Chapter 13

STEMI Interventions – The Case for Bare-Metal Stents

Eulogio García, MD, Raúl Moreno, MD

The authors report no conflicts of interest regarding the content herein.

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Background
In-stent restenosis (ISR) has been the main limitation of percutaneous coronary interventions (PCI) for more than a decade. Drug-eluting stents (DES) have dramatically reduced the risk of both angiographic restnosis and the need for new revascularization procedures in comparison with bare-metal stents (BMS), and for that reason, they represent a revolution in interventional cardiology. ST-segment elevation myocardial infarction (STEMI), however, has been one of the last scenarios in which DES have been tested. Although some randomized trials have shown a reduction of restenosis and new revascularization with DES in patients with STEMI, the use of these devices in this type of patients is still controversial. We believe that BMS should be used as first choice in most patients with STEMI, mainly because the efficacy is lower than in other clinical settings, but also due to the concerns about early and late safety of DES in this clinical setting.

Re-Occlusion and Restenosis in Primary Percutaneous Coronary Intervention for STsegment Elevation Acute Myocardial Infarction
Primary angioplasty (PA) is superior to thrombolysis as reperfusion strategy for STEMI. This is mainly because of three reasons. 1-4 First, PA allows a higher rate of successful recanalization of the infarct-related artery (IRA) in different clinical and angiographic situations, leading to a reduction in the infarct size in comparison with thrombolysis. This probably also explains the

lower incidence of mechanical complications of patients treated with PA in comparison with thrombolysis. Second, PA reduces the incidence of re-occlusion of the infarct vessel, leading to a reduction in the rate of re-infarction. Third, PA virtually eliminates the risk of intra-cranial bleeding, which occurs in about 1% of patients treated with systemic thrombolysis. As a result, PA is associated with a mortality reduction in comparison with thrombolysis. In a meta-analysis that included 23 randomized trials comparing PA with thrombolysis in 7,739 patients, mortality rate in patients allocated to PA was significantly lower than in those allocated to thrombolysis (7% vs. 9%). By treating 50 patients with PA instead of thrombolysis,we can prevent one death.1 Apart from the advantages of PA over thrombolysis in patients that may be considered as candidates for both types of reperfusion strategies, we should also consider that PA may be safely performed in most patients with contra-indications to thrombolytic therapy.
Despite the benefit of PA over thrombolysis, PA with plain old balloon angioplasty is associated with some limitations, such as a lower rate of angiographic successful result in comparison with coronary stenting, a 3-5% incidence of re-infarction, and a high rate of angiographic restenosis.5-8 The most important limitation of PA at mid- and long-term is restenosis and vessel re-occlusion, occurring in 40% and 10% of cases, respectively.9-12 Among STEMI patients treated with PA, those with restenosis undergo not only a high rate of new revascularization procedures at the target vessel, but also present with a lower left ventricular ejection fraction during follow up. Probably this is due to the fact

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Textbook of STEMI Interventions