Increasing Surgical Experience with Off-Pump Coronary Surgery Does Not Mitigate the Morbidity of Emergency Conversion to Cardiopulmonary Bypass

OBJECTIVE: Emergency conversion during off-pump coronary artery bypass (OPCAB) confers significant morbidity. We sought to determine whether the outcomes in these patients have changed as our experience with off-pump techniques has increased.

METHODS: Between January 1999 and December 2010, 4763 patients underwent coronary artery surgery. An off-pump strategy was attempted in 4415 cases (92.7%). The results of the most recent 50 patients who required emergency conversion were compared with the preceding 50 conversions and with patients who underwent either OPCAB (n = 2737) or on-pump coronary surgery (coronary artery bypass grafting) (n = 268) during the same time frame.

RESULTS: The emergency conversion rate was 2.27% (n = 100), being 2.97% for the first 50 cases and 1.77% for the subsequent 50 patients. The two sequential groups of emergency conversions had similar indications and timing of conversion and comparable outcomes. When compared with patients who underwent OPCAB, the more recent 50 conversions had higher mortality (P = 0.002) and more frequent sternal wound infection (P = 0.036), hemorrhage requiring reoperation (P = 0.003), respiratory failure (P < 0.0001), and all-cause sepsis (P = 0.001). Compared with the on-pump group, the more recent conversions had higher mortality (P = 0.055) and a greater rate of postoperative sepsis (P = 0.002).

CONCLUSIONS: The incidence of emergency conversion during OPCAB has decreased with increasing surgical experience; however, the morbidity in these patients remains essentially unchanged. The outcomes in these patients remain worse than those in nonconverted patients. Safer bailout strategies during OPCAB are still warranted.