Optical coherence tomography to guide percutaneous coronary intervention of the left main coronary artery: the LEMON study.

Background: Intravascular ultrasound (IVUS)-guided PCI improves the prognosis of left main stem (LMS) PCI and is currently recommended by international guidelines. Although OCT resolution is greater than that of IVUS, this tool is not yet recommended in LMS angioplasty due to the absence of data.

Aims: This pilot study aimed to analyse the feasibility, safety and impact of OCT-guided LMS PCI.

Methods: This prospective, multicentre trial investigated whether patients might benefit from OCT-guided PCI for mid/distal LMS according to a pre-specified protocol. The primary endpoint was procedural success defined as follows: residual angiographic stenosis <50% + TIMI 3 flow in all branches + adequate OCT stent expansion (LEMON criteria).

Results: Seventy patients were included in the final analysis (median age: 72 [64-81] years, 73% male). The OCT pre-specified protocol was applied in all patients. The primary endpoint was achieved in 86% of subjects. Adequate stent expansion was observed in 86%, significant edge dissection in 30% and residual significant strut malapposition in 24% of the cases. OCT guidance modified the operators' strategy in 26% of the patients. The rate of one-year survival free from major adverse clinical events was 98.6% (97.2-100).

Conclusions: This pilot study is the first to report the feasibility and performance of OCT-guided LMS PCI according to a pre-specified protocol.