Surgical proficiency and quality indicators in off-pump coronary artery bypass

Background Off-pump coronary artery bypass (OPCAB) was developed to decrease postoperative mortality and morbidity. Surgeon experience influences outcome. The required levels of surgical proficiency and maturation of technical skills are uncertain. We sought to assess the surgical proficiency in OPCAB and to identify the required levels of technical maturation. Methods We included 1,055 consecutive patients undergoing OPCAB. Patients were divided by 100s into 11 groups by timing of operation. Surgical proficiency was evaluated by 2 quality indicators: revascularization index and conversion rate in nonemergency cases. Results Mode of intervention was elective in 768 patients, urgent in 185 patients, and emergent in 102 patients (9.7%). The in-hospital mortality rate was 5.1% and ranged from 3% (group 3) to 9% (group 11). The percentage of triple-vessel disease and the mean number of diseased vessels increased over time. The mean number of distal anastomoses increased over time, from 2.64 ± 0.82 in group 1 to 4.13 ± 0.98 in group 11. It reached a plateau of 4.0 at group 7 (cases 600-700). The revascularization index also increased over time, from 1.01 ± 0.20 in group 1 to 1.41 ± 0.28 in group 11. It reached a plateau of 1.4 at group 7 (cases 600-700). The conversion rate in nonemergent cases decreased rapidly as the volume of OPCAB increased, and it reached a baseline of 5% at group 3 (cases 200-300). Conclusions Surgical proficiency at performing OPCAB could be evaluated with 2 quality indicators: revascularization index of 1.4 or more and conversion rate in nonemergent cases of 5% or less. The required case number for technical maturation was 200 to 300 for conversion and 600 to 700 for complete revascularization.