Background: Stent thrombosis (ST) is a rare, but extremely severe complication of PCI. Outside clinical trials, data are limited regarding the risks and the impact of this phenomenon.
Aims: To assess prevalence, predictors, and clinical outcome of ST after implantation of drug eluting stents (DES) compared with bare metal stents (BMS), in a large case-control study in a real world scenario, as well as the relation between ST and duration of combined antiplatelet treatment.
Methods: In a case-control registry we included 475 patients who received at least 1 DES (sirolimus, zotarolimus, everolimus, paclitaxel), compared with a group of 475 patients who received at least 1 BMS. We used 1.22 DES/patient vs. 1.26 BMS/patient (p=ns), treating 1.02 DES/lesion vs. 1.05 BMS/lesion (p=ns). Main outcome was ST defined by the Academic Research Consortium (ARC) as definite (acute, sub-acute, late), probable, and possible.
Results: At 15 months we found 0.8% (4) patients in the DES group vs. 1.1% (5) patients in the BMS group with definite ST (ns); 0.4% (2) patients from each group had acute ST, while 0.4% (2) vs. 0.7% (3) patients had sub-acute ST (both comparisons were ns). None of the patients from the DES group died, whereas two patients with definite ST from the BMS group died, with a case fatality rate of 40% (2/5). 0.2% (1) patient from each group had probable ST (ns) and 0.6% (3) vs. 0.4% (2) patients had possible ST (ns). Independent predictors of stent thrombosis in merged groups were antiplatelet therapy discontinuation (HR 3.8; 95%CI 1.9-7.6; p<0.01), diabetes (HR 2.15; 95%CI 1.4-5.1; p<0.01), a lower left ventricular ejection fraction (EF) (HR 1.1; 95%CI 1.0-1.9; p<0.01 for each 10% decrease), and LAD lesions (HR 1.0; 95%CI, 0.93-1.9; P<0.01).
Conclusions: ST is a rare complication (0.95%), similar after DES or BMS implantation. Premature discontinuation of antiplatelet therapy, followed by diabetes and a lower LVEF, are the independent predictors of ST.