Key takeaways

• Implanting stents into the distal left main coronary artery is complex because of the vessel’s branches (bifurcation).

• Two imaging techniques to guide stenting were compared in patients with true distal left main bifurcation lesions: optical coherence tomography (OCT) and intravascular ultrasound (IVUS).

• Noninferiority was demonstrated, suggesting that OCT may be considered an alternative to IVUS to guide stenting of left main bifurcation lesions.

Munich, Germany – 31 August 2026: Optical coherence tomography was noninferior to intravascular ultrasound to guide stenting in patients with left main coronary artery disease, according to results presented in a Hot Line session today at ESC Congress 2026.¹

Percutaneous coronary intervention (PCI) with stent implantation is used to treat narrowed coronary arteries. The left main coronary artery supplies most of the blood to the left ventricle. Performing PCI in this main artery can be technically demanding where it divides into two branches (distal left main bifurcation).

Intravascular imaging helps operators assess the lesion, select devices and optimise stent implantation. Intravascular ultrasound (IVUS) is a widely used technique that provides good tissue penetration and a large field of view, whereas optical coherence tomography (OCT) provides higher-resolution assessment of the vessel lumen and stent.

“Although OCT-guided PCI has been shown to be noninferior to IVUS-guided PCI in a broad PCI population,² direct randomised evidence in true distal left main bifurcation lesions has been lacking,” explained Principal Investigator of the ISOLEDS trial, Professor Yong Zeng from Beijing Anzhen Hospital, Capital Medical University, Beijing, China. He continued: “We conducted a dedicated randomised trial to determine whether OCT guidance is noninferior to IVUS guidance in this setting.”

The open-label, noninferiority ISOLEDS trial enrolled 664 patients with true distal left main bifurcation lesions at 24 centres in China and randomised them (1:1) to OCT- or IVUS-guided PCI. The 12-month primary endpoint was target lesion failure, comprising cardiac death, target lesion-related myocardial infarction or clinically driven target lesion revascularisation. The mean age of the study population was 63.5 years and 22.1% were women.

At a median follow-up of 362 days, target lesion failure with OCT-guided PCI was noninferior to IVUS-guided PCI (12-month Kaplan–Meier estimates: 14.4% vs. 19.6%; adjusted hazard ratio 0.90; 95% confidence interval 0.59 to 1.36; p for noninferiority=0.0003).

The finding remained consistent when periprocedural myocardial infarction was excluded and was supported by the per-protocol and competing-risk analyses.

Discussing the implications of the findings, Professor Zeng said: “ISOLEDS shows that OCT guidance may be considered an alternative to IVUS guidance for appropriately selected patients undergoing PCI for true distal left main bifurcation lesions. The findings do not establish equivalence or superiority. In practice, selection of the imaging modality should account for coronary anatomy, image-acquisition feasibility and local expertise.”

ENDS