Microplegia in cardiac surgery: Systematic review and meta-analysis.

Background: Consensus on the optimum choice of cardioplegia remains elusive. One possibility that has been suggested to have beneficial properties is microplegia, a cardioplegia of reduced crystalloid volume. The aim of this meta-analysis is to comprehensively investigate microplegia against a range of clinical outcomes.

Methods: To identify potential studies, systematic searches were carried out in four databases (eg, Pubmed, EMBASE). The search strategy included the key concepts of "microplegia" OR "mini-cardioplegia" OR "miniplegia" AND "cardiac surgery." This was followed by a meta-analysis investigating: mortality, crystalloid volume; cardiopulmonary bypass time; cross-clamp time; intra-aortic balloon pump use; spontaneous heartbeat recovery; inotropic support; low cardiac output syndrome; myocardial infarction; acute renal failure; atrial fibrillation, reoperation for bleeding; creatine kinase myocardial band (CK-MB); intensive care unit (ICU) time and hospital stay.

Results: Eleven studies comprising 5798 participants were analyzed. Microplegia used a lower volume of crystalloids and led to a higher spontaneous return of heartbeat, odds ratio (OR) 4.271 (95% confidence intervals [CIs]: 1.935, 9.423; I  = 76.57%; P < .001) and a lower requirement for inotropic support, OR: 0.665 (95% CI: 0.47, 0.941; I  = 3.53%; P = .021). Microplegia was also associated with a lower CK-MB release, mean difference (MD) -6.448 ng/mL (95% CI: -9.386, -3.511; I  = 0%; P < .001) and a shorter ICU stay, MD: -0.411 days (95% CI: -0.812, -0.009; I  = 17.65%; P = .045). All other comparisons were nonsignificant.

Conclusions: Microplegia has similar effects to other types of cardioplegia and is beneficial with regard to spontaneous return of heartbeat, inotropic support, ICU stay, and CK-MB release.