AS-267: The Impact of Intravascular Ultrasound for Late Stent Thrombosis after Drug-Eluting Stent Implantation

Abstract

Background: Stent thrombosis (ST) is a serious complication of drugeluting stent (DES) implantation, regardless of the timing (acute, subacute, or late). The US Food and Drug Administration (FDA) panel accepts ST but rejects increased death/myocardial infarction (MI) risk for on-label DES use. To date, the safety and efficacy of intravascular ultrasound (IVUS) use in DES implantation has been well evaluated, but there are few data regarding IVUS for ST. We evaluated the impact of IVUS for ST in DES implantation. Methods: A total 1,448 patients with DES implantation were included from January 2006 to February 2008 and were divided into a phase I group (from January 2006 to December 2006; before IVUS use; n 731) and a phase II group (from March 2007 to February 2008; after IVUS use; n 717). ST was defined by the Academic Research Consortium (ARC) as reported at the Transcatheter Cardiovascular Therapeutics 2006 meeting. Results: The median follow-up duration was 6 months in both phases. In all, 31 (2.1%) ST occurred: 21 (2.9 %) in phase I (4 subacute, 17 late ST) and 10 (1.4%) in phase II (4 subacute, 6 late ST). The incidence of ST in phase I was higher than in phase II (2.9% vs 1.4 %, p 0.052) but was not significant. Subacute ST in phase I was not higher than phase II (0.5% vs 0.6 %, p 0.978). Late ST in phase I was significantly higher than in phase II (2.3% vs 0.8 %, p 0.023). The univariate logistic regression showed the hazard ratio (HR) for late ST was 0.376 (95% confidence interval [CI], 0.146–0.971) for IVUS use and 0.959 (95% CI, 0.936–0.981) for high-density lipoprotein (HDL). After adjustment for age, sex, and HDL, IVUS use showed a trend for predicting late ST (HR, 0.223; 95% CI, 0.049–1.003; p 0.050). Conclusion: The incidence of late ST was higher in phase I before IVUS use compared with phase II after IVUS use. The use of IVUS showed the trend for decreasing late ST, but a large-scale study is needed for the evaluation of the impact of IVUS use in DES implantation. AS-268