Can minimally invasive coronary artery bypass grafting be initiated and practiced safely?: a learning curve analysis.

Objective: We examined the effects of learning curve on clinical outcomes and operative time in minimally invasive coronary artery bypass grafting (MICS CABG).
Methods: We studied 210 consecutive MICS CABG cases performed by the same surgeon, composed of 3 cardiopulmonary bypass (CPB)-assisted single-vessel small thoracotomy (SVST), 87 off-pump SVST, 51 CPB-assisted multivessel small thoracotomy (MVST), and 69 off-pump MVST. For each MICS CABG technique, the frequency of early clinical events (mortality, reopening, stroke, myocardial infarction, and revascularization) was compared between the first 25 cases and the remainder. Logarithmic curve regression analysis and a cumulative summation technique were performed to assess the correlation between operative time and the performed number of each technique.
Results: There was no mortality, and there were 10 conversions to standard sternotomy, all of which were intended as off-pump MVST (P < 0.001, vs other procedures). Experience was otherwise not associated with perioperative outcome. However, experience numbers correlated with operative time in off-pump SVST and off-pump MVST (122 ± 30 minutes, R = 0.18, P < 0.001, and 241 ± 80 minutes, R = 0.38, P < 0.001, respectively) but not in CPB-assisted MVST (258 ± 44 minutes, R = 0.004, P = 0.7). No complications occurred as a result of CPB assistance.
Conclusions: Minimally invasive coronary artery bypass grafting can be safely initiated, with a very low perioperative risk. Pump assistance is a good strategy to alleviate some of the learning curve and avoid conversions to sternotomy when initiating a multivessel MICS CABG program.