IRIS-MAIN Study Compares PCI and CABG  for Left Main Coronary Artery Disease 

November 5, 2026—Ten-year results from the contemporary real-world IRIS-MAIN registry showed no significant difference in long-term all-cause mortality in patients with left main coronary artery disease (LMCAD) treated with percutaneous coronary interventions (PCI) with drug-eluting stents (DES) and those treated with coronary artery bypass grafting (CABG).

The findings were presented at TCT 2026 by Duk-Woo Park, MD, an interventional cardiologist at Asan Medical Center, University of Ulsan College of Medicine in Seoul, South Korea. The IRIS MAIN registry findings were simultaneously published by Seong-Bong Wee, MD, et al in The Lancet.

According to the TCT press release, the IRIS-MAIN registry included 6,900 patients with unprotected left main disease (≥ 50% diameter stenosis by visual estimation) who underwent either PCI with DES (n = 3836) or CABG (n = 1543).

The procedures were performed at 46 academic and community hospitals in five Asian countries between January 2003 and December 2025. In the PCI group, intravascular imaging was used in 81.1% of cases, and second- or newer-generation DES were implanted in 83% of patients.

As summarized in the TCT press release, the study findings over a median follow-up of 10 years included the following:

• The primary endpoint of all-cause death was similar between the PCI group and the CABG group (24% vs 22.9%; weighted hazard ratio [HR], 1.00; 95% CI, 0.87-1.14; P = .99).
• The secondary outcome of spontaneous myocardial infarction (MI) occurred more frequently in PCI than CABG (4.6% vs 1.9%; specific HR [sHR], 2.06; 95% CI, 1.16-3.66; P = .014).
• The incidence of stroke was lower in PCI than CABG (3.0% vs 6.2%; sHR, 0.53; 95% CI, 0.33-0.86; P = .01).
• Procedural MI was higher in PCI than CABG (1.8% vs 0.4%; weighted odds ratio, 4.44; 95% CI, 1.33-14.88; P = .016).
• The incidence of target-vessel revascularization was higher in PCI than CABG (11.8% vs 4.6%; sHR, 2.57; 95% CI, 1.74-3.79; P < .001).

“In this real-world registry of Asian patients with LMCAD, there was no significant difference in all-cause mortality between PCI with DES and CABG over long-term follow-up,” commented Dr. Park in the company’s press release. “These findings complement existing randomized trial evidence by comparing the two approaches in a broad, contemporary population treated in routine clinical practice.”