Primary Stenting in Acute Myocardial Infarction The Promise and the Proof

With the demonstration that the timely administration of thrombolytic therapy after coronary arterial occlusion results in myocardial salvage and improved survival, the treatment of patients with evolving AMI has forever been changed. To overcome the inherent limitations of thrombolytic therapy (TIMI 3 flow rates of ≈55% at best, and rare but unavoidable life-threatening or incapacitating hemorrhagic complications), mechanical reperfusion by balloon angioplasty without antecedent thrombolysis (primary PTCA) has been adopted at many centers. Ten prospective, randomized trials comparing primary PTCA and lytic therapy in 2606 patients have now been performed and examined in a recent meta-analysis by Weaver et al,1 demonstrating that compared with thrombolytic therapy, primary PTCA results in reduced rates of mortality, reinfarction, and stroke. Other randomized trials2 3 have shown that primary PTCA, by reducing early and late recurrent ischemic events and facilitating earlier discharge, is as or more cost-effective than thrombolysis. Despite these attributes, balloon-induced medial disruption and platelet activation result in recurrent ischemia in 10% to 15% of patients treated with primary PTCA before hospital discharge, including reinfarction in 3% to 5% of patients.4 Although improvements in operator technique, exclusive use of ionic contrast, and attention to anticoagulation status can minimize these complications,5 the significant residual stenosis remaining in many patients after balloon angioplasty, in concert with intimal hyperplasia, unopposed vessel recoil, and late remodeling, results in angiographic restenosis in 30% to 50% of infarct vessels within 6 months.4 As a result, ≈20% of patients after primary PTCA require TVR with repeat angioplasty or bypass surgery during this time period.4 Furthermore, not all operators have been able to achieve optimal results of primary PTCA at their institutions. With the demonstration that the implantation of balloon-expandable slotted-tube stents can reduce clinical and angiographic restenosis compared with PTCA in patients undergoing …