Can Cardiac Surgeons Safely Initiate and Practice Minimally Invasive Coronary Artery Bypass Grafting?
Dai Une, Harry Lapierre, Benjamin Sohmer, Vaneet Rai, Marc Ruel.
University of Ottawa Heart Institute, Ottawa, ON, Canada.
Objective: Although the safety and efficacy of minimally invasive coronary artery bypass grafting (MICS CABG) have been reported, the procedure is still limited to a few experienced surgeons because specialized techniques are required. This study examined the effects of learning curve on clinical outcomes and operation time in MICS CABG.
Methods: Logistic regression analysis was performed to investigate the relationship between 1-year clinical outcomes (bleeding, myocardial infarction, revascularization, mortality) and the number of MICS CABG performed by a surgeon. Curve regression analysis was performed to assess the correlation between operation time and number of MICS CABG performed. Follow-up beyond the first postoperative year was 100% complete. Also, a cumulative summation (CUSUM) technique was performed to evaluate learning curves.
Results: MICS CABG was performed in 200 consecutive patients by the same surgeon [3 cardiopulmonary bypass (CPB)- assisted single vessel small thoracotomy (SVST), 82 off-pump SVST, 50 CPB-assisted multivessel small thoracotomy (MVST) and 65 off-pump MVST]. There was no perioperative mortality, and 5 patients (2.5%) underwent reopening for perioperative bleeding. No complications occurred as a result of CPB assistance. At 1 year follow-up, 1 patient had a myocardial infarction, 1 patient had a percutaneous coronary intervention, and there were 2 non-cardiac deaths. Logistic regression analysis revealed that experience was not associated with adverse events; however, in off-pump SVST and off-pump MVST, experience numbers correlated with operation time (mean duration 124±31 and 241±80 minutes, respectively; R2 = 0.16 and R2=0.38; P<0.001 and P<0.001). Conversely, experience was not associated with operation time in pump-assisted MVST (mean duration 254±42 minutes; R2 < 0.001; P=0.9) (Figure 1). By using a CUSUM analysis, the learning period for off-pump MVST to reach optimization was calculated to be 45 cases..
Conclusions: MICS CABG can be safely initiated, with a very low 1-year cardiac event risk. Pump assistance is safe and may be a good strategy to alleviate some of the learning curve when initiating a multi-vessel MICS CABG program.
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