Unprotected left main percutaneous coronary intervention (PCI) didn’t catch on much after SYNTAX’s 5-year data were released in 2013 suggesting similar outcomes to surgery, which may be “judicious” given real-world outcomes shown in a U.S. registry.
Unprotected left main PCI numerically doubled over time from 2009 to 2016, but “it remains a small proportion of all PCI, modestly increasing from 0.7% to 1.3% over the study period,” Javier Valle, MD, of the Rocky Mountain Veterans Affairs Medical Center in Aurora, Colorado, and colleagues reported online in JAMA Cardiology.
Unprotected left main cases were associated with more deaths, MIs, strokes and emergent coronary artery bypass grafting (CABG) compared with other PCI procedures (9.0% vs 2.6%, adjusted OR 1.46, 95% CI 1.39-1.53), according to an analysis of the more than 3 million PCI cases recorded in the CathPCI Registry of the National Cardiovascular Data Registry from mid-2009 to mid-2016.
Rates of mortality and stroke after unprotected left main PCI didn’t budge over time in the registry. However, from 2009 to 2011, in-hospital MI rates did drop significantly from 9.3% to 7.8% (P=0.01).
Operators averaged 0.5 left main PCIs a year — only 16.5% of operators averaged one or more of these cases annually. Centers averaged 3.2 such cases per year. The higher the overall operator or institutional PCI volume, the lower the event rate after unprotected left main cases, the investigators found.
They called it “perhaps unsurprising and even judicious that ULM PCI remains infrequent, given limited operator experience and observed poor outcomes in a high-risk patient population.”
Valle’s group also found that mortality and stroke occurred more frequently in the registry than was observed in EXCEL and NOBLE, two trials with 3- to 5-year data presented in 2016. The former suggested similar outcomes between PCI and CABG in left main disease, whereas the latter favored CABG.
“These findings suggest that randomized clinical trials demonstrating safety and efficacy of ULM PCI do not reflect contemporary clinical practice and suggest an opportunity to refine patient selection and increase operator and institutional experience as potential means to improving outcomes,” the authors said.
A sign in the registry that the operators did not have enough experience was the five-fold higher use of mechanical circulatory support compared to the trials, they suggested.
Over the study period, mechanical circulatory support usage grew modestly, with the exception of the falling popularity of intra-aortic balloon pumps. Left main PCIs also saw more operators opting for radial access and atherectomy over time.
Residual confounding is a major potential limitation to this retrospective study, Valle and colleagues acknowledged. The researchers also had to assume that all data was collected accurately and lacked SYNTAX scores to account for anatomic complexity.
The guidelines call a heart team approach appropriate for determining whether patients with left main stenoses should get PCI or CABG.
Valle disclosed no relevant conflicts of interest.
Co-authors reported several ties to industry.