Comprehensive Intravascular Ultrasound Assessment of Stent Area and Its Impact on Restenosis and Adverse Cardiac Events in 403 Patients With Unprotected Left Main Disease

BACKGROUND: We assessed the optimal intravascular ultrasound (IVUS) stent area to predict angiographic in-stent restenosis (ISR) after sirolimus-eluting stent implantation for unprotected left main coronary artery (LM) disease. METHODS AND RESULTS: A total of 403 patients treated with single- or 2-stent strategies (crushing and T-stent) had immediate poststenting IVUS and 9-month follow-up angiography. Poststenting minimal stent area (MSA) was measured in each of 4 segments: ostial left anterior descending (LAD), ostial left circumflex (LCX) polygon of confluence (POC, confluence zone of LAD and LCX), and proximal LM above the POC. Overall, 46 (11.4%) showed angiographic restenosis at 9 months: 3 of 67 (4.5%) nonbifurcation lesions treated with a single-stent, 14 of 222 (6.3%) bifurcation lesions treated with single-stent crossover, and 29 of 114 (25.4%) of bifurcation lesions treated with 2 stents. The MSA cutoffs that best predicted ISR on a segmental basis were 5.0 mm(2) (ostial LCX ISR), 6.3 mm(2) (ostial LAD ISR), 7.2 mm(2) (ISR within the POC), and 8.2 mm(2) (ISR within the LM above the POC). Using these criteria, 133 (33.8%) had underexpansion of at least 1 segment. Angiographic ISR (at any location) was more frequent in lesions with underexpansion of at least 1 segment versus lesions with no underexpansion (24.1% versus 5.4%, P<0.001). Two-year major adverse coronary event-free survival rate was significantly lower in patients with underexpansion of at least 1 segment versus lesions with no underexpansion (90±3% versus 98±1%, log-rank P<0.001), and poststenting underexpansion was an independent predictor for major adverse cardiac events (adjusted hazard ratio, 5.56; 95% confidence interval, 1.99-15.49; P=0.001). CONCLUSIONS: With these criteria, IVUS optimization during LMCA stenting procedures may improve clinical outcomes.