Optimal minimal stent area after crossover stenting in patients with unprotected left main coronary artery disease.

Background: Intracoronary imaging-guided percutaneous coronary intervention (PCI) has demonstrated clinical benefit over angiography-guided PCI for left main coronary artery (LM) disease. However, the optimal minimal stent area (MSA) thresholds to predict cardiovascular outcomes remain incompletely defined.

Aims: This study aimed to evaluate intravascular ultrasound (IVUS)-measured segmental MSA after LM crossover stenting.

Methods: We identified 829 consecutive patients who underwent IVUS-guided PCI for unprotected LM disease using a single-stent crossover technique. The final MSA was measured at the proximal LM, distal LM, and left anterior descending artery (LAD) ostium. The primary outcome was 5-year major adverse cardiac events (MACE), including all-cause death, myocardial infarction, and target lesion revascularisation.

Results: The MSA cutoff values best predicting 5-year MACE were 11.4 mm² for the proximal LM (area under the curve [AUC] 0.62), 8.4 mm² for the distal LM (AUC 0.58), and 8.1 mm² for the LAD ostium (AUC 0.57). Based on these cutoff values, stent underexpansion in the proximal LM was significantly associated with increased risk of 5-year MACE (adjusted hazard ratio [HR] 2.34; p<0.001). Additionally, patients with simultaneous stent underexpansion in both the distal LM and LAD ostium exhibited a significantly higher risk of 5-year MACE compared with those having adequate expansion or only single-site underexpansion (adjusted HR 2.57; p<0.001).

Conclusions: Achieving sufficient stent expansion in the proximal LM and preventing underexpansion in both the distal LM and LAD ostium are critical for improving long-term clinical outcomes. The identified MSA thresholds may serve as practical benchmarks for stent optimisation during LM PCI.