were single, 99 double, and 32 triple. Of the OPCAB group, 12% of patients were redo operations and 17% had severe comorbidities. Conversion to CPB was necessary for 10 patients (4.4%) because of hemodynamic instability. No cerebrovascular accident (CVA) was seen in any group. There were no hospital deaths in the MIDCAB group, but there were three deaths (1.3%) in the OPCAB group. Age, previous bypass surgery, and severe comorbidities did not influence early mortality. Early postoperative reoperation due to graft failure was necessary for three patients (2.7%) after MIDCAB and for three patients (1.3%) after OPCAB. Confirmed by angiography, the early postoperative total graft patency rate was 96.2% in the MIDCAB group and 96.6% in the OPCAB group; the perfect patency rate (no stenosis greater than 50%) was 92.4% and 93.1%, respectively.
Conclusions: Coronary bypass surgery without the use of CPB is feasible and safe, and offers good early results. Nevertheless, MIDCAB grafting is a challenging technique and should only be performed in selected patients with favorable coronary anatomy. On the other hand, with the sternotomy approach, exposure of all vessels was well tolerated and made complete revascularization feasible. OPCAB can be performed safely even on high-risk patients.