CHAPTER 42: PERCUTANEOUS CORONARY INTERVENTIONS IN ACUTE MYOCARDIAL INFARCTION AND ACUTE CORONARY SYNDROMES

INTRODUCTION

At its inception,¹ coronary angioplasty was envisioned as a procedure for patients with stable, single-vessel coronary artery disease (CAD). Original angioplasty balloon catheters were too large, bulky, and difficult to navigate through vessels other than the proximal portions of major epicardial vessels. Coronary lesions were required to be concentric and noncalcified. Even in these simple lesions, the initial success rate was 64%.² Over the past 40 years, improvements in catheter design, development of atraumatic steerable guidewires, development of flexible, highly deliverable stents, and development of highly effective antithrombotic and antiplatelet therapy have made percutaneous coronary intervention (PCI) a dominant revascularization strategy. Furthermore, use of PCI has revolutionized the care of patients with acute myocardial infarction (AMI) and acute coronary syndrome (ACS).

Although PCI was originally used in stable patients, recent data from the National Cardiovascular Data Registry³ demonstrate that the use of PCI has now shifted to use in AMI and ACS (Fig. 42–1); from 2010 to 2014, use of PCI has remained constant in AMI/ACS, whereas there has been a 50% reduction in use for stable CAD patients. Currently, in US practice, PCI is used in 80% of AMI/ACS patients and only 20% of stable CAD patients.

This chapter will provide a historical perspective and review of the seminal trials that led to establishment of PCI as the backbone of therapy for AMI/ACS. ST-segment elevation myocardial infarction (STEMI) can be easily diagnosed with an inexpensive, widely available tool (12-lead electrocardiogram [ECG]); similarly, ACS can be easily diagnosed with biomarker (troponin) and ECG changes. These illnesses present dramatically, can be lethal, and have been a scourge of Western civilization for the past 50 years. Fortunately, the enormous mortality risk has prompted AMI/ACS to be prospectively studied in hundreds of thousands patients. As a result, an enormously robust data set of clinical trials has tested all aspects of care from ambulance arrival to hospital discharge. We will review the evidence base using a patient-centered approach. We will discuss evidence-based decisions from admission to discharge. We will conclude with review of the evidence that widespread adoption of PCI for AMI/ACS has contributed to decline in overall adjusted cardiovascular mortality in the West.

HISTORICAL OVERVIEW OF MECHANICAL REPERFUSION IN ACUTE MYOCARDIAL INFARCTION

Reperfusion therapy for AMI had its inception with the initial treatise by Fletcher et al⁴ describing the use of intravenous (IV) thrombolytic therapy in patients with thromboembolic disorders, including myocardial infarction (MI).⁴ Shortly after this, Boucek and Murphy⁵ published their observations of using catheters ...