Unprotected left main (LM) percutaneous coronary intervention (PCI) appears to be safe at centres without onsite cardiac surgery, an Australian study suggests.

Data from the Victorian Cardiac Outcomes Registry shows that the presence of onsite cardiac surgery had no significant impact on short-term and long-term outcomes in patients who had unprotected LM PCI.

Despite presenting with greater acuity of illness, results from 136 patients who underwent LM PCI at non-surgical centres between 2014 and 2018 showed no greater increased risk of long term adverse outcomes compared to 594 patients who had the same treatment of a centre with cardiac surgical centres.

The study, led by Dr Laura Hanson of the Department of Cardiology, Western Health, Melbourne, found that compared with the surgical centre treated patients, those treated at non-surgical centres were younger (69 vs 72 years), presented with more ST-elevation myocardial infarction (35% vs 16%) and cardiogenic shock (25% vs 15%) and had higher rates of preprocedural intubation (17% vs 11%) and mechanical circulatory support (20% vs 9.3%, all p <0.01).

In unadjusted data, the rates of in-hospital mortality (23% vs 11.4%) and 30-day major adverse cardiac events (26% vs 16%) were higher in non-surgical centre patients.

However, after multivariable adjustment, the availability of onsite cardiac surgical support was not significantly associated with in-hospital mortality (odds ratio 0.68, 95% confidence interval [CI] 0.32 to 1.43, p = 0.31). Similarly, treatment in a surgical centre was not a predictor of 30-day mortality (odds ratio 0.70, p = 0.35) nor long-term survival at 60 months (hazard ratio 0.88, 95% CI 0.62 to 1.27, p = 0.51).

This suggested the differences in outcomes in the acute period of patient presentation were related to the severity of their presenting illness, the study authors said.

Propensity score analysis confirmed a neutral effect of onsite cardiac surgery on long-term survival (hazard ratio 0.99, 95% CI 0.66 to 1.50, p = 0.97).

The study investigators said it was also notable that onsite cardiac surgery was not associated with improved long-term survival in a subgroup of haemodynamically stable patients who did not have cardiogenic shock, out-of-hospital cardiac arrest, or required preprocedural intubation, or mechanical circulatory support.

Writing in the American Journal of Cardiology, Dr Hanson and colleagues said many centres without onsite cardiac surgery are now performing PCI routinely with excellent outcomes, but unprotected LM PCI at non-surgical centres remained controversial because of perceived potential complications and haemodynamic instability. Victorian Cardiac Outcomes Registry data from 2019 showed that unprotected LM PCI cases represented approximately 1.6% of the total PCI cases.

CSANZ guidelines support primary PCI at non-surgical centres, the authors noted, and there were low rates of emergency CABG in both groups in the study, consistent with low rates of surgical bailout for PCI reported in trials and registry data worldwide.

“That a protective effect of onsite cardiac surgery on long-term mortality was not observed in a haemodynamically stable subset of patients … underscores the feasibility and acceptable safety performance of unprotected LM PCI at NSCs,” they concluded.