Fewer Grafts Performed in Off-Pump Bypass Surgery: Patient Selection or Incomplete Revascularization?

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Comparisons of off-pump (OPCAB) versus conventional on-pump coronary artery bypass (CCAB) consistently report fewer grafts per patient with OPCAB. Performing fewer grafts than indicated based on angiographic assessment could result in incomplete revascularization. We questioned whether OPCAB influenced surgeons to perform fewer grafts than needed. Preoperative angiographic and surgical data were collected prospectively on 945 patients undergoing coronary artery bypass grafting (370 OPCAB, 575 CCAB) at 8 hospitals between February 1, 2004, and July 31, 2004. The number of grafts needed per patient was determined from the reported number of vessels with angiographic stenoses of 50% or greater, and compared with the number received per patient, stratified by coronary artery bypass grafting technique. The OPCAB and CCAB groups were demographically similar. The mean number of grafts needed per patient was significantly less in the OPCAB group (2.95 versus 3.48), accounting for fewer grafts received in that group (2.75 versus 3.36). The ratio of grafts (received/needed) was the same in both groups. Patients receiving more than three grafts were more likely to have CCAB (71.2%), whereas those receiving fewer than three grafts were almost as likely to have OPCAB as CCAB (55.5%). The rate of 1-year major adverse events (death, myocardial infarction, repeat revascularization) was the same in OPCAB and CCAB (15.5% versus 14.1%; p = 0.57). Completeness of revascularization, determined by comparing the number of grafts performed to the number needed, was equivalent in OPCAB and CCAB patients, and 18-month clinical outcomes were equivalent. Preferential selection of patients needing more bypass grafts to CCAB results in the lower mean number of grafts per patient with OPCAB.