Effect of intravascular ultrasound findings on long-term repeat revascularization in patients undergoing drug-eluting stent implantation for severe unprotected left main bifurcation narrowing

Abstract

We studied the effect of the preprocedural intravascular ultrasound findings on stent expansion and the pre- and postprocedural findings on the long-term clinical outcomes in patients undergoing drug-eluting stent implantation for unprotected left main (LM) bifurcation disease. Using a left anterior descending (LAD) pullback, we evaluated the ostial LAD artery (3 mm distal to the carina), the polygon of confluence (POC; the confluent zone of the LAD artery and left circumflex artery), and the distal LM artery (3 mm just proximal to the POC). The measurements included the minimum lumen area (MLA) and minimum stent area within each segment. In 168 LM bifurcations, the preprocedural MLA and post-stenting minimum stent area within the LM artery were located within the POC in 41% and 70%, respectively. Independent predictors for the post-stent minimum stent area within the distal portion of LM artery above the LAD carina were the preprocedural lumen area of the LAD carina (β = 0.253, 95% confidence interval [CI] 0.10 to 0.36, p = 0.001) and preprocedural MLA within the POC (β = 0.205, 95% CI 0.04 to 0.23, p = 0.008). During the 41.8 ± 18.0-month follow-up period, 26 patients experienced cardiac events. In the multivariate Cox model, female gender (adjusted hazard ratio 2.56, 95% CI 1.173 to 5.594, p = 0.018) and preprocedural MLA within the POC (adjusted hazard ratio 0.829, 95% CI 0.708 to 0.971, p = 0.020) were independent predictors for the occurrence of events at 3 years of follow-up. In conclusion, as assessed by the LAD pullback, the preprocedural MLA within the POC was a surrogate reflecting the overall severity of LM bifurcation disease, contributed to the post-stent minimum stent area within the distal segment of LM bifurcation, and was a predictor of clinical events during follow-up.