What Is the Clinical Impact of Stress CMR After the ISCHEMIA Trial?

Abstract

After progressively receding for decades, cardiovascular mortality due to coronary artery disease has recently increased, and the associated healthcare costs are projected to double by 2030. While the 2019 European Society of Cardiology guidelines for chronic coronary syndromes recommend non-invasive cardiac imaging for patients with suspected coronary artery disease, the impact of non-invasive imaging strategies to guide initial coronary revascularization and improve long-term outcomes is still under debate. Recently, the ISCHEMIA trial has highlighted the fundamental role of optimized medical therapy and the lack of overall benefit of early invasive strategies at a median follow-up of 3.2 years. However, sub-group analyses excluding procedural infarctions with longer follow-ups of up to 5 years have suggested that patients undergoing revascularization had better outcomes than those receiving medical therapy alone. A recent sub-study of ISCHEMIA in patients with heart failure or reduced left ventricular ejection fraction (LVEF <45%) indicated that revascularization improved clinical outcomes compared to medical therapy alone. Furthermore, other large observational studies have suggested a favorable prognostic impact of coronary revascularization in patients with severe inducible ischemia assessed by stress cardiovascular magnetic resonance (CMR). Indeed, some data suggest that stress CMR-guided revascularization assessing the extent of the ischemia could be useful in identifying patients who would most benefit from invasive procedures such as myocardial revascularization. Interestingly, the MR-INFORM trial has recently shown that a first-line stress CMR-based non-invasive assessment was non-inferior in terms of outcomes, with a lower incidence of coronary revascularization compared to an initial invasive approach guided by fractional flow reserve in patients with stable angina. In the present review, we will discuss the current state-of-the-art data on the prognostic value of stress CMR assessment of myocardial ischemia in light of the ISCHEMIA trial results, highlighting meaningful sub-analyses, and still unanswered opportunities of this pivotal study. We will also review the available evidence for the potential clinical application of quantifying the extent of ischemia to stratify cardiovascular risk and to best guide invasive and non-invasive treatment strategies.

Additional prognostic value of stress cardiovascular magnetic resonance for cardiovascular risk stratification after a cryptogenic ischemic stroke

“…An improved risk stratification using stress CMR could allow to identify high-risk patients who could benefit from treatment intensification, new therapy, and/or revascularization. Although the quantification of myocardial blood flow (MBF) by CMR was not performed in the current study, several reports described its potential interest in accurately and reproducibly assessing the burden of ischemia to guide optimal therapy ( 46 ). Along with its added prognostic value, the steadily increasing expertise and availability of stress CMR make it a safe, reproducible, and reliable test to stratify the risk of cardiovascular events in asymptomatic patients with prior stroke and without known CAD.…”

Heart Failure and Cardiomyopathies: CT and MR from Basics to Advanced Imaging

“…In this regard, from the extended STICHES, revascularization strategies plus medical therapies seem more effective than medical therapy alone in the treatment of patients with reduced EF, thus suggesting a real benefit to coronary revascularization in patients with both ischemia and HFrEF [ 167 , 168 ].…”

Stress Perfusion Cardiac Magnetic Resonance in Long-Standing Non-Infarcted Chronic Coronary Syndrome with Preserved Systolic Function

“…From ISCHEMIA, different questions arise regarding which ischemia test should be performed and which subcategories can benefit from a more aggressive treatment [16]. In this regard, from the extended STICHES, revascularization strategies plus medical therapies seem more effective than medical therapy alone in treatment of patients with reduced left ventricular ejection fraction (LVEF), thus suggesting a real benefit to coronary revascularization in patients with both ischemia and reduced EF heart failure (HFrEF) [17,18].…”

“…During the latest years, stress perfusion cardiac magnetic resonance (spCMR) showed a relevant impact in CAD stratification in many trial and registry studies [16,[19][20][21][22][23][24][25]. Differently from other imaging techniques, spCMR offers a holistic approach to the heart patient through the simultaneous evaluation of the triad systolic function-perfusion abnormalitiestissue characterization [26].…”