Early or deferred cardiovascular magnetic resonance after ST-segment-elevation myocardial infarction for effective risk stratification

Sex-based differences in adverse left ventricular remodelling and clinical outcomes after ST-segment elevation myocardial infarction

AIMS

The impact of sex on adverse left ventricular remodelling (LVR) after ST-elevation myocardial infarction (STEMI) is unclear due to conflicting results. This study sought to establish sex-based differences in adverse LVR using cardiovascular magnetic resonance (CMR) among STEMI patients and their impact on clinical outcomes.

METHODS AND RESULTS

The study included patients with a first STEMI who underwent primary percutaneous coronary intervention (PCI). Cardiovascular magnetic resonance was performed at 6 days (interquartile range [IQR]: 4-9 days) and after 6 months (6.42 months; IQR: 5.98-7.47 months). Follow-up was 6.94 years (IQR: 4.48-9.32 years). The primary endpoint was the presence of adverse LVR (>15% of LV end-diastolic volume and a decrease of >3% in LV ejection fraction) at 6 months. The secondary endpoint was major adverse cardiac events (MACEs), defined as a combined variable: cardiovascular death, heart failure admission, or ventricular arrhythmias. One thousand sixty-seven patients were included (17.5% women; mean age: 58.71 ± 11.85 years). Women were older and had more cardiovascular risk factors (CVRF). There was no association between sex and adverse LVR [OR: 0.80; 95% confidence interval (CI), 0.39-1.64; P = 0.536]. Major adverse cardiac events occurred in 177 patients (16.7%) and was more frequent in women (22.6% vs. 15.4%; P = 0.017). However, after adjusting for baseline differences and CVRF, the female sex was not associated with MACE (hazard ratio: 1.21; 95% CI, 0.81-1.81; P = 0.343).

CONCLUSION

The higher rate of MACE after STEMI in women compared to men appears to be associated with a higher prevalence of CVRF and comorbidities rather than a more significant occurrence of adverse LVR.

Hepatic T1 mapping as a novel cardio-hepatic axis imaging biomarker early after ST-elevation myocardial infarction

AIMS

The hepatic response after ST-elevation myocardial infarction (STEMI) may be associated with mortality and morbidity. We aimed to assess the cardio-hepatic axis post-STEMI using cardiovascular magnetic resonance (CMR).

METHODS AND RESULTS

This prospective, observational, single-centre study included consecutive patients with STEMI who underwent CMR after primary angioplasty from January 2015 to January 2019. Standard infarct characteristics were analysed, and hepatic T1 and hepatic extracellular volume (ECV) were assessed using pre- and post-contrast T1 mapping sequences. The primary endpoint was the relationship between native hepatic T1 values and ischaemic right ventricular (RV) involvement, determined by RV ejection fraction (EF) dysfunction and/or the presence of RV acute myocardial infarction (AMI). The diagnostic performance of hepatic T1 values for detecting RV involvement was assessed using the area under the receiver operating characteristic curve (AUC). Of 177 consecutive patients with STEMI undergoing CMR, 142 were included. Patients with RV ischaemic involvement, compared with those without, had significantly higher native hepatic T1 (P < 0.001) and hepatic ECV (P = 0.016). Hepatic T1 values demonstrated a good diagnostic performance in detecting RV involvement (AUC 0.826, P < 0.001) and correlated positively with NT-proBNP values (r = 0.754, P < 0.001). Patients with high hepatic T1 values (> 605 ms) had significantly higher NT-proBNP levels (< 0.001), larger RV end-diastolic volume (P < 0.001), lower RVEF (P < 0.001), and a higher prevalence of RV AMI (P = 0.022) compared with those with hepatic T1 ≤ 605 ms, whereas left ventricular EF and infarct size were similar. Multivariable logistic regression analysis identified RVEF (P = 0.010) and NT-proBNP values (P < 0.001) as independent predictors of increased hepatic T1 values. Patients with increased hepatic T1 values had a higher rate of rehospitalization for heart failure at 17-month follow-up (12.1 vs. 2.0%, P = 0.046).

CONCLUSION

Hepatic T1 mapping has emerged as a possible novel imaging biomarker of the cardio-hepatic axis in STEMI, being associated with RV involvement and increased NT-proBNP values.

Prognostic Value of Left Ventricular Longitudinal Function and Myocardial Fibrosis in Patients With Ischemic and Non-Ischemic Dilated Cardiomyopathy Concomitant With Type 2 Diabetes Mellitus: A 3.0 T Cardiac MR Study

BACKGROUND

Poorly controlled type 2 diabetes mellitus (T2DM) is known to result in left ventricular (LV) dysfunction, myocardial fibrosis, and ischemic/nonischemic dilated cardiomyopathy (ICM/NIDCM). However, less is known about the prognostic value of T2DM on LV longitudinal function and late gadolinium enhancement (LGE) assessed with cardiac MRI in ICM/NIDCM patients.

PURPOSE

To measure LV longitudinal function and myocardial scar in ICM/NIDCM patients with T2DM and to determine their prognostic values.

STUDY TYPE

Retrospective cohort.

POPULATION

Two hundred thirty-five ICM/NIDCM patients (158 with T2DM and 77 without T2DM).

FIELD STRENGTH/SEQUENCE

3T; steady-state free precession cine; phase-sensitive inversion recovery segmented gradient echo LGE sequences.

ASSESSMENT

Global peak longitudinal systolic strain rate (GLPSSR) was evaluated to LV longitudinal function with feature tracking. The predictive value of GLPSSR was determined with ROC curve. Glycated hemoglobin (HbA1c) was measured. The primary adverse cardiovascular endpoint was follow up every 3 months.

STATISTICAL TESTS

Mann-Whitney U test or student's t-test; Intra and inter-observer variabilities; Kaplan-Meier method; Cox proportional hazards analysis (threshold = 5%).

RESULTS

ICM/NIDCM patients with T2DM exhibited significantly lower absolute value of GLPSSR (0.39 ± 0.14 vs. 0.49 ± 0.18) and higher proportion of LGE positive (+) despite similar LV ejection fraction, compared to without T2DM. LV GLPSSR was able to predict primary endpoint (AUC 0.73) and optimal cutoff point was 0.4. ICM/NIDCM patients with T2DM (GLPSSR < 0.4) had more markedly impaired survival. Importantly, this group (GLPSSR < 0.4, HbA1c ≥ 7.8%, or LGE (+)) exhibited the worst survival. In multivariate analysis, GLPSSR, HbA1c, and LGE (+) significantly predicted primary adverse cardiovascular endpoint in overall ICM/NIDCM and ICM/NIDCM patients with T2DM.

CONCLUSIONS

T2DM has an additive deleterious effect on LV longitudinal function and myocardial fibrosis in ICM/NIDCM patients. Combining GLPSSR, HbA1c, and LGE could be promising markers in predicting outcomes in ICM/NIDCM patients with T2DM.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: 5.

Advanced Imaging Supports the Mechanistic Role of Autoimmunity and Plaque Rupture in COVID-19 Heart Involvement

The cardiovascular system is frequently affected by coronavirus disease-19 (COVID-19), particularly in hospitalized cases, and these manifestations are associated with a worse prognosis. Most commonly, heart involvement is represented by myocarditis, myocardial infarction, and pulmonary embolism, while arrhythmias, heart valve damage, and pericarditis are less frequent. While the clinical suspicion is necessary for a prompt disease recognition, imaging allows the early detection of cardiovascular complications in patients with COVID-19. The combination of cardiothoracic approaches has been proposed for advanced imaging techniques, i.e., CT scan and MRI, for a simultaneous evaluation of cardiovascular structures, pulmonary arteries, and lung parenchyma. Several mechanisms have been proposed to explain the cardiovascular injury, and among these, it is established that the host immune system is responsible for the aberrant response characterizing severe COVID-19 and inducing organ-specific injury. We illustrate novel evidence to support the hypothesis that molecular mimicry may be the immunological mechanism for myocarditis in COVID-19. The present article provides a comprehensive review of the available evidence of the immune mechanisms of the COVID-19 cardiovascular injury and the imaging tools to be used in the diagnostic workup. As some of these techniques cannot be implemented for general screening of all cases, we critically discuss the need to maximize the sustainability and the specificity of the proposed tests while illustrating the findings of some paradigmatic cases.

Left Ventricular Adverse Remodeling in Ischemic Heart Disease: Emerging Cardiac Magnetic Resonance Imaging Biomarkers

Post-ischemic left ventricular (LV) remodeling is a biologically complex process involving myocardial structure, LV shape, and function, beginning early after myocardial infarction (MI) and lasting until 1 year. Adverse remodeling is a post-MI maladaptive process that has been associated with long-term poor clinical outcomes. Cardiac Magnetic Resonance (CMR) is the best tool to define adverse remodeling because of its ability to accurately measure LV end-diastolic and end-systolic volumes and their variation over time and to characterize the underlying myocardial changes. Therefore, CMR is the gold standard method to assess in vivo myocardial infarction extension and to detect the presence of microvascular obstruction and intramyocardial hemorrhage, both associated with adverse remodeling. In recent times, new CMR quantitative biomarkers emerged as predictive of post-ischemic adverse remodeling, such as T1 mapping, myocardial strain, and 4D flow. Additionally, CMR T1 mapping imaging may depict infarcted tissue and assess diffuse myocardial fibrosis by using surrogate markers such as extracellular volume fraction, which may predict functional recovery or risk stratification of remodeling. Finally, there is emerging evidence supporting the utility of intracavitary blood flow kinetic energy and hemodynamic features assessed by the 4D flow CMR technique as early predictors of remodeling.

Clinical implications of cardiac magnetic resonance imaging fibrosis

Cardiac magnetic resonance (CMR) is a non-invasive imaging method that allows to characterize myocardial tissue. In particular, using the late gadolinium enhancement technique, it is possible to identify areas of focal fibrosis. Specific distribution patterns of this fibrosis allow us to distinguish ischaemic cardiomyopathy (iCMP) from non-ischaemic cardiomyopathy (nCMP) and sometimes to identify the aetiology of the latter. Diffuse fibrosis can also be identified using the parametric T1 mapping sequences. For this purpose, the native T1 of the tissue is measured before the administration of the contrast agent (c.a.) or the extracellular volume is calculated after c.a. Both focal and diffuse fibrosis evaluated with CMR appear to be strong prognostic predictors for the identification of threatening ventricular arrhythmias and sudden cardiac death. These evidence open the doors to a possible role of CMR in the selection of the patient to be sent to a defibrillator implant in primary prevention. In this review, we will briefly review the techniques used in CMR for the evaluation of fibrosis. We will then focus on the clinical role of myocardial tissue fibrosis detection in iCMP and nCMP.

Protective Value of Aspirin Loading Dose on Left Ventricular Remodeling After ST-Elevation Myocardial Infarction

AIMS

Left ventricular (LV) remodeling after ST-elevation myocardial infarction (STEMI) is a complex process, defined as changes of LV volumes over time. CMR feature tracking analysis (CMR-FT) offers an accurate quantitative assessment of LV wall deformation and myocardial contractile function. This study aimed to evaluate the role of myocardial strain parameters in predicting LV remodeling and to investigate the effect of Aspirin (ASA) dose before primary coronary angioplasty (pPCI) on myocardial injury and early LV remodeling.

METHODS AND RESULTS

Seventy-eight patients undergoing CMR, within 9 days from symptom onset and after 6 months, were enrolled in this cohort retrospective study. We divided the study population into three groups based on a revised Bullock's classification and we evaluated the role of baseline CMR features in predicting early LV remodeling. Regarding CMR strain analysis, worse global circumferential and longitudinal strain (GCS and GLS) values were associated with adverse LV remodeling. Patients were also divided based on pre-pPCI ASA dosage. Significant differences were detected in patients receiving ASA 500 mg dose before pPCI, which showed lower infarct size extent and better strain values compared to those treated with ASA 250 mg. The stepwise multivariate logistic regression analysis, adjusted for covariates, indicated that a 500 mg ASA dose remained an inverse independent predictor of early adverse LV remodeling.

CONCLUSION

GCS and GLS have high specificity to detect early LV adverse remodeling. We first reported a protective effect of ASA loading dose of 500 mg before pPCI on LV myocardial damage and in reducing early LV adverse remodeling.

Impact of myocardial scars on left ventricular deformation in type 2 diabetes mellitus after myocardial infarction by contrast-enhanced cardiac magnetic resonance

Background

Type 2 diabetes mellitus (T2DM) is a major risk factor for coronary artery disease and myocardial infarction (MI). The interaction of diabetic cardiomyopathy and MI scars on myocardial deformation in T2DM patients is unclear. Therefore, we aimed to evaluate myocardial deformation using cardiac magnetic resonance (CMR) in T2DM patients with previous MI and investigated the influence of myocardial scar on left ventricular (LV) deformation.

Methods

Overall, 202 T2DM patients, including 46 with MI (T2DM(MI+)) and 156 without MI (T2DM(MI−)), and 59 normal controls who underwent CMR scans were included. Myocardial scars were assessed by late gadolinium enhancement. LV function and deformation, including LV global function index, LV global peak strain (PS), peak systolic strain rate (PSSR), and peak diastolic strain rate (PDSR), were compared among these groups. Correlation and multivariate linear regression analyses were used to investigate the relationship between myocardial scars and LV deformation.

Results

Decreases were observed in LV function and LV global PS, PSSR, and PDSR in the T2DM(MI+) group compared with those of the other groups. Reduced LV deformation (p < 0.017) was observed in the T2DM(MI+) group with anterior wall infarction. The increased total LV infarct extent and infarct mass of LV were related to decreased LV global PS (radial, circumferential, and longitudinal directions; p < 0.01) and LV global PSSR (radial and circumferential directions, p < 0.02). Multivariate analysis demonstrated that NYHA functional class and total LV infarct extent were independently associated with LV global radial PS (β =  − 0.400 and β =  − 0.446, respectively, all p < 0.01; model R² = 0.37) and circumferential PS (β = 0.339 and β = 0.530, respectively, all p < 0.01; model R² = 0.41), LV anterior wall infarction was independently associated with LV global longitudinal PS (β = 0.398, p = 0.006).

Conclusions

The myocardial scarring size in T2DM patients after MI is negatively correlated with LV global PS and PSSR, particularly in the circumferential direction. Additionally, different MI regions have different effects on the reduction of LV deformation, and relevant clinical evaluations should be strengthened.

The year 2020 in the European Heart Journal - Cardiovascular Imaging: part I

The European Heart Journal - Cardiovascular Imaging was launched in 2012 and has during these 9 years become one of the leading multimodality cardiovascular imaging journals. The journal is currently ranked as number 20 among all cardiovascular journals. Our journal is well established as one of the top cardiovascular journals and is the most important cardiovascular imaging journal in Europe. The most important studies published in our Journal in 2020 will be highlighted in two reports. Part I of the review will focus on studies about myocardial function and risk prediction, myocardial ischaemia, and emerging techniques in cardiovascular imaging, while Part II will focus on valvular heart disease, heart failure, cardiomyopathies, and congenital heart disease.

Cardiac Magnetic Resonance Tissue Characterization in Ischemic Cardiomyopathy

Ischemic cardiomyopathy (ICM) is one of the most common causes of congestive heart failure. In patients with ICM, tissue characterization with cardiac magnetic resonance imaging (CMR) allows for evaluation of myocardial abnormalities in acute and chronic settings. Myocardial edema, microvascular obstruction (MVO), intracardiac thrombus, intramyocardial hemorrhage, and late gadolinium enhancement of the myocardium are easily depicted using standard CMR sequences. In the acute setting, tissue characterization is mainly focused on assessment of ventricular thrombus and MVO, which are associated with poor prognosis. Conversely, in chronic ICM, it is important to depict late gadolinium enhancement and myocardial ischemia using stress perfusion sequences. Overall, with CMR's ability to accurately characterize myocardial tissue in acute and chronic ICM, it represents a valuable diagnostic and prognostic imaging method for treatment planning. In particular, tissue characterization abnormalities in the acute setting can provide information regarding the patients that may develop major adverse cardiac event and show the presence of ventricular thrombus; in the chronic setting, evaluation of viable myocardium can be fundamental for planning myocardial revascularization. In this review, the main findings on tissue characterization are illustrated in acute and chronic settings using qualitative and quantitative tissue characterization.

Radiomics of Non-Contrast-Enhanced T1 Mapping: Diagnostic and Predictive Performance for Myocardial Injury in Acute ST-Segment-Elevation Myocardial Infarction

OBJECTIVE

To evaluate the feasibility of texture analysis on non-contrast-enhanced T1 maps of cardiac magnetic resonance (CMR) imaging for the diagnosis of myocardial injury in acute myocardial infarction (MI).

MATERIALS AND METHODS

This study included 68 patients (57 males and 11 females; mean age, 55.7 ± 10.5 years) with acute ST-segment-elevation MI who had undergone 3T CMR after a percutaneous coronary intervention. Forty patients of them also underwent a 6-month follow-up CMR. The CMR protocol included T2-weighted imaging, T1 mapping, rest first-pass perfusion, and late gadolinium enhancement. Radiomics features were extracted from the T1 maps using open-source software. Radiomics signatures were constructed with the selected strongest features to evaluate the myocardial injury severity and predict the recovery of left ventricular (LV) longitudinal systolic myocardial contractility.

RESULTS

A total of 1088 segments of the acute CMR images were analyzed; 103 (9.5%) segments showed microvascular obstruction (MVO), and 557 (51.2%) segments showed MI. A total of 640 segments were included in the 6-month follow-up analysis, of which 160 (25.0%) segments showed favorable recovery of LV longitudinal systolic myocardial contractility. Combined radiomics signature and T1 values resulted in a higher diagnostic performance for MVO compared to T1 values alone (area under the curve [AUC] in the training set; 0.88, 0.72, p = 0.031: AUC in the test set; 0.86, 0.71, p002). Combined radiomics signature and T1 values also provided a higher predictive value for LV longitudinal systolic myocardial contractility recovery compared to T1 values (AUC in the training set; 0.76, 0.55, p < 0.001: AUC in the test set; 0.77, 0.60, p < 0.001).

CONCLUSION

The combination of radiomics of non-contrast-enhanced T1 mapping and T1 values could provide higher diagnostic accuracy for MVO. Radiomics also provides incremental value in the prediction of LV longitudinal systolic myocardial contractility at six months.

Fibrosis after Myocardial Infarction: An Overview on Cellular Processes, Molecular Pathways, Clinical Evaluation and Prognostic Value

The ischemic injury caused by myocardial infarction activates a complex healing process wherein a powerful inflammatory response and a reparative phase follow and balance each other. An intricate network of mediators finely orchestrate a large variety of cellular subtypes throughout molecular signaling pathways that determine the intensity and duration of each phase. At the end of this process, the necrotic tissue is replaced with a fibrotic scar whose quality strictly depends on the delicate balance resulting from the interaction between multiple actors involved in fibrogenesis. An inflammatory or reparative dysregulation, both in term of excess and deficiency, may cause ventricular dysfunction and life-threatening arrhythmias that heavily affect clinical outcome. This review discusses cellular process and molecular signaling pathways that determine fibrosis and the imaging technique that can characterize the clinical impact of this process in-vivo.

Stress CMR in Known or Suspected CAD: Diagnostic and Prognostic Role

The recently published 2019 guidelines on chronic coronary syndromes (CCS) focus on the need for noninvasive imaging modalities to accurately establish the diagnosis of coronary artery disease (CAD) and assess the risk of clinical scenario occurrence. Appropriate patient management should rely on controlling symptoms, improving prognosis, and guiding each therapeutic strategy as well as monitoring disease progress. Among the noninvasive imaging modalities, cardiovascular magnetic resonance (CMR) has gained broad acceptance in past years due to its unique features in providing a complete assessment of CAD through data on cardiac anatomy and function and myocardial viability, with high spatial and temporal resolution and without ionizing radiation. In detail, evaluation of the presence and extent of myocardial ischemia through stress CMR (S-CMR) has shown a high rule-in power in detecting functionally significant coronary artery stenosis in patients suspected of CCS. Moreover, S-CMR technique may add significant prognostic value, as demonstrated by different studies which have progressively evidenced the valuable power of this multiparametric imaging modality in predicting adverse cardiac events. The latest scientific progress supports a greater expansion of S-CMR with improvement of quantitative myocardial perfusion analysis, myocardial strain, and native mapping within the same examination. Although further study is warranted, these techniques, which are currently mostly restricted to the research field, are likely to become increasingly prevalent in the clinical setting with the scope of increasing accuracy in the selection of patients to be sent to invasive revascularization. This review investigates the diagnostic and prognostic role of S-CMR in the context of CAD, by analysing a strong, long-standing, scientific evidence together with an appraisal of new advanced techniques which may potentially enrich CAD management in the next future.

Role of Cardiac Magnetic Resonance to Improve Risk Prediction Following Acute ST-Elevation Myocardial Infarction

Cardiac magnetic resonance (CMR) imaging allows comprehensive assessment of myocardial function and tissue characterization in a single examination after acute ST-elevation myocardial infarction. Markers of myocardial infarct severity determined by CMR imaging, especially infarct size and microvascular obstruction, strongly predict recurrent cardiovascular events and mortality. The prognostic information provided by a comprehensive CMR analysis is incremental to conventional risk factors including left ventricular ejection fraction. As such, CMR parameters of myocardial tissue damage are increasingly recognized for optimized risk stratification to further ameliorate the burden of recurrent cardiovascular events in this population. In this review, we provide an overview of the current impact of CMR imaging on optimized risk assessment soon after acute ST-elevation myocardial infarction.