How Minimalized Extracorporeal Circulation Compares with the Off-Pump Technique in Coronary Artery Bypass Grafting

Abstract

Recognition of the adverse effects of conventional extracorporeal circulation (CECC) led to the development of alternative technologies and techniques to minimize their impact while maintaining circulation during coronary artery bypass grafting (CABG). Off-pump coronary artery bypass (OPCAB) grafting has become established as one such alternative and more recently minimalized extracorporeal circulation (MECC) circuits have been developed with the aim of providing circulatory support while minimizing the interface between blood and the foreign surfaces of the circuit that initiates the associated adverse effects of CECC. Recently, some authors have suggested that MECC may be an alternative to OPCAB in patients undergoing CABG; the aim of this article is to systematically analyze and compare the impact of CABG with MECC with that of OPCAB, studying the adverse outcomes related to CECC. We performed a systematic search to identify all studies directly comparing OPCAB and MECC. Endpoints were subcategorized into four key areas of interest: length of stay (LOS), hemorrhage, cerebrovascular injury, and 30-day mortality. Random effect modeling techniques were applied to identify differences in outcomes between the two groups. Six studies fulfilled the inclusion criteria, incorporating 2,072 patients of whom 930 underwent OPCAB and 1,142 underwent revascularization supported by MECC. We found no statistically significant difference in hospital or intensive care unit (ICU) LOS, blood loss, mean number of patients transfused, neurocognitive disturbance, or 30-day mortality between the two groups but a trend toward an increased number of cerebrovascular events in the MECC group was observed. The number of studies comparing these alternative techniques for coronary revascularization is small, and there is a lack of high-quality data. Currently, there seems little difference between MECC and OPCAB but larger randomized controlled trials focusing on high-risk patients are required.

Miniaturized extracorporeal circulation vs. off-pump coronary artery bypass grafting: What the evidence shows?

“…One recent randomised, controlled trial comparing mECC and CECC (N=291; mECC 146, CECC 145) showed a significant reduction in hospital stay (p=0.01) and ventilation period (p=0.02) with mECC 22 , although others have failed to find a statistically significant difference 21,27,28 . In our recent systematic review, we showed no significant difference in hospital stay between OPCAB and mECC, suggesting mECC may confer comparable benefit to OPCAB in this regard 8 . It is pertinent, however, to note that the number of studies analysed is small (3 studies; N=715 mECC, 716 OPCAB) and, as yet, there are no large, randomised, controlled trials on which to base further analysis.…”

“…One proposed benefit of the mECC circuit is that, by reducing haemodilution, platelet activation and mechanical damage to blood components 33 , consequently, it may reduce transfusion requirements. Analysis of the data presently available has shown no significant difference in mean blood loss or number of patients transfused when mECC is compared to OPCAB 8 . Interestingly, however, despite reporting a higher mean blood loss than in similar studies, Gerritsen et al 34 reported a significantly lower blood loss with mECC than with OPCAB (p<0.05).…”

“…The evidence directly comparing mECC and OPCAB is, at present, confined to only eight studies (Table 2) and there is a lack of large, randomized, controlled trials. A recent systematic review of 6 studies using the Jostra (Maquet) MECC ® system (N=2072; 930 (44.9%) OPCAB, 1142 (55.1%) MECC) identified no significant difference between mECC and OPCAB for endpoints, including 30-day mortality (p=0.40), length of hospital stay (p=0.09), neurocognitive disturbance (p=0.29), cerebrovascular events (p=0.10), mean blood loss (p=0.95) and the number of patients requiring blood transfusion (p=0.19) 8 . In this section, we will look at each of these endpoints in turn and follow this by highlighting some new research comparing the completeness of revascularization between mECC and OPCAB.…”

“…The evidence directly comparing mECC and OPCAB is, at present, confined to only eight studies ( 8 . In this section, we will look at each of these endpoints in turn and follow this by highlighting some new research comparing the completeness of revascularization between mECC and OPCAB.…”

“…This has led to mECC becoming increasingly popular in Great Britain and Ireland over recent years, with up to 40% of centres now using mECC in certain clinical scenarios 7 . However, at the present time, there are no multi-centre randomized controlled trials comparing OPCAB and mECC and, although there is a suggestion from several smaller studies that both show a comparable benefit over standard extracorporeal techniques 8 , further evidence is needed to guide its use in daily cardiac surgical practice.…”