Comparison of the use of minimized cardiopulmonary bypass with conventional techniques on the incidence of retinal microemboli during aortic valve replacement surgery.

OBJECTIVES: Minimized cardiopulmonary bypass (MCPB) circuits have been shown to reduce cerebral and retinal microembolisation during coronary artery bypass graft (CABG) surgery compared to conventional CPB (CCPB) circuits. Our aim was to evaluate whether the reduction of microembolisation is sustained in aortic valve surgery, as well as to evaluate the effects of MCPB on inflammatory, endothelial, and platelet activation markers. MATERIAL AND METHODS: Patients were randomized to undergo aortic valve replacement (AVR), with or without CABG, with MPCB (n=20) or CCPB (n=20). After anaesthesia induction and termination of CPB, standardized digital retinal fluorescein angiography images were obtained on both eyes and analyzed in a blinded fashion. Blood samples were collected at eight time points until the third postoperative day. RESULTS: Fewer patients in the MCPB group showed evidence of microembolic perfusion defects on postperfusion retinal fluorescein angiographs compared to the CCPB group (37% vs. 63%, absolute difference 26%, 95% CI -5% -51%, P = 0.194). Polymorphonuclear leukocyte (PMN) elastase and von Willebrand factor release were statistically significantly reduced in the MCPB group, but there were no significant differences in other markers of inflammation, coagulation or endothelial activation. A significantly higher three-fold increase in the amount of shed blood was collected to the cell saver with a higher rate of intraoperative platelet transfusion in the MCPB group compared to CCPB. CONCLUSIONS: The use of MCPB was associated statistically insignificantly with less retinal microemboli compared to CCPB. MCPB was complicated by excess bleeding and need for transfusion. The feasibility of MCPB techniques in valve surgery requires further studies.

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: -0.01, 95% CI -0.14 to 0.12, p = 0.87). Mini-CPB was associated with a significantly lower amount of postoperative blood loss (mean difference: -96.55, 95% CI -147.48 to -45.62, 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.

Outcome after coronary artery bypass surgery with miniaturized versus conventional cardiopulmonary bypass.

We have reviewed the results of our experience with the use of miniaturized (Mini-CPB) versus conventional (C-CPB) cardiopulmonary bypass in coronary artery bypass surgery (CABG). This study included 365 patients who underwent CABG with C-CPB and 101 patients with Mini-CPB. In-hospital mortality was lower in the C-CPB group (1.4% vs. 3.0%, P = 0.38). A better, but not statistically significant, immediate outcome was observed in the C-CPB group as indicated by a shorter length of stay in the intensive care unit as well as a lower incidence of combined adverse end-point. However, this was probably due to significantly higher operative risk in the Mini-CPB group (logistic EuroSCORE: 8.5 +/- 10.0 vs. 4.6 +/- 7.1, P < 0.0001). Seventy-seven propensity score-matched pairs had similar immediate postoperative results after Mini-CPB and C-CPB (30-day mortality: 1.3% vs. 1.3%; stroke: 0% vs. 0%; intensive care unit stay > or = 5 days: 6.5% vs. 9.1%; combined adverse events: 14.3% vs. 11.7%). Mini-CPB achieves similar results to C-CPB in patients undergoing isolated CABG. The potential efficacy of Mini-CPB is expected to be more evident in high-risk patients or in complex cardiac surgery requiring much longer cardiopulmonary perfusion.