IVUS – Measured Optimal Minimal Stent Area in Left Main Crossover Stenting

The current guidelines recommend the use of intravascular ultrasound (IVUS) during left main stenting to optimized PCI outcomes, to make sure devices are well positioned and adequately expanded. Even though there is no standard consensus on the definition of stent underexpansion, minimal stent area (MSA) measured by IVUS, is considered the most reliable predictor of future adverse events after left main PCI. 

Several studies have looked into MSA criteria in two-stent techniques; however, there is still little information on the optimal MSA values in left main PCI when using a single-stent crossover technique. 

The aim of this study was to identify IVUS-derived segmental MSA cutoff after left main crossover stenting aiming at predicting mayor adverse cardiovascular events (MACE) at 5 years.

The primary outcome was 5-year MACE, defined as the combination of all cause death, target vessel related acute MI and clinically driven target lesion revascularization (TLR). 

The study looked at 829 patients undergoing left main PCI towards the left anterior descending artery (LAD), assessed by IVUS after stenting. Patient mean age was 64 and they were mostly men. 37% of cases presented as acute coronary syndrome. Most patients presented single vessel left main disease (35.5%). Left main lesions involved the distal bifurcation in 73% of patients. 

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Final MSA was measured in three segments: proximal LM, distal LM and LAD ostium. Cutoff values that best predicted 5-year MACE were 11.4 mm² for proximal LM (area under the curve [AUC]: 0.62), 8.4 mm² for distal LM (AUC: 0.58) and 8.1 mm² for LAD ostium (AUC: 0.57). Based on these thresholds, stent underexpansion in proximal LM was significantly associated with greater risk of MACE at 5 years (HR: 2.34; p < 0.001). In addition, patients with simultaneous underexpansion in distal LM and LAD ostium presented a significantly higher risk of MACE at 5 years, vs. adequate expansion or limited underexpansion in one single location (HR: 2.57; p < 0.001).

Conclusion 

This study looked at segmental MSA cutoff values assessed by IVUS in patients undergoing left main crossover stenting from the left main to the LAD for unprotected left main disease. Achieving optimal stent expansion in proximal left main and preventing underexpansion both in distal LM and AD ostium is paramount to improve long-term clinical outcomes. The identified optimal MSA thresholds may serve as practical references to stent optimization during left main PCI.

Original Title: Ultrasonido intravascular. Tronco de coronaria izquierda. Optimal minimal stent area after crossover stenting in patients with unprotected left main coronary artery disease.

Reference: Ju Hyeon Kim1, MD, PhD et al Eurointervention 2025;21:e1069-e1080.