Cardiac magnetic resonance imaging findings and the risk of cardiovascular events in patients with recent myocardial infarction or suspected or known coronary artery disease: a systematic review of prognostic studies

Correlation of greyzone fibrosis compared to troponin T and late gadolinium enhancement with survival and ejection fraction in patients after acute myocardial infarction

AIMS

To quantify greyzone fibrosis (GZF) in patients after acute myocardial infarction (MI) and to evaluate its correlation with MI-free survival and improvements in left ventricular ejection fraction (LVEF) compared with the established risk factors high-sensitivity cardiac troponin T (hs-cTnT) and Late Gadolinium Enhancement (LGE).

METHODS AND RESULTS

The study involved 176 patients who experienced acute MI and underwent cardiac magnetic resonance (CMR) prior to hospital discharge, followed by a second CMR on average six months later. LGE was quantified in both examinations, a separate analysis of the GZF was conducted only in the follow-up CMR after resolution of the initial infarct edema. LVEF was measured in both CMR. hs-cTnT levels were assessed at hospital admission, as well as 8, 16, 24, 48 and 72 h after coronary intervention. Telephone follow-ups were conducted annually for up to 8 years. LGE measurements showed better correlation with MI-free survival (Harrell's C of 0.711 of LGE mass) compared to GZF (0.579 of GZF mass). Additionally, hs-cTnT outperformed GZF (Harrell's C of 0.645). As an univariable predictor for MI-free survival, only hs-cTnT reached significance (p < 0.05). With regard to improvements in ejection fraction, both hs-cTnT and LGE measurements showed acceptable correlation with improvement in ejection fraction (p < 0.05), while GZF measurements showed no correlation (p > 0.5).

CONCLUSIONS

In CMR, the assessment of GZF demonstrated inferior p correlation compared to hs-cTnT and LGE in patients after acute MI with respect to the endpoint of MI-free survival. Furthermore, GZF showed no correlation with the improvement of LVEF.

Translating thyroid hormone into clinical practice: lessons learned from the post-hoc analysis on data available from the ThyRepair study

Background

Thyroid hormone (TH) appears to have a reparative action on the postinfarcted myocardium. This novel action was recently tested in a pilot, randomized, double-blind, placebo-controlled trial (ThyRepair). The present study performed a post-hoc analysis of data from the ThyRepair study to provide further insights into the novel actions of TH on the human postischemic myocardium.

Methods

Data from 41 patients participating in the ThyRepair study (n = 20 placebo and n = 21 LT3) were included in the analysis. LT3 treatment started after stenting and continued intravenously for 48 h. All patients had cardiac magnetic resonance (CMR) at hospital discharge; left ventricular (LV) ejection fraction (LVEF%), LV end-diastolic volume index (LVEDVi; mL/m2), LV end-systolic volume index (LVESVi; mL/m2), infarct volume (IV), left ventricular mass index (LVMi) as edema index, and microvascular obstruction (MVO) were assessed. Patients were divided into two groups based on the median value of the IV: patients with IV ≤ 20% of the LV (group A) and patients with IV > 20% (group B). CMR measurements at discharge are expressed as mean ± SD.

Results

In group A, the placebo and T3-treated groups had similar LVEF% (56.8 ± 10.2 vs. 52.2 ± 10.5), LVEDVi (90.9 ± 19.8 vs. 92.8 ± 14.5), and LVESVi (40.8 ± 18.2 vs. 44.9 ± 14.1) at discharge. In group B, LVEDVi and LVESVi were 112 ± 23.8 and 68.3 ± 21.5 for placebo vs. 91.8 ± 18.6 and 49.0 ± 14.0 for the T3-treated group, respectively, p < 0.05. LVEF% was significantly increased in the T3-treated group vs. placebo, 47.3 ± 6.5 vs. 39.9 ± 8.7, p < 0.05. In group B, CMR LVMi was lower in T3-treated patients vs. placebo but did not reach statistical significance (p = 0.1). MVO was 1.95 ± 2.2 in placebo vs. 0.84 ± 0.9 in the LT3-treated group, p = 0.15.

Conclusion

The present study suggests that acute LT3 treatment may exert more favorable effects on the recovery of cardiac function in patients with large infarct size. Furthermore, it signals a potential effect of LT3 on myocardial edema and microvascular obstruction. These novel findings merit further investigation in large trials.

Cardiovascular medications, high-sensitivity cardiac troponin T concentrations, and long-term outcome in non-ST segment elevation acute coronary syndrome

AIMS

Cardiac troponin plays an essential role in the management of non-ST segment elevation acute coronary syndrome (NSTE-ACS). However, it is not clear whether troponin concentrations provide guidance regarding the initiation of prognostically beneficial cardiovascular medications [i.e. betablockers, renin-angiotensin-aldosterone system (RAAS) inhibitors, and statins] in NSTE-ACS.

METHODS AND RESULTS

Registry-based study investigating three NSTE-ACS cohorts (n = 43 075, 40 162, and 46 698) with elevated high-sensitivity cardiac troponin concentrations >14 ng/L. Cox proportional regression models with the addition of interaction terms were used to analyse the interrelations of high-sensitivity cardiac troponin T (hs-cTnT) concentrations, new initiated medications with the respective three drug classes, and long-term risk of all-cause mortality and major adverse events (MAE). Betablockers were associated with risk reductions of 8 and 5% regarding all-cause mortality and MAE, respectively. There was no evidence of an interaction with hs-cTnT concentrations. RAAS inhibitors were associated with 13 and 8% risk reductions, respectively, with a weak interaction between hs-cTnT and MAE (Pinteraction = 0.016). However, no increasing prognostic benefit was noted at hs-cTnT concentrations >100 ng/L. Statins were associated with 38 and 32% risk reductions, respectively, with prognostic benefit across the entire range of hs-cTnT concentrations, and with a weak interaction regarding MAE (Pinteraction = 0.011).

CONCLUSION

Cardiovascular medications provide different prognostic benefit in patients with NSTE-ACS with elevated hs-cTnT, and there was some evidence of greater treatment effects regarding MAE along with higher hs-cTnT concentrations. However, hs-cTnT appears only to have limited value overall for customizing such treatments.

Diagnostic and prognostic value of angiography-derived index of microvascular resistance: a systematic review and meta-analysis

Background

The angiography-derived index of microvascular resistance (A-IMR) is a novel tool for diagnosing coronary microvascular dysfunction (CMD) addressing limitation of unavailability. However, the clinical value of A-IMR remains controversial.

Methods

A systematic review and meta-analysis was conducted. PubMed, EMBASE, Cochrane Library and Web of Science were searched for relevant studies. Studies that reported estimates of A-IMR's diagnostic accuracy (with thermodilution-based IMR as the reference test) and/or predictions of adverse cardiovascular events were selected. Pooled sensitivity, specificity, area under the summary receiver operating characteristic curve (sROC) were calculated to measure diagnostic performance; pooled hazard/risk ratio (HR/RR) and 95% confidence interval (95% CI) of major adverse cardiovascular events (MACE) or other independent adverse events were calculated to measure prognostic effect. This study was registered with PROSPERO (CRD42023451884).

Results

A total of 12 diagnostic studies pooling 1,642 vessels and 12 prognostic studies pooling 2,790 individuals were included. A-IMR yielded an area under sROC of 0.93 (95% CI: 0.91, 0.95), a pooled sensitivity of 0.85 (95% CI: 0.79, 0.89) and a pooled specificity of 0.89 (95% CI: 0.83, 0.93) for the diagnosis of CMD. CMD diagnosed using A-IMR was associated with higher risks of MACE (HR, 2.73, 95% CI: 2.16, 3.45), CV death (RR, 2.39, 95% CI: 1.49, 3.82) and heart failure hospitalization (HR, 2.30, 95% CI: 1.53, 3.45).

Conclusion

A-IMR demonstrated high diagnostic accuracy for CMD and showed a strong prognostic capability in predicting the risk of adverse CV outcomes.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023451884, PROSPERO (CRD42023451884).

A novel intracoronary hypothermia device reduces myocardial reperfusion injury in pigs

BACKGROUND

Hypothermia therapy has been suggested to attenuate myocardial necrosis; however, the clinical implementation as a valid therapeutic strategy has failed, and new approaches are needed to translate into clinical applications. This study aimed to assess the feasibility, safety, and efficacy of a novel selective intracoronary hypothermia (SICH) device in mitigating myocardial reperfusion injury.

METHODS

This study comprised two phases. The first phase of the SICH was performed in a normal porcine model for 30 minutes ( n = 5) to evaluate its feasibility. The second phase was conducted in a porcine myocardial infarction (MI) model of myocardial ischemia/reperfusion was performed by balloon occlusion of the left anterior descending coronary artery for 60 minutes and maintained for 42 days. Pigs in the hypothermia group ( n = 8) received hypothermia intervention onset reperfusion for 30 minutes and controls ( n = 8) received no intervention. All animals were followed for 42 days. Cardiac magnetic resonance analysis (5 and 42 days post-MI) and a series of biomarkers/histological studies were performed.

RESULTS

The average time to lower temperatures to a steady state was 4.8 ± 0.8 s. SICH had no impact on blood pressure or heart rate and was safely performed without complications by using a 3.9 F catheter. Interleukin-6 (IL-6), tumor necrosis factor-α, C-reactive protein (CRP), and brain natriuretic peptide (BNP) were lower at 60 min post perfusion in pigs that underwent SICH as compared with the control group. On day 5 post MI/R, edema, intramyocardial hemorrhage, and microvascular obstruction were reduced in the hypothermia group. On day 42 post MI/R, the infarct size, IL-6, CRP, BNP, and matrix metalloproteinase-9 were reduced, and the ejection fraction was improved in pigs that underwent SICH.

CONCLUSIONS

The SICH device safely and effectively reduced the infarct size and improved heart function in a pig model of MI/R. These beneficial effects indicate the clinical potential of SICH for treatment of myocardial reperfusion injury.

Clinical-imaging-pathological correlation in pulmonary hypertension associated with left heart disease

Pulmonary hypertension (PH) is highly prevalent in patients with left heart disease (LHD) and negatively impacts prognosis. The most common causes of PH associated with LHD (PH-LHD) are left heart failure and valvular heart disease. In LHD, passive backward transmission of increased left-sided filling pressures leads to isolated post-capillary PH. Additional pulmonary vasoconstriction and remodelling lead to a higher vascular load and combined pre- and post-capillary PH. The increased afterload leads to right ventricular dysfunction and failure. Multimodality imaging of the heart plays a central role in the diagnostic work-up and follow-up of patients with PH-LHD. Echocardiography provides information about the estimated pulmonary artery pressure, morphology and function of the left and right side of the heart, and valvular abnormalities. Cardiac magnetic resonance imaging is the gold standard for volumetric measurements and provides myocardial tissue characterisation. Computed tomography of the thorax may show general features of PH and/or LHD and is helpful in excluding other PH causes. Histopathology reveals a spectrum of pre- and post-capillary vasculopathy, including intimal fibrosis, media smooth muscle cell hyperplasia, adventitial fibrosis and capillary congestion. In this paper, we provide an overview of clinical, imaging and histopathological findings in PH-LHD based on three clinical cases.

High-Density Lipoproteins at the Interface between the NLRP3 Inflammasome and Myocardial Infarction

Despite significant therapeutic advancements, morbidity and mortality following myocardial infarction (MI) remain unacceptably high. This clinical challenge is primarily attributed to two significant factors: delayed reperfusion and the myocardial injury resulting from coronary reperfusion. Following reperfusion, there is a rapid intracellular pH shift, disruption of ionic balance, heightened oxidative stress, increased activity of proteolytic enzymes, initiation of inflammatory responses, and activation of several cell death pathways, encompassing apoptosis, necroptosis, and pyroptosis. The inflammatory cell death or pyroptosis encompasses the activation of the intracellular multiprotein complex known as the NLRP3 inflammasome. High-density lipoproteins (HDL) are endogenous particles whose components can either promote or mitigate the activation of the NLRP3 inflammasome. In this comprehensive review, we explore the role of inflammasome activation in the context of MI and provide a detailed analysis of how HDL can modulate this process.

Diagnostic and Prognostic Value of Stress Cardiovascular Magnetic Resonance Imaging in Patients With Known or Suspected Coronary Artery Disease: A Systematic Review and Meta-analysis

Importance

The clinical utility of stress cardiovascular magnetic resonance imaging (CMR) in stable chest pain is still debated, and the low-risk period for adverse cardiovascular (CV) events after a negative test result is unknown.

Objective

To provide contemporary quantitative data synthesis of the diagnostic accuracy and prognostic value of stress CMR in stable chest pain.

Data Sources

PubMed and Embase databases, the Cochrane Database of Systematic Reviews, PROSPERO, and the ClinicalTrials.gov registry were searched for potentially relevant articles from January 1, 2000, through December 31, 2021.

Study Selection

Selected studies evaluated CMR and reported estimates of diagnostic accuracy and/or raw data of adverse CV events for participants with either positive or negative stress CMR results. Prespecified combinations of keywords related to the diagnostic accuracy and prognostic value of stress CMR were used. A total of 3144 records were evaluated for title and abstract; of those, 235 articles were included in the full-text assessment of eligibility. After exclusions, 64 studies (74 470 total patients) published from October 29, 2002, through October 19, 2021, were included.

Data Extraction and Synthesis

This systematic review and meta-analysis adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

Main Outcomes and Measures

Diagnostic odds ratios (DORs), sensitivity, specificity, area under the receiver operating characteristic curve (AUROC), odds ratio (OR), and annualized event rate (AER) for all-cause death, CV death, and major adverse cardiovascular events (MACEs) defined as the composite of myocardial infarction and CV death.

Results

A total of 33 diagnostic studies pooling 7814 individuals and 31 prognostic studies pooling 67 080 individuals (mean [SD] follow-up, 3.5 [2.1] years; range, 0.9-8.8 years; 381 357 person-years) were identified. Stress CMR yielded a DOR of 26.4 (95% CI, 10.6-65.9), a sensitivity of 81% (95% CI, 68%-89%), a specificity of 86% (95% CI, 75%-93%), and an AUROC of 0.84 (95% CI, 0.77-0.89) for the detection of functionally obstructive coronary artery disease. In the subgroup analysis, stress CMR yielded higher diagnostic accuracy in the setting of suspected coronary artery disease (DOR, 53.4; 95% CI, 27.7-103.0) or when using 3-T imaging (DOR, 33.2; 95% CI, 19.9-55.4). The presence of stress-inducible ischemia was associated with higher all-cause mortality (OR, 1.97; 95% CI, 1.69-2.31), CV mortality (OR, 6.40; 95% CI, 4.48-9.14), and MACEs (OR, 5.33; 95% CI, 4.04-7.04). The presence of late gadolinium enhancement (LGE) was associated with higher all-cause mortality (OR, 2.22; 95% CI, 1.99-2.47), CV mortality (OR, 6.03; 95% CI, 2.76-13.13), and increased risk of MACEs (OR, 5.42; 95% CI, 3.42-8.60). After a negative test result, pooled AERs for CV death were less than 1.0%.

Conclusion and Relevance

In this study, stress CMR yielded high diagnostic accuracy and delivered robust prognostication, particularly when 3-T scanners were used. While inducible myocardial ischemia and LGE were associated with higher mortality and risk of MACEs, normal stress CMR results were associated with a lower risk of MACEs for at least 3.5 years.

Safety of Stress Cardiac Magnetic Resonance in Patients With Moderate to Severe Aortic Valve Stenosis

BACKGROUND

Dobutamine and adenosine stress cardiac magnetic resonance (CMR) imaging is relatively contraindicated in patients with moderate to severe aortic valve stenosis (AS). We aimed to determine the safety of dobutamine and adenosine stress CMR in patients with moderate to severe AS.

METHODS

In this retrospective study patients with AS who underwent either dobutamine or adenosine stress CMR for exclusion of obstructive coronary artery disease were enrolled. We recorded clinical data, CMR and echocardiography findings, and complications as well as minor symptoms. Patients with AS were compared to matched individuals without AS.

RESULTS

A total of 187 patients with AS were identified and compared to age-, gender- and body mass index-matched 187 patients without AS. No severe complications were reported in the study nor the control group. The reported frequency of non-severe complications and minor symptoms were similar between the study and the control groups. Nineteen patients with AS experienced non-severe complications or minor symptoms during dobutamine stress CMR compared to eighteen patients without AS (p = 0.855). One patient with AS and two patients without AS undergoing adenosine stress CMR experienced minor symptoms (p = 0.562). Four examinations were aborted because of chest pain, paroxysmal atrial fibrillation and third-degree atrioventricular block. Inducible ischaemia, prior coronary artery bypass grafting, prior stroke and age were associated with a higher incidence of complications and minor symptoms.

CONCLUSIONS

Moderate to severe AS was not associated with complications during CMR stress test. The incidence of non-severe complications and minor symptoms was greater with dobutamine.

Incremental prognostic value of left atrial strain in patients with heart failure

AIMS

The present study aimed to evaluate the prognostic value of atrial strain and strain rate (SR) parameters derived from cardiac magnetic resonance (CMR) feature tracking (FT) in patients with ischaemic and non-ischaemic dilated cardiomyopathy with heart failure with reduced ejection fraction (HFrEF) but without atrial fibrillation.

METHODS AND RESULTS

A total of 300 patients who underwent CMR with left ventricular ejection fraction (LVEF) ≤ 40% and ischaemic or non-ischaemic dilated cardiomyopathy were analysed in this retrospective study. Major adverse cardiac events (MACEs) include cardiovascular death, heart transplantation, and rehospitalization for worsening HF. Ninety-four patients had MACEs during median follow-up of 3.84 years. Multivariate Cox regression models adjusted for common clinical and CMR risk factors detected a significant association between LA-εs and MACE in ischaemic (HR = 0.94/%; P = 0.002), non-ischaemic dilated cardiomyopathy (HR = 0.88/%; P = 0.001), or all included patients (HR = 0.87; P < 0.001). LA-εs provided incremental prognostic value over conventional outcome predictors (Uno C statistical comparison model: from 0.776 to 0.801, P < 0.0001; net reclassification improvement: 0.075, 95% CI: 0.0262-0.1301). Kaplan-Meier analysis revealed that the risk of MACE occurrence increased significantly with lower tertiles of left atrial reservoir strain (LA-εs) (log-rank P < 0.0001). Patients in the worst LA-εs tertile faced a significantly increased risk of MACEs irrespective of late gadolinium enhancement (LGE) (log-rank P < 0.0001).

CONCLUSIONS

LA-εs derived from CMR FT has a significant prognostic impact on patients with ischaemic or non-ischaemic dilated cardiomyopathy, incremental to common clinical and CMR risk-factors.

The Role of Artificial Intelligence in Predicting Outcomes by Cardiovascular Magnetic Resonance: A Comprehensive Systematic Review

Background and Objectives: Interest in artificial intelligence (AI) for outcome prediction has grown substantially in recent years. However, the prognostic role of AI using advanced cardiac magnetic resonance imaging (CMR) remains unclear. This systematic review assesses the existing literature on AI in CMR to predict outcomes in patients with cardiovascular disease. Materials and Methods: Medline and Embase were searched for studies published up to November 2021. Any study assessing outcome prediction using AI in CMR in patients with cardiovascular disease was eligible for inclusion. All studies were assessed for compliance with the Checklist for Artificial Intelligence in Medical Imaging (CLAIM). Results: A total of 5 studies were included, with a total of 3679 patients, with 225 deaths and 265 major adverse cardiovascular events. Three methods demonstrated high prognostic accuracy: (1) three-dimensional motion assessment model in pulmonary hypertension (hazard ratio (HR) 2.74, 95%CI 1.73−4.34, p < 0.001), (2) automated perfusion quantification in patients with coronary artery disease (HR 2.14, 95%CI 1.58−2.90, p < 0.001), and (3) automated volumetric, functional, and area assessment in patients with myocardial infarction (HR 0.94, 95%CI 0.92−0.96, p < 0.001). Conclusion: There is emerging evidence of the prognostic role of AI in predicting outcomes for three-dimensional motion assessment in pulmonary hypertension, ischaemia assessment by automated perfusion quantification, and automated functional assessment in myocardial infarction.

2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure" replaces the "2013 ACCF/AHA Guideline for the Management of Heart Failure" and the "2017 ACC/AHA/HFSA Focused Update of the 2013 ACCF/AHA Guideline for the Management of Heart Failure." The 2022 guideline is intended to provide patient-centric recommendations for clinicians to prevent, diagnose, and manage patients with heart failure.

METHODS

A comprehensive literature search was conducted from May 2020 to December 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from MEDLINE (PubMed), EMBASE, the Cochrane Collaboration, the Agency for Healthcare Research and Quality, and other relevant databases. Additional relevant clinical trials and research studies, published through September 2021, were also considered. This guideline was harmonized with other American Heart Association/American College of Cardiology guidelines published through December 2021. Structure: Heart failure remains a leading cause of morbidity and mortality globally. The 2022 heart failure guideline provides recommendations based on contemporary evidence for the treatment of these patients. The recommendations present an evidence-based approach to managing patients with heart failure, with the intent to improve quality of care and align with patients' interests. Many recommendations from the earlier heart failure guidelines have been updated with new evidence, and new recommendations have been created when supported by published data. Value statements are provided for certain treatments with high-quality published economic analyses.

Role of cardiac magnetic resonance imaging in troponinemia syndromes

Cardiac magnetic resonance imaging (MRI) is an evolving technology, proving to be a highly accurate tool for quantitative assessment. Most recently, it has been increasingly used in the diagnostic and prognostic evaluation of conditions involving an elevation in troponin or troponinemia. Although an elevation in troponin is a nonspecific marker of myocardial tissue damage, it is a frequently ordered investigation leaving many patients without a specific diagnosis. Fortunately, the advent of newer cardiac MRI protocols can provide additional information. In this review, we discuss several conditions associated with an elevation in troponin such as myocardial infarction, myocarditis, Takotsubo cardiomyopathy, coronavirus disease 2019 related cardiac dysfunction and athlete’s heart syndrome.

2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure

AIM

The "2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure" replaces the "2013 ACCF/AHA Guideline for the Management of Heart Failure" and the "2017 ACC/AHA/HFSA Focused Update of the 2013 ACCF/AHA Guideline for the Management of Heart Failure." The 2022 guideline is intended to provide patient-centric recommendations for clinicians to prevent, diagnose, and manage patients with heart failure.

METHODS

A comprehensive literature search was conducted from May 2020 to December 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from MEDLINE (PubMed), EMBASE, the Cochrane Collaboration, the Agency for Healthcare Research and Quality, and other relevant databases. Additional relevant clinical trials and research studies, published through September 2021, were also considered. This guideline was harmonized with other American Heart Association/American College of Cardiology guidelines published through December 2021.

STRUCTURE

Heart failure remains a leading cause of morbidity and mortality globally. The 2022 heart failure guideline provides recommendations based on contemporary evidence for the treatment of these patients. The recommendations present an evidence-based approach to managing patients with heart failure, with the intent to improve quality of care and align with patients' interests. Many recommendations from the earlier heart failure guidelines have been updated with new evidence, and new recommendations have been created when supported by published data. Value statements are provided for certain treatments with high-quality published economic analyses.

Challenges in ensuring the generalizability of image quantitation methods for MRI

Image quantitation methods including quantitative MRI, multiparametric MRI, and radiomics offer great promise for clinical use. However, many of these methods have limited clinical adoption, in part due to issues of generalizability, that is, the ability to translate methods and models across institutions. Researchers can assess generalizability through measurement of repeatability and reproducibility, thus quantifying different aspects of measurement variance. In this article, we review the challenges to ensuring repeatability and reproducibility of image quantitation methods as well as present strategies to minimize their variance to enable wider clinical implementation. We present possible solutions for achieving clinically acceptable performance of image quantitation methods and briefly discuss the impact of minimizing variance and achieving generalizability towards clinical implementation and adoption.

Dark-blood late gadolinium-enhancement cardiac magnetic resonance imaging for myocardial scar detection based on simplified timing scheme: single-center experience in patients with suspected coronary artery disease

Background

This study aims to examine scar detectability using dark-blood late gadolinium enhancement (LGE) with simplified timing scheme and fixed parameters comparing to two conventional bright-blood approaches in patients with known or suspected coronary artery disease.

Methods

Three LGE techniques were performed in all patients with known or suspected coronary artery disease at 3 T: dark blood two-dimensional (2D) phase-sensitive inversion recovery (PSIR) preceded with a T2-preparation pulse (DB-LGE), conventional three-dimensional (3D) gradient-echo inversion recovery (3D-IR) and conventional 2D PSIR. Timing parameters in DB-LGE were tested in five clinically confirmed coronary artery disease patients with scars and fixed for the rest of the study. Two independent readers evaluated images at both patient and segment levels. Image quality and contrast ratio between scar and adjacent tissues were assessed. Concordance between the three techniques and detection rate based on expert consensus were reported.

Results

Forty-six patients were recruited in the study (average age 66.8 years, 69.6% male). DB-LGE demonstrated superior image quality (P=0.001 vs. 3D-IR) and scar-to-blood contrast ratio (P<0.001 vs. 3D-IR and PSIR). Among 41 patients with suspected coronary artery disease, myocardial scar was present in 30 patients (73.2%), all detected by DB-LGE, yielding a detection rate of 100% compared to 93.3% and 96.7% for bright-blood 3D-IR and PSIR. For subendocardial scar detection among 656 segments, DB-LGE had a detection rate of 99.4% compared to 57.8% for 3D-IR and 61.0% for PSIR (both P<0.001).

Conclusions

DB-LGE improves detection of myocardial scar compared with conventional bright-blood LGE techniques, particularly of subendocardial scar.

Rationale and Design of the Groningen Intervention Study for the Preservation of Cardiac Function with Sodium Thiosulfate after St-segment Elevation Myocardial Infarction (GIPS-IV) trial

BACKGROUND

Ischemia and subsequent reperfusion cause myocardial injury in patients presenting with ST-segment elevation myocardial infarction (STEMI). Hydrogen sulfide (H₂S) reduces "ischemia-reperfusion injury" in various experimental animal models, but has not been evaluated in humans. This trial will examine the efficacy and safety of the H₂S-donor sodium thiosulfate (STS) in patients presenting with a STEMI.

STUDY DESIGN

The Groningen Intervention study for the Preservation of cardiac function with STS after STEMI (GIPS-IV) trial (NCT02899364) is a double-blind, randomized, placebo-controlled, multicenter trial, which will enroll 380 patients with a first STEMI. Patients receive STS 12.5 grams intravenously or matching placebo in addition to standard care immediately at arrival at the catheterization laboratory after providing consent. A second dose is administered 6 hours later at the coronary care unit. The primary endpoint is myocardial infarct size as quantified by cardiac magnetic resonance imaging 4 months after randomization. Secondary endpoints include the effect of STS on peak CK-MB during admission and left ventricular ejection fraction and NT-proBNP levels at 4 months follow-up. Patients will be followed-up for 2 years to assess clinical endpoints.

CONCLUSIONS

The GIPS-IV trial is the first study to determine the effect of a H₂S-donor on myocardial infarct size in patients presenting with STEMI.

Radiogenomics and Artificial Intelligence Approaches Applied to Cardiac Computed Tomography Angiography and Cardiac Magnetic Resonance for Precision Medicine in Coronary Heart Disease: A Systematic Review

The risk of coronary heart disease (CHD) clinical manifestations and patient management is estimated according to risk scores accounting multifactorial risk factors, thus failing to cover the individual cardiovascular risk. Technological improvements in the field of medical imaging, in particular, in cardiac computed tomography angiography and cardiac magnetic resonance protocols, laid the development of radiogenomics. Radiogenomics aims to integrate a huge number of imaging features and molecular profiles to identify optimal radiomic/biomarker signatures. In addition, supervised and unsupervised artificial intelligence algorithms have the potential to combine different layers of data (imaging parameters and features, clinical variables and biomarkers) and elaborate complex and specific CHD risk models allowing more accurate diagnosis and reliable prognosis prediction. Literature from the past 5 years was systematically collected from PubMed and Scopus databases, and 60 studies were selected. We speculated the applicability of radiogenomics and artificial intelligence through the application of machine learning algorithms to identify CHD and characterize atherosclerotic lesions and myocardial abnormalities. Radiomic features extracted by cardiac computed tomography angiography and cardiac magnetic resonance showed good diagnostic accuracy for the identification of coronary plaques and myocardium structure; on the other hand, few studies exploited radiogenomics integration, thus suggesting further research efforts in this field. Cardiac computed tomography angiography resulted the most used noninvasive imaging modality for artificial intelligence applications. Several studies provided high performance for CHD diagnosis, classification, and prognostic assessment even though several efforts are still needed to validate and standardize algorithms for CHD patient routine according to good medical practice.

Stress Cardiac Magnetic Resonance Myocardial Perfusion Imaging: JACC Review Topic of the Week

Stress cardiovascular magnetic resonance imaging (CMR) is a cost-effective, noninvasive test that accurately assesses myocardial ischemia, myocardial viability, and cardiac function without the need for ionizing radiation. There is a large body of literature, including randomized controlled trials, validating its diagnostic performance, risk stratification capabilities, and ability to guide appropriate use of coronary intervention. Specifically, stress CMR has shown higher diagnostic sensitivity than single-photon emission computed tomography imaging in detecting angiographically significant coronary artery disease. Stress CMR is particularly valuable for the evaluation of patients with moderate to high pretest probability of having stable ischemic heart disease and for patients known to have challenging imaging characteristics, including women, individuals with prior revascularization, and those with left ventricular dysfunction. This paper reviews the basics principles of stress CMR, the data supporting its clinical use, the added-value of myocardial blood flow quantification, and the assessment of myocardial function and viability routinely obtained during a stress CMR study.

Cardiac Magnetic Resonance Imaging and Blood Biomarkers for Evaluation of Radiation-Induced Cardiotoxicity in Patients With Breast Cancer: Results of a Phase 2 Clinical Trial

PURPOSE

Radiation therapy (RT) can increase the risk of cardiac events in patients with breast cancer (BC), but biomarkers predicting risk for developing RT-induced cardiac disease are currently lacking. We report results from a prospective clinical trial evaluating early magnetic resonance imaging (MRI) and serum biomarker changes as predictors of cardiac injury and risk of subsequent cardiac events after RT for left-sided disease.

METHODS

Women with node-negative and node-positive (N-/+) left-sided BC were enrolled on 2 institutional review board (IRB)-approved protocols at 2 institutions. MRI was conducted pretreatment (within 1 week of starting radiation), at the end of treatment (last day of treatment ±1 week), and 3 months after the last day of treatment (±2 weeks) to quantify left and right ventricular volumes and function, myocardial fibrosis, and edema. Perfusion changes during regadenoson stress perfusion were also assessed on a subset of patients (n = 28). Serum was collected at the same time points. Whole heart and cardiac substructures were contoured using CT and MRI. Models were constructed using baseline cardiac and clinical risk factors. Associations between MRI-measured changes and dose were evaluated.

RESULTS

Among 51 women enrolled, mean heart dose ranged from 0.80 to 4.7 Gy and mean left ventricular (LV) dose from 1.1 to 8.2 Gy, with mean heart dose 2.0 Gy. T1 time, a marker of fibrosis, and right ventricular (RV) ejection fraction (EF) significantly changed with treatment; these were not dose dependent. T2 (marker of edema) and LV EF did not significantly change. No risk factors were associated with baseline global perfusion. Prior receipt of doxorubicin was marginally associated with decreased myocardial perfusion after RT (P = .059), and mean MHD was not associated with perfusion changes. A significant correlation between baseline IL-6 and mean heart dose (MHD) at the end of RT (ρ 0.44, P = .007) and a strong trend between troponin I and MHD at 3 months post-treatment (ρ 0.33, P = .07) were observed. No other significant correlations were identified.

CONCLUSIONS

In this prospective study of women with left-sided breast cancer treated with contemporary treatment planning, cardiac radiation doses were very low relative to historical doses reported by Darby et al. Although we observed significant changes in T1 and RV EF shortly after RT, these changes were not correlated with whole heart or substructure doses. Serum biomarker analysis of cardiac injury demonstrates an interesting trend between markers and MHD that warrants further investigation.

Clinical Validation of a 3-Dimensional Ultrafast Cardiac Magnetic Resonance Protocol Including Single Breath-Hold 3-Dimensional Sequences

OBJECTIVES

This study sought to clinically validate a novel 3-dimensional (3D) ultrafast cardiac magnetic resonance (CMR) protocol including cine (anatomy and function) and late gadolinium enhancement (LGE), each in a single breath-hold.

BACKGROUND

CMR is the reference tool for cardiac imaging but is time-consuming.

METHODS

A protocol comprising isotropic 3D cine (Enhanced sensitivity encoding [SENSE] by Static Outer volume Subtraction [ESSOS]) and isotropic 3D LGE sequences was compared with a standard cine+LGE protocol in a prospective study of 107 patients (age 58 ± 11 years; 24% female). Left ventricular (LV) mass, volumes, and LV and right ventricular (RV) ejection fraction (LVEF, RVEF) were assessed by 3D ESSOS and 2D cine CMR. LGE (% LV) was assessed using 3D and 2D sequences.

RESULTS

Three-dimensional and LGE acquisitions lasted 24 and 22 s, respectively. Three-dimensional and LGE images were of good quality and allowed quantification in all cases. Mean LVEF by 3D and 2D CMR were 51 ± 12% and 52 ± 12%, respectively, with excellent intermethod agreement (intraclass correlation coefficient [ICC]: 0.96; 95% confidence interval [CI]: 0.94 to 0.97) and insignificant bias. Mean RVEF 3D and 2D CMR were 60.4 ± 5.4% and 59.7 ± 5.2%, respectively, with acceptable intermethod agreement (ICC: 0.73; 95% CI: 0.63 to 0.81) and insignificant bias. Both 2D and 3D LGE showed excellent agreement, and intraobserver and interobserver agreement were excellent for 3D LGE.

CONCLUSIONS

ESSOS single breath-hold 3D CMR allows accurate assessment of heart anatomy and function. Combining ESSOS with 3D LGE allows complete cardiac examination in <1 min of acquisition time. This protocol expands the indication for CMR, reduces costs, and increases patient comfort.

Cardiovascular Magnetic Resonance Imaging and Heart Failure

Purpose of Review

The purpose of this review is to summarize the application of cardiac magnetic resonance (CMR) in the diagnostic and prognostic evaluation of patients with heart failure (HF).

Recent Findings

CMR is an important non-invasive imaging modality in the assessment of ventricular volumes and function and in the analysis of myocardial tissue characteristics. The information derived from CMR provides a comprehensive evaluation of HF. Its unique ability of tissue characterization not only helps to reveal the underlying etiologies of HF but also offers incremental prognostic information.

Summary

CMR is a useful non-invasive tool for the diagnosis and assessment of prognosis in patients suffering from heart failure.

Eosinophilic heart disease: diagnostic and prognostic assessment by cardiac magnetic resonance

AIMS 

Eosinophilic heart disease (EHD) is a rare cardiac condition with a wide spectrum of phenotypes. The diagnostic and prognostic value of cardiac magnetic resonance (CMR) in EHD remains unknown.

METHODS AND RESULTS 

This was a retrospective analysis of 250 patients with eosinophilia referred for a CMR scan (period 2000-2020). CMR data sets and clinical/laboratory data were collected. Patients were followed up for a mean of 24 months (range 1-224) for the composite endpoint of death, acute coronary syndrome, hospitalization for acute heart failure, malignant ventricular arrhythmias, or the need for implantable cardiac defibrillator/pacemaker. The main objectives were to explore the diagnostic value of CMR in EHD; relationships between cardiac function, late gadolinium enhancement (LGE), and EHD phenotypes; and the prognostic value of fibrosis and oedema by CMR. The prevalence of findings compatible with EHD was 39% (patients with cardiac symptoms: 57% vs. screening: 20%, P < 0.001). EHD phenotypes included subendocardial LGE (n = 58), mid-wall/subepicardial LGE (n = 26), pericarditis (n = 5) or dilated cardiomyopathy (n = 8). Myocardial oedema was present in 10% of patients. Intracardiac thrombi (7%) were associated with EHD phenotype (χ2=47.3, P = 1.3×10-8). LGE extent correlated with LVEDVi (rho = 0.268, P = 5.3×10-5) and LVEF (rho=-0.415, P = 8.6×10-11). A CMR scan positive for EHD [hazard ratio (HR) = 5.61, 95% confidence interval (CI): 1.82-17.89, P = 0.0026] or a subendocardial LGE pattern (HR = 5.13, 95% CI: 1.29-20.38, P = 0.020) were independently associated with the composite clinical endpoint.

CONCLUSION 

The diagnostic yield of CMR screening in patients with persistent eosinophilia, even if asymptomatic, is high. The extent of subendocardial fibrosis correlates with LV remodelling and independently predicts clinical outcomes in patients with eosinophilia.

Intravenous Statin Administration During Myocardial Infarction Compared With Oral Post-Infarct Administration

BACKGROUND

Beyond lipid-lowering, statins exert cardioprotective effects. High-dose statin treatment seems to reduce cardiovascular complications in high-risk patients. The ideal timing and administration regime remain unknown.

OBJECTIVES

This study compared the cardioprotective effects of intravenous statin administration during myocardial infarction (MI) with oral administration immediately post-MI.

METHODS

Hypercholesterolemic pigs underwent MI induction (90 min of ischemia) and were kept for 42 days. Animals were distributed in 3 arms (A): A1 received an intravenous bolus of atorvastatin during MI; A2 received an intravenous bolus of vehicle during MI; and A3 received oral atorvastatin within 2 h post-MI. A1 and A3 remained on daily oral atorvastatin for the following 42 days. Cardiac magnetic resonance analysis (days 3 and 42 post-MI) and molecular/histological studies were performed.

RESULTS

At day 3, A1 showed a 10% reduction in infarct size compared with A3 and A2 and a 50% increase in myocardial salvage. At day 42, both A1 and A3 showed a significant decrease in scar size versus A2; however, A1 showed a further 24% reduction versus A3. Functional analyses revealed improved systolic performance in A1 compared with A2 and less wall motion abnormalities in the jeopardized myocardium versus both groups at day 42. A1 showed enhanced collagen content and AMP-activated protein kinase activation in the scar, increased vessel density in the penumbra, higher tumor necrosis factor α plasma levels and lower peripheral blood mononuclear cell activation versus both groups.

CONCLUSIONS

Intravenous administration of atorvastatin during MI limits cardiac damage, improves cardiac function, and mitigates remodeling to a larger extent than when administered orally shortly after reperfusion. This therapeutic approach deserves to be investigated in ST-segment elevation MI patients.

Prognostic Significance of CMR Findings in Patients with Known Coronary Artery Disease - Experience from a South Asian Country

Objectives:

South Asians (SA) have a higher burden of coronary artery disease (CAD) and are known to have a worse prognosis compared to other ethnicities. Therefore, it is imperative to improve the risk stratification of SA patient with CAD and to seek out newer prognostic markers beyond the conventional echocardiography.The aim of this study was to investigate whether variables obtained by cardiac magnetic resonance (CMR) improve risk stratification of South Asian patients with known CAD.

Material and Methods:

We retrospectively analyzed 147 patients with evidence of CAD that had a CMR at our center between January 2011 and January 2019. LV volumes and regional wall motions were acquired by cine images, while infarct size (IS) was measured by late gadolinium enhancement. At a mean follow-up of 3.36 ± 2.22 years, cardiac events (non-fatal myocardial infarction, hospitalization due to heart failure, life-threatening arrhythmia, or cardiac death) occurred in 49 patients. An IS ≥35%, left ventricular ejection fraction (LVEF) ≤31%, and a wall motion score index (WMSI) ≥1.9 were strongly associated with follow-up cardiac events (P < 0.001). Patients that had none or less than 3 of these factors, showed a lower risk of cardiac events (HR 0.22 CI [0.11–0.44] P < 0.001 and HR 0.12 CI [0.04–0.32] P < 0.001, respectively) compared to those with all three factors.

Conclusion:

Integration of CMR derived factors such as IS and WMSI with LVEF can improve the prognostication of the SA population with CAD. Better risk stratification of patients can lead to improved and cost-effective therapeutic strategies to ameliorate the prognosis of these patients.

CMR in the diagnosis of ischemic heart disease

Cardiovascular magnetic resonance has always been more often used in the last 10 years in evaluation of heart disease. Role in diagnosis of ischemia and in evaluation of myocardial infarction is well established by many scientific papers and included in current guidelines. High accuracy in evaluation of stress-induced ischemia, tissue characterization and functional parameters are the pillars the make the method widely used. In this paper are described role and techniques in diagnosis of ischemia, myocardial infarction and its sequelae.

A Novel Clinical and Stress Cardiac Magnetic Resonance (C-CMR-10) Score to Predict Long-Term All-Cause Mortality in Patients with Known or Suspected Chronic Coronary Syndrome

Vasodilator stress cardiac magnetic resonance (stressCMR) has shown robust diagnostic and prognostic value in patients with known or suspected chronic coronary syndrome (CCS). However, it is unknown whether integration of stressCMR with clinical variables in a simple clinical-imaging score can straightforwardly predict all-cause mortality in this population. We included 6187 patients in a large registry that underwent stressCMR for known or suspected CCS. Several clinical and stressCMR variables were collected, such as left ventricular ejection fraction (LVEF) and ischemic burden (number of segments with stress-induced perfusion defects (PD)). During a median follow-up of 5.56 years, we registered 682 (11%) all-cause deaths. The only independent predictors of all-cause mortality in multivariable analysis were age, male sex, diabetes mellitus (DM), LVEF and ischemic burden. Based on the weight of the chi-square increase at each step of the multivariable analysis, we created a simple clinical-stressCMR (C-CMR-10) score that included these variables (age ≥ 65 years = 3 points, LVEF ≤ 50% = 3 points, DM = 2 points, male sex = 1 point, and ischemic burden > 5 segments = 1 point). This 0 to 10 points C-CMR-10 score showed good performance to predict all-cause annualized mortality rate ranging from 0.29%/year (score = 0) to >4.6%/year (score ≥ 7). The goodness of the model and of the C-CMR-10 score was separately confirmed in 2 internal cohorts (n > 3000 each). We conclude that a novel and simple clinical-stressCMR score, which includes clinical and stressCMR variables, can provide robust prediction of the risk of long-term all-cause mortality in a population of patients with known or suspected CCS.

Whole blood transcriptome profile at hospital admission discriminates between patients with ST-segment elevation and non-ST-segment elevation acute myocardial infarction

Whether ST-segment (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI) should be regarded as distinct pathophysiological entities is a matter of debate. We tested the hypothesis that peripheral blood gene-expression profiles at presentation distinguish STEMI from NSTEMI. We performed a case-control study collecting whole-blood from 60 STEMI and 58 NSTEMI (defined according to the third universal definition of MI) consecutive patients on hospital admission. We used RNA-sequencing for the discovery phase, comparing 15 STEMI vs. 15 NSTEMI patients, matched for age, sex, and cardiovascular risk factors, and quantitative PCR in the remaining unmatched patients for validating top-significant genes. Gene-level differential expression analysis identified significant differences in the expression of 323 genes: 153 genes withstood correction for admission cardiac troponin I (cTnI), differentiating the two conditions independently of myocardial necrosis extent. Functional annotation analysis uncovered divergent modulation in leukocyte and platelet activation, cell migration, and mitochondrial respiratory processes. Linear regression analysis revealed gene expression patterns on admission predicting infarct size, as indexed by cTnI peak (R² = 0.58–0.75). Our results unveil distinctive pathological traits for these two MI subtypes and provide insights into the early assessment of injury extent. This could translate into RNA-based disease-specific biomarkers for precision diagnosis and risk stratification.

Contemporary Cardiac MRI in Chronic Coronary Artery Disease

Chronic coronary artery disease remains an unconquered clinical problem, affecting an increasing number of people worldwide. Despite the improved understanding of the disease development, the implementation of the many advances in diagnosis and therapy is lacking. Many clinicians continue to rely on patient's symptoms and diagnostic methods, which do not enable optimal clinical decisions. For example, echocardiography and invasive coronary catheterisation remain the mainstay investigations for stable angina patients in many places, despite the evidence on their limitations and availability of better diagnostic options. Cardiac MRI is a powerful diagnostic method, supporting robust measurements of crucial markers of cardiac structure and function, myocardial perfusion and scar, as well as providing detailed insight into myocardial tissue. Accurate and informative diagnostic readouts can help with guiding therapy, monitoring disease progress and tailoring the response to treatment. In this article, the authors outline the evidence supporting the state-of-art applications based on cardiovascular magnetic resonance, allowing the clinician optimal use of this insightful diagnostic method in everyday clinical practice.

Estimating Myocardial Infarction Size With a Simple Electrocardiographic Marker Score

Background

Myocardial infarction (MI) size is a key predictor of prognosis in post‐MI patients. Cardiovascular magnetic resonance (CMR) is the gold standard test for MI quantification, but the ECG is less expensive and more widely available. We sought to quantify the relationship between ECG markers and cardiovascular magnetic resonance infarct size.

Methods and Results

Patients with prior MI enrolled in the DETERMINE (Defibrillators to Reduce Risk by Magnetic Resonance Imaging Evaluation) and PRE‐DETERMINE Trial and Registry were included. ECG leads were analyzed for markers of MI: Q waves, fragmented QRS, and T wave inversion. DETERMINE Score=number of leads with [Q waves×2]+[fragmented QRS]+[T wave inversion]. Left ventricular ejection fraction (LVEF) and infarct size as a percentage of left ventricular mass (MI%) were quantified by cardiovascular magnetic resonance. The Modified Selvester Score estimates MI size from 37 ECG criteria. In 551 patients (aged 62.1±10.9 years, 79% men, and LVEF=40.3±11.0%), MI% increased as the number of ECG markers increased (P<0.001). By univariable linear regression, the DETERMINE Score (range 0–26) estimated MI% (R²=0.18, P<0.001) with an accuracy approaching that of LVEF (R²=0.22, P<0.001) and higher than the Modified Selvester Score (R²=0.09, P<0.001). By multivariable linear regression, addition of the DETERMINE Score improved estimation of MI% over LVEF alone (P<0.001) and over Modified Selvester Score alone (P<0.001).

Conclusions

In patients with prior MI, a simple ECG score estimates infarct size and improves infarct size estimation over LVEF alone. Because infarct size is a powerful prognostic indicator, the DETERMINE Score holds promise as a simple and inexpensive risk assessment tool.

Machine learning in cardiovascular magnetic resonance: basic concepts and applications

Machine learning (ML) is making a dramatic impact on cardiovascular magnetic resonance (CMR) in many ways. This review seeks to highlight the major areas in CMR where ML, and deep learning in particular, can assist clinicians and engineers in improving imaging efficiency, quality, image analysis and interpretation, as well as patient evaluation. We discuss recent developments in the field of ML relevant to CMR in the areas of image acquisition & reconstruction, image analysis, diagnostic evaluation and derivation of prognostic information. To date, the main impact of ML in CMR has been to significantly reduce the time required for image segmentation and analysis. Accurate and reproducible fully automated quantification of left and right ventricular mass and volume is now available in commercial products. Active research areas include reduction of image acquisition and reconstruction time, improving spatial and temporal resolution, and analysis of perfusion and myocardial mapping. Although large cohort studies are providing valuable data sets for ML training, care must be taken in extending applications to specific patient groups. Since ML algorithms can fail in unpredictable ways, it is important to mitigate this by open source publication of computational processes and datasets. Furthermore, controlled trials are needed to evaluate methods across multiple centers and patient groups.

Accurate identification of myocardial viability after myocardial infarction with novel manganese chelate-based MR imaging

We developed a novel manganese (Mn²⁺ ) chelate for magnetic resonance imaging (MRI) assessment of myocardial viability in acute and chronic myocardial infarct (MI) models, and compared it with Gadolinium-based delay enhancement MRI (Gd³⁺ -DEMRI) and histology. MI was induced in 14 rabbits by permanent occlusion of the left circumflex coronary artery. Gd³⁺ -DEMRI and Mn²⁺ chelate-based delayed enhancement MRI (Mn²⁺ chelate-DEMRI) were performed at 7 days (acute MI, n = 8) or 8 weeks (chronic MI, n = 6) after surgery with sequential injection of 0.15 mmol/kg Gd³⁺ and Mn²⁺ chelate. The biodistribution of Mn²⁺ in tissues and blood was measured at 1.5 and 24 h. Blood pressure, heart rate (HR), left ventricular (LV) function, and infarct fraction (IF) were analyzed, and IF was compared with the histology. The Mn²⁺ chelate group maintained a stable hemodynamic status during experiment. For acute and chronic MI, all rabbits survived without significant differences in HR or LV function before and after injection of Mn²⁺ chelate or Gd³⁺ (p > 0.05). Mn²⁺ chelate mainly accumulated in the kidney, liver, spleen, and heart at 1.5 h, with low tissue uptake and urine residue at 24 h after injection. In the acute MI group, there was no significant difference in IF between Mn²⁺ chelate-DEMRI and histology (22.92 ± 2.21% vs. 21.79 ± 2.25%, respectively, p = 0.87), while Gd³⁺ -DEMRI overestimated IF, as compared with histology (24.54 ± 1.73%, p = 0.04). In the chronic MI group, there was no significant difference in IF between the Mn²⁺ chelate-DEMRI, Gd³⁺ -DEMRI, and histology (29.50 ± 11.39%, 29.95 ± 9.40%, and 29.00 ± 10.44%, respectively, p > 0.05), and all three were well correlated (r = 0.92-0.96, p < 0.01). We conclude that the use of Mn²⁺ chelate-DEMRI is reliable for MI visualization and identifies acute MI more accurately than Gd³⁺ -DEMRI.

Echocardiographic global longitudinal strain is associated with infarct size assessed by cardiac magnetic resonance in acute myocardial infarction

The aim of this study was to investigate if there was an association between infarct size (IS) measured by cardiac magnetic resonance (CMR) and echocardiographic global longitudinal strain (GLS) in the early stage of acute myocardial infarction in patients with preserved left ventricular ejection fraction (LVEF). Patients with ST-segment elevation myocardial infarction who underwent primary percutaneous coronary intervention were assessed with CMR and transthoracic echocardiogram within 1 week of hospital admission. Two-dimensional speckle tracking was performed using a semi-automatic algorithm (EchoPac, GE Healthcare). Longitudinal strain curves were generated in a 17-segment model covering the entire left ventricular myocardium. GLS was calculated automatically. LVEF was measured by auto-LVEF in EchoPac. IS was measured by late gadolinium enhancement CMR in short-axis views covering the left ventricle. The study population consisted of 49 patients (age 60.4 ± 9.7 years; 92% male). The study population had preserved echocardiographic LVEF with a mean of 45.8 ± 8.7%. For each percent increase of IS, we found an impairment in GLS by 1.59% (95% CI 0.57–2.61), P = 0.02, after adjustment for sex, age and LVEF. No significant association between IS and echocardiographic LVEF was found: −0.25 (95% CI: −0.61 to 0.11), P = 0.51. At the segmental level, the strongest association between IS and longitudinal strain was found in the apical part of the LV: impairment of 1.69% (95% CI: 1.14–2.23), P < 0.001, for each percent increase in IS. In conclusion, GLS was significantly associated with IS in the early stage of acute myocardial infarction in patients with preserved LVEF, and this association was strongest in the apical part of the LV. No association between IS and LVEF was found.

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.

Native T1 and ECV of Noninfarcted Myocardium and Outcome in Patients With Coronary Artery Disease

BACKGROUND

Coronary artery disease (CAD) remains the major cause of cardiac morbidity and mortality worldwide, despite the advances in treatment with coronary revascularization and modern antiremodeling therapy. Risk stratification in CAD patients is primarily based on left ventricular volumes, ejection fraction (LVEF), risk scores, and the presence and extent of late gadolinium enhancement (LGE). The prognostic role of T1 mapping in noninfarcted myocardium in CAD patients has not yet been determined.

OBJECTIVES

This study sought to examine prognostic significance of native T1 mapping of noninfarcted myocardium in patients with CAD.

METHODS

A prospective, observational, multicenter longitudinal study of consecutive patients undergoing routine cardiac magnetic resonance imaging with T1 mapping and LGE. The primary endpoint was all-cause mortality. Major adverse cardiocerebrovascular events (MACCE) (cardiac mortality, nonfatal acute coronary syndrome, stroke, and appropriate device discharge) are also reported.

RESULTS

A total of 34 deaths and 71 MACCE (n = 665, males n = 424, median age [interquartile range] 57 [22] years; 64%; median follow-up period of 17 [11] months) were observed. Native T1 and extracellular volume were univariate predictors of outcome. Native T1 and LGE were stronger predictors of survival and MACCE compared with extracellular volume, LVEF, cardiac volumes, and clinical scores (p < 0.001). Native T1 of noninfarcted myocardium was the sole independent predictor of all-cause mortality (chi-square = 21.7; p < 0.001), which was accentuated in the absence of LGE or LVEF ≤35%. For MACCE, native T1 and LGE extent were joint independent predictors (chi-square = 25.6; p < 0.001).

CONCLUSIONS

Characterization of noninfarcted myocardium by native T1 is an important predictor of outcome in CAD patients, over and above the traditional risk stratifiers. The current study's results provide a basis for a novel risk stratification model in CAD based on a complementary assessment of noninfarcted myocardium and post-infarction scar, by native T1 mapping and LGE, respectively.

A national registry to assess the value of cardiovascular magnetic resonance imaging after primary percutaneous coronary intervention pathway activation: a feasibility cohort study

Background

Cardiovascular magnetic resonance (CMR) is increasingly used in patients who activate the primary percutaneous coronary intervention (PPCI) pathway to assess heart function. It is uncertain whether having CMR influences patient management or the risk of major adverse cardiovascular events in these patients.

Objective

To determine whether or not it is feasible to set up a national registry, linking routinely collected data from hospital information systems (HISs), to investigate the role of CMR in patients who activate the PPCI pathway.

Design

A feasibility prospective cohort study.

Setting

Four 24/7 PPCI hospitals in England and Wales (two with and two without a dedicated CMR facility).

Participants

Patients who activated the PPCI pathway and underwent an emergency coronary angiogram.

Interventions

CMR either performed or not performed within 10 weeks of the index event.

Main outcome measures

A. Feasibility parameters – (1) patient consent implemented at all hospitals, (2) data extracted from more than one HIS and successfully linked for > 90% of consented patients at all four hospitals, (3) HIS data successfully linked with Hospital Episode Statistics (HES) and Patient Episode Database Wales (PEDW) for > 90% of consented patients at all four hospitals and (4) CMR requested and carried out for ≥ 10% of patients activating the PPCI pathway in CMR hospitals. B. Key drivers of cost-effectiveness for CMR (identified from simple cost-effectiveness models) in patients with (1) multivessel disease and (2) unobstructed coronary arteries. C. A change in clinical management arising from having CMR (defined using formal consensus and identified using HES follow-up data in the 12 months after the index event).

Results

A. (1) Consent was implemented (for all hospitals, consent rates were 59–74%) and 1670 participants were recruited. (2) Data submission was variable – clinical data available for ≥ 82% of patients across all hospitals, biochemistry and echocardiography (ECHO) data available for ≥ 98%, 34% and 87% of patients in three hospitals and medications data available for 97% of patients in one hospital. (3) HIS data were linked with hospital episode data for 99% of all consented patients. (4) At the two CMR hospitals, 14% and 20% of patients received CMR. B. In both (1) multivessel disease and (2) unobstructed coronary arteries, the difference in quality-adjusted life-years (QALYs) between CMR and no CMR [‘current’ comparator, stress ECHO and standard ECHO, respectively] was very small [0.0012, 95% confidence interval (CI) –0.0076 to 0.0093 and 0.0005, 95% CI –0.0050 to 0.0077, respectively]. The diagnostic accuracy of the ischaemia tests was the key driver of cost-effectiveness in sensitivity analyses for both patient subgroups. C. There was consensus that CMR leads to clinically important changes in management in five patient subgroups. Some changes in management were successfully identified in hospital episode data (e.g. new diagnoses/procedures, frequency of outpatient episodes related to cardiac events), others were not (e.g. changes in medications, new diagnostic tests).

Conclusions

A national registry is not currently feasible. Patients were consented successfully but conventional consent could not be implemented nationally. Linking HIS and hospital episode data was feasible but HIS data were not uniformly available. It is feasible to identify some, but not all, changes in management in the five patient subgroups using hospital episode data. The delay in obtaining hospital episode data influenced the relevance of some of our study objectives.

Future work

To test the feasibility of conducting the study using national data sets (e.g. HES, British Cardiovascular Intervention Society audit database, Diagnostic Imaging Dataset, Clinical Practice Research Datalink).

Funding

The National Institute for Health Research (NIHR) Health Services and Delivery Research programme. This study was designed and delivered in collaboration with the Clinical Trials and Evaluation Unit, a UK Clinical Research Collaboration-registered clinical trials unit that, as part of the Bristol Trials Centre, is in receipt of NIHR clinical trials unit support funding.

Rubidium-82 PET imaging is feasible in a rat myocardial infarction model

BACKGROUND

Small-animal myocardial infarct models are frequently used in the assessment of new cardioprotective strategies. A validated quantification of perfusion using a non-cyclotron-dependent PET tracer would be of importance in monitoring response to therapy. We tested whether myocardial PET perfusion imaging is feasible with Rubidium-82 (82Rb) in a small-animal scanner using a rat myocardial infarct model.

METHODS

18 Sprague-Dawley rats underwent permanent coronary artery ligation (infarct group), and 11 rats underwent ischemia-reperfusion (reperfusion group) procedure. 82Rb-PET and magnetic resonance imaging (MRI) were conducted before and after the intervention. Perfusion was compared to both left ventricle ejection fraction (LVEF) and infarct size assessed by MRI.

RESULTS

Follow-up global 82Rb-uptake correlated significantly with infarct size (infarct group: r = -0.81, P < 0.001 and reperfusion group: r = -0.61, P = 0.04). Only 82Rb-uptake in the infarct group correlated with LVEF. At follow-up, a higher segmental 82Rb-uptake in the infarct group was associated with better wall motion (β = 0.034, CI [0.028;0.039], P < 0.001, R2 = 0.30), and inversely associated with scar transmurality (β = -2.4 [-2.6; -2.2], P < 0.001, R2 = 0.59). The associations were similar for the reperfusion group.

CONCLUSION

82Rb-PET is feasible in small animal scanners despite the long positron range and enables fast and time-efficient myocardial perfusion imaging in rat models.

Quantitative myocardial perfusion evaluation with positron emission tomography and the risk of cardiovascular events in patients with coronary artery disease: a systematic review of prognostic studies

Aims

To evaluate the prognostic value of quantitative myocardial perfusion imaging with positron emission tomography (PET) for adverse cardiovascular outcomes in patients with known or suspected coronary artery disease (CAD).

Methods and results

A search in MEDLINE and Embase was conducted for studies that evaluated (i) myocardial perfusion in absolute terms with PET, (ii) prognostic value for the development of major adverse cardiovascular events (MACE), cardiac death, and/or all-cause mortality, and (iii) patients with known or suspected CAD. Studies were divided according to the radiotracer utilized and their included population (patients with and without previous infarction). Comprehensive description and a selected instance of pooling were performed. Eight studies (n = 6804) were analysed and documented clear variability in population, quantitative PET variables operationalization [stress myocardial blood flow (sMBF) and flow reserve (MFR)], statistical covariate structure, follow-up, and radiotracer utilized. MFR was independently associated with MACE in eight studies [range of adjusted hazard ratios (HRs): 1.19–2.93]. The pooling instance demonstrated that MFR significantly associates with the development of MACEs (HR: 1.92 [1.29, 2.84]; P = 0.001). sMBF was only associated with MACE in two studies that evaluated it, and only one study documented sMBF as a better predictor than MFR.

Conclusion

This systematic review demonstrates the prognostic value of quantitative myocardial perfusion evaluated with PET, in the form of MFR and sMBF, for the development of major adverse cardiovascular outcomes in populations with known or suspected CAD. In the qualitative comparison, MFR seems to outperform sMBF as an independent prognostic factor. Evidence is still lacking for assessing quantitative PET for the occurrence of cardiac death and all-cause mortality. There is clear heterogeneity in predictor operationalization and study performances.

Effect of Dual-Source Radiofrequency Transmission on Left Ventricular Measurements and Measurement Reproducibility at 3.0 T Cardiac MR Imaging: Comparison with Conventional Single-Source Transmission Reference

RATIONALE AND OBJECTIVES

To prospectively assess effect of dual-source radiofrequency (RF) transmission on left ventricular (LV) measurements and measurements reproducibility at 3.0 T MR using balanced steady-state free precession (b-SSFP) cine imaging, compared to the conventional single-source RF transmission reference approach.

MATERIALS AND METHODS

Cardiac b-SSFP cine imaging was performed in 19 subjects at 3.0 T MR equipped with dual-source RF transmission. All images were analyzed to obtain LV end-diastolic volume, end-systolic volume, stroke volume, ejection fraction, mass, LV end-diastolic inferior wall thickness, and interventricular septal thickness. The difference of all LV measurements between the two imaging techniques was tested with the paired t test and the intertechnique agreement was tested through linear regression and Bland-Altman analyses. Additionally, repeated LV measurements were performed to determine intra and interobserver variability with the Bland-Altman method, the 95% limits of agreement, the coefficient of variation (CV) and the intraclass correlation coefficient.

RESULTS

Compared to conventional single-source, dual-source slightly overestimated end-diastolic volume, end-systolic volume, and stroke volume (mean differences, 3.9 mL ± 9.7, 1.1 mL ± 2.6, and 2.8 mL ± 9.1, respectively; p > 0.05), resulting in a small but significant positive bias in ejection fraction (1.5% ± 2.6; p = 0.021). Mass was significantly smaller with dual-source than with single-source (-4.0 g ± 6.5, p = 0.001). Dual-source slightly underestimated interventricular septal thickness (-0.29 mm ± 0.6, p = 0.067) and significantly underestimated LV end-diastolic inferior wall thickness (-0.55 mm ± 0.4, p < 0.0001). The two techniques in measurements correlated highly (r² = 0.81 to 0.96, p < 0.0001). Intra and interobserver variability in dual-source measurements was much lower than that in single-source, and variability values were <14.0%.

CONCLUSION

Improved image quality of b-SSFP cine imaging at 3.0 T MR with dual-source RF transmission may provide more reproducible LV measurements compared to conventional single-source approach. Dual-source RF transmission also provides a reasonable estimate of the LV measurements.

Cost-impact of cardiac magnetic resonance imaging with Fast-SENC compared to SPECT in the diagnosis of coronary artery disease in the U.S

AIMS

The purpose of this study is to assess the economic cost differences and the associated treatment resource changes between the developing coronary artery disease (CAD) diagnostic tool fast strain-encoded cardiac imaging (Fast-SENC) and the current commonly used stress test single-photon emission computed tomography (SPECT).

MATERIALS AND METHODS

A "payer perspective" model was created first, consisting of long-term and short-term components that used a hypothetical cohort of patients of average age (60.8 years) presenting with chest pain and suspected CAD to assess cost-impact. A cost impact model was then built that assessed likely savings from a "hospital perspective" from substituting Fast-SENC for a portion of SPECTs assuming an average number of annual SPECT tests performed in US hospitals.

RESULTS

In the payer model, using Fast-SENC followed by coronary angiography (CA) and percutaneous coronary intervention (PCI) treatment when necessary is less costly than the SPECT method when considering both direct and indirect costs of testing. Expected costs of the Fast-SENC were between $2,510 and $2,632 per correct diagnosis, while expected costs for the SPECT were between $3,157 and $4,078. Fast-SENC reduced false positives by 50% and false negatives by 86%, generating additional cost savings. The hospital model showed total costs per CAD patient visit of $825 for SPECT and $376 for Fast-SENC.

LIMITATIONS

Limitations of this study are that clinical data are sourced from other published clinical trials on how CAD diagnostic strategies impact clinical outcome, and that necessary assumptions were made which impact health outcomes.

CONCLUSION

The lower cost, higher sensitivity and specificity rates, and faster, less burdensome process for detecting CAD patients make Fast-SENC a more capable and economically beneficial stress test than SPECT. The payer model and hospital model demonstrate an alignment between payer and provider economics as Fast-SENC provides monetary savings for patients and resource benefits for hospitals.

Early risk stratification using Rubidium-82 positron emission tomography in STEMI patients

BACKGROUND

Assessment of infarct size after myocardial infarction is predictive of subsequent morphological changes and clinical outcome. This study aimed to assess subacute post-intervention Rubidium-82 (82Rb)-PET imaging in predicting left ventricle ejection fraction, regional wall motion, and final infarct size by CMR at 3-months after STEMI.

METHODS

STEMI patients undergoing percutaneous coronary intervention were included prospectively. Rest-only 82Rb-PET perfusion imaging was performed at median 36 hours [IQR: 22 to 50] after the treatment. The extent of hypoperfusion and absolute blood flow (mL·min·g) were estimated on a global and a 17-segment model with dedicated software. At 3-months follow-up patients completed the CMR functional and late gadolinium enhancement imaging.

RESULTS

42 patients were included, but only 35 had follow-up CMR and constituted the study population. Absolute blood flow was significantly lower in the infarct-related territory compared to remote myocardium, P < .005. Extent of hypoperfusion correlated with final infarct size, r = 0.58, P < .001, while blood flow correlated with ejection fraction, r = 0.41, P < .05. In linear mixed models, higher subacute absolute blood flow (β = 4.6, confidence interval [3.5; 5.2], P < .001, R2 = 0.67) was associated with greater wall motion. Segmental extent of subacute hypoperfusion (β = 0.43 [0.38; 0.49], P < .001, R2 = 0.58) was associated with the degree of late gadolinium enhancement at 3-months.

CONCLUSIONS

Subacute rest-only 82Rb-PET is feasible following STEMI and seems predictive of myocardial function and infarct size at 3-months.

Beyond Reperfusion: Acute Ventricular Unloading and Cardioprotection During Myocardial Infarction

Heart failure is a major cause of morbidity and mortality around the world, and myocardial infarction is its leading cause. Myocardial infarction destroys viable myocardium, and this dead tissue is replaced by a non-contractile scar that results in impaired cardiac function and a significantly increased likelihood of the patient developing heart failure. Limiting infarct scar size has been the target of pre-clinical and clinical investigations for decades. However, beyond reperfusion, few therapies have translated into the clinic that limit its formation. New approaches are needed. This review will focus on new clinical and pre-clinical data demonstrating that acute ventricular unloading prior to reperfusion by means of percutaneous left ventricular support devices reduces ischemia-reperfusion injury and limits infarct scar size. Emphasis will be given to summarizing our current mechanistic understanding of this new therapeutic approach to treating myocardial infarction.

Myocardial Perfusion Imaging: A Brief Review of Nuclear and Nonnuclear Techniques and Comparative Evaluation of Recent Advances

Coronary artery disease (CAD) is the leading cause of morbidity and mortality worldwide. Invasive coronary angiography (ICA) is the gold standard for the evaluation of epicardial CAD. In the pathogenesis of the CAD, myocardial perfusion abnormalities are the first changes that appear followed by wall motion abnormalities, electrocardiogram changes, and angina. Myocardial perfusion imaging (MPI) demonstrates the cumulative effect of pathology at epicardial coronary arteries, small vessels, and endothelium. Thus, it evaluates the overall burden of ischemic heart disease (IHD). MPI is used noninvasively to diagnose early asymptomatic CAD or to know the functional significance of known CAD. There are evidence that early detection of myocardial perfusion abnormalities followed by aggressive intervention against cardiovascular risk factors may restore myocardial perfusion. This may lead to reduce morbidity and mortality. Various MPI modalities have been used to diagnose and define the severity of CAD. Cardiac myocardial perfusion single-photon emission computed tomography (myocardial perfusion scintigraphy [MPS]) has been in use since decades. Several newer modalities such as positron emission tomography, cardiac magnetic resonance imaging, computed tomography perfusion, and myocardial contrast echocardiography are developing utilizing the similar principle of MPS. We shall be reviewing briefly these modalities, their performance, comparison to each other, and with ICA.

Usefulness of Cardiac Magnetic Resonance Imaging in Patients With Acute Spontaneous Coronary Artery Dissection

Cardiac magnetic resonance (CMR) has significant diagnostic and prognostic utility in myocardial infarction evaluation. However, its application in spontaneous coronary artery dissection (SCAD) is not described. Patients with confirmed SCAD who had CMR performed within 8 days of the index SCAD were reviewed. Clinical variables including demographics and medical history were recorded. CMR indexes, including myocardial delayed enhancement (MDE), microvascular obstruction, perfusion defects, left ventricular ejection fraction, and wall motion score index were measured. A total of 18 patients (all women, mean age 47.1 years) were included. Overall burden of atherosclerotic risk factors was low; 3 had a previous SCAD. Two patients underwent CMR before coronary angiography, whereas the others received CMR thereafter. Mean time between SCAD diagnosis and CMR completion was 2.7 days (range 0 to 8). Mean left ventricular ejection fraction and wall motion score index were 56.1% and 1.27, respectively. A total of 15 patients had MDE consistent with myocardial infarction in the SCAD distribution(s) identified on coronary angiography, with 8 patients having concomitant microvascular obstruction. Ten patients had transmural MDE. At follow-up (mean 386 days), all patients were alive; extracoronary vascular abnormalities were identified in 14; 6 had recurrent chest pain; and 2 had recurrent SCAD. Both patients with recurrent SCAD had no unique features on CMR to predict a future event. In conclusion, CMR provided significant value in clarifying the diagnosis and assessing for adverse sequelae after acute SCAD. Further studies are needed to determine its role in SCAD prognostication.