Minimally invasive ECC curbs post-cardiac surgery SAEs

Extracorporeal circulation (ECC), a technique for providing cardiopulmonary support during cardiac surgery, has a reduced risk of postoperative serious adverse events (SAEs) when delivered via a minimally invasive ECC (MiECC) system rather than conventional ECC (CECC) technologies, according to results of the randomized COMICS trial.

Up to 30 days after surgery, the risk of experiencing ≥1 qualifying SAEs was 26.8 percent lower with MiECC (risk ratio [RR], 0.732; 95 percent confidence interval [CI], 0.556–0.962; p=0.025), after adjusting for stratification factors and centres.

However, the absolute risk difference did not reach statistical significance in the secondary analysis, even though primary endpoint SAEs occurred less frequently in the MiECC arm vs the CECC arm (9.7 percent vs 13.2 percent; risk difference, −3.5 percentage points; p=0.073). [Perfusion 2025;40:730-741]

“This finding was of borderline significance,” wrote lead author Professor Gianni Angelini, a cardiac surgeon at the Bristol Heart Institute, University of Bristol, Bristol, UK. However, when contrasting the results from large-scale, published meta-analyses, “the magnitude of the treatment effect for the primary outcome was clinically important and consistent with effects observed previously.”

Any type II, III, or IV MiECC

The implications of the primary results were limited by the early termination of the trial due to slow recruitment during the COVID-19 pandemic. Investigators planned to recruit 3,500 patients across 20–30 centres; however, only 1,084 patients from 14 centres had consented to participate. [Perfusion 2021;36:388-394]

Still, COMICS remains the largest randomized trial comparing MiECC with CECC. Moreover, it was designed to be pragmatic in nature, allowing for the use of any type II, III, or IV MiECC instead of a specific MiECC system.

The intention-to-treat population comprised 1,071 adults aged <85 years (median age 66 years, 83.1 percent male, 29.5 percent left ventricular ejection fraction ≤50 percent) undergoing elective or urgent cardiac surgery (either coronary artery bypass grafting [CABG], aortic valve replacement [AVR], or both concurrently) with the use of extracorporeal circulation (ECC) without circulatory arrest.

The majority of surgeries were CABG (84.4 percent), followed by AVR (9.1 percent) and concurrent CABG and AVR (6.5 percent). The mean cardiopulmonary bypass and aortic cross-clamping times were 88 and 57 minutes, respectively.

The 12 qualifying postoperative SAEs were death, myocardial infarction, stroke, bowel infarction, stage 3 acute kidney injury (AKI) or need for haemofiltration, reintubation, tracheostomy, mechanical ventilation for >48 hours, reoperation, percutaneous intervention, sternal wound infection with dehiscence, and culture-confirmed septicaemia.

In a subgroup analysis, the risk of primary endpoint SAEs was reduced with MiECC vs CECC in patients undergoing isolated CABG or isolated AVR (significantly for the former), while the risk increased non-significantly in patients undergoing concurrent CABG and AVR (interaction p=0.48).

Deaths occurred at a similar rate between the two arms (1.5 percent vs 1.9 percent; RR, 0.796, 95 percent CI, 0.364–1.740; p=0.568).

There was also a significant benefit of MiECC vs CECC in health-related quality-of-life measured with visual analogue score of the EuroQol 5 dimensions 5-level (EQ-5D-5L) questionnaire.