EARLY THROMBOTIC OCCLUSION FOLLOWING CORONARY STENT IMPLANTATION: A COMPARATIVE STUDY BETWEEN CONVENTIONAL STENTS AND DRUG ELUTING STENTS

Abstract

Over the last decade, coronary stent implantation has become the new standard angioplasty procedure and has fundamentally changed the practice of interventional cardiology by reducing early complications and i_mproving the late clinical outcomes in a broad array of patients (AI Suwaidi eta/., 2002). The early use of coronary stents was limited by high (3.5 to 8.6

percent) subacute thrombosis rates despite aggressive antithrombotic therapy with aspirin (325 mg daily), dipyridamole (225 mg daily), periprocedural dextran 40, intravenous heparin followed by oral warfarin. Clinical events associated with subacute coronary thrombosis were profound, virtually always resulting in an untoward outcome (e.g., death, myocardial infarction, or emergency surgical revascularization (Cutlip et al., 2001). Patients at high risk for coronary thrombosis following coronary stent implantation include those with unstable angina, residual proximal or distal dissection or recent myocardial infarction. Anatomical factors after stent deployment (e.g. under dilatation of the stent, poor inflow or outflow obstruction and vessel diameter less than 3 mm) appeared to play a role in the development of coronary thrombosis in the early stent experience (James et al., 2002).

Lower frequencies of coronary thrombosis following coronary stent implantation have been achieved with optimal antiplatelet regimens and optimal stent deployment (Rainer eta/., 2002). A recent 900 patient, randomized controlled trial with multiple

different stents reported a 1.7-1.9% SAT rates with high or low-pressure deployment, aspirin and ticlid (Dirscltinger et al., 1999). However, studying stent thrombosis remains an important issue as most patients who suffer such an event either die or suffer myocardial infarction (Rainer et al., 2002).