An artificial intelligence tool for automated analysis of large-scale unstructured clinical cine cardiac magnetic resonance databases

Aims

Artificial intelligence (AI) techniques have been proposed for automating analysis of short-axis (SAX) cine cardiac magnetic resonance (CMR), but no CMR analysis tool exists to automatically analyse large (unstructured) clinical CMR datasets. We develop and validate a robust AI tool for start-to-end automatic quantification of cardiac function from SAX cine CMR in large clinical databases.

Methods and results

Our pipeline for processing and analysing CMR databases includes automated steps to identify the correct data, robust image pre-processing, an AI algorithm for biventricular segmentation of SAX CMR and estimation of functional biomarkers, and automated post-analysis quality control to detect and correct errors. The segmentation algorithm was trained on 2793 CMR scans from two NHS hospitals and validated on additional cases from this dataset (n = 414) and five external datasets (n = 6888), including scans of patients with a range of diseases acquired at 12 different centres using CMR scanners from all major vendors. Median absolute errors in cardiac biomarkers were within the range of inter-observer variability: <8.4 mL (left ventricle volume), <9.2 mL (right ventricle volume), <13.3 g (left ventricular mass), and <5.9% (ejection fraction) across all datasets. Stratification of cases according to phenotypes of cardiac disease and scanner vendors showed good performance across all groups.

Conclusion

We show that our proposed tool, which combines image pre-processing steps, a domain-generalizable AI algorithm trained on a large-scale multi-domain CMR dataset and quality control steps, allows robust analysis of (clinical or research) databases from multiple centres, vendors, and cardiac diseases. This enables translation of our tool for use in fully automated processing of large multi-centre databases.

Prognostic Value of Cardiac Magnetic Resonance Imaging in Patients With a Working Diagnosis of MINOCA-An Outcome Study With up to 10 Years of Follow-Up

BACKGROUND

Patients with a working diagnosis of myocardial infarction with unobstructed coronary arteries (MINOCA) represent a heterogeneous cohort. The prognosis could vary substantially depending on the underlying cause. Although cardiac magnetic resonance (CMR) is considered a key diagnostic tool in these patients, there are limited data linking the CMR diagnosis with the outcome.

METHODS

This study is a prospective outcomes registry of consecutive patients presenting with a working diagnosis of MINOCA who were clinically referred for CMR at an academic hospital from October 2003 to February 2020. We assessed the relationships between the prespecified CMR diagnoses of acute myocardial infarction (AMI), myocarditis, nonischemic cardiomyopathy (NICM), normal CMR study, and major adverse cardiac events (MACEs).

RESULTS

Of 252 patients, the CMR diagnosis was AMI in 63 (25%), myocarditis in 33 (13%), NICM in 111 (44%), normal CMR in 37 (15%), and other diagnoses in 8 (3%). A specific nonischemic cause was diagnosed allowing true MINOCA to be ruled-out in 57% of the cohort. During up to 10 years of follow-up (1595 patient-years), MACE occurred in 84 patients (33%), which included 64 deaths (25%). The unadjusted cumulative 10-year rate of MACE was 47% in AMI, 24% in myocarditis, 50% in NICM, and 3.5% in patients with a normal CMR (Log-rank P<0.001). The CMR diagnosis provided incremental prognostic value over clinical factors including age, gender, coronary artery disease risk factors, presentation with ST-elevation, and peak troponin (incremental χ² 17.9, P<0.001); and patients with diagnoses of AMI, myocarditis, and NICM had worse MACE-free survival than patients with a normal CMR.

CONCLUSIONS

In patients with a working diagnosis of MINOCA, CMR allows ruling-out true MINOCA in over half of the patients. CMR diagnoses of AMI, myocarditis, and NICM are associated with worse MACE-free survival, whereas a normal CMR study portends a benign prognosis.

Society for cardiovascular magnetic resonance recommendations for training and competency of CMR technologists

The Society for Cardiovascular Magnetic Resonance (SCMR) recommendations for training and competency of cardiovascular magnetic resonance (CMR) technologists document will define the knowledge, experiences and skills required for a technologist to be competent in CMR imaging. By providing a framework for CMR training and competency the overarching goal is to promote the performance of high-quality CMR and to foster the increased adoption of CMR into clinical care.

Primary left ventricular unloading with delayed reperfusion in patients with anterior ST-elevation myocardial infarction: Rationale and design of the STEMI-DTU randomized pivotal trial

BACKGROUND

Despite successful primary percutaneous coronary intervention (PCI) in ST-elevation myocardial infarction (STEMI), myocardial salvage is often suboptimal, resulting in large infarct size and increased rates of heart failure and mortality. Unloading of the left ventricle (LV) before primary PCI may reduce infarct size and improve prognosis.

STUDY DESIGN AND OBJECTIVES

STEMI-DTU (NCT03947619) is a prospective, randomized, multicenter trial designed to compare mechanical LV unloading with the Impella CP device for 30 minutes prior to primary PCI to primary PCI alone without LV unloading. The trial aims to enroll approximately 668 subjects, with a potential sample size adaptation, with anterior STEMI with a primary end point of infarct size as a percent of LV mass evaluated by cardiac magnetic resonance at 3-5 days after PCI. The key secondary efficacy end point is a hierarchical composite of the 1-year rates of cardiovascular mortality, cardiogenic shock ≥24 hours after PCI, use of a surgical left ventricular assist device or heart transplant, heart failure, intra-cardiac defibrillator or chronic resynchronization therapy placement, and infarct size at 3 to 5 days post-PCI. The key secondary safety end point is Impella CP-related major bleeding or major vascular complications within 30 days. Clinical follow-up is planned for 5 years.

CONCLUSIONS

STEMI-DTU is a large-scale, prospective, randomized trial evaluating whether mechanical unloading of the LV by the Impella CP prior to primary PCI reduces infarct size and improves prognosis in patients with STEMI compared to primary PCI alone without LV unloading.

Native T1 Mapping for the Diagnosis of Myocardial Fibrosis in Patients With Chronic Myocardial Infarction

BACKGROUND

Myocardial fibrosis is a fundamental process in cardiac injury. Cardiac magnetic resonance native T1 mapping has been proposed for diagnosing myocardial fibrosis without the need for gadolinium contrast. However, recent studies suggest that T1 measurements can be erroneous in the presence of intramyocardial fat.

OBJECTIVES

The purpose of this study was to investigate whether the presence of fatty metaplasia affects the accuracy of native T1 maps for the diagnosis of myocardial replacement fibrosis in patients with chronic myocardial infarction (MI).

METHODS

Consecutive patients (n = 312) with documented chronic MI (>6 months old) and controls without MI (n = 50) were prospectively enrolled. Presence and size of regions with elevated native T1 and infarction were quantitatively determined (mean + 5SD) on modified look-locker inversion-recovery and delayed-enhancement images, respectively, at 3.0-T. The presence of fatty metaplasia was determined using an out-of-phase steady-state free-precession cine technique and further verified with standard fat-water Dixon methods.

RESULTS

Native T1 mapping detected chronic MI with markedly higher sensitivity in patients with fatty metaplasia than those without fatty metaplasia (85.6% vs 13.3%) with similar specificity (100% vs 98.9%). In patients with fatty metaplasia, the size of regions with elevated T1 significantly underestimated infarct size and there was a better correlation with fatty metaplasia size than infarct size (r = 0.76 vs r = 0.49). In patients without fatty metaplasia, most of the modest elevation in T1 appeared to be secondary to subchronic infarcts that were 6 to 12 months old; the T1 of infarcts >12 months old was not different from noninfarcted myocardium.

CONCLUSIONS

Native T1 mapping is poor at detecting replacement fibrosis but may indirectly detect chronic MI if there is associated fatty metaplasia. Native T1 mapping for the diagnosis and characterization of myocardial fibrosis is unreliable.

Assessment of Papillary Muscle Infarction with Dark-Blood Delayed Enhancement Cardiac MRI in Canines and Humans

Background The relationship between papillary muscle infarction (papMI) and the culprit coronary lesion has not been fully investigated. Delayed enhancement cardiac MRI may detect papMI, yet its accuracy is unknown. Flow-independent dark-blood delayed enhancement (FIDDLE) cardiac MRI has been shown to improve the detection of myocardial infarction adjacent to blood pool. Purpose To assess the diagnostic performance of delayed enhancement and FIDDLE cardiac MRI for the detection of papMI, and to investigate the prevalence of papMI and its relationship to the location of the culprit coronary lesion. Materials and Methods A prospective canine study was used to determine the accuracy of conventional delayed enhancement imaging and FIDDLE imaging for detection of papMI, with pathology-based findings as the reference standard. Participants with first-time myocardial infarction with a clear culprit lesion at coronary angiography were prospectively enrolled at a single hospital from 2015 to 2018 and compared against control participants with low Framingham risk scores. In canines, diagnostic accuracy was calculated for delayed enhancement and FIDDLE imaging. Results In canines (n = 27), FIDDLE imaging was more sensitive (100% [23 of 23] vs 57% [13 of 23], P < .001) and accurate (100% [54 of 54] vs 80% [43 of 54], P = .01) than delayed enhancement imaging for detection of papMI. In 43 participants with myocardial infarction (mean age, 56 years ± 16 [SD]; 28 men), the infarct-related artery was the left anterior descending coronary artery (LAD), left circumflex coronary artery (LCX), and right coronary artery in 47% (20 of 43), 26% (11 of 43), and 28% (12 of 43), respectively. The prevalence of anterior papMI was lower than posterior papMI (37% [16 of 43 participants] vs 44% [19 of 43 participants]) despite more LAD culprit lesions. Culprits leading to papMI were restricted to a smaller "at-risk" portion of the coronary tree for anterior papMI (subtended first diagonal branch of the LAD or first marginal branch of the LCX) compared with posterior (subtended posterior descending artery or third obtuse marginal branch of the LCX). Culprits within these at-risk portions were predictive of papMI at a similar rate (anterior, 83% [15 of 18 participants] vs posterior, 86% [18 of 21 participants]). Conclusion Flow-independent dark-blood delayed enhancement cardiac MRI, unlike conventional delayed enhancement cardiac MRI, was highly accurate in the detection of papillary muscle infarction (papMI). Anterior papMI was less prevalent than posterior papMI, most likely due to culprit lesions being restricted to a smaller portion of the coronary tree rather than because of redundant, dual vascular supply. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Kawel-Boehm and Bremerich in this issue.

Assessment of myocardial lipomatous metaplasia using an optimized out-of-phase cine steady-state free-precession sequence: Validation and clinical implementation

Myocardial lipomatous metaplasia, which can serve as substrate for ventricular arrhythmias, is usually composed of regions in which there is an admixture of fat and nonfat tissue. Although dedicated sequences for the detection of fat are available, it would be time-consuming and burdensome to routinely use these techniques to image the entire heart of all patients as part of a typical cardiac MRI exam. Conventional steady-state free-precession (SSFP) cine imaging is insensitive to detecting myocardial regions with partial fatty infiltration. We developed an optimization process for SSFP imaging to set fat signal consistently "out-of-phase" with water throughout the heart, so that intramyocardial regions with partial volume fat would be detected as paradoxically dark regions. The optimized SSFP sequence was evaluated using a fat phantom, through simulations, and in 50 consecutive patients undergoing clinical cardiac MRI. Findings were validated using standard Dixon gradient-recalled-echo (GRE) imaging as the reference. Phantom studies of test tubes with diverse fat concentrations demonstrated good agreement between measured signal intensity and simulated values calculated using Bloch equations. In patients, a line of signal cancellation at the interface between myocardium and epicardial fat was noted in all cases, confirming that SSFP images were consistently out-of-phase throughout the entire heart. Intramyocardial dark regions identified on out-of-phase SSFP images were entirely dark throughout in 33 patients (66%) and displayed an India-ink pattern in 17 (34%). In all cases, dark intramyocardial regions were also seen in the same locations on out-of-phase GRE and were absent on in-phase GRE, confirming that these regions represent areas with partial fat. In conclusion, if appropriately optimized, SSFP cine imaging allows for consistent detection of myocardial fatty metaplasia in patients undergoing routine clinical cardiac MRI without the need for additional image acquisitions using dedicated fat-specific sequences.

Left Ventricular Remodeling After Anterior-STEMI PCI: Imaging Observations in the Door-to-Unload (DTU) Pilot Trial

OBJECTIVES

To determine the predictive value of cardiac magnetic resonance (CMR) and echocardiographic parameters on left ventricular (LV) remodeling in ST-segment elevation myocardial infarction (STEMI) patients without cardiogenic shock and treated with mechanical LV unloading followed by immediate or delayed percutaneous coronary intervention (PCI)-mediated reperfusion.

BACKGROUND

In STEMI, infarct size (IS) directly correlates with major cardiovascular outcomes. Preclinical models demonstrate mechanical LV unloading before reperfusion reduces IS. The door-to-unload (DTU)-STEMI pilot trial evaluated the safety and feasibility of LV unloading and delayed reperfusion in patients with STEMI.

METHODS

This multicenter, prospective, randomized, safety and feasibility trial evaluated patients with anterior STEMI randomized 1:1 to LV unloading with the Impella CP (Abiomed) followed by immediate reperfusion vs delayed reperfusion after 30 minutes of unloading. Patients were assessed by CMR at 3-5 days and 30 days post PCI. Echocardiographic evaluations were performed at 3-5 and 90 days post PCI. At 3-5 days post PCI, patients were compared based on IS as percentage of LV mass (group 1 ≤25%, group 2 >25%). Selection of IS threshold was performed post hoc.

RESULTS

Fifty patients were enrolled from April 2017 to May 2018. At 90 days, group 1 (IS ≤25%) exhibited improved LV ejection fraction (from 53.1% to 58.9%; P=.001) and group 2 (IS >25%) demonstrated no improvement (from 37.6% to 39.1%; P=.55). LV end-diastolic volume and end-systolic volume were unchanged in group 1 and worsened in group 2. There was correlation between 3-5 day and 30-day CMR measurements of IS and 90-day echocardiography-derived LV ejection fraction.

CONCLUSIONS

Immediate 3-5 day post-therapy IS by CMR correlates with 90-day echocardiographic LVEF and indices of remodeling. Patients with post-therapy IS >25% demonstrated evidence of adverse remodeling. Larger studies are needed to corroborate these findings with implications on patient management and prognosis.

Myocardial Contractile Mechanics in Ischemic Mitral Regurgitation: Multicenter Data Using Stress Perfusion Cardiovascular Magnetic Resonance

BACKGROUND

Left ventricular (LV) ischemia has been variably associated with functional mitral regurgitation (FMR). Determinants of FMR in patients with ischemia are poorly understood.

OBJECTIVES

This study sought to test whether contractile mechanics in ischemic myocardium underlying the mitral valve have an impact on likelihood of FMR.

METHODS

Vasodilator stress perfusion cardiac magnetic resonance was performed in patients with coronary artery disease (CAD) at multiple centers. FMR severity was confirmed quantitatively via core lab analysis. To test relationship of contractile mechanics with ischemic FMR, regional wall motion and strain were assessed in patients with inducible ischemia and minimal (≤5% LV myocardium, nontransmural) infarction.

RESULTS

A total of 2,647 patients with CAD were studied; 34% had FMR (7% moderate or greater). FMR severity increased with presence (P < 0.001) and extent (P = 0.01) of subpapillary ischemia: patients with moderate or greater FMR had more subpapillary ischemia (odds ratio [OR]: 1.13 per 10% LV; 95% CI: 1.05-1.21; P = 0.001) independent of ischemia in remote regions (P = NS); moderate or greater FMR prevalence increased stepwise with extent of ischemia and infarction in subpapillary myocardium (P < 0.001); stronger associations between FMR and infarction paralleled greater wall motion scores in infarct-affected territories. Among patients with inducible ischemia and minimal infarction (n = 532), wall motion and radial strain analysis showed impaired subpapillary contractile mechanics to associate with moderate or greater FMR (P < 0.05) independent of remote regions (P = NS). Conversely, subpapillary ischemia without contractile dysfunction did not augment FMR likelihood. Mitral and interpapillary dimensions increased with subpapillary radial strain impairment; each remodeling parameter associated with impaired subpapillary strain (P < 0.05) independent of remote strain (P = NS). Subpapillary radial strain (OR: 1.13 per 5% [95% CI: 1.02-1.25]; P = 0.02) and mitral tenting area (OR: 1.05 per 10 mm2 [95% CI: 1.00-1.10]; P = 0.04) were associated with moderate or greater FMR controlling for global remodeling represented by LV end-systolic volume (P = NS): when substituting sphericity for LV volume, moderate or greater FMR remained independently associated with subpapillary radial strain impairment (OR: 1.22 per 5% [95% CI: 1.02-1.47]; P = 0.03).

CONCLUSIONS

Among patients with CAD and ischemia, FMR severity and adverse mitral apparatus remodeling increase in proportion to contractile dysfunction underlying the mitral valve.

Cardiovascular magnetic resonance imaging in suspected cardiac tumour: a multicentre outcomes study

AIMS

Cardiovascular magnetic resonance (CMR) imaging is a key diagnostic tool for the evaluation of patients with suspected cardiac tumours. Patient management is guided by the CMR diagnosis, including no further testing if a mass is excluded or if only a pseudomass is found. However, there are no outcomes studies validating this approach.

METHODS AND RESULTS

In this multicentre study of patients undergoing clinical CMR for suspected cardiac tumour, CMR diagnoses were assigned as no mass, pseudomass, thrombus, benign tumour, or malignant tumour. A final diagnosis was determined after follow-up using all available data. The primary endpoint was all-cause mortality. Among 903 patients, the CMR diagnosis was no mass in 25%, pseudomass in 16%, thrombus in 16%, benign tumour in 17%, and malignant tumour in 23%. Over a median of 4.9 years, 376 patients died. Compared with the final diagnosis, the CMR diagnosis was accurate in 98.4% of patients. Patients with CMR diagnoses of pseudomass and benign tumour had similar mortality to those with no mass, whereas those with malignant tumour [hazard ratio (HR) 3.31 (2.40-4.57)] and thrombus [HR 1.46 (1.00-2.11)] had greater mortality. The CMR diagnosis provided incremental prognostic value over clinical factors including left ventricular ejection fraction, coronary artery disease, and history of extracardiac malignancy (P < 0.001).

CONCLUSION

In patients with suspected cardiac tumour, CMR has high diagnostic accuracy. Patients with CMR diagnoses of no mass, pseudomass, and benign tumour have similar long-term mortality. The CMR diagnosis is a powerful independent predictor of mortality incremental to clinical risk factors.

Double spectral attenuated inversion recovery (DSPAIR)-an efficient fat suppression technique for late gadolinium enhancement at 3 tesla

Despite clinical use of late gadolinium enhancement (LGE) for two decades, an efficient, robust fat suppression (FS) technique still does not exist for this CMR mainstay. In ischemic and non-ischemic heart disease, differentiating fibrotic tissue from infiltrating and adjacent fat is crucial. Multiple groups have independently developed an FS technique for LGE, double spectral attenuated inversion recovery (DSPAIR), but no comprehensive evaluation was performed. This study aims to fill this gap. DSPAIR uses two SPAIR pulses and one non-selective IR pulse to enable FS LGE, including compatibility with phase sensitive inversion recovery (PSIR). We implemented a magnitude (MAGN) and a PSIR variant and compared them with LGE without FS (CONTROL) and with spectral presaturation with inversion recovery (SPIR) in simulations, phantoms, and patients. Fat magnetization by SPIR, MAGN DSPAIR, and PSIR DSPAIR was simulated as a function of pulse B₁ , readout (RO) pulse number, and fat T_I . A phantom with fat, fibrosis, and myocardium compartments was imaged using all FS methods and modifying pulse B₁ , RO pulse number, and heart rate. Signal was measured in SNR units. Fat, myocardium, and fibrosis SNR and fibrosis-to-fat CNR were obtained. Patient images were acquired with all FS techniques. Fat, myocardium, and fibrosis SNR, fibrosis-to-fat CNR, and image and FS quality were assessed. In the phantom, both DSPAIR variants provided superior FS compared with SPIR, independent of heart rate and RO pulse number. MAGN DSPAIR reduced fat signal by 99% compared with CONTROL, PSIR DSPAIR by 116%, and SPIR by 67% (25 RO pulses). In patients, both DSPAIR variants substantially reduced fat signal (MAGN DSPAIR by 87.1% ± 10.0%, PSIR DSPAIR by 130.5% ± 36.3%), but SPIR did not (35.8% ± 25.5%). FS quality was good to excellent for MAGN and PSIR DSPAIR, and moderate to poor for SPIR. DSPAIR provided highly effective FS across a wide range of parameters. PSIR DSPAIR performed best.

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

Cardiac 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.

Prognostic Value of Feature-Tracking Right Ventricular Longitudinal Strain in Severe Functional Tricuspid Regurgitation: A Multicenter Study

OBJECTIVES

This study sought to evaluate the prognostic value of cardiac magnetic resonance (CMR) feature-tracking-derived right ventricular (RV) free wall longitudinal strain (RVFWLS) in a large multicenter population of patients with severe functional tricuspid regurgitation.

BACKGROUND

Tricuspid regurgitation imposes a volume overload on the RV that can lead to progressive RV dilation and dysfunction. Overt RV dysfunction is associated with poor prognosis and increased operative risk. Abnormalities of myocardial strain may provide the earliest evidence of ventricular dysfunction. CMR feature-tracking techniques now allow assessment of strain from routine cine images, without specialized pulse sequences. Whether abnormalities of RV strain measured using CMR feature tracking have prognostic value in patients with tricuspid regurgitation is unknown.

METHODS

Consecutive patients with severe functional tricuspid regurgitation undergoing CMR at 4 U.S. medical centers were included in this study. Feature-tracking RVFWLS was calculated from 4-chamber cine views. The primary endpoint was all-cause death. Cox proportional hazards regression modeling was used to examine the independent association between RVFWLS and death. The incremental prognostic value of RVFWLS was assessed in nested models.

RESULTS

Of the 544 patients in this study, 128 died during a median follow-up of 6 years. By Kaplan-Meier analysis, patients with RVFWLS ≥median (-16%) had significantly reduced event-free survival compared with those with RVFWLS 

CONCLUSIONS

CMR feature-tracking-derived RVFWLS is an independent predictor of mortality in patients with severe functional tricuspid regurgitation, incremental to common clinical and imaging risk factors.

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Key Words

• cardiac magnetic resonance
• feature tracking
• global longitudinal strain
• mortality
• prognosis
• right ventricular function
• tricuspid regurgitation

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MESH Headings

• Heart Ventricles
• Humans
• Predictive Value of Tests
• Prognosis
• Tricuspid Valve Insufficiency/diagnostic imaging
• Ventricular Dysfunction, Right/diagnostic imaging

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Grants

• R01 HL128278 NHLBI NIH HHS
• T32 HL160520 NHLBI NIH HHS

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Segment Length in Cine Strain Analysis Predicts Cardiac Resynchronization Therapy Outcome Beyond Current Guidelines

BACKGROUND

Patients with a class I recommendation for cardiac resynchronization therapy (CRT) are likely to benefit, but the effect of CRT in class II patients is more heterogeneous and additional selection parameters are needed in this group. The recently validated segment length in cine strain analysis of the septum (SLICE-ESS_sep) measurement on cardiac magnetic resonance cine imaging predicts left ventricular functional recovery after CRT but its prognostic value is unknown. This study sought to evaluate the prognostic value of SLICE-ESS_sep for clinical outcome after CRT.

METHODS

Two hundred eighteen patients with a left bundle branch block or intraventricular conduction delay and a class I or class II indication for CRT who underwent preimplantation cardiovascular magnetic resonance examination were enrolled. SLICE-ESS_sep was manually measured on standard cardiovascular magnetic resonance cine imaging. The primary combined end point was all-cause mortality, left ventricular assist device, or heart transplantation. Secondary end points were (1) appropriate implantable cardioverter defibrillator therapy and (2) heart failure hospitalization.

RESULTS

Two-thirds (65%) of patients had a positive SLICE-ESS_sep ≥0.9% (ie, systolic septal stretching). During a median follow-up of 3.8 years, 66 (30%) patients reached the primary end point. Patients with positive SLICE-ESS_sep were at lower risk to reach the primary end point (hazard ratio 0.36; P<0.001) and heart failure hospitalization (hazard ratio 0.41; P=0.019), but not for implantable cardioverter defibrillator therapy (hazard ratio, 0.66; P=0.272). Clinical outcome of class II patients with a positive ESS_sep was similar to those of class I patients (hazard ratio, 1.38 [95% CI, 0.66-2.88]; P=0.396).

CONCLUSIONS

Strain assessment of the septum (SLICE-ESS_sep) provides a prognostic measure for clinical outcome after CRT. Detection of a positive SLICE-ESS_sep in patients with a class II indication predicts improved CRT outcome similar to those with a class I indication whereas SLICE-ESS_sep negative patients have poor prognosis after CRT implantation.

Patients With Acute Myocarditis Following mRNA COVID-19 Vaccination

Importance

Vaccine-associated myocarditis is an unusual entity that has been described for the smallpox vaccine, but only anecdotal case reports have been described for other vaccines. Whether COVID-19 vaccination may be linked to the occurrence of myocarditis is unknown.

Objective

To describe a group of 7 patients with acute myocarditis over 3 months, 4 of whom had recent messenger RNA (mRNA) COVID-19 vaccination.

Design, Setting, and Participants

All patients referred for cardiovascular magnetic resonance imaging at Duke University Medical Center were asked to participate in a prospective outcomes registry. Two searches of the registry database were performed: first, to identify patients with acute myocarditis for the 3-month period between February 1 and April 30 for 2017 through 2021, and second, to identify all patients with possible vaccine-associated myocarditis for the past 20 years. Once patients with possible vaccine-associated myocarditis were identified, data available in the registry were supplemented by additional data collection from the electronic health record and a telephone interview.

Exposures

mRNA COVID-19 vaccine.

Main Outcomes and Measures

Occurrence of acute myocarditis by cardiovascular magnetic resonance imaging.

Results

In the 3-month period between February 1 and April 30, 2021, 7 patients with acute myocarditis were identified, of which 4 occurred within 5 days of COVID-19 vaccination. Three were younger male individuals (age, 23-36 years) and 1 was a 70-year-old female individual. All 4 had received the second dose of an mRNA vaccine (2 received mRNA-1273 [Moderna], and 2 received BNT162b2 [Pfizer]). All presented with severe chest pain, had biomarker evidence of myocardial injury, and were hospitalized. Coincident testing for COVID-19 and respiratory viruses provided no alternative explanation. Cardiac magnetic resonance imaging findings were typical for myocarditis, including regional dysfunction, late gadolinium enhancement, and elevated native T1 and T2.

Conclusions and Relevance

In this study, magnetic resonance imaging findings were found to be consistent with acute myocarditis in 7 patients; 4 of whom had preceding COVID-19 vaccination. Further investigation is needed to determine associations of COVID-19 vaccination and myocarditis.

Antioxidant effects on hypoxia-induced oxidative stress and apoptosis in rat rotator cuff fibroblasts

Most cells, highly sensitive to oxygen levels, undergo apoptosis under hypoxia. Therefore, the involvement of hypoxia in rotator cuff tendon degeneration has been proposed. While previous studies have reported that hypoxia induces apoptosis in rotator cuff fibroblasts (RCFs), little research has investigated whether antioxidants have cytoprotective effects against RCF apoptosis. The present study aimed at determining whether the antioxidant N-acetylcysteine (NAC) exerted cytoprotective effects against hypoxia-induced RCF apoptosis. Third-passage rat RCFs were divided into normoxia, NAC, hypoxia and NAC-hypoxia groups. The hypoxia inducer was 1,000 µmol/L cobalt chloride (CoCl2); the antioxidant was 20 mmol/L NAC. Expressions of hypoxia-inducible factor-1α (HIF-1α) and heme oxygenase-1 (HO-1), cell viability, intracellular reactive oxygen species (ROS) production, apoptosis rates as well as expressions of cleaved caspase-3, cleaved poly ADP-ribose polymerase-1 (PARP-1), vascular endothelial growth factors-β (VEGF-β) and matrix metalloproteinase-2 (MMP-2) were evaluated. Expression of HIF-1α and HO-1 was significantly higher in the hypoxia group than in the normoxia group (p < 0.001). Cell viability was significantly lower in the hypoxia group than in the normoxia group (p < 0.001). Intracellular ROS production, apoptosis rate and expressions of cleaved caspase-3, cleaved PARP-1, VEGF-β and MMP-2 were significantly higher in the hypoxia group than in the normoxia group (p < 0.001). All these responses were significantly attenuated by pre-treatment with NAC (p ≤ 0.001). ROS were involved in hypoxic RCF apoptosis induced by CoCl2; NAC, an ROS scavenger, inhibited hypoxia-induced RCF apoptosis by inhibiting ROS production.

Risk stratification of cardiac metastases using late gadolinium enhancement cardiovascular magnetic resonance: prognostic impact of hypo-enhancement evidenced tumor avascularity

BACKGROUND

Late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) is widely used to identify cardiac neoplasms, for which diagnosis is predicated on enhancement stemming from lesion vascularity: Impact of contrast-enhancement pattern on clinical outcomes is unknown. The objective of this study was to determine whether cardiac metastasis (CMET) enhancement pattern on LGE-CMR impacts prognosis, with focus on heterogeneous lesion enhancement as a marker of tumor avascularity.

METHODS

Advanced (stage IV) systemic cancer patients with and without CMET matched (1:1) by cancer etiology underwent a standardized CMR protocol. CMET was identified via established LGE-CMR criteria based on lesion enhancement; enhancement pattern was further classified as heterogeneous (enhancing and non-enhancing components) or diffuse and assessed via quantitative (contrast-to-noise ratio (CNR); signal-to-noise ratio (SNR)) analyses. Embolic events and mortality were tested in relation to lesion location and contrast-enhancement pattern.

RESULTS

224 patients were studied, including 112 patients with CMET and unaffected (CMET -) controls matched for systemic cancer etiology/stage. CMET enhancement pattern varied (53% heterogeneous, 47% diffuse). Quantitative analyses were consistent with lesion classification; CNR was higher and SNR lower in heterogeneously enhancing CMET (p < 0.001)-paralleled by larger size based on linear dimensions (p < 0.05). Contrast-enhancement pattern did not vary based on lesion location (p = NS). Embolic events were similar between patients with diffuse and heterogeneous lesions (p = NS) but varied by location: Patients with right-sided lesions had threefold more pulmonary emboli (20% vs. 6%, p = 0.02); those with left-sided lesions had lower rates equivalent to controls (4% vs. 5%, p = 1.00). Mortality was higher among patients with CMET (hazard ratio [HR] = 1.64 [CI 1.17-2.29], p = 0.004) compared to controls, but varied by contrast-enhancement pattern: Diffusely enhancing CMET had equivalent mortality to controls (p = 0.21) whereas prognosis was worse with heterogeneous CMET (p = 0.005) and more strongly predicted by heterogeneous enhancement (HR = 1.97 [CI 1.23-3.15], p = 0.005) than lesion size (HR = 1.11 per 10 cm [CI 0.53-2.33], p = 0.79).

CONCLUSIONS

Contrast-enhancement pattern and location of CMET on CMR impacts prognosis. Embolic events vary by CMET location, with likelihood of PE greatest with right-sided lesions. Heterogeneous enhancement-a marker of tumor avascularity on LGE-CMR-is a novel marker of increased mortality risk.

Cardiovascular magnetic resonance accurately detects obstructive coronary artery disease in suspected non-ST elevation myocardial infarction: a sub-analysis of the CARMENTA Trial

BACKGROUND

Invasive coronary angiography (ICA) is still the reference test in suspected non-ST elevation myocardial infarction (NSTEMI), although a substantial number of patients do not have obstructive coronary artery disease (CAD). Early cardiovascular magnetic resonance (CMR) may be a useful gatekeeper for ICA in this setting. The main objective was to investigate the accuracy of CMR to detect obstructive CAD in NSTEMI.

METHODS

This study is a sub-analysis of a randomized controlled trial investigating whether a non-invasive imaging-first strategy safely reduced the number of ICA compared to routine clinical care in suspected NSTEMI (acute chest pain, non-diagnostic electrocardiogram, high sensitivity troponin T > 14 ng/L), and included 51 patients who underwent CMR prior to ICA. A stepwise approach was used to assess the diagnostic accuracy of CMR to detect (1) obstructive CAD (diameter stenosis ≥ 70% by ICA) and (2) an adjudicated final diagnosis of acute coronary syndrome (ACS). First, in all patients the combination of cine, T2-weighted and late gadolinium enhancement (LGE) imaging was evaluated for the presence of abnormalities consistent with a coronary etiology in any sequence. Hereafter and only when the scan was normal or equivocal, adenosine stress-perfusion CMR was added.

RESULTS

Of 51 patients included (63 ± 10 years, 51% male), 34 (67%) had obstructive CAD by ICA. The sensitivity, specificity and overall accuracy of the first step to diagnose obstructive CAD were 79%, 71% and 77%, respectively. Additional vasodilator stress-perfusion CMR was performed in 19 patients and combined with step one resulted in an overall sensitivity of 97%, specificity of 65% and accuracy of 86%. Of the remaining 17 patients with non-obstructive CAD, 4 (24%) had evidence for a myocardial infarction on LGE, explaining the modest specificity. The sensitivity, specificity and overall accuracy to diagnose ACS (n = 43) were 88%, 88% and 88%, respectively.

CONCLUSION

CMR accurately detects obstructive CAD and ACS in suspected NSTEMI. Non-obstructive CAD is common with CMR still identifying an infarction in almost one-quarter of patients. CMR should be considered as an early diagnostic approach in suspected NSTEMI.

TRIAL REGISTRATION

The CARMENTA trial has been registered at ClinicalTrials.gov with identifier NCT01559467.

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

BACKGROUND

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.

Relationship of LVEF and Myocardial Scar to Long-Term Mortality Risk and Mode of Death in Patients With Nonischemic Cardiomyopathy

BACKGROUND

Nonischemic cardiomyopathy is a leading cause of reduced left ventricular ejection fraction (LVEF) and is associated with high mortality risk from progressive heart failure and arrhythmias. Myocardial scar on cardiovascular magnetic resonance imaging is increasingly recognized as a risk marker for adverse outcomes; however, left ventricular dysfunction remains the basis for determining a patient's eligibility for primary prophylaxis with implantable cardioverter-defibrillator. We investigated the relationship of LVEF and scar with long-term mortality and mode of death in a large cohort of patients with nonischemic cardiomyopathy.

METHODS

This study is a prospective, longitudinal outcomes registry of 1020 consecutive patients with nonischemic cardiomyopathy who underwent clinical cardiovascular magnetic resonance imaging for the assessment of LVEF and scar at 3 centers.

RESULTS

During a median follow-up of 5.2 (interquartile range, 3.8, 6.6) years, 277 (27%) patients died. On survival analysis, LVEF ≤35% and scar were strongly associated with all-cause (log-rank test P=0.002 and P<0.001, respectively) and cardiac death (P=0.001 and P<0.001, respectively). Whereas scar was strongly related to sudden cardiac death (SCD; P=0.001), there was no significant association between LVEF ≤35% and SCD risk (P=0.57). On multivariable analysis including established clinical factors, LVEF and scar are independent risk markers of all-cause and cardiac death. The addition of LVEF provided incremental prognostic value but insignificant discrimination improvement by C-statistic for all-cause and cardiac death, but no incremental prognostic value for SCD. Conversely, scar extent demonstrated significant incremental prognostic value and discrimination improvement for all 3 end points. On net reclassification analysis, the addition of LVEF resulted in no significant improvement for all-cause death (11.0%; 95% CI, -6.2% to 25.9%), cardiac death (9.8%; 95% CI, -5.7% to 29.3%), or SCD (7.5%; 95% CI, -41.2% to 42.9%). Conversely, the addition of scar extent resulted in significant reclassification improvement of 25.5% (95% CI, 11.7% to 41.0%) for all-cause death, 27.0% (95% CI, 11.6% to 45.2%) for cardiac death, and 40.6% (95% CI, 10.5% to 71.8%) for SCD.

CONCLUSIONS

Myocardial scar and LVEF are both risk markers for all-cause and cardiac death in patients with nonischemic cardiomyopathy. However, whereas myocardial scar has strong and incremental prognostic value for SCD risk stratification, LVEF has no incremental prognostic value over clinical measures. Scar assessment should be incorporated into patient selection criteria for primary prevention implantable cardioverter-defibrillator placement.

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.

Comparison of magnetization transfer-preparation and T2-preparation for dark-blood delayed-enhancement imaging

Recently developed dark-blood techniques such as Flow-Independent Dark-blood DeLayed Enhancement (FIDDLE) allow simultaneous visualization of tissue contrast-enhancement and blood-pool suppression. Critical to FIDDLE is the magnetization preparation, which accentuates differences between myocardium and blood-pool. Here, we compared magnetization transfer (MT)-preparation and T2-preparation for use with FIDDLE. Variants of FIDDLE were developed with MT- or T2-preparation modules and tested in 35 patients (11 at 1.5 T, 24 at 3 T). Images were acquired with each FIDDLE variant in an interleaved fashion 10 minutes after gadolinium administration with otherwise identical acquisition parameters. Images were visually and quantitatively assessed for artifacts and differences in right ventricle to left ventricle (RV-to-LV) blood-pool suppression. Bright artifacts, reflecting incomplete blood-pool suppression, were frequently observed in the left atrium with T2-preparation FIDDLE at 1.5 and 3 T (82% and up to 100% of patients, respectively). MT-preparation FIDDLE resulted in fewer patients with artifacts (0% at 1.5 T, 22% at 3 T; P < .01). Left atrial blood-pool signal was significantly more homogeneous with MT-preparation than with T2-preparation at 1.5 and 3 T (P < .001 for all comparisons). Visibly different RV-to-LV blood-pool suppression was observed with T2-preparation in 36% of patients at 1.5 T and up to 94% at 3 T. In these patients, RV blood-pool signal was elevated, reducing the conspicuity of the myocardial-RV blood-pool border. Conversely, there were no visible differences in RV-to-LV blood-pool suppression with MT-preparation. Quantitative assessment of differences in blood-pool suppression and blood-pool artifacts was consistent with visual analyses. We conclude that for dark blood-blood delayed-enhancement imaging of the heart, MT-preparation results in fewer bright blood-pool artifacts and more uniform blood-pool suppression than T2-preparation.

Late Gadolinium Enhancement Cardiac Magnetic Resonance Tissue Characterization for Cancer-Associated Cardiac Masses: Metabolic and Prognostic Manifestations in Relation to Whole-Body Positron Emission Tomography

Background

Cardiac magnetic resonance (CMR) differentiates neoplasm from thrombus via contrast enhancement; positron emission tomography (PET) assesses metabolism. The relationship between CMR contrast enhancement and metabolism on PET is unknown.

Methods and Results

The population included 121 cancer patients undergoing CMR and ¹⁸F‐fluorodeoxyglucose (¹⁸F‐FDG)–PET, including 66 with cardiac masses and cancer‐matched controls. Cardiac mass etiology (neoplasm, thrombus) on CMR was defined by late gadolinium enhancement; PET was read blinded to CMR for diagnostic performance, then colocalized to measure FDG avidity. Of CMR‐evidenced thrombi (all nonenhancing), none were detected by PET. For neoplasm, PET yielded reasonable sensitivity (70–83%) and specificity (75–88%). Lesions undetected by PET were more likely to be highly mobile (P=0.001) despite similar size (P=0.33). Among nonmobile neoplasms, PET sensitivity varied in relation to extent of CMR‐evidenced avascularity; detection of diffusely enhancing or mixed lesions was higher versus predominantly avascular neoplasms (87% versus 63%). Colocalized analyses demonstrated 2‐ to 4‐fold higher FDG uptake in neoplasm versus thrombus (P<0.001); FDG uptake decreased stepwise when neoplasms were partitioned based on extent of avascularity on late gadolinium enhancement CMR (P≤0.001). Among patients with neoplasm, signal‐to‐noise ratio on late gadolinium enhancement CMR moderately correlated with standardized uptake values on PET (r=0.42–0.49, P<0.05). Mortality was higher among patients with CMR‐evidenced neoplasm versus controls (hazard ratio: 1.99 [95% CI, 1.1–3.6]; P=0.03) despite nonsignificant differences when partitioned via FDG avidity (hazard ratio: 1.56 [95% CI, 0.85–2.74]; P=0.16). Among FDG‐positive neoplasms detected concordantly with CMR, mortality risk versus cancer‐matched controls was equivalently increased (hazard ratio: 2.12 [95% CI, 1.01–4.44]; P=0.047).

Conclusions

CMR contrast enhancement provides a criterion for neoplasm that parallels FDG‐evidenced metabolic activity and stratifies prognosis. Extent of tissue avascularity on late gadolinium enhancement CMR affects cardiac mass identification by FDG‐PET.

Effects of the chymase inhibitor fulacimstat on adverse cardiac remodeling after acute myocardial infarction-Results of the Chymase Inhibitor in Adverse Remodeling after Myocardial Infarction (CHIARA MIA) 2 trial

BACKGROUND

Adverse cardiac remodeling is a major risk factor for the development of post myocardial infarction (MI) heart failure (HF). This study investigates the effects of the chymase inhibitor fulacimstat on adverse cardiac remodeling after acute ST-segment-elevation myocardial infarction (STEMI).

METHODS

In this double-blind, randomized, placebo-controlled trial patients with first STEMI were eligible. To preferentially enrich patients at high risk of adverse remodeling, main inclusion criteria were a left-ventricular ejection fraction (LVEF) ≤45% and an infarct size >10% on day 5 to 9 post MI as measured by cardiac MRI. Patients were then randomized to 6 months treatment with either 25 mg fulacimstat (n = 54) or placebo (n = 53) twice daily on top of standard of care starting day 6 to 12 post MI. The changes in LVEF, LV end-diastolic volume index (LVEDVI), and LV end-systolic volume index (LVESVI) from baseline to 6 months were analyzed by a central blinded cardiac MRI core laboratory.

RESULTS

Fulacimstat was safe and well tolerated and achieved mean total trough concentrations that were approximately tenfold higher than those predicted to be required for minimal therapeutic activity. Comparable changes in LVEF (fulacimstat: 3.5% ± 5.4%, placebo: 4.0% ± 5.0%, P = .69), LVEDVI (fulacimstat: 7.3 ± 13.3 mL/m², placebo: 5.1 ± 18.9 mL/m², P = .54), and LVESVI (fulacimstat: 2.3 ± 11.2 mL/m², placebo: 0.6 ± 14.8 mL/m², P = .56) were observed in both treatment arms.

CONCLUSION

Fulacimstat was safe and well tolerated in patients with left-ventricular dysfunction (LVD) after first STEMI but had no effect on cardiac remodeling.

Standardized image interpretation and post-processing in cardiovascular magnetic resonance - 2020 update : Society for Cardiovascular Magnetic Resonance (SCMR): Board of Trustees Task Force on Standardized Post-Processing

With mounting data on its accuracy and prognostic value, cardiovascular magnetic resonance (CMR) is becoming an increasingly important diagnostic tool with growing utility in clinical routine. Given its versatility and wide range of quantitative parameters, however, agreement on specific standards for the interpretation and post-processing of CMR studies is required to ensure consistent quality and reproducibility of CMR reports. This document addresses this need by providing consensus recommendations developed by the Task Force for Post-Processing of the Society for Cardiovascular Magnetic Resonance (SCMR). The aim of the Task Force is to recommend requirements and standards for image interpretation and post-processing enabling qualitative and quantitative evaluation of CMR images. Furthermore, pitfalls of CMR image analysis are discussed where appropriate. It is an update of the original recommendations published 2013.

Standardized cardiovascular magnetic resonance imaging (CMR) protocols: 2020 update

This document is an update to the 2013 publication of the Society for Cardiovascular Magnetic Resonance (SCMR) Board of Trustees Task Force on Standardized Protocols. Concurrent with this publication, 3 additional task forces will publish documents that should be referred to in conjunction with the present document. The first is a document on the Clinical Indications for CMR, an update of the 2004 document. The second task force will be updating the document on Reporting published by that SCMR Task Force in 2010. The 3rd task force will be updating the 2013 document on Post-Processing. All protocols relative to congenital heart disease are covered in a separate document.The section on general principles and techniques has been expanded as more of the techniques common to CMR have been standardized. A section on imaging in patients with devices has been added as this is increasingly seen in day-to-day clinical practice. The authors hope that this document continues to standardize and simplify the patient-based approach to clinical CMR. It will be updated at regular intervals as the field of CMR advances.

Effects of Elamipretide on Left Ventricular Function in Patients With Heart Failure With Reduced Ejection Fraction: The PROGRESS-HF Phase 2 Trial

BACKGROUND

Elamipretide, a novel mitochondrial modulating agent, improves myocardial energetics; however, it is unknown whether this mechanistic benefit translates into improved cardiac structure and function in heart failure (HF) with reduced ejection fraction (HFrEF). The objective of this study was to evaluate the effects of multiple subcutaneous doses of elamipretide on left ventricular end systolic volume (LVESV) as assessed by cardiac magnetic resonance imaging.

METHODS

We randomized 71 patients with HFrEF (LVEF ≤ 40%) in a double-blind, placebo-controlled trial in a 1:1:1 ratio to receive placebo, 4 mg or 40 mg elamipretide once daily for 28 consecutive days.

RESULTS

The mean age (standard deviation) of the study population was 65 ± 10 years, 24% were females, and the mean EF was 31% ± 7%. The change in LVESV from baseline to week 4 was not significantly different between elamipretide 4 mg (89.4 mL to 85 mL; difference, -4.4 mL) or 40 mg (77.9 mL to 76.6 mL; difference, -1.2 mL) compared with placebo (77.7 mL to 74.6 mL; difference, -3.8 mL) (4 mg vs placebo: difference of means, -0.3; 95% CI, -4.6 to 4.0; P  =  0.90; and 40 mg vs placebo: difference of means, 2.3; 95% CI, -1.9 to 6.5; P  =  0.28). Also, no significant differences in change in LVESV and LVEF were observed between placebo and either of the elamipretide groups. Rates of any study drug-related adverse events were similar in the 3 groups.

CONCLUSIONS

Elamipretide was well tolerated but did not improve LVESV at 4 weeks in patients with stable HFrEF compared with placebo.

Feature-Tracking Global Longitudinal Strain Predicts Mortality in Patients With Preserved Ejection Fraction: A Multicenter Study

OBJECTIVES

The goal of this study was to evaluate the prognostic value of global longitudinal strain (GLS) derived from cardiac magnetic resonance (CMR) feature-tracking in a large multicenter population of patients with preserved ejection fraction.

BACKGROUND

Ejection fraction is the principal parameter used clinically to assess cardiac mechanics and provides prognostic information. However, significant abnormalities of myocardial deformation can be present despite preserved ejection fraction. CMR feature-tracking techniques now allow assessment of strain from routine cine images, without specialized pulse sequences. Whether abnormalities of strain measured by using CMR feature-tracking have prognostic value in patients with preserved ejection fraction is unknown.

METHODS

Consecutive patients with preserved ejection fraction (≥50%) and a clinical indication for CMR at 4 U.S. medical centers were included in this retrospective study. Feature-tracking GLS was calculated from 3 long-axis cine views. The primary endpoint was all-cause death. Cox proportional hazards regression modeling was used to examine the independent association between GLS and death. The incremental prognostic value of GLS was assessed in nested models.

RESULTS

Of the 1,274 patients in this study, 115 died during a median follow-up of 6.2 years. By Kaplan-Meier analysis, patients with GLS ≥ median (-20%) had significantly reduced event-free survival compared with those with GLS < median (log-rank test, p < 0.001). By Cox multivariable regression modeling, each 1% worsening in GLS was associated with a 22.8% increased risk of death after adjustment for clinical and imaging risk factors (hazard ratio: 1.228 per percent; p < 0.001). Addition of GLS in this model resulted in significant improvement in the global chi-square test (94 to 183; p < 0.001) and Harrell's C-statistic (0.75 to 0.83; p < 0.001).

CONCLUSIONS

GLS derived from CMR feature-tracking is a powerful independent predictor of mortality in patients with preserved ejection fraction, incremental to common clinical and imaging risk factors.

Diastolic Dysfunction in Patients With Human Immunodeficiency Virus Receiving Antiretroviral Therapy: Results From the CHART Study

BACKGROUND

Diastolic dysfunction (DD) is common and occurs at an earlier age among human immunodeficiency virus-infected (HIV+) individuals, but the mechanisms and consequences of DD among HIV+ individuals are unclear.

METHODS AND RESULTS

The Characterization of Heart Function on Antiretroviral Therapy (CHART) study was a multicenter cross-sectional case-control study of treated and virally suppressed HIV+ individuals with (DD+) and without DD (DD-). All patients had normal ejection fraction (>50%), no significant valvular disease, and no history of coronary revascularization or persistent atrial fibrillation. Overall, 94 DD+ and 101 DD- patients were included. DD+ patients were older with higher body mass index (BMI) and more likely to have hypertension, renal dysfunction, and dyslipidemia. Groups were similar with respect to sex, race, CD4 count, and HIV RNA copies. N-terminal pro-B-type natriuretic peptide levels (median 36 [23, 85] vs 26 [12, 49] pg/mL, P < .01) and high-sensitivity troponin I (3.6 [2.6, 5.1] vs 2.5 [1.8, 3.5] pg/mL, P < .01) were higher among DD+ patients. The latter had similar left atrial size, but increased stiffness (conduit strain: 23.5 [17.5, 36.9] vs 30.0 [22.9, 37.0], P < .01) and impaired relaxation (reservoir strain: 39.7 [32.0, 58.0] vs 45.9 [37.0, 60.6], P = .04). On cardiac magnetic resonance, the prevalence of focal fibrosis was higher among DD+ patients (19.0% vs 5.3%, P < .01). DD+ patients demonstrated higher levels of carboxyl-terminal telopeptide of collagen type I (P = .04), and trends toward higher interleukin-6 and oxidized low-density lipoprotein levels (P ≤ .08). Kansas City Cardiomyopathy Questionnaire physical limitation (87.1±21.4 vs 93.1±18.1, P = .01) and symptom frequency scores were lower among DD+ patients (86.0±21.5 vs 92.5±16.8, P = .01).

CONCLUSIONS

In this contemporary HIV+ population receiving antiretroviral therapy, DD was associated with multiple alterations in cardiac structure and function, including myocardial fibrosis and left atrial abnormalities, and worse quality of life. Further studies are needed to assess longitudinal changes in these parameters and their potential as therapeutic targets to prevent progressive cardiac remodeling and dysfunction in HIV.

P1021Comparative efficacy of microfidelity technology vs standard ablation for atrioventricular nodal ablation

Background

Microfidelity Cateter Technology has proven efficacy in ablating atrial arrhythmias in multiple pilot studies. Closely spaced radial microelectrodes render a focused near-field electrogram. Case series suggest that this catheter design facilitates accurate ablations with fewer radiofrequency (RF) lesions. Atrioventricular junction (AVJ) ablation is regarded as a straightforward procedure, but case records show wide variance in procedure times and number of RF lesions required.

Methods

Twenty-four patients scheduled for AVJ ablation were randomized to treatment with either the Microfidelity technology or standard 8mm/8 French ablation catheter. Both groups located the AVJ by fluoroscopic landmarks and His electrograms, and the MiFi group used electroanatomical mapping to create the location of his electrograms. The primary endpoints were development of Junctional Rhythm (JR) or Complete Heart Block (CHB), and time from first RF lesion until rhythm change. Secondary endpoints included number of RF applications.

Results

Patients were randomized one-to-one to the MiFi arm or standard ablation arm. JR or CHB was achieved in all patients. Time from first RF lesion until JR/CHB was: (Median/IQR) 325 sec/250–1270 sec. vs 287 sec/101–406 sec. Number of RF applications was 5/3–15 applications vs 4.5/1–5 applications. Total procedure time in the lab was 134 min/73.5–172.5 min vs 58 min/52–146 min.

Microfidelity Technology vs Standard

Conclusion

Analysis suggests that the MiFi catheter is efficacious in ablating the AVJ, but requires greater RF duration and number of lesions, with wider case-by-case variability to achieve JR or CHB. Microfidelity technology and electroanatomical mapping did not result in faster time to completion than using fluoroscopic landmarks and His electrograms alone. Preoperative choice of sheath for catheter stability and contact may also play a role in a more efficient timely successful ablation of the AV node.

Acknowledgement/Funding

Boston Scientific

87Effects of the chymase inhibitor fulacimstat on adverse cardiac remodelling after acute myocardial infarction - Results of the CHIARA MIA 2 trial

Introduction

Adverse cardiac remodelling represents the most important risk factor for the development of heart failure (HF) after myocardial infarction (MI). Chymase is a protease that generates locally pro-fibrotic factors such as angiotensin II, TGFβ, and matrixmetallproteases that contribute to tissue remodelling.

Purpose

This phase IIa study examined the effects of the chymase inhibitor fulacimstat on functional parameters of adverse cardiac remodelling after acute MI.

Methods

A double-blind, multinational, randomized, placebo-controlled study was performed in patients after first STEMI who were treated with primary percutaneous coronary intervention within 24h of symptom onset. To enrich for patients at risk of adverse remodelling, main inclusion criteria were a left-ventricular ejection fraction (LVEF)≤45% and an infarct size>10% on day 5 to 9 post MI as measured by cardiac MRI. On day 6 to 12 post MI, patients were randomized to treatment with either 25 mg fulacimstat (n=54) or placebo (n=53) twice daily on top of standard of care. The changes in LVEF, LVEDVI, and LVESVI from baseline to 6 months of treatment were analyzed by a central blinded cardiac MRI core laboratory.

Results

Fulacimstat was safe and well tolerated, 64.8% of patients treated with fulacimstat and 75.5% of patients treated with placebo reported treatment emergent adverse events. Fulacimstat achieved exposures that were approximately 10-fold higher than those predicted to be required for minimal therapeutic activity. After six months of treatment, there were no effects of fulacimstat compared to placebo on the changes in LVEF, LVEDVI, and LVESVI (see Table).

Analysis of primary efficacy parameters Parameter Placebo Fulacimstat p-value LVEF (%) baseline 37.2±6.1 39.1±5.5 0.15 6 months 41.2±8.4 42.6±8.4 0.45 delta 4.0±5.0 3.5±5.4 0.69 LVEDVI (mL/m2) baseline 80.0±17.1 77.4±18.2 0.51 6 months 85.1±19.1 84.7±23.4 0.94 delta 5.1±18.9 7.3±13.3 0.54 LVESVI (mL/m2) baseline 50.5±13.0 47.3±12.3 0.26 6 months 51.1±16.9 49.6±18.1 0.71 delta 0.6±14.8 2.3±11.2 0.56 Data are given as mean ± standard deviation.

Conclusion

Fulacimstat was safe and well tolerated in patients with left-ventricular dysfunction (LVD) after first STEMI but had no effect on adverse cardiac remodelling in the experimental setting of this study.

Acknowledgement/Funding

The study was funded by its sponsor BAYER AG

Cardiac MRI Endpoints in Myocardial Infarction Experimental and Clinical Trials: JACC Scientific Expert Panel

After a reperfused myocardial infarction (MI), dynamic tissue changes occur (edema, inflammation, microvascular obstruction, hemorrhage, cardiomyocyte necrosis, and ultimately replacement by fibrosis). The extension and magnitude of these changes contribute to long-term prognosis after MI. Cardiac magnetic resonance (CMR) is the gold-standard technique for noninvasive myocardial tissue characterization. CMR is also the preferred methodology for the identification of potential benefits associated with new cardioprotective strategies both in experimental and clinical trials. However, there is a wide heterogeneity in CMR methodologies used in experimental and clinical trials, including time of post-MI scan, acquisition protocols, and, more importantly, selection of endpoints. There is a need for standardization of these methodologies to improve the translation into a real clinical benefit. The main objective of this scientific expert panel consensus document is to provide recommendations for CMR endpoint selection in experimental and clinical trials based on pathophysiology and its association with hard outcomes.

Prevalence and Prognosis of Unrecognized Myocardial Infarction in Asymptomatic Patients With Diabetes: A Two-Center Study With Up to 5 Years of Follow-up

OBJECTIVE

To determine the prevalence and prognostic significance of unrecognized myocardial infarction (MI) by delayed-enhancement MRI (DE-MRI) in asymptomatic patients with diabetes.

RESEARCH DESIGN AND METHODS

In this prospective, two-center study of asymptomatic patients without known cardiac disease (n = 120), two prespecified cohorts underwent a research MRI: 1) a high-risk group with type 1 diabetes and chronic renal insufficiency (n = 50) and 2) an average-risk group with type 2 diabetes (n = 70). The primary end point was a composite of all-cause mortality and clinical MI.

RESULTS

Overall, the prevalence of unrecognized MI was 19% by DE-MRI (28% high-risk group and 13% average-risk group) and 5% by electrocardiography. During up to 5 years of follow-up with a total of 460 patient-years of follow-up, the rate of death/MI was markedly higher in patients with diabetes with (vs. without) unrecognized MI (all 44% vs. 7%, high-risk group 43% vs. 6%, and average-risk group 44% vs. 8%; all P < 0.01). After adjustment for Framingham risk score, left ventricular ejection fraction, and diabetes type, the presence of unrecognized MI by DE-MRI conferred an eightfold increase in risk of death/MI (95% CI 3.0-21.1, P < 0.0001). Addition of unrecognized MI to clinical indices significantly improved model discrimination for adverse events (integrated discrimination improvement = 0.156, P = 0.001).

CONCLUSIONS

Unrecognized MI is prevalent in asymptomatic patients with diabetes without a history of cardiac disease and confers a markedly increased risk of death and clinical MI.

Prognostic Value of Vasodilator Stress Cardiac Magnetic Resonance Imaging: A Multicenter Study With 48 000 Patient-Years of Follow-up

Importance

Stress cardiac magnetic resonance imaging (CMR) is not widely used in current clinical practice, and its ability to predict patient mortality is unknown.

Objective

To determine whether stress CMR is associated with patient mortality.

Design, Setting, and Participants

Real-world evidence from consecutive clinically ordered CMR examinations. Multicenter study of patients undergoing clinical evaluation of myocardial ischemia. Patients with known or suspected coronary artery disease (CAD) underwent clinical vasodilator stress CMR at 7 different hospitals. An automated process collected data from the finalized clinical reports, deidentified and aggregated the data, and assessed mortality using the US Social Security Death Index.

Main Outcomes and Measures

All-cause patient mortality.

Results

Of the 9151 patients, the median (interquartile range) patient age was 63 (51-70) years, 55% were men, and the median (interquartile range) body mass index was 29 (25-33) (calculated as weight in kilograms divided by height in meters squared). The multicenter automated process yielded 9151 consecutive patients undergoing stress CMR, with 48 615 patient-years of follow-up. Of these patients, 4408 had a normal stress CMR examination, 4743 had an abnormal examination, and 1517 died during a median follow-up time of 5.0 years. Using multivariable analysis, addition of stress CMR improved prediction of mortality in 2 different risk models (model 1 hazard ratio [HR], 1.83; 95% CI, 1.63-2.06; P < .001; model 2: HR, 1.80; 95% CI, 1.60-2.03; P < .001) and also improved risk reclassification (net improvement: 11.4%; 95% CI, 7.3-13.6; P < .001). After adjustment for patient age, sex, and cardiac risk factors, Kaplan-Meier survival analysis showed a strong association between an abnormal stress CMR and mortality in all patients (HR, 1.883; 95% CI, 1.680-2.112; P < .001), patients with (HR, 1.955; 95% CI, 1.712-2.233; P < .001) and without (HR, 1.578; 95% CI, 1.235-2.2018; P < .001) a history of CAD, and patients with normal (HR, 1.385; 95% CI, 1.194-1.606; P < .001) and abnormal left ventricular ejection fraction (HR, 1.836; 95% CI, 1.299-2.594; P < .001).

Conclusions and Relevance

Clinical vasodilator stress CMR is associated with patient mortality in a large, diverse population of patients with known or suspected CAD as well as in multiple subpopulations defined by history of CAD and left ventricular ejection fraction. These findings provide a foundational motivation to study the comparative effectiveness of stress CMR against other modalities.

Association of left atrial volume index and all-cause mortality in patients referred for routine cardiovascular magnetic resonance: a multicenter study

BACKGROUND

Routine cine cardiovascular magnetic resonance (CMR) allows for the measurement of left atrial (LA) volumes. Normal reference values for LA volumes have been published based on a group of European individuals without known cardiovascular disease (CVD) but not on one of similar United States (US) based volunteers. Furthermore, the association between grades of LA dilatation by CMR and outcomes has not been established. We aimed to assess the relationship between grades of LA dilatation measured on CMR based on US volunteers without known CVD and all-cause mortality in a large, multicenter cohort of patients referred for a clinically indicated CMR scan.

METHOD

We identified 85 healthy US subjects to determine normal reference LA volumes using the biplane area-length method and indexed for body surface area (LAVi). Clinical CMR reports of patients with LA volume measures (n = 11,613) were obtained. Data analysis was performed on a cloud-based system for consecutive CMR exams performed at three geographically distinct US medical centers from August 2008 through August 2017. We identified 10,890 eligible cases. We categorized patients into 4 groups based on LAVi partitions derived from US normal reference values: Normal (21-52 ml/m2), Mild (52-62 ml/m2), Moderate (63-73 ml/m2) and Severe (> 73 ml/m2). Mortality data were ascertained for the patient group using electronic health records and social security death index. Cox proportional hazard risk models were used to derive hazard ratios for measuring association of LA enlargement and all-cause mortality.

RESULTS

The distribution of LAVi from healthy subjects without known CVD was 36.3 ± 7.8 mL/m2. In clinical patients, enlarged LA was associated with older age, atrial fibrillation, hypertension, heart failure, inpatient status and biventricular dilatation. The median follow-up duration was 48.9 (IQR 32.1-71.2) months. On univariate analyses, mild [Hazard Ratio (HR) 1.35 (95% Confidence Interval [CI] 1.11 to 1.65], moderate [HR 1.51 (95% CI 1.22 to 1.88)] and severe LA enlargement [HR 2.14 (95% CI 1.81 to 2.53)] were significant predictors of death. After adjustment for significant covariates, moderate [HR 1.45 (95% CI 1.1 to 1.89)] and severe LA enlargement [HR 1.64 (95% CI 1.29 to 2.08)] remained independent predictors of death.

CONCLUSION

LAVi determined on routine cine-CMR is independently associated with all-cause mortality in patients undergoing a clinically indicated CMR.

Machine learning derived segmentation of phase velocity encoded cardiovascular magnetic resonance for fully automated aortic flow quantification

BACKGROUND

Phase contrast (PC) cardiovascular magnetic resonance (CMR) is widely employed for flow quantification, but analysis typically requires time consuming manual segmentation which can require human correction. Advances in machine learning have markedly improved automated processing, but have yet to be applied to PC-CMR. This study tested a novel machine learning model for fully automated analysis of PC-CMR aortic flow.

METHODS

A machine learning model was designed to track aortic valve borders based on neural network approaches. The model was trained in a derivation cohort encompassing 150 patients who underwent clinical PC-CMR then compared to manual and commercially-available automated segmentation in a prospective validation cohort. Further validation testing was performed in an external cohort acquired from a different site/CMR vendor.

RESULTS

Among 190 coronary artery disease patients prospectively undergoing CMR on commercial scanners (84% 1.5T, 16% 3T), machine learning segmentation was uniformly successful, requiring no human intervention: Segmentation time was < 0.01 min/case (1.2 min for entire dataset); manual segmentation required 3.96 ± 0.36 min/case (12.5 h for entire dataset). Correlations between machine learning and manual segmentation-derived flow approached unity (r = 0.99, p < 0.001). Machine learning yielded smaller absolute differences with manual segmentation than did commercial automation (1.85 ± 1.80 vs. 3.33 ± 3.18 mL, p < 0.01): Nearly all (98%) of cases differed by ≤5 mL between machine learning and manual methods. Among patients without advanced mitral regurgitation, machine learning correlated well (r = 0.63, p < 0.001) and yielded small differences with cine-CMR stroke volume (∆ 1.3 ± 17.7 mL, p = 0.36). Among advanced mitral regurgitation patients, machine learning yielded lower stroke volume than did volumetric cine-CMR (∆ 12.6 ± 20.9 mL, p = 0.005), further supporting validity of this method. Among the external validation cohort (n = 80) acquired using a different CMR vendor, the algorithm yielded equivalently small differences (∆ 1.39 ± 1.77 mL, p = 0.4) and high correlations (r = 0.99, p < 0.001) with manual segmentation, including similar results in 20 patients with bicuspid or stenotic aortic valve pathology (∆ 1.71 ± 2.25 mL, p = 0.25).

CONCLUSION

Fully automated machine learning PC-CMR segmentation performs robustly for aortic flow quantification - yielding rapid segmentation, small differences with manual segmentation, and identification of differential forward/left ventricular volumetric stroke volume in context of concomitant mitral regurgitation. Findings support use of machine learning for analysis of large scale CMR datasets.

Prognostic Implications of Mitral Annular Plane Systolic Excursion in Patients with Hypertension and a Clinical Indication for Cardiac Magnetic Resonance Imaging: A Multicenter Study

OBJECTIVES

This study sought to evaluate the prognostic value of cardiac magnetic resonance (CMR)-derived mitral annular plane systolic excursion (MAPSE) in a large multicenter population of patients with hypertension.

BACKGROUND

In patients with hypertension, cardiac abnormalities are powerful predictors of adverse outcomes. Long-axis mitral annular movement plays a fundamental role in cardiac mechanics and is an early marker for a number of pathological processes. Given the adverse consequences of cardiac involvement in hypertension, the authors hypothesized that lateral MAPSE may provide incremental prognostic information in these patients.

METHODS

Consecutive patients with hypertension and a clinical indication for CMR at 4 U.S. medical centers were included in this study (n = 1,735). Lateral MAPSE was measured in the 4-chamber cine view. The primary endpoint was all-cause death. Cox proportional hazards regression modeling was used to examine the association between lateral MAPSE and death. The incremental prognostic value of lateral MAPSE was assessed in nested models.

RESULTS

Over a median follow-up period of 5.1 years, 235 patients died. By Kaplan-Meier analysis, risk of death was significantly higher in patients with a lateral MAPSE < median (10 mm) (log-rank; p < 0.0001). Lateral MAPSE was associated with risk of death after adjustment for clinical and imaging risk factors (hazard ratio [HR]: 1.402-per-millimeter decrease; p < 0.001). Addition of lateral MAPSE in this model resulted in significant improvement in the C-statistic (0.735 to 0.815; p < 0.0001). Continuous net reclassification improvement was 0.739 (95% confidence interval: 0.601 to 0.902). Lateral MAPSE remained significantly associated with death even after adjustment for feature tracking global longitudinal strain (HR: 1.192-per-millimeter decrease; p < 0.001). Lateral MAPSE was independently associated with death among the subgroups of patients with preserved ejection fraction (HR = 1.339; p < 0.001) and in those without history of myocardial infarction (HR: 1.390; p < 0.001).

CONCLUSIONS

CMR-derived lateral MAPSE is a powerful, independent predictor of mortality in patients with hypertension and a clinical indication for CMR, incremental to common clinical and CMR risk factors. These findings may suggest a role for CMR-derived lateral MAPSE in identifying hypertensive patients at highest risk of death.

Unexpected Cardiac MRI Findings in Patients Presenting to the Emergency Department for Possible Acute Coronary Syndrome

BACKGROUND

Stress cardiac magnetic resonance imaging (CMR) has become increasingly used in patients presenting to the emergency department (ED) with symptoms concerning for acute coronary syndrome (ACS). We hypothesized that CMR detects a number of alternative diagnoses (diagnoses other than ACS that could explain symptoms) and incidental findings in patients presenting to the ED for potential ACS.

METHODS

We prospectively enrolled adult patients who presented to an academic ED from 2011 to 2015 for possible ACS and subsequently had an adenosine stress perfusion CMR as part of their diagnostic evaluation. All medical charts were reviewed to verify accurate prospective data collection and to collect follow-up data.

RESULTS

A total of 391 patients were included. On stress CMR, abnormalities attributable to coronary artery disease (CAD) were found in 106 (27.1%) of patients. Previously undiagnosed moderate to severe valvular disease was the most common non-CAD cardiac finding, occurring in 20 (5.1%) cases. Other alternative diagnoses were rare with 7 cases of cardiomyopathy, 1 case of aortic aneurysm, 1 case of aortic dissection, 1 case of acute myocarditis, 3 cases of pericarditis, and 2 cases of moderate pleural effusion. Cardiac incidental findings were rare. Extracardiac incidental findings were found in 79 patients (20.2%). Only 18.6% of the patients recommended for follow-up imaging had this completed within 1 year after CMR.

CONCLUSIONS

This experience suggests that stress CMR is useful in not only diagnosing symptomatic CAD but also potentially important non-CAD-related disease. These factors may impact their use in ED-based ACS workups.

Feature-Tracking Global Longitudinal Strain Predicts Death in a Multicenter Population of Patients With Ischemic and Nonischemic Dilated Cardiomyopathy Incremental to Ejection Fraction and Late Gadolinium Enhancement

OBJECTIVES

The aim of this study was to evaluate the prognostic value of cardiac magnetic resonance (CMR) feature-tracking-derived global longitudinal strain (GLS) in a large multicenter population of patients with ischemic and nonischemic dilated cardiomyopathy.

BACKGROUND

Direct assessment of myocardial fiber deformation with GLS using echocardiography or CMR feature tracking has shown promise in providing prognostic information incremental to ejection fraction (EF) in single-center studies. Given the growing use of CMR for assessing persons with left ventricular (LV) dysfunction, we hypothesized that feature-tracking-derived GLS may provide independent prognostic information in a multicenter population of patients with ischemic and nonischemic dilated cardiomyopathy.

METHODS

Consecutive patients at 4 U.S. medical centers undergoing CMR with EF <50% and ischemic or nonischemic dilated cardiomyopathy were included in this study. Feature-tracking GLS was calculated from 3 long-axis cine-views. The primary endpoint was all-cause death. Cox proportional hazards regression modeling was used to examine the association between GLS and death. Incremental prognostic value of GLS was assessed in nested models.

RESULTS

Of the 1,012 patients in this study, 133 died during median follow-up of 4.4 years. By Kaplan-Meier analysis, the risk of death increased significantly with worsening GLS tertiles (log-rank p < 0.0001). Each 1% worsening in GLS was associated with an 89.1% increased risk of death after adjustment for clinical and imaging risk factors including EF and late gadolinium enhancement (LGE) (hazard ratio [HR]:1.891 per %; p < 0.001). Addition of GLS in this model resulted in significant improvement in the C-statistic (0.628 to 0.867; p < 0.0001). Continuous net reclassification improvement (NRI) was 1.148 (95% confidence interval: 0.996 to 1.318). GLS was independently associated with death after adjustment for clinical and imaging risk factors (including EF and late gadolinium enhancement) in both ischemic (HR: 1.942 per %; p < 0.001) and nonischemic dilated cardiomyopathy subgroups (HR: 2.101 per %; p < 0.001).

CONCLUSIONS

CMR feature-tracking-derived GLS is a powerful independent predictor of mortality in a multicenter population of patients with ischemic or nonischemic dilated cardiomyopathy, incremental to common clinical and CMR risk factors including EF and LGE.