Should Ischemia Be the Main Target in Selecting a Percutaneous Coronary Intervention Strategy?

Kristel Longman; Nick Curzen

Disclosures

Expert Rev Cardiovasc Ther. 2013;11(8):1051-1059. 

In This Article

Abstract and Introduction

Abstract

Contemporary studies have demonstrated that revascularization therapy targeted at coronary anatomy alone has not been able to consistently yield significant prognostic clinical outcomes. The practice of specific ischemia-targeted intervention for coronary disease in certain study populations has, however, produced important and reproducible clinical outcomes in terms of both symptoms and prognosis. We discuss the recent evidence and propose an ischemia-driven approach for selecting a percutaneous coronary intervention strategy.

Introduction

For many years the practice of Interventional Cardiology has involved the application of revascularization procedures such as percutaneous coronary intervention (PCI) to treat coronary stenosis targeted according to angiographic estimations of severity. The evidence demonstrating the symptomatic benefit of PCI is robust. In contrast, the evidence for prognostic benefit using an angiogram-alone-guided PCI is significantly more limited.

Specifically, outside the arena of acute coronary syndromes (ACSs), in which the data clearly demonstrate clinical outcome benefit for early PCI,[1–4] the evidence has, generally, failed to demonstrate similar robust positive results for outcome in the stable angina population. At best, the data up until this year were discrepant in this regard, and the evidence circumstantial. Large observational studies have indeed reported mortality benefit for PCI in stable patients when compared with medical therapy alone in cases when demonstrable moderate to large amounts of inducible ischemia were present.[5] Furthermore, one meta-analysis of randomized trials has also demonstrated mortality benefit for PCI versus medical therapy alone.[6] However, the headline result from the COURAGE trial[7] suggested that PCI in fact offers no prognostic benefit in patients with stable coronary artery disease (CAD) compared with optimal medical therapy (OMT). While the study itself had several features of its design that are open to criticism, reviewed fully previously,[8] and to which we will return later, this overall lack of clinical outcome benefit warrants close consideration and scrutiny.

The availability of noninvasive tests for reversible ischemia that are vastly superior to the conventional exercise test, and in particular, the advent of the pressure wire to invasively assess the functional significance of coronary stenosis offers an important step change in our investigation and management of such patients. This step change in management is allied to the persuasive concept, backed by a wide spectrum of clinical data, that it may be the presence of reversible myocardial ischemia that determines the outcome, rather than coronary anatomy. For example, the data demonstrating superiority of clinical outcome using fractional flow reserve (FFR) guidance for PCI rather than the angiogram alone seen in studies such as DEFER,[9] FAME[10] and FAME-2[11] constructs a convincing case for this care pathway approach in patients with stable angina. The persuasive concept is this: the modern target for PCI is ischemia first and anatomy second. Proof of ischemia, both at a patient level and then at lesion level should become a consideration as part of our routine practice. The aim of this review is to analyze the basis for this statement and the evidence that provides its foundation.

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