Background: Coronary artery bypass grafting (CABG) is one of the commonest forms of cardiac surgery. It is usually performed using cardiopulmonary bypass (CPB), but the potentially deleterious effects associated with CPB prompted the development of off-pump coronary artery bypass (OPCAB) surgery. CPB and OPCAB have different long- and short-term outcomes, with neither technique demonstrating superiority, so miniaturised extracorporeal circulation (MECC) has been suggested as a potential alternative that may combine some of the advantages of both techniques.

Objectives: This review aims to establish current opinion on the use of MECC, to analyse recent studies to determine if this opinion is justified, and to identify potential areas for future research.

Methods: An electronic literature search was conducted across 4 online libraries for studies comparing MECC to CPB and/or OPCAB between January 2015 and May 2021. Studies were assessed for eligibility based on predefined inclusion and exclusion criteria, and methodological quality was assessed using the Critical Appraisal Skills Programme (CASP) checklist.

Results: The search identified 2,848 records, of which 2,821 were deemed irrelevant to this review, and 7 failed to meet the inclusion criteria. 2 meta-analyses and 6 retrospective studies were used to establish current opinion, while 12 randomised controlled trials were included in the qualitative analysis. 487 patients underwent first-time CABG with two or more grafts via sternotomy using MECC, while 533 underwent the same operation using CPB or OPCAB. There was no obvious difference in inflammatory response, renal dysfunction, or clinical outcomes, but MECC was associated with a reduction in homologous blood transfusions.

Conclusions: MECC is a safe and feasible alternative to CPB and OPCAB in CABG, but any significant advantages have yet to be demonstrated. MECC research so far is very limited, and large-scale trials are needed to determine its usefulness.