Cardiovascular Magnetic Resonance in Acute ST-Segment–Elevation Myocardial Infarction

Abstract

While mortality following ST-segment elevation myocardial infarction (STEMI) is on the decline, the number of patients developing heart failure due to prior myocardial infarction (MI) is on the rise. Apart from timely reperfusion by primary percutaneous coronary intervention (PPCI), there is currently no established therapy for reducing MI size. As such new cardioprotective therapies are required to improve clinical outcomes following STEMI. Cardiovascular magnetic resonance (CMR) has emerged as an important imaging modality for assessing the efficacy of novel therapies for reducing MI size and preventing subsequent adverse left ventricular remodeling. The recent availability of multi-parametric mapping CMR has provided new insights into the pathophysiology underlying myocardial edema, microvascular obstruction, intramyocardial hemorrhage, and changes in the remote myocardial interstitial space following STEMI. In this article, we provide an overview of the recent advances in CMR imaging in reperfused STEMI patients, discuss the controversies surrounding its use, and explore future applications of CMR in this setting.

Role of Cardiac Magnetic Resonance to Improve Risk Prediction following Acute ST-elevation Myocardial Infarction

“…Accordingly, myocardial salvage index has frequently been used in previous large randomized clinical trials to evaluate treatment efficacy [80,81]. The optimal technique for the evaluation of AAR is still debated [3]. In consideration of the limitations of T2-weighted STIR imaging [75], more promising sequences have been introduced over the last years.…”

“…Cardiac magnetic resonance (CMR) imaging performed during the early phase post-STEMI has been intensively investigated for this purpose. This technique is uniquely suitable to comprehensively assess functional and morphological myocardial tissue alterations as well as post-infarct complications [3]. Cine imaging, which is an essential part of each CMR protocol, provides a detailed analysis of right and left chamber volumes and cardiac function (mainly ejection fraction) with crucial prognostic implications [4].…”

“…Importantly, cine CMR holds much more detailed information that enables assessment of more comprehensive markers of cardiac function, such as myocardial strain that may be even more informative for prognostication after STEMI than standard chamber volumes and ejection fraction [5][6][7]. A large body of evidence has demonstrated the great value of infarct severity assessment with CMR for the prediction of future cardiovascular events [3]. In this regard, late gadolinium enhancement (LGE) CMR, which is currently considered the reference method for infarct sizing, and microvascular obstruction (MVO) assessment, as a marker of severe reperfusion injury, has been increasingly used for improved long-term risk stratification and to evaluate cardioprotective interventions [3].…”

“…A large body of evidence has demonstrated the great value of infarct severity assessment with CMR for the prediction of future cardiovascular events [3]. In this regard, late gadolinium enhancement (LGE) CMR, which is currently considered the reference method for infarct sizing, and microvascular obstruction (MVO) assessment, as a marker of severe reperfusion injury, has been increasingly used for improved long-term risk stratification and to evaluate cardioprotective interventions [3]. Additional imaging biomarkers of myocardial tissue alterations using novel CMR sequences have also been recently evaluated and may provide further insights into STEMI pathophysiology and risk prediction.…”

Feasibility to Perform T2* Mapping Postcontrast Administration in Reperfused STEMI Patients for the Detection of Intramyocardial Hemorrhage

“…A comprehensive cardiac magnetic resonance imaging (MRI) scan takes about an hour. 7,8 This may be poorly tolerated by the acute STEMI patients. As IMH invariably occurs in areas of MVO (occurring in 50% of patients), 1 it may not be necessary to perform T 2 * mapping in those without MVO.…”