Back to Annual Meeting Program

OBJECTIVE: Emergency conversion during off-pump coronary artery bypass (OPCAB) confers significant morbidity and mortality. We sought to determine whether the outcomes in these patients have changed over time as our experience with off-pump techniques has increased.
METHODS: Between January 1999 and December 2010, 4763 consecutive patients underwent isolated coronary artery surgery. A primary 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 emergency conversions, and also with patients who underwent either successful OPCAB (n=2737) or on-pump coronary artery bypass grafting (CABG) (n=268) during the same time period.
RESULTS: The overall emergency conversion rate was 2.3% (n=100), being 2.97% for the first 50 cases, and 1.77% for the subsequent 50 patients. The 2 sequential groups of emergency conversions had similar indications for conversion, timing of conversion, and comparable morbidity and mortality (Table 1). When compared with patients who underwent successful OPCAB (Table 1), the more recent group of 50 conversions had higher mortality (p=0.002), greater postoperative complications (p<0.0001), and more frequent deep sternal wound infection (p=0.036), hemorrhage requiring reoperation (p=0.003), respiratory failure (p<0.0001), and sepsis of any cause (p=0.001). Compared with the on-pump group (Table 1), the more recent conversions had higher mortality (p=0.055), and a greater rate of postoperative sepsis (p=0.002).
CONCLUSIONS: Emergency conversion during OPCAB has decreased with increasing surgical experience, however, the morbidity and mortality in these patients is unchanged. The outcomes in these patients remain significantly worse than those in non-converted patients, be they off-pump or on-pump. Safer and more consistent bail-out strategies during OPCAB are thus still warranted.

Table 1. Major clinical outcomes according to technique of coronary revascularization

Variable	1st 50 emergency conversions (n = 50) n (%)	2nd 50 emergency conversions (n = 50) n (%)	Successful OPCAB (n = 2737) n (%)	Successful CABG (n = 268) n (%)
Freedom from all complications	32 (64.0)	36 (72.0)	2524 (92.2)	216 (80.6)
In-hospital mortality	6 (12.0)	4 (8.0)	26 (0.9)	6 (2.2)
Deep sternal wound infection	4 (8.0)	3 (6.0)	38 (1.4)	7 (2.6)
Reoperation for hemorrhage	5 (10.0)	6 (12.0)	74 (2.7)	25 (9.3)
Respiratory failure	14 (28.0)	7 (14.0)	58 (2.1)	21 (7.8)
Sepsis	1 (2.0)	4 (8.0)	19 (0.7)	1 (0.4)
Stroke	3 (6.0)	0	31 (1.1)	5 (1.9)
Perioperative myocardial infarction	1 (2.0)	1 (2.0)	6 (0.2)	0