Stent Expansion Indexes to Predict Clinical Outcomes: An IVUS Substudy From ADAPT-DES

Objectives: The aim of this study was to evaluate various stent expansion indexes to determine the best predictor of clinical outcomes.

Background: Numerous intravascular ultrasound (IVUS) studies have shown minimum stent area (MSA) to be the most powerful predictor of future events.

Methods: ADAPT-DES (Assessment of Dual Antiplatelet Therapy With Drug-Eluting Stents) was a prospective, multicenter registry of 8,582 patients undergoing percutaneous coronary intervention (PCI) with drug-eluting stents. Native coronary artery lesions treated with IVUS-guided PCI with final analyzable IVUS were included. Ten stent expansion indexes (MSA, MSA/vessel area at MSA site, conventional stent expansion [MSA/average of proximal and distal reference luminal area], minimum stent expansion using Huo-Kassab or linear model accounting for vessel tapering, stent asymmetry [minimum/maximum stent diameter within the entire stent], stent eccentricity [smallest minimum/maximum stent diameter at a single slice within the stent], IVUS-XPL [Impact of intravascular Ultrasound Guidance on Outcomes of Xience Prime Stents in Long Lesions] criteria, ULTIMATE [Intravascular Ultrasound Guided Drug Eluting Stents Implantation in "All-Comers" Coronary Lesions] criteria, and ILUMIEN IV criteria) were evaluated for their associations with lesion-specific 2-year clinically driven target lesion revascularization (TLR) or definite stent thrombosis.

Results: Overall, 2,140 lesions in 1,831 patients were included; final MSA measured 6.2 ± 2.4 mm². Among the 10 stent expansion indexes, only MSA/vessel area at the MSA site was independently associated with 2-year clinically driven TLR or definite stent thrombosis (hazard ratio: 0.77; 95% confidence interval: 0.59-0.99; P = 0.04) after adjusting for morphologic and procedural parameters.

Conclusions: In this IVUS-guided PCI cohort with excellent final MSA overall, stent/vessel area at the MSA site, an index of relative stent expansion, was superior to absolute MSA and other expansion indexes in predicting 2-year clinically driven TLR or definite stent thrombosis.