Chapter 12

STEMI Interventions – The Case for Drug-Eluting Stents

Arashk Motiei, MD, David R. Holmes, Jr., MD, FACC

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

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Introduction
Primary percutaneous intervention (PCI) is the mainstay of therapy for patients with acute ST-segment elevation myocardial infarction (STEMI).When performed in a timely fashion, the outcomes of patients are significantly improved in comparison with thrombolytic therapy.1,2 Compared with balloon angioplasty alone, stent implantation in the setting of acute myocardial infarction (MI) is associated with a lower rate of target vessel revascularization (TVR).3 For these reasons, primary stenting of the infarct artery has become the standard approach to treating these patients. Although the introduction of bare metal stents led to a considerable improvement in the outcomes of patients undergoing percutaneous coronary intervention, restenosis and the attendant need for TVR still continued to plague a considerable fraction of patients. A pooled analyses of 6186 patients from bare-metal stent (BMS) trials showed a 12-month target lesion revascularization (TLR) rate of 12.2%,TVR rate of 14.3% and target vessel failure (TVF) rate of 16%.4 The advent of drug-eluting stents (DES) has represented a significant development in attempts to reduce the incidence of restenosis and its clinical correlates.A meta-analysis of clinical trials comparing DES with BMS demonstrated a significant reduction in angiographic restenosis (10.5% vs. 31.7%, and TLR (6.2% vs. 16.6 %).5 The original trials comparing DES with BMS excluded patients who presented with acute MI. However, given the salutary effects of DES in the elective setting, it has been hoped that a similar improvement in outcomes would be seen in patients undergoing primary PCI for acute MI, particularly with

respect to restenosis and TVR.This point has been used to support the use of DES for these patients. In the process of building a case in favor of this use of DES, two additional issues would need to be addressed.The first issue relates to the fact that restenosis is considered by many to be a benign process.The second problem relates to concerns about stent thrombosis, particularly when these stents are used in patients presenting with acute MI. In this chapter, we will review the data relevant to these issues in an attempt to support the use of DES for primary PCI.

Restenosis
Restenosis leading to TVR is a common problem after primary PCI for acute MI.The incidence of TVR after stent placement was nearly 7.5% at six months and 10% at one year in a pooled analysis of trials that compared balloon angioplasty with stenting during primary PCI for acute MI.3 Restenosis has a significant impact on quality of life. In the OPUS-1 (Optimum Percutaneous Transluminal Coronary Angioplasty Compared with Routine Stent Strategy) trial, patients without restenosis experienced fewer physical limitations and an improved quality of life compared with patients with restenosis.6 Data from the Stent-PAMI (Stent Primary Angioplasty in Myocardial Infarction) trial suggest that, in comparison with conventional balloon angioplasty, stent placement is associated with significantly better patient quality of life due to a reduction in restenosis.59
There has been a tendency to regard restenosis as a benign process. This perception has evolved in part under the influence

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Textbook of STEMI Interventions