Adverse Left Ventricular Remodeling and Age Assessed with Cardiac MR Imaging: The Multi-Ethnic Study of Atherosclerosis

Differences in Cardiovascular Aging in Men and Women

Cardiovascular diseases increase dramatically with age in both men and women. While it is clear that advanced age allows more time for individuals to be exposed to risk factors in general, there is strong evidence that age itself is a major independent risk factor for cardiovascular disease. Indeed, there are distinct age-dependent cellular, structural, and functional changes in both the heart and blood vessels, even in individuals with no clinical evidence of cardiovascular disease. Studies in older humans and in animal models of aging indicate that this age-related remodeling is maladaptive. An emerging view is that the heart and blood vessels accumulate cellular and subcellular deficits with age and these deficits increase susceptibility to disease in older individuals. Aspects of this age-dependent remodeling of the heart and blood vessels differ between the sexes. There is also new evidence that these maladaptive changes are more prominent in older animals and humans with a high degree of frailty. These observations may help explain why men and women are susceptible to different cardiovascular diseases as they age and why frail older adults are most often affected by these diseases.

Association of Aortic Root Dilation from Early Adulthood to Middle Age with Cardiac Structure and Function: The CARDIA Study

BACKGROUND

The human aorta dilates with advancing age. However, the association between progressive aortic dilation with aging and cardiac remodeling has not been established in studies of community-dwelling adults. The aim of this study was to test the hypothesis that there would be a relationship between aortic size increase over the early adult life span with left ventricular (LV) structural remodeling and subclinical LV dysfunction in middle age, even in the absence of overt cardiovascular and valvular disease.

METHODS

Included were Coronary Artery Risk Development in Young Adults study participants (N = 2,933) aged 23 to 35 years with available transthoracic echocardiographic measurements during 20 years of follow-up. Multivariate linear regression models assessed sex-specific associations between 20-year change in aortic root diameter with LV structure and function.

RESULTS

Larger aortic root diameter at 20-year follow-up was associated with greater LV mass (2.77 vs 2.18 g/mm in men and women, respectively, P < .001). In longitudinal analyses, increase in aortic root diameter over 20-year follow-up was associated with a greater 20-year increase in LV mass and ratio of LV mass to LV end-diastolic volume ratio in both sexes. In women but not in men, increased aortic root diameter over 20 years was associated with increased left atrial dimension, impaired E/E', and impaired early diastolic longitudinal and circumferential strain rates assessed by speckle-tracking echocardiography.

CONCLUSIONS

Progressive increase in aortic root diameter from early adulthood to middle age was associated with increased LV mass and LV concentric remodeling in both sexes and impaired diastolic function predominantly in women.

Comparison of Two-Dimensional and Three-Dimensional Echocardiography in Determination of Left Ventricle Volumes and Ejection Fraction in Adult Population

INTRODUCTION

Left ventricle (LV) volumes and ejection fraction (EF) determined with two-dimensional echocardiography (2DE) and three-dimensional echocardiography (3DE) show significant differences.The aim of this study is to determine the agreement of the measurements of LV volumes and EF with 2DE and 3DE in the general adult population, with preserved LV systolic function.

MATERIAL AND METHODS

In 52 subjects, older than 65 years, LV end-diastolic volume index (EDVi), end-systolic volume index (ESVi) and EF were measured with 2DE and 3DE according to the official recommendations, and reproducibility of both methods and their agreement were determined.

RESULTS

Intraclass correlation coefficient for intra-observer reproducibility in the measurement of EDVi, ESVi and EF with 2DE was 0.861, 0.891 and 0.917 respectively, whereas with 3DE 0.854, 0.893 and 0.913, respectively. The difference in the measurement of EDVi and ESVi was significant (p<0.001) whereas the measurement of EF was insignificant (p=0.153). The mean difference value EDVi and ESVi determined with 2DE and 3DE was 5.6+/-5.21 and 3.01+/-2.69 ml/m2 (p<0.001), and of EF 0.306+/-1.475%. Spearman's correlation coefficient for EDV was 0.693, for ESV 0.763 and for EF 0.97.

CONCLUSION

Larger LV volumes were measured in the adult population using 3DE compared to 2DE, but identical values for EF were obtained. This difference in the measured values could not be attributed to the largeness of the LV volume and EF itself.. 3DE demonstrated better intra-observer reproducibility for LV volumes and EF as a major parameter in many clinical decisions.

Sex hormone levels and change in left ventricular structure among men and post-menopausal women: The Multi-Ethnic Study of Atherosclerosis (MESA)

OBJECTIVE

Sex hormone (SH) levels may contribute to sex differences in the risk of heart failure with preserved ejection fraction (HFpEF). We examined the associations of SH levels with left ventricular mass (LVM) and mass (M):volume (V) ratio, which are risk markers for HFpEF.

STUDY DESIGN

We studied 1941 post-menopausal women and 2221 men, aged 45-84 years, participating in the Multi-Ethnic Study of Atherosclerosis (MESA). Serum SH levels, cardiac magnetic resonance imaging (MRI) and ejection fraction (EF) ≥50% had been recorded at baseline (2000-2002). Of these participants, 2810 underwent repeat MRI at Exam 5 (2010-2012). Stratified by sex, linear mixed-effect models were used to test associations between SH and sex hormone binding globulin (SHBG) level [per 1 SD greater log-transformed (SH)] with baseline and change in LV structure. Models were adjusted for age, race/ethnicity, center, height, weight, education, physical activity and smoking, and, in women, for hormone therapy and years since menopause.

MAIN OUTCOME MEASURES

LVM and M:V ratio.

RESULTS

After a median of 9.1 years, higher free testosterone levels were independently associated with a modest increase in LVM (g/yr) in women [0.05 (95% CI 0.01, 0.10)] and men [0.16 (0.03, 0.28)], while higher SHBG levels were associated with less LVM change (g/yr) in women [-0.07 (-0.13, -0.01)] and men [-0.15 (-0.27, -0.02)]. In men, higher dehydroepiandrosterone and estradiol levels were associated with increased LVM. Among women, free testosterone levels were positively and SHBG levels inversely associated with change in M:V ratio.

CONCLUSION

A more androgenic profile (higher free testosterone and lower SHBG levels) is associated with a greater increase in LVM in men and women and greater increase in M:V ratio in women over the course of 9 years.

Aging in the Cardiovascular System: Lessons from Hutchinson-Gilford Progeria Syndrome

Aging, the main risk factor for cardiovascular disease (CVD), is becoming progressively more prevalent in our societies. A better understanding of how aging promotes CVD is therefore urgently needed to develop new strategies to reduce disease burden. Atherosclerosis and heart failure contribute significantly to age-associated CVD-related morbimortality. CVD and aging are both accelerated in patients suffering from Hutchinson-Gilford progeria syndrome (HGPS), a rare genetic disorder caused by the prelamin A mutant progerin. Progerin causes extensive atherosclerosis and cardiac electrophysiological alterations that invariably lead to premature aging and death. This review summarizes the main structural and functional alterations to the cardiovascular system during physiological and premature aging and discusses the mechanisms underlying exaggerated CVD and aging induced by prelamin A and progerin. Because both proteins are expressed in normally aging non-HGPS individuals, and most hallmarks of normal aging occur in progeria, research on HGPS can identify mechanisms underlying physiological aging.

Cardiovascular magnetic resonance in an adult human population: serial observations from the multi-ethnic study of atherosclerosis

The Multi-Ethnic Study of Atherosclerosis (MESA) is the first large-scale multi-ethnic population study in the U.S. to use advanced cardiovascular magnetic resonance (CMR) imaging. MESA participants were free of cardiovascular disease at baseline between 2000 and 2002, and were followed up between 2009 and 2011 with repeated CMR examinations as part of MESA. CMR allows the clinician to visualize and accurately quantify volume and dimensions of all four cardiac chambers; measure systolic and diastolic ventricular function; assess myocardial fibrosis; assess vessel lumen size, vessel wall morphology, and vessel stiffness. CMR has a number of advantages over other imaging modalities such as echocardiography, computed tomography, and invasive angiography, and has been proposed as a diagnostic strategy for high-risk populations. MESA has been extensively evaluating CMR imaging biomarkers, as markers of subclinical disease, in the last 15 years for low-risk populations. On a more practical level, some of the imaging biomarkers developed and studied are translatable to at-risk populations. In this review, we discuss the progression of subclinical cardiovascular disease and the mechanisms responsible for the transition to symptomatic clinical outcomes based on our findings from MESA.

Gender, High-Sensitivity Troponin I, and the Risk of Cardiovascular Events (from the Nord-Trøndelag Health Study)

Gender is an important determinant of cardiovascular risk, and men generally develop cardiovascular disease earlier than women. Increased levels of high-sensitivity cardiac troponin I (hs-TnI) have been shown to be predictive of cardiovascular death, with stronger effects in women. However, it remains unclear whether the stronger association between hs-TnI and cardiovascular death in women is based on the ability of hs-TnI to predict myocardial infarction (MI) or heart failure (HF). Accordingly, we aimed to assess the influence of gender on the association between levels of hs-TnI and incident MI and HF. hs-TnI was measured in 5,060 women and 4,054 men participating in the prospective observational Nord-Trøndelag Health Study using the Architect STAT High-Sensitive Troponin assay. All subjects were free from known coronary heart disease at baseline. After a median follow-up of 5,105 and 6,169 days, 292 MIs and 209 admissions for HF were registered, respectively. In our total cohort, hs-TnI was associated with the incidence of both end points, with adjusted hazard ratio per 1 SD in log hs-TnI 1.19 (95% CI 1.02 to 1.39) for MI and 1.58 (1.38 to 1.82) for HF. The corresponding values for women and men were 1.35 (1.02 to 1.78) versus 1.13 (0.93 to 1.38) for MI and 1.55 (1.26 to 1.91) versus 1.61 (1.36 to 1.90) for HF. The C-index for hs-TnI was stronger for women than men for MI (p <0.001), and no such difference was observed for HF (p = 0.06). In conclusion, in the general population, the association between hs-TnI concentrations and MI is stronger in women than in men. For HF, the impact of gender on the prognostic value of hs-TnI is less pronounced. Increased levels of troponin I in women may thus reflect an adverse phenotype more prone to the development of cardiovascular disease.

Mediterranean diet score and left ventricular structure and function: the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Data are limited on the relation between dietary patterns and left ventricular (LV) structure and function.

OBJECTIVE

We examined cross-sectional associations of a diet-score assessment of a Mediterranean dietary pattern with LV mass, volume, mass-to-volume ratio, stroke volume, and ejection fraction.

DESIGN

We measured LV variables with the use of cardiac MRI in 4497 participants in the Multi-Ethnic Study of Atherosclerosis study who were aged 45-84 y and without clinical cardiovascular disease. We calculated a Mediterranean diet score from intakes of fruit, vegetables, nuts, legumes, whole grains, fish, red meat, the monounsaturated fat:saturated fat ratio, and alcohol that were self-reported with the use of a food-frequency questionnaire. We used linear regression with adjustment for body size, physical activity, and cardiovascular disease risk factors to model associations and assess the shape of these associations (linear or quadratic).

RESULTS

The Mediterranean diet score had a slight U-shaped association with LV mass (adjusted means: 146, 145, 146, and 147 g across quartiles of diet score, respectively; P-quadratic trend = 0.04). The score was linearly associated with LV volume, stroke volume, and ejection fraction: for each +1-U difference in score, LV volume was 0.4 mL higher (95% CI: 0.0, 0.8 mL higher), the stroke volume was 0.5 mL higher (95% CI: 0.2, 0.8 mL higher), and the ejection fraction was 0.2 percentage points higher (95% CI: 0.1, 0.3 percentage points higher). The score was not associated with the mass-to-volume ratio.

CONCLUSIONS

A higher Mediterranean diet score is cross-sectionally associated with a higher LV mass, which is balanced by a higher LV volume as well as a higher ejection fraction and stroke volume. Participants in this healthy, multiethnic sample whose dietary patterns most closely conformed to a Mediterranean-type pattern had a modestly better LV structure and function than did participants with less-Mediterranean-like dietary patterns. This trial was registered at clinicaltrials.gov as NCT00005487.

Role of tissue transglutaminase in age-associated ventricular stiffness

Aging is associated with increased cardiomyocyte loss, left-ventricular hypertrophy, and the accumulation of extracellular matrix, which results in declining cardiac function. The role of the matrix crosslinking enzyme, tissue transglutaminase (TG2), in age-related myocardial stiffness, and contractile function remains incompletely understood. In this study, we examined the role of TG2 in cardiac function, and determined whether TG2 inhibition can prevent age-associated changes in cardiac function. Male Fisher rats (18-month-old) were administered the transglutaminase inhibitor cystamine (study group) or saline (age-matched controls) for 12 weeks via osmotic mini-pumps. Cardiac function was determined by echocardiography and invasive pressure-volume loops. Rat hearts were dissected out, and TG2 expression, activity, and S-nitrosation were determined. Young (6-month-old) males were used as controls. TG2 activity significantly increased in the saline-treated but not in the cystamine-treated aging rat hearts. TG2 expression also increased with age and was unaltered by cystamine treatment. Aged rats showed increased left ventricular (LV) end-systolic dimension and a decrease in fractional shortening compared with young, which was not affected by cystamine. However, cystamine treatment preserved the preload-independent index of LV filling pressure and restored end-diastolic pressure, end-diastolic pressure-volume relationships, and arterial elastance toward young. An increase in TG2 activity contributes to age-associated increase in diastolic stiffness, thereby contributing to age-associated diastolic dysfunction. TG2 may thus represent a novel target for age-associated diastolic heart failure.

Relationship between body composition and left ventricular geometry using three dimensional cardiovascular magnetic resonance

BACKGROUND

Although obesity is associated with alterations in left ventricular (LV) mass and volume which are of prognostic significance, widely differing patterns of remodelling have been attributed to adiposity. Our aim was to define the relationship between body composition and LV geometry using three-dimensional cardiovascular magnetic resonance.

METHODS

In an observational study 1530 volunteers (55 % female, mean age 41.3 years) without known cardiovascular disease underwent investigation including breath-hold high spatial resolution 3D cines. Atlas-based segmentation and co-registration was used to create a statistical model of wall thickness (WT) and relative wall thickness (RWT) throughout the LV. The relationship between bio-impedence body composition and LV geometry was assessed using 3D regression models adjusted for age, systolic blood pressure (BP), gender, race and height, with correction to control the false discovery rate.

RESULTS

LV mass was positively associated with fat mass in women but not in men (LV mass: women β = 0.11, p < 0.0001; men β = -0.01, p = 0.82). The 3D models revealed that in males fat mass was strongly associated with a concentric increase in relative wall thickness (RWT) throughout most of the LV (β = 0.37, significant area = 96 %) and a reduced mid-ventricular cavity (β = -0.22, significant area = 91 %). In women the regional concentric hypertrophic association was weaker, and the basal lateral wall showed an inverse relationship between RWT and fat mass (β = -0.11, significant area = 4.8 %).

CONCLUSIONS

In an adult population without known cardiovascular disease increasing body fat is predominately associated with asymmetric concentric hypertrophy independent of systolic BP, with women demonstrating greater cavity dilatation than men. Conventional mass and volume measurements underestimate the impact of body composition on LV structure due to anatomic variation in remodelling.