Do Miniaturized Extracorporeal Circuits Confer Significant Clinical Benefit Without Compromising Safety? A Meta-Analysis of Randomized Controlled Trials

Miniaturized extracorporeal circulation (mECC) attempts to reduce the adverse effects of conventional extracorporeal circulation (CECC) bypass. However, the potential benefits remain unclear and safety concerns persist. A systematic literature review identified 29 studies incorporating 2,355 patients: 1,181 (50.1%) who underwent cardiac surgery with CECC and 1,174 (49.9%) with mECC. These were meta-analyzed using random effects modeling. Heterogeneity, subgroup analysis, and risk of bias were assessed. Primary endpoints were 30-day mortality, neurovascular compromise, and end organ dysfunction. Secondary endpoints were length of stay and transfusion burden. Miniaturized extracorporeal circulation significantly reduced postoperative arrhythmias (p = 0.03), but no significant difference in 30-day mortality, neurocognitive disturbance, cerebrovascular events, renal failure, or myocardial infarction was identified. Miniaturized extracorporeal circulation also significantly reduced mean blood loss (p < 0.00001) and number of patients transfused (p < 0.00001); however, duration of hospitalization, units transfused per patient, chest tube drainage, and revision for rebleeding remained unchanged. Subgroup analysis of larger studies (10 studies, n ≥ 31) showed mECC to significantly reduce ventilation period, hospital stay, and intensive care unit (ICU) stay. Similarly, a significant reduction in neurocognitive disturbance was seen in studies with closely matched demographic groups. Miniaturized extracorporeal circulation is not associated with increased cerebrovascular injury and may confer an advantage, reducing postoperative arrhythmia, blood loss, and transfusion burden.