Off-pump versus on-pump coronary artery bypass surgery: does the pump influence outcome?

Background: This study assessed hospitalization outcome differences for patients undergoing off-pump coronary artery bypass (OPCAB) grafting compared with patients having coronary artery bypass grafting with cardiopulmonary bypass.

Study Design: We conducted a nested case-control study from an 8-year, hospitalization cohort (n = 7,905) in which the data were collected prospectively. Inclusion criteria included a coronary artery bypass graft only and age greater than 18 years. Cases were patients undergoing OPCAB (n = 360) and controls were patients undergoing coronary artery bypass grafting with cardiopulmonary bypass (n = 1,080). Cases were matched to controls 1:3 on five variables: age (+/- 3 years), gender, diabetes, New York Heart Association Functional Classification, and surgical year (+/- 3 years). The 13 outcomes of interest were mortality, length of hospitalization, ICU length of stay, return to ICU, ventilator time, intraoperative complications, pulmonary complications, neurologic complications, renal complications, gastrointestinal complications, sternal wound infections, highest postoperative creatine kinase level, and units of blood products given during the procedure. Using logistic regression we controlled for eight confounding variables.

Results: Patients undergoing OPCAB had a significantly shorter length of hospitalization (relative risk [RR] = 0.95; 95% CI, 0.91-0.99%), fewer pulmonary complications (RR = 0.45; 95% CI, 0.22-0.88%), fewer intraoperative complications (RR = 0.04; 95% CI, 0.0048-0.31%) fewer blood product units given (RR = 0.31; 95% CI, 0.14-0.42%) and lower postoperative creatine kinase (RR = 0.99; 95% CI, 0.98-0.99%). There were no considerable differences for the remaining nine outcomes, including mortality and neurologic complications.

Conclusions: Patients undergoing OPCAB had a considerably shorter length of hospitalization, had fewer pulmonary and intraoperative complications, and received a lower volume of blood products.