Meta-analysis of randomised trials comparing the effectiveness of miniaturised versus conventional cardiopulmonary bypass in adult cardiac surgery

Objectives: The aim of this meta-analysis is to summarise the results of prospective, randomised studies comparing miniaturised (Mini-CPB) versus conventional cardiopulmonary bypass (C-CPB). Design: Meta-analysis of randomised trials. Methods: After retrieval from literature search of 33 comparative studies, 13 studies have been included in this meta-analysis. Results: There were 562 patients in the Mini-CPB group and 599 in the C-CPB group. Mini-CPB was associated with a somewhat lower mortality during the immediate postoperative period (1.1% vs 2.2%, OR 0.58, 95% CI 0.23 to 1.47, p=0.25). Postoperative stroke rate was significantly lower in the Mini-CPB group (0.2% vs 2.0%, OR 0.25, 95% CI 0.06 to 1.00, p=0.05). The length of stay in intensive care unit was similar in the study groups ( mean difference: 20.01, 95% CI 20.14 to 0.12, p=0.87). Mini-CPB was associated with a significantly lower amount of postoperative blood loss ( mean difference: 296.55, 95% CI 2147.48 to 245.62, p=0.0002) along with a higher platelet count 6 h after surgery ( mean difference: 23 480, 95% CI 2 130 to 44 830, p=0.03). The risk of resternotomy for bleeding was similar in the study groups ( OR 1.06, 95% CI 0.32 to 3.57, p=0.92). Conclusions: This meta-analysis suggests that the use of Mini-CPB may be associated with lower risk of postoperative stroke and blood losses and with a somewhat decreased mortality. However, due to the large heterogeneity of methods and the small number of studies and patients evaluated so far, larger and homogeneous studies should be performed to obtain more conclusive results on the safety and efficacy of Mini-CPB.