Abstract 2501: Incidence and Predictors of Angiographic Stent Thrombosis in Patients Treated With Drug-Eluting Stent Implantation for ST Segment Elevation Myocardial Infarction
Objectives: To investigate the incidence and predictors of angiographic stent thrombosis (ST) in an unselected patient population undergoing drug-eluting stent (DES) implantation for STEMI.
Methods: From April 2002 until December 2004, 812 consecutive patients with STEMI underwent DES implantation [204 patients with sirolimus-eluting (SES) and 608 with paclitaxel-eluting (PES) stents]. Thrombus burden (TB) was scored as small (TBS) when greatest thrombus dimension was ≤2 vessel diameters and large (TBL) when >2 vessel diameters by visual assessment. In SES patients dual antiplatelet medication was prescribed for 3 months and in PES patients for 6 months. Rheolytic thrombectomy (RT) (the only thrombectomy device used in our institution) was at the discretion of the operator. The incidence of ST was computed by the Kaplan-Meier method and multivariate Cox regression was used for identifying the independent predictors for ST.
Results: Complete follow-up was available in 798 patients (98.3%) with a mean duration of 18.2 ± 7.8 months. TB was classified in 792 (TBS 71.6%, TBL 28.4%) and RT was used in 63 (8%) patients [59 (93.6%) in TBL patients]. During the whole follow-up period (33 months) there were 23 ST events; 9 (39.1%) in ≤30 days (early ST) and 14 (60.9%) after 30 days (late ST, latest event at 884 days). Seventeen (21.5%) occurred in the group of TBL without RT. The 24-month cumulative ST rate was 3.2%. The cumulative ST rate was significantly higher in the TBL compared to the TBS group (8.2% vs. 1.3% at 24 months respectively, p<0.001). In the TBL group a significantly lower 24-month cumulative ST rate was observed when RT was performed (0% vs. 11.3%, p<0.001). Independent predictors for ST were TBL (HR: 8.7, 95% CI: 3.4 –22.5, p=0.001), stent thrombosis as presentation at the index procedure (HR: 6.2, 95% CI: 2.1–18.9, p=0.001), bifurcation stenting (HR: 4.1, 95% CI: 1.6 –10, p=0.002), age per 10 years (HR: 0.6, 95% CI: 0.4 – 0.8, p=0.003) and RT (HR: 0.1, 95% CI: 0.01– 0.8, p=0.03). Stent type was not a predictor for ST.
Conclusions: A high incidence of ST was observed in patients undergoing DES implantation for STEMI. This is mainly due to the very high incidence in patients with TBL. Thrombus aspiration using RT in this group of patients prevents this complication.