Multi-Ethnic Study of Atherosclerosis: objectives and design

The Multi-Ethnic Study of Atherosclerosis was initiated in July 2000 to investigate the prevalence, correlates, and progression of subclinical cardiovascular disease (CVD) in a population-based sample of 6,500 men and women aged 45-84 years. The cohort will be selected from six US field centers. Approximately 38% of the cohort will be White, 28% African-American, 23% Hispanic, and 11% Asian (of Chinese descent). Baseline measurements will include measurement of coronary calcium using computed tomography; measurement of ventricular mass and function using cardiac magnetic resonance imaging; measurement of flow-mediated brachial artery endothelial vasodilation, carotid intimal-medial wall thickness, and distensibility of the carotid arteries using ultrasonography; measurement of peripheral vascular disease using ankle and brachial blood pressures; electrocardiography; and assessments of microalbuminuria, standard CVD risk factors, sociodemographic factors, life habits, and psychosocial factors. Blood samples will be assayed for putative biochemical risk factors and stored for use in nested case-control studies. DNA will be extracted and lymphocytes will be immortalized for genetic studies. Measurement of selected subclinical disease indicators and risk factors will be repeated for the study of progression over 7 years. Participants will be followed through 2008 for identification and characterization of CVD events, including acute myocardial infarction and other coronary heart disease, stroke, peripheral vascular disease, and congestive heart failure; therapeutic interventions for CVD; and mortality.

Coronary calcium as a predictor of coronary events in four racial or ethnic groups

BACKGROUND

In white populations, computed tomographic measurements of coronary-artery calcium predict coronary heart disease independently of traditional coronary risk factors. However, it is not known whether coronary-artery calcium predicts coronary heart disease in other racial or ethnic groups.

METHODS

We collected data on risk factors and performed scanning for coronary calcium in a population-based sample of 6722 men and women, of whom 38.6% were white, 27.6% were black, 21.9% were Hispanic, and 11.9% were Chinese. The study subjects had no clinical cardiovascular disease at entry and were followed for a median of 3.8 years.

RESULTS

There were 162 coronary events, of which 89 were major events (myocardial infarction or death from coronary heart disease). In comparison with participants with no coronary calcium, the adjusted risk of a coronary event was increased by a factor of 7.73 among participants with coronary calcium scores between 101 and 300 and by a factor of 9.67 among participants with scores above 300 (P<0.001 for both comparisons). Among the four racial and ethnic groups, a doubling of the calcium score increased the risk of a major coronary event by 15 to 35% and the risk of any coronary event by 18 to 39%. The areas under the receiver-operating-characteristic curves for the prediction of both major coronary events and any coronary event were higher when the calcium score was added to the standard risk factors.

CONCLUSIONS

The coronary calcium score is a strong predictor of incident coronary heart disease and provides predictive information beyond that provided by standard risk factors in four major racial and ethnic groups in the United States. No major differences among racial and ethnic groups in the predictive value of calcium scores were detected.

Forecasting the impact of heart failure in the United States: a policy statement from the American Heart Association

BACKGROUND

Heart failure (HF) is an important contributor to both the burden and cost of national healthcare expenditures, with more older Americans hospitalized for HF than for any other medical condition. With the aging of the population, the impact of HF is expected to increase substantially.

METHODS AND RESULTS

We estimated future costs of HF by adapting a methodology developed by the American Heart Association to project the epidemiology and future costs of HF from 2012 to 2030 without double counting the costs attributed to comorbid conditions. The model assumes that HF prevalence will remain constant by age, sex, and race/ethnicity and that rising costs and technological innovation will continue at the same rate. By 2030, >8 million people in the United States (1 in every 33) will have HF. Between 2012 and 2030, real (2010$) total direct medical costs of HF are projected to increase from $21 billion to $53 billion. Total costs, including indirect costs for HF, are estimated to increase from $31 billion in 2012 to $70 billion in 2030. If one assumes all costs of cardiac care for HF patients are attributable to HF (no cost attribution to comorbid conditions), the 2030 projected cost estimates of treating patients with HF will be 3-fold higher ($160 billion in direct costs).

CONCLUSIONS

The estimated prevalence and cost of care for HF will increase markedly because of aging of the population. Strategies to prevent HF and improve the efficiency of care are needed.

Diagnosis of arrhythmogenic right ventricular cardiomyopathy/dysplasia: proposed modification of the task force criteria

BACKGROUND

In 1994, an International Task Force proposed criteria for the clinical diagnosis of arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) that facilitated recognition and interpretation of the frequently nonspecific clinical features of ARVC/D. This enabled confirmatory clinical diagnosis in index cases through exclusion of phenocopies and provided a standard on which clinical research and genetic studies could be based. Structural, histological, electrocardiographic, arrhythmic, and familial features of the disease were incorporated into the criteria, subdivided into major and minor categories according to the specificity of their association with ARVC/D. At that time, clinical experience with ARVC/D was dominated by symptomatic index cases and sudden cardiac death victims-the overt or severe end of the disease spectrum. Consequently, the 1994 criteria were highly specific but lacked sensitivity for early and familial disease.

METHODS AND RESULTS

Revision of the diagnostic criteria provides guidance on the role of emerging diagnostic modalities and advances in the genetics of ARVC/D. The criteria have been modified to incorporate new knowledge and technology to improve diagnostic sensitivity, but with the important requisite of maintaining diagnostic specificity. The approach of classifying structural, histological, electrocardiographic, arrhythmic, and genetic features of the disease as major and minor criteria has been maintained. In this modification of the Task Force criteria, quantitative criteria are proposed and abnormalities are defined on the basis of comparison with normal subject data.

CONCLUSIONS

The present modifications of the Task Force Criteria represent a working framework to improve the diagnosis and management of this condition.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00024505.

Diagnosis of arrhythmogenic right ventricular cardiomyopathy/dysplasia: proposed modification of the Task Force Criteria

BACKGROUND

In 1994, an International Task Force proposed criteria for the clinical diagnosis of arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) that facilitated recognition and interpretation of the frequently nonspecific clinical features of ARVC/D. This enabled confirmatory clinical diagnosis in index cases through exclusion of phenocopies and provided a standard on which clinical research and genetic studies could be based. Structural, histological, electrocardiographic, arrhythmic, and familial features of the disease were incorporated into the criteria, subdivided into major and minor categories according to the specificity of their association with ARVC/D. At that time, clinical experience with ARVC/D was dominated by symptomatic index cases and sudden cardiac death victims-the overt or severe end of the disease spectrum. Consequently, the 1994 criteria were highly specific but lacked sensitivity for early and familial disease.

METHODS AND RESULTS

Revision of the diagnostic criteria provides guidance on the role of emerging diagnostic modalities and advances in the genetics of ARVC/D. The criteria have been modified to incorporate new knowledge and technology to improve diagnostic sensitivity, but with the important requisite of maintaining diagnostic specificity. The approach of classifying structural, histological, electrocardiographic, arrhythmic, and genetic features of the disease as major and minor criteria has been maintained. In this modification of the Task Force criteria, quantitative criteria are proposed and abnormalities are defined on the basis of comparison with normal subject data.

CONCLUSIONS

The present modifications of the Task Force Criteria represent a working framework to improve the diagnosis and management of this condition. Clinical Trial Registration clinicaltrials.gov Identifier: NCT00024505.

Standardized image interpretation and post processing in cardiovascular magnetic resonance: 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 MR (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.

MRI evaluation of the contralateral breast in women with recently diagnosed breast cancer

BACKGROUND

Even after careful clinical and mammographic evaluation, cancer is found in the contralateral breast in up to 10% of women who have received treatment for unilateral breast cancer. We conducted a study to determine whether magnetic resonance imaging (MRI) could improve on clinical breast examination and mammography in detecting contralateral breast cancer soon after the initial diagnosis of unilateral breast cancer.

METHODS

A total of 969 women with a recent diagnosis of unilateral breast cancer and no abnormalities on mammographic and clinical examination of the contralateral breast underwent breast MRI. The diagnosis of MRI-detected cancer was confirmed by means of biopsy within 12 months after study entry. The absence of breast cancer was determined by means of biopsy, the absence of positive findings on repeat imaging and clinical examination, or both at 1 year of follow-up.

RESULTS

MRI detected clinically and mammographically occult breast cancer in the contralateral breast in 30 of 969 women who were enrolled in the study (3.1%). The sensitivity of MRI in the contralateral breast was 91%, and the specificity was 88%. The negative predictive value of MRI was 99%. A biopsy was performed on the basis of a positive MRI finding in 121 of the 969 women (12.5%), 30 of whom had specimens that were positive for cancer (24.8%); 18 of the 30 specimens were positive for invasive cancer. The mean diameter of the invasive tumors detected was 10.9 mm. The additional number of cancers detected was not influenced by breast density, menopausal status, or the histologic features of the primary tumor.

CONCLUSIONS

MRI can detect cancer in the contralateral breast that is missed by mammography and clinical examination at the time of the initial breast-cancer diagnosis. (ClinicalTrials.gov number, NCT00058058 [ClinicalTrials.gov].).

The relationship of left ventricular mass and geometry to incident cardiovascular events: the MESA (Multi-Ethnic Study of Atherosclerosis) study

OBJECTIVE

The purpose of this study was to evaluate the relationship of left ventricular (LV) mass and geometry measured with cardiac magnetic resonance imaging (MRI) to incident cardiovascular events in the MESA (Multi-Ethnic Study of Atherosclerosis) study.

BACKGROUND

MRI is highly accurate for evaluation of heart size and structure and has not previously been used in a large epidemiologic study to predict cardiovascular events.

METHODS

A total of 5,098 participants in the MESA study underwent cardiac MRI at the baseline examination and were followed up for a median of 4 years. Cox proportional hazard models were constructed to predict the end points of coronary heart disease (CHD), stroke, and heart failure (HF) after adjustment for cardiovascular risk factors.

RESULTS

A total of 216 incident events were observed during the follow-up period. In adjusted models, the end points of incident CHD and stroke were positively associated with increased LV mass-to-volume ratio (CHD, hazard ratio [HR]: 2.1 per g/ml, p = 0.02; stroke, HR: 4.2 per g/ml, p = 0.005). In contrast, LV mass showed the strongest association with incident HF events (HR: 1.4 per 10% increment, p < 0.0001). The HF events occurred primarily in participants with LV hypertrophy, that is, >or=95th percentile of LV mass (HR: 8.6, 95% confidence interval: 3.7 to 19.9, reference group <50th percentile of LV mass).

CONCLUSIONS

The LV size was related to incident HF, stroke, and CHD in this multiethnic cohort. Whereas body size-adjusted LV mass alone predicted incident HF, concentric ventricular remodeling predicted incident stroke and CHD.

Infarct tissue heterogeneity by magnetic resonance imaging identifies enhanced cardiac arrhythmia susceptibility in patients with left ventricular dysfunction

BACKGROUND

The extent of the peri-infarct zone by magnetic resonance imaging (MRI) has been related to all-cause mortality in patients with coronary artery disease. This relationship may result from arrhythmogenesis in the infarct border. However, the relationship between tissue heterogeneity in the infarct periphery and arrhythmic substrate has not been investigated. In the present study, we quantify myocardial infarct heterogeneity by contrast-enhanced MRI and relate it to an electrophysiological marker of arrhythmic substrate in patients with left ventricular (LV) systolic dysfunction undergoing prophylactic implantable cardioverter defibrillator placement.

METHODS AND RESULTS

Before implantable cardioverter defibrillator implantation for primary prevention of sudden cardiac death, 47 patients underwent cine and contrast-enhanced MRI to measure LV function, volumes, mass, and infarct size. A method for quantifying the heterogeneous infarct periphery and the denser infarct core is described. MRI indices were related to inducibility of sustained monomorphic ventricular tachycardia during electrophysiological or device testing. For the noninducible versus inducible patients, LV ejection fraction (30+/-10% versus 29+/-7%, P=0.79), LV end-diastolic volume (220+/-70 versus 228+/-57 mL, P=0.68), and infarct size by standard contrast-enhanced MRI definitions (P=NS) were similar. Quantification of tissue heterogeneity at the infarct periphery was strongly associated with inducibility for monomorphic ventricular tachycardia (noninducible versus inducible: 13+/-9 versus 19+/-8 g, P=0.015) and was the single significant factor in a stepwise logistic regression.

CONCLUSIONS

Tissue heterogeneity is present and quantifiable within human infarcts. More extensive tissue heterogeneity correlates with increased ventricular irritability by programmed electrical stimulation. These findings support the hypothesis that anatomic tissue heterogeneity increases susceptibility to ventricular arrhythmias in patients with prior myocardial infarction and LV dysfunction.

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.

Coronary artery calcification compared with carotid intima-media thickness in the prediction of cardiovascular disease incidence: the Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

Coronary artery calcium (CAC) and carotid intima-media thickness (IMT) are noninvasive measures of atherosclerosis that consensus panels have recommended as possible additions to risk factor assessment for predicting the probability of cardiovascular disease (CVD) occurrence. Our objective was to assess whether maximum carotid IMT or CAC (Agatston score) is the better predictor of incident CVD.

METHODS

A prospective cohort study of subjects aged 45 to 84 years in 4 ethnic groups, who were initially free of CVD (n = 6698) was performed, with standardized carotid IMT and CAC measures at baseline, in 6 field centers of the Multi-Ethnic Study of Atherosclerosis (MESA). The main outcome measure was the risk of incident CVD events (coronary heart disease, stroke, and fatal CVD) over a maximum of 5.3 years of follow-up.

RESULTS

There were 222 CVD events during follow-up. Coronary artery calcium was associated more strongly than carotid IMT with the risk of incident CVD. After adjustment for each other (CAC score and IMT) and age, race, and sex [corrected], the hazard ratio of CVD increased 2.1-fold (95% confidence interval [CI], 1.8-2.5) for each 1-standard deviation (SD) increment of log-transformed CAC score, vs 1.3-fold (95% CI, 1.1-1.4) for each 1-SD increment of the maximum IMT. For coronary heart disease, the hazard ratios per 1-SD increment increased 2.5-fold (95% CI, 2.1-3.1) for CAC score and 1.2-fold (95% CI, 1.0-1.4) for IMT. A receiver operating characteristic curve analysis also suggested that CAC score was a better predictor of incident CVD than was IMT, with areas under the curve of 0.81 vs 0.78, respectively.

CONCLUSION

Although whether and how to clinically use bioimaging tests of subclinical atherosclerosis remains a topic of debate, this study found that CAC score is a better predictor of subsequent CVD events than carotid IMT.

Normal values for cardiovascular magnetic resonance in adults and children

Morphological and functional parameters such as chamber size and function, aortic diameters and distensibility, flow and T1 and T2* relaxation time can be assessed and quantified by cardiovascular magnetic resonance (CMR). Knowledge of normal values for quantitative CMR is crucial to interpretation of results and to distinguish normal from disease. In this review, we present normal reference values for morphological and functional CMR parameters of the cardiovascular system based on the peer-reviewed literature and current CMR techniques and sequences.

Differences in the incidence of congestive heart failure by ethnicity: the multi-ethnic study of atherosclerosis

BACKGROUND

The relationship between incident congestive heart failure (CHF) and ethnicity as well as racial/ethnic differences in the mechanisms leading to CHF have not been demonstrated in a multiracial, population-based study. Our objective was to evaluate the relationship between race/ethnicity and incident CHF.

METHODS

The Multi-Ethnic Study of Atherosclerosis (MESA) is a cohort study of 6814 participants of 4 ethnicities: white (38.5%), African American (27.8%), Hispanic (21.9%), and Chinese American (11.8%). Participants with a history of cardiovascular disease at baseline were excluded. Cox proportional hazards models were used for data analysis.

RESULTS

During a median follow-up of 4.0 years, 79 participants developed CHF (incidence rate: 3.1 per 1000 person-years). African Americans had the highest incidence rate of CHF, followed by Hispanic, white, and Chinese American participants (incidence rates: 4.6, 3.5, 2.4, and 1.0 per 1000 person-years, respectively). Although risk of developing CHF was higher among African American compared with white participants (hazard ratio, 1.8; 95% confidence interval, 1.1-3.1), adding hypertension and/or diabetes mellitus to models including ethnicity eliminated statistical ethnic differences in incident CHF. Moreover, African Americans had the highest proportion of incident CHF not preceded by clinical myocardial infarction (75%) compared with other ethnic groups (P = .06).

CONCLUSIONS

The higher risk of incident CHF among African Americans was related to differences in the prevalence of hypertension and diabetes mellitus as well as socioeconomic status. The mechanisms of CHF also differed by ethnicity; interim myocardial infarction had the least influence among African Americans, and left ventricular mass increase had the greatest effect among Hispanic and white participants.

Late gadolinium enhancement by cardiovascular magnetic resonance heralds an adverse prognosis in nonischemic cardiomyopathy

OBJECTIVES

We examined whether the presence and extent of late gadolinium enhancement (LGE) by cardiovascular magnetic resonance (CMR) predict adverse outcomes in nonischemic cardiomyopathy (NICM) patients.

BACKGROUND

Morbidity and mortality is high in NICM patients. However, the clinical course of an individual patient is unpredictable and current risk stratification approaches are limited. Cardiovascular magnetic resonance detects myocardial fibrosis, which appears as LGE after contrast administration and may convey prognostic importance.

METHODS

In a prospective cohort study, 65 NICM patients with left ventricular (LV) ejection fraction < or =35% underwent CMR before placement of an implantable cardioverter-defibrillator (ICD) for primary prevention of sudden cardiac death. The CMR images were analyzed for the presence and extent of LGE and for LV function, volumes, and mass. Patients were followed for an index composite end point of 3 cardiac events: hospitalization for heart failure, appropriate ICD firing, and cardiac death.

RESULTS

A total of 42% (n = 27) of patients had CMR LGE, averaging 10 +/- 13% of LV mass. During a 17-month median follow-up, 44% (n = 12) of patients with LGE had an index composite outcome event versus only 8% (n = 3) of those without LGE (p < 0.001 for Kaplan-Meier survival curves). After adjustment for LV volume index and functional class, patients with LGE had an 8-fold higher risk of experiencing the primary outcome (hazard ratio 8.2, 95% confidence interval 2.2 to 30.9; p = 0.002).

CONCLUSIONS

A CMR LGE in NICM patients strongly predicts adverse cardiac outcomes. The CMR LGE may represent the end-organ consequences of sustained adrenergic activation and adverse LV remodeling, and its identification may significantly improve risk stratification strategies in this high risk population. (Imaging Techniques for Identifying Factors of Sudden Cardiac Death Risk; NCT00181233).

Testing of low-risk patients presenting to the emergency department with chest pain: a scientific statement from the American Heart Association

The management of low-risk patients presenting to emergency departments is a common and challenging clinical problem entailing 8 million emergency department visits annually. Although a majority of these patients do not have a life-threatening condition, the clinician must distinguish between those who require urgent treatment of a serious problem and those with more benign entities who do not require admission. Inadvertent discharge of patients with acute coronary syndrome from the emergency department is associated with increased mortality and liability, whereas inappropriate admission of patients without serious disease is neither indicated nor cost-effective. Clinical judgment and basic clinical tools (history, physical examination, and electrocardiogram) remain primary in meeting this challenge and affording early identification of low-risk patients with chest pain. Additionally, established and newer diagnostic methods have extended clinicians' diagnostic capacity in this setting. Low-risk patients presenting with chest pain are increasingly managed in chest pain units in which accelerated diagnostic protocols are performed, comprising serial electrocardiograms and cardiac injury markers to exclude acute coronary syndrome. Patients with negative findings usually complete the accelerated diagnostic protocol with a confirmatory test to exclude ischemia. This is typically an exercise treadmill test or a cardiac imaging study if the exercise treadmill test is not applicable. Rest myocardial perfusion imaging has assumed an important role in this setting. Computed tomography coronary angiography has also shown promise in this setting. A negative accelerated diagnostic protocol evaluation allows discharge, whereas patients with positive findings are admitted. This approach has been found to be safe, accurate, and cost-effective in low-risk patients presenting with chest pain.

Percent emphysema, airflow obstruction, and impaired left ventricular filling

BACKGROUND

Very severe chronic obstructive pulmonary disease causes cor pulmonale with elevated pulmonary vascular resistance and secondary reductions in left ventricular filling, stroke volume, and cardiac output. We hypothesized that emphysema, as detected on computed tomography (CT), and airflow obstruction are inversely related to left ventricular end-diastolic volume, stroke volume, and cardiac output among persons without very severe lung disease.

METHODS

We measured left ventricular structure and function with the use of magnetic resonance imaging in 2816 persons who were 45 to 84 years of age. The extent of emphysema (expressed as percent emphysema) was defined as the percentage of voxels below -910 Hounsfield units in the lung windows on cardiac computed tomographic scans. Spirometry was performed according to American Thoracic Society guidelines. Generalized additive models were used to test for threshold effects.

RESULTS

Of the study participants, 13% were current smokers, 38% were former smokers, and 49% had never smoked. A 10-point increase in percent emphysema was linearly related to reductions in left ventricular end-diastolic volume (-4.1 ml; 95% confidence interval [CI], -3.3 to -4.9; P<0.001), stroke volume (-2.7 ml; 95% CI, -2.2 to -3.3; P<0.001), and cardiac output (-0.19 liters per minute; 95% CI, -0.14 to -0.23; P<0.001). These associations were of greater magnitude among current smokers than among former smokers and those who had never smoked. The extent of airflow obstruction was similarly associated with left ventricular structure and function, and smoking status had similar modifying effects on these associations. Percent emphysema and airflow obstruction were not associated with the left ventricular ejection fraction.

CONCLUSIONS

In a population-based study, a greater extent of emphysema on CT scanning and more severe airflow obstruction were linearly related to impaired left ventricular filling, reduced stroke volume, and lower cardiac output without changes in the ejection fraction.

Quantitative assessment of intrinsic regional myocardial deformation by Doppler strain rate echocardiography in humans: validation against three-dimensional tagged magnetic resonance imaging

BACKGROUND

Tissue Doppler echocardiography-derived strain rate and strain measurements (SDE) are new quantitative indices of intrinsic cardiac deformation. The aim of this study was to validate and compare these new indices of regional cardiac function to measurements of 3-dimensional myocardial strain by tagged MRI.

METHODS AND RESULTS

The study population included 33 healthy volunteers, 17 patients with acute myocardial infarction, and 8 patients with suspected coronary artery disease who were studied during dobutamine stress echocardiography. Peak systolic myocardial velocities were measured by tissue Doppler echocardiography, peak systolic strain rates and strains by SDE, and strains by tagged MRI. In healthy individuals, longitudinal myocardial Doppler velocities decreased progressively from base to apex, whereas myocardial strain rates and strains were uniform in all segments. In patients with acute infarction, abnormal strains clearly identified dysfunctional areas. In infarcted regions, SDE showed 1.5+/-4.3% longitudinal stretching compared with -15.0+/-3.9% shortening in remote myocardium (P<0.001), and radial measurements showed -6.9+/-4.1% thinning and 14.3+/-5.0% thickening (P<0.001), respectively. During dobutamine infusion, longitudinal strains by SDE increased significantly from -13.5% to -23.8% (P<0.01) and radial strains increased from 13.1+/-3.1% to 29.3+/-11.5% (P<0.01). Comparisons between myocardial strains by SDE and tagged MRI in healthy individuals (n=11), in infarct patients (n=17), and during stress echo (n=4) showed excellent correlations (r=0.89 and r=0.96 for longitudinal and radial strains, respectively, P< 0.001).

CONCLUSIONS

The present study demonstrates the ability of Doppler echocardiography to measure myocardial strains in a clinical setting. Myocardial strains by Doppler may represent a new powerful method for quantifying left ventricular function noninvasively in humans.

Cardiovascular Function in Multi-Ethnic Study of Atherosclerosis: Normal Values by Age, Sex, and Ethnicity

OBJECTIVE

MRI provides accurate and high-resolution measurements of cardiac anatomy and function. The purpose of this study was to describe the imaging protocol and normal values of left ventricular (LV) function and mass in the Multi-Ethnic Study of Atherosclerosis (MESA).

SUBJECTS AND METHODS

Eight hundred participants (400 men, 400 women) in four age strata (45-54, 55-64, 65-74, 75-84 years) were chosen at random. Participants with the following known cardiovascular risk factors were excluded: current smoker, systolic blood pressure > 140 mm Hg, diastolic blood pressure > 90 mm Hg, fasting glucose > 110 mg/dL, total cholesterol > 240 mg/dL, and high-density lipoprotein (HDL) cholesterol < 40 mg/dL. Cardiac MR images were analyzed using MASS software (version 4.2). Mean values, SDs, and correlation coefficients in relationship to patient age were calculated.

RESULTS

There were significant differences in LV volumes and mass between men and women. LV volumes were inversely associated with age (p < 0.05) for both sexes except for the LV end-systolic volume index. For men, LV mass was inversely associated with age (slope = -0.72 g/year, p = 0.0021), but LV mass index was not associated with age (slope = -0.179 g/m2/year, p = 0.075). For women, LV mass (slope = -0.15 g/year, p = 0.30) and LV mass index (slope = 0.0044 g/m2/year, p = 0.95) were not associated with age. LV mass was the largest in the African-American group (men, 181.6 +/- 35.8 [SD] g; women, 128.8 +/- 28.1 g) and was smallest in the Asian-American group (men, 129.1 +/- 20.0 g; women, 89.4 +/- 13.3 g).

CONCLUSION

The normal LV differs in volume and mass between sexes and among certain ethnic groups. When indexed by body surface area, LV mass was independent of age for both sexes. Studies that assess cardiovascular risk factors in relationship to cardiac function and structure need to account for these normal variations in the population.

Long COVID: post-acute sequelae of COVID-19 with a cardiovascular focus

Emerging as a new epidemic, long COVID or post-acute sequelae of coronavirus disease 2019 (COVID-19), a condition characterized by the persistence of COVID-19 symptoms beyond 3 months, is anticipated to substantially alter the lives of millions of people globally. Cardiopulmonary symptoms including chest pain, shortness of breath, fatigue, and autonomic manifestations such as postural orthostatic tachycardia are common and associated with significant disability, heightened anxiety, and public awareness. A range of cardiovascular (CV) abnormalities has been reported among patients beyond the acute phase and include myocardial inflammation, myocardial infarction, right ventricular dysfunction, and arrhythmias. Pathophysiological mechanisms for delayed complications are still poorly understood, with a dissociation seen between ongoing symptoms and objective measures of cardiopulmonary health. COVID-19 is anticipated to alter the long-term trajectory of many chronic cardiac diseases which are abundant in those at risk of severe disease. In this review, we discuss the definition of long COVID and its epidemiology, with an emphasis on cardiopulmonary symptoms. We further review the pathophysiological mechanisms underlying acute and chronic CV injury, the range of post-acute CV sequelae, and impact of COVID-19 on multiorgan health. We propose a possible model for referral of post-COVID-19 patients to cardiac services and discuss future directions including research priorities and clinical trials that are currently underway to evaluate the efficacy of treatment strategies for long COVID and associated CV sequelae.

Cardiovascular Event Prediction by Machine Learning: The Multi-Ethnic Study of Atherosclerosis

RATIONALE

Machine learning may be useful to characterize cardiovascular risk, predict outcomes, and identify biomarkers in population studies.

OBJECTIVE

To test the ability of random survival forests, a machine learning technique, to predict 6 cardiovascular outcomes in comparison to standard cardiovascular risk scores.

METHODS AND RESULTS

We included participants from the MESA (Multi-Ethnic Study of Atherosclerosis). Baseline measurements were used to predict cardiovascular outcomes over 12 years of follow-up. MESA was designed to study progression of subclinical disease to cardiovascular events where participants were initially free of cardiovascular disease. All 6814 participants from MESA, aged 45 to 84 years, from 4 ethnicities, and 6 centers across the United States were included. Seven-hundred thirty-five variables from imaging and noninvasive tests, questionnaires, and biomarker panels were obtained. We used the random survival forests technique to identify the top-20 predictors of each outcome. Imaging, electrocardiography, and serum biomarkers featured heavily on the top-20 lists as opposed to traditional cardiovascular risk factors. Age was the most important predictor for all-cause mortality. Fasting glucose levels and carotid ultrasonography measures were important predictors of stroke. Coronary Artery Calcium score was the most important predictor of coronary heart disease and all atherosclerotic cardiovascular disease combined outcomes. Left ventricular structure and function and cardiac troponin-T were among the top predictors for incident heart failure. Creatinine, age, and ankle-brachial index were among the top predictors of atrial fibrillation. TNF-α (tissue necrosis factor-α) and IL (interleukin)-2 soluble receptors and NT-proBNP (N-Terminal Pro-B-Type Natriuretic Peptide) levels were important across all outcomes. The random survival forests technique performed better than established risk scores with increased prediction accuracy (decreased Brier score by 10%-25%).

CONCLUSIONS

Machine learning in conjunction with deep phenotyping improves prediction accuracy in cardiovascular event prediction in an initially asymptomatic population. These methods may lead to greater insights on subclinical disease markers without apriori assumptions of causality.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00005487.

Magnitude and time course of microvascular obstruction and tissue injury after acute myocardial infarction

BACKGROUND

Microvascular obstruction within an area of myocardial infarction indicates worse functional recovery and a higher risk of postinfarction complications. After prolonged coronary occlusion, contrast-enhanced MRI identifies myocardial infarction as a hyperenhanced region containing a hypoenhanced core. Because the time course of microvascular obstruction after infarction/reperfusion is unknown, we examined whether microvascular obstruction reaches its full extent shortly after reperfusion or shows significant progression over the following 2 days.

METHODS AND RESULTS

Seven dogs underwent 90-minute balloon occlusion of the left anterior descending coronary artery (LAD) followed by reflow. Gadolinium-DTPA-enhanced MRI performed at 2, 6, and 48 hours after reperfusion was compared with radioactive microsphere blood flow (MBF) measurements and myocardial staining to define microvascular obstruction (thioflavin S) and infarct size (triphenyltetrazolium chloride, TTC). The MRI hypoenhanced region increased 3-fold during 48 hours after reperfusion (3.2+/-1.8%, 6.7+/-4.4%, and 9.9+/-3.2% of left ventricular mass at 2, 6, and 48 hours, respectively, P<0.03) and correlated well with microvascular obstruction (MBF <50% of remote region, r=0.99 and thioflavin S, r=0.93). MRI hyperenhancement also increased (21.7+/-4.0%, 24.3+/-4.6%, and 28.8+/-5.1% at 2, 6, and 48 hours, P<0.006) and correlated well with infarct size by TTC (r=0.92). The microvascular obstruction/infarct size ratio increased from 13.0+/-4.8% to 22.6+/-8.9% and to 30.4+/-4.2% over 48 hours (P=0.024).

CONCLUSION

The extent of microvascular obstruction and the infarct size increase significantly over the first 48 hours after myocardial infarction. These results are consistent with progressive microvascular and myocardial injury well beyond coronary occlusion and reflow.

The association of pericardial fat with incident coronary heart disease: the Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

Pericardial fat (ie, fat around the heart) may have a direct role in the atherosclerotic process in coronary arteries through local release of inflammation-related cytokines. Cross-sectional studies suggest that pericardial fat is positively associated with coronary artery disease independent of total body fat.

OBJECTIVE

We investigated whether pericardial fat predicts future coronary heart disease events.

DESIGN

We conducted a case-cohort study in 998 individuals, who were randomly selected from 6814 Multi-Ethnic Study of Atherosclerosis (MESA) participants and 147 MESA participants (26 from those 998 individuals) who developed incident coronary heart disease from 2000 to 2005. The volume of pericardial fat was determined from cardiac computed tomography at baseline.

RESULTS

The age range of the subjects was 45-84 y (42% men, 45% white, 10% Asian American, 22% African American, and 23% Hispanic). Pericardial fat was positively correlated with both body mass index (correlation coefficient = 0.45, P < 0.0001) and waist circumference (correlation coefficient = 0.57, P < 0.0001). In unadjusted analyses, pericardial fat (relative hazard per 1-SD increment: 1.33; 95% CI: 1.15, 1.54), but not body mass index (1.00; 0.84, 1.18), was associated with the risk of coronary heart disease. Waist circumference (1.14; 0.97, 1.34; P = 0.1) was marginally associated with the risk of coronary heart disease. The relation between pericardial fat and coronary heart disease remained significant after further adjustment for body mass index and other cardiovascular disease risk factors (1.26; 1.01, 1.59). The relation did not differ by sex.

CONCLUSION

Pericardial fat predicts incident coronary heart disease independent of conventional risk factors, including body mass index.

Diagnostic Architectural and Dynamic Features at Breast MR Imaging: Multicenter Study

PURPOSE

To prospectively determine the prevalence and predictive value of three-dimensional (3D) and dynamic breast magnetic resonance (MR) imaging and contrast material kinetic features alone and as part of predictive diagnostic models.

MATERIALS AND METHODS

The study protocol was approved by the institutional review board or ethics committees of all participating institutions, and informed consent was obtained from all participants. Although study data collection was performed before HIPAA went into effect, standards that would be compliant with HIPAA were adhered to. Data from the International Breast MR Consortium trial 6883 were used in the analysis. Women underwent 3D (minimum spatial resolution, 0.7 x 1.4 x 3 mm; minimal temporal resolution, 4 minutes) and dynamic two-dimensional (temporal resolution, 15 seconds) MR imaging examinations. Readers rated enhancement shape, enhancement distribution, border architecture, enhancement intensity, presence of rim enhancement or internal septations, and the shape of the contrast material kinetic curve. Regression was performed for each feature individually and after adjustment for associated mammographic findings. Multivariate models were also constructed from multiple architectural and dynamic features. Areas under the receiver operating characteristic curve (Az values) were estimated for all models.

RESULTS

There were 995 lesions in 854 women (mean age, 53 years +/- 12 [standard deviation]; range, 18-80 years) for whom pathology data were available. The absence of enhancement was associated with an 88% negative predictive value for cancer. Qualitative characterization of the dynamic enhancement pattern was associated with an Az value of 0.66 across all lesion architectures. Focal mass margins (Az = 0.76) and signal intensity (Az = 0.70) were highly predictive imaging features. Multivariate models were constructed with an Az value of 0.880.

CONCLUSION

Architectural and dynamic features are important in breast MR imaging interpretation. Multivariate models involving feature assessment have a diagnostic accuracy superior to that of qualitative characterization of the dynamic enhancement pattern.

Magnetic resonance imaging of the breast prior to biopsy

CONTEXT

Breast magnetic resonance imaging (MRI) has been shown to have high sensitivity for cancer detection and is increasingly used following mammography to evaluate suspicious breast lesions.

OBJECTIVE

To determine the accuracy of breast MRI in conjunction with mammography for the detection of breast cancer in patients with suspicious mammographic or clinical findings.

DESIGN, SETTING, AND PATIENTS

Prospective multicenter investigation of the International Breast MR Consortium conducted at 14 university hospitals in North America and Europe from June 2, 1998, through October 31, 2001, of 821 patients referred for breast biopsy for American College of Radiology category 4 or 5 mammographic assessment or suspicious clinical or ultrasound finding.

INTERVENTIONS

MRI examinations performed prior to breast biopsy; MRI results were interpreted at each site, which were blinded to pathological results.

MAIN OUTCOME MEASURES

Area under the receiver operating characteristic curve (AUC), sensitivity, and specificity of breast MRI.

RESULTS

Among the 821 patients, there were 404 malignant index lesions, of which 63 were ductal carcinoma in situ (DCIS) and 341 were invasive carcinoma. Of the 417 nonmalignant index lesions, 366 were benign, 47 showed atypical histology, and 4 were lobular carcinoma in situ. The AUC pooled over all institutions was 0.88 (95% confidence interval [CI], 0.86-0.91). MRI correctly detected cancer in 356 of 404 cancer cases (DCIS or invasive cancer), resulting in a sensitivity of 88.1% (95% CI, 84.6%-91.1%), and correctly identified as negative for cancer 281 of 417 cases without cancer, resulting in a specificity of 67.7% (95% CI, 62.7%-71.9%). MRI performance was not significantly affected by mammographic breast density, tumor histology, or menopausal status. The positive predictive values for 356 of 492 patients was 72.4% (95% CI, 68.2%-76.3%) and of mammography for 367 of 695 patients was 52.8% (95% CI, 49.0%-56.6%) (P<.005). Dynamic MRI did not improve the AUC compared with 3-dimensional MRI alone, but the specificity of a washout pattern for 123 of 136 patients without cancer was 90.4% (95% CI, 84%-95%).

CONCLUSIONS

Breast MRI has high sensitivity but only moderate specificity independent of breast density, tumor type, and menopausal status. Although the positive predictive value of MRI is greater than mammography, MRI does not obviate the need for subsequent tissue sampling in this setting.