Cardiovascular magnetic resonance techniques for tissue characterization after acute myocardial injury

Contains fulltext : 209405.pdf (publisher's version ) (Closed access)The annual incidence of hospital admission for acute myocardial infarction lies between 90 and 312 per 100 000 inhabitants in Europe. Despite advances in patient care 1 year mortality after ST-segment elevation myocardial infarction (STEMI) remains around 10%. Cardiovascular magnetic resonance imaging (CMR) has emerged as a robust imaging modality for assessing patients after acute myocardial injury. In addition to accurate assessment of left ventricular ejection fraction and volumes, CMR offers the unique ability of visualization of myocardial injury through a variety of imaging techniques such as late gadolinium enhancement and T2-weighted imaging. Furthermore, new parametric mapping techniques allow accurate quantification of myocardial injury and are currently being exploited in large trials aiming to augment risk management and treatment of STEMI patients. Of interest, CMR enables the detection of microvascular injury (MVI) which occurs in approximately 40% of STEMI patients and is a major independent predictor of mortality and heart failure. In this article, we review traditional and novel CMR techniques used for myocardial tissue characterization after acute myocardial injury, including the detection and quantification of MVI. Moreover, we discuss clinical scenarios of acute myocardial injury in which the tissue characterization techniques can be applied and we provide proposed imaging protocols tailored to each scenario

Epicardial Surface Area of Infarction:A Stable Surrogate of Microvascular Obstruction in Acute Myocardial Infarction

Item does not contain fulltextBACKGROUND: Microvascular obstruction (MO) is a pathophysiologic complication of acute myocardial infarction that portends poor prognosis; however, it is transient and disappears with infarct healing. Much remains unknown regarding its pathophysiology and whether there are predictors of MO that could function as stable surrogates. We tested for clinical and cardiovascular magnetic resonance predictors of MO to gain insight into its pathophysiology and to find a stable surrogate. METHODS: Three hundred two consecutive patients from 2 centers underwent cardiovascular magnetic resonance within 2 weeks of first acute myocardial infarction. Three measures of infarct morphology: infarct size, transmurality, and a new index-the epicardial surface area (EpiSA) of full-thickness infarction-were quantified on delayed-enhancement cardiovascular magnetic resonance. RESULTS: Considering all clinical characteristics, only measures of infarct morphology were independent predictors of MO. EpiSA was the strongest predictor of MO and provided incremental predictive value beyond that of infarct size and transmurality (P<0.0001). In patients with 3-month follow-up cardiovascular magnetic resonance (n=81), EpiSA extent remained stable while MO disappeared, and EpiSA was a predictor of adverse ventricular remodeling. After 20 months of follow-up, 11 died and 1 had heart transplantation. Patients with an EpiSA larger than the median value (≥6%) had worse outcome than those with less than the median value (adverse events: 6.4% versus 1.9%, P=0.045). CONCLUSIONS: The EpiSA of infarction is a novel index of infarct morphology which accurately predicts MO during the first 2 weeks of MI, but unlike MO, does not disappear with infarct healing. This index has potential as a stable surrogate of the presence of acute MO and may be useful as a predictor of adverse remodeling and outcome which is less dependent on the time window of patient assessment

Cardiac MRI to Visualize Myocardial Damage after ST-Segment Elevation Myocardial Infarction: A Review of Its Histologic Validation

Item does not contain fulltextCardiac MRI is a noninvasive diagnostic tool using nonionizing radiation that is widely used in patients with ST-segment elevation myocardial infarction (STEMI). Cardiac MRI depicts different prognosticating components of myocardial damage such as edema, intramyocardial hemorrhage (IMH), microvascular obstruction (MVO), and fibrosis. But how do cardiac MRI findings correlate to histologic findings? Shortly after STEMI, T2-weighted imaging and T2* mapping cardiac MRI depict, respectively, edema and IMH. The acute infarct size can be determined with late gadolinium enhancement (LGE) cardiac MRI. T2-weighted MRI should not be used for area-at-risk delineation because T2 values change dynamically over the first few days after STEMI and the severity of T2 abnormalities can be modulated with treatment. Furthermore, LGE cardiac MRI is the most accurate method to visualize MVO, which is characterized by hemorrhage, microvascular injury, and necrosis in histologic samples. In the chronic setting post-STEMI, LGE cardiac MRI is best used to detect replacement fibrosis (ie, final infarct size after injury healing). Finally, native T1 mapping has recently emerged as a contrast material-free method to measure infarct size that, however, remains inferior to LGE cardiac MRI. Especially LGE cardiac MRI-defined infarct size and the presence and extent of MVO may be used to monitor the effect of new therapeutic interventions in the treatment of reperfusion injury and infarct size reduction. © RSNA, 2021 Online supplemental material is available for this article

Instantaneous wave-free ratio guided multivessel revascularisation during percutaneous coronary intervention for acute myocardial infarction: study protocol of the randomised controlled iMODERN trial

INTRODUCTION: Recent randomised clinical trials showed benefit of non-culprit lesion revascularisation in ST-elevation myocardial infarction (STEMI) patients. However, it remains unclear whether revascularisation should be performed at the index procedure or at a later stage. METHODS AND ANALYSIS: The instantaneous wave-free ratio (iFR) Guided Multivessel Revascularisation During Percutaneous Coronary Intervention for Acute Myocardial Infarction trial is a multicentre, randomised controlled prospective open-label trial with blinded evaluation of endpoints. After successful primary percutaneous coronary intervention (PCI), eligible STEMI patients with residual non-culprit lesions are randomised, to instantaneous wave-free ratio guided treatment of non-culprit lesions during the index procedure versus deferred cardiac MR-guided management within 4 days to 6 weeks. The primary endpoint of the study is the combined occurrence of all-cause death, recurrent myocardial infarction and hospitalisation for heart failure at 12 months follow-up. Clinical follow-up includes questionnaires at 3 months and outpatient visits at 6 months and 12 months after primary PCI. Furthermore, a cost-effectiveness analysis will be performed. ETHICS AND DISSEMINATION: Permission to conduct this trial has been granted by the Medical Ethical Committee of the Amsterdam University Medical Centres (loc. VUmc, ID NL60107.029.16). The primary results of this trial will be shared in a main article and subgroup analyses or spin-off studies will be shared in secondary papers. TRIAL REGISTRATION NUMBER: NCT03298659