Subacute stent thrombosis in a nonselected population using antiplatelet therapy: Frequency and predictors

Introduction. After coronary stenting, the incidence of subacute stent thro mbosis have been reduced to 0% using aspirin and ticlopidine, in studies wi th selected populations and intracoronary ultrasounds. Objective. To evaluate the incidence and predictors of subacute stent throm bosis in a nonselected population, using antithrombotic therapy. Methods. We studied 285 stents, consecutively and successfully implanted in 268 lesions of 226 patients. We used high pressure balloon inflation witho ut intracoronary ultrasound. Post-stenting protocol included aspirin and ti clopidine during four weeks with no anticoagulation. We defined subacute st ent thrombosis as death, acute myocardial infarction myocardial infarction or angiographic occlusion of stent, with TIMI flow 0-1, after the first 24 hours and during the first month. Results. Four patients presented events (1.7%): Three nonfatal myocardial i nfarction after discharge, with documented angiographic thrombosis of stent , and one death due to in-hospital myocardial infarction. All three non-fat al AMI, occurred in vessels less than 3 mm (p = 0.07) and in patients takin g aspirin without ticlopidine (p < 0.001). After discharge, three (17%) of 18 patients with inadvertent discontinuation of ticlopidine presented subac ute stent thrombosis, in contrast to none of 25 patients taking ticlopidine without aspirin. Excluded patients with discontinuation of ticlopidine, th e incidence of subacute stent thrombosis was 0.5%. Conclusion. After intracoronary stenting in a nonselected population, using antithrombotic treatment with aspirin and ticlopidine, we may expect a rat e of subacute stent thrombosis about 1%. Ticlopidine seems to have the main role in preventing subacute stent thrombosis, above all in predisposing ci rcumstances as small vessels.