Outcome of Patients with Elevated Risk of Bleeding in on- versus off-pump Coronary Artery Bypass Grafting (CABG)

Objectives: Although controversial discussions are held concerning outcome differences between on- and off-pump CABG, robust data suggests higher rates of bleeding complications in on-pump surgery (Jarral, O. A. et al, ASAIO J., 2012). Therefore, we evaluated outcome differences between patients with a preoperatively estimated high risk of bleeding undergoing on- and off-pump surgery.

Methods: A total of 7,350 consecutive patients who underwent isolated CABG from 2015 to 2017 were registered in the multicenter E-CABG database and retrospectively analyzed. The (post)operative bleeding risk was estimated using the WILL-BLEED Risk Score (WBS). But 3,548 patients had a WBS ≥ 4, correlating with an estimated risk of severe bleeding of 24.6% (Biancari, F. et al, Thromb Haemost, 2017). Clinical and follow-up characteristics of these patients were compared undergoing either on- or off-pump surgery. Comparisons of outcome parameters were adjusted for differences in baseline characteristics between the two groups using logistic regression and multiple linear regression analysis.

Results: The mean age was 67.9 ± 9.7 years. Off-pump surgery was performed in 721 patients (20.3%). In off-pump patients, the number of distal anastomoses was lower (2.5 ± 1.2 vs. 2.8 ± 0.9, p < 0.001). Although there was no difference in blood loss within the first 12 hours following surgery (off-pump: 465.9 ± 352.3 mL, on-pump: 463.2 ± 334.9 mL, p = 0.593), off-pump patients received less packed red blood cell units (1.3 ± 2.3 vs. 1.8 ± 3.0, p < 0.001) and showed lower rates of treatment with platelet units, FFPs, fibrinogen, factor VII, or prothrombin (n = 113 [15.8%] vs. n = 527 [18.6%], adjusted OR = 0.77, p = 0.032). Off-pump surgery was associated with lower rates of postoperative use of IABP (n = 25 [3.5%] vs. n = 251 [8.9%], adjusted OR = 0.38, p = 0.001) and prolonged inotropic therapy (> 12 hours; n = 192 [26.6%] vs. n = 960 [34.0%], adjusted OR = 0.72, p = 0.001). Off-pump patients tended to have a lower 30-day mortality (off-pump: n = 21 [2.9%], on-pump: n = 98 [3.5%], adjusted OR = 0.61, p = 0.071).

Conclusion: Our data suggest lower rates of bleeding and hemodynamic postoperative complication rates in patients undergoing off-pump surgery when compared to on-pump patients. Therefore, despite the lower rate of distal anastomoses in off-pump patients, we conclude that patients with a preoperatively estimated high risk of bleeding might benefit from off-pump surgery when suitable.