Cyclic Guanosine Monophosphate and Risk of Incident Heart Failure and Other Cardiovascular Events: the ARIC Study

Background

Cyclic guanosine monophosphate (cGMP) is a second messenger regulated through natriuretic peptide and nitric oxide pathways. Stimulation of cGMP signaling is a potential therapeutic strategy for heart failure with preserved ejection fraction (HFpEF) and atherosclerotic cardiovascular disease (ASCVD). We hypothesized that plasma cGMP levels would be associated with lower risk for incident HFpEF, any HF, ASCVD, and coronary heart disease (CHD).

Methods and Results

We conducted a case–cohort analysis nested in the ARIC (Atherosclerosis Risk in Communities) study. Plasma cGMP was measured in 875 participants at visit 4 (1996–1998), with oversampling of incident HFpEF cases. We used Cox proportional hazard models to assess associations of cGMP with incident HFpEF, HF, ASCVD (CHD+stroke), and CHD. The mean (SD) age was 62.4 (5.6) years and median (interquartile interval) cGMP was 3.4 pmol/mL (2.4–4.6). During a median follow‐up of 9.9 years, there were 283 incident cases of HFpEF, 329 any HF, 151 ASCVD, and 125 CHD. In models adjusted for CVD risk factors, the hazard ratios (95% CI) associated with the highest cGMP tertile compared with lowest for HFpEF, HF, ASCVD, and CHD were 1.88 (1.17–3.02), 2.18 (1.18–4.06), 2.84 (1.44–5.60), and 2.43 (1.19–5.00), respectively. In models further adjusted for N‐terminal‐proB‐type natriuretic peptide, associations were attenuated for HFpEF and HF but remained statistically significant for ASCVD (2.56 [1.26–5.20]) and CHD (2.25 [1.07–4.71]).

Conclusions

Contrary to our hypothesis, higher cGMP levels were associated with incident CVD in a community‐based cohort. The associations of cGMP with HF or HFpEF may be explained by N‐terminal‐proB‐type natriuretic peptide, but not for ASCVD and CHD.

Ambient air pollution as a mediator in the pathway linking race/ethnicity to blood pressure elevation: The multi-ethnic study of atherosclerosis (MESA)

BACKGROUND

Racial/ethnic disparities in blood pressure and hypertension have been evident in previous studies, as were associations between race/ethnicity with ambient air pollution and those between air pollution with hypertension. The role of air pollution exposure to racial/ethnic differences in hypertension has not been explored.

OBJECTIVE

To assess the potential mediating effects of ambient air pollution on the association between race/ethnicity and blood pressure levels.

METHODS

We studied 6,463 White, Black, Hispanic and Chinese adults enrolled across 6 US cities. Systolic (SBP) and diastolic blood pressure (DBP) were measured at Exam 1 (2000-2002) and Exam 2 (2002-2004). Household-level annual average concentrations of fine particulate matter (PM_2.5), oxides of nitrogen (NO_X), and ozone (O₃) for the year 2000 were estimated for participants.

RESULTS

The difference in SBP levels by race/ethnicity that was related to higher PM_2.5 concentrations compared with White men ("indirect associations") was 0.3 (95% CI: 0.1, 0.6) mmHg for Black men, 0.3 (95% CI: 0.1, 0.6) mmHg for Hispanic men and 1.0 (95% CI: 0.2, 1.8) mmHg for Chinese men. Findings were similar although not statistically significant for women. PM_2.5 did not mediate racial/ethnic differences in DBP. Indirect associations were significant for O₃ for SBP among women and men and for DBP among men. In contrast, racial/ethnic disparities were attenuated due to exposure to NO_X.

CONCLUSION

Racial disparities in blood pressure were reduced after accounting for PM_2.5 and ozone while increased after accounting for NO_X.

Change in NT-proBNP (N-Terminal Pro-B-Type Natriuretic Peptide) Level and Risk of Dementia in Multi-Ethnic Study of Atherosclerosis (MESA)

Cross-sectionally measured NT-proBNP (N-terminal pro-B-type natriuretic peptide) is related to incident dementia. However, data linking changes in NT-proBNP to risk of future dementia are lacking. We aimed to examine the association of change in NT-proBNP over 3.2 years with incident dementia. We included 4563 participants in MESA (Multi-Ethnic Study of Atherosclerosis) prospective cohort who were free of cardiovascular disease at enrollment, had NT-proBNP level measured at MESA exams 1 (baseline, 2000-2002) and 3 (2004-2005), and had no diagnosis of dementia before exam 3. The association of change in NT-proBNP level between MESA exams 1 through 3 and all-cause hospitalized dementia (by International Classification of Diseases, Ninth Revision, codes) after MESA exam 3 (2004-2005) through 2015 was assessed using competing-risks Cox proportional hazard regression analysis. During 45 522 person-years of follow-up, 223 dementia cases were documented. Increase in log-NT-proBNP from MESA exams 1 through 3 was positively associated with incidence of dementia (multivariable hazard ratio, 1.28 [95% CI, 1.001-1.64]; P=0.049). An increase of at least 25% in NT-proBNP level from MESA exam 1 through 3 was associated with a 55% (P=0.02) increase in the risk of dementia in multivariable analysis. Addition of temporal NT-proBNP change to a model including risk factors and baseline NT-proBNP improved the prediction of dementia (Harrell C statistic from 0.85 to 0.87, P=0.049). Increase in NT-proBNP is independently associated with future all-cause hospitalized dementia and offers a moderately better predictive performance for risk of dementia compared with risk factors and baseline NT-proBNP. Clinical Trial Registration- URL: https://www.clinicaltrials.gov. Unique identifier: NCT00005487.

Associations Between the Cyclic Guanosine Monophosphate Pathway and Cardiovascular Risk Factors: MESA

Background

cGMP mediates numerous cardioprotective functions and is a potential therapeutic target for cardiovascular disease. Preclinical studies suggest that plasma cGMP is reflective of natriuretic peptide stimulation. Epidemiologic associations between cGMP and natriuretic peptide, as well as cardiovascular disease risk factors, are unknown.

Methods and Results

We measured plasma cGMP in 542 men and 496 women free of cardiovascular disease and heart failure in MESA (Multi‐Ethnic Study of Atherosclerosis). Cross‐sectional associations of N‐terminal pro‐B type natriuretic peptide, sex hormones, and cardiovascular disease/heart failure risk factors with log(cGMP) were analyzed using multivariable linear regression models. Mean (SD) cGMP was 4.7 (2.6) pmol/mL, with no difference between the sexes. After adjusting for cardiovascular risk factors, N‐terminal pro‐B type natriuretic peptide was significantly positively associated with cGMP (P<0.05). Higher blood pressure and lower estimated glomerular filtration rate were associated with higher cGMP (P<0.05). Triglyceride levels, total/high‐density lipoprotein cholesterol ratio, presence of diabetes mellitus, and the homeostatic model assessment of insulin resistance were inversely associated with cGMP (P<0.05). Among women, free testosterone and dehydroepiandrosterone were inversely associated with cGMP, while sex hormone binding globulin was positively associated (P<0.05).

Conclusions

In a community‐cohort, plasma cGMP was associated with natriuretic peptide signaling. Higher blood pressure and greater renal dysfunction were positively associated with cGMP, while adverse metabolic risk factors were inversely associated. Increased androgenicity in postmenopausal women was inversely associated with cGMP. These novel associations further our understanding of the role of cGMP in a general population.

Greater IL-6, D-dimer, and ICAM-1 Levels Are Associated With Lower Small HDL Particle Concentration in the Multicenter AIDS Cohort Study

OBJECTIVE

Low HDL cholesterol (HDL-C) is common in people living with HIV infection, which is associated with inflammation, and correlates with greater cardiovascular disease (CVD) risk. Particles of HDL are HDL subfractions, and in some general population studies, higher small HDL particle number (HDL-P) has been associated with lower CVD risk. The objective of this study was to determine whether HIV serostatus and systemic inflammation were associated with small HDL-P in the Multicenter AIDS Cohort Study (MACS).

METHOD

The MACS is composed of HIV-infected and HIV-uninfected men. Separate linear regression analyses were conducted to evaluate the associations between outcomes (small HDL-P, large HDL-P, total HDL-P, and HDL size) and variables of interest (interleukin-6 [IL-6], D-dimer, and intercellular adhesion molecule-1 [ICAM-1] levels), with adjustment for other CVD risk factors.

RESULTS

The study population included 553 HIV-infected (88.1% on current ART) and 319 HIV-uninfected men. The mean age was 52.7 years for HIV-infected men and 55.3 years for HIV-uninfected men. In separate models of the study population, higher log IL-6 was associated with lower total and small HDL-P (P < .01 for both), independent of HIV serostatus and CVD risk factors. Similar results were seen with ICAM-1. Positive HIV serostatus was associated with lower small and total HDL-P, adjusted for inflammatory markers.

CONCLUSIONS

Greater systemic inflammation and HIV infection both were associated with lower atheroprotective small HDL-P. This may be a potential mechanism contributing to increased cardiovascular risk among HIV-infected people.

Sex Hormone-Binding Globulin Levels Are Inversely Associated With Nonalcoholic Fatty Liver Disease in HIV-Infected and -Uninfected Men

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a leading cause of liver disease worldwide. Elevated sex hormone-binding globulin (SHBG) levels have been observed in the setting of HIV and may protect against some metabolic disorders. We aimed to investigate whether higher SHBG levels may protect against NAFLD in men with/without HIV.

METHODS

NAFLD was assessed using noncontrast computed tomography in 530 men in the Multicenter AIDS Cohort Study (MACS) who drank <3 alcoholic drinks/d and were uninfected with chronic hepatitis C or B (340HIV+, 190HIV-). Morning serum samples were tested for SHBG, total testosterone (TT), and adiponectin. Multivariable logistic regression was used to assess associations between HIV, SHBG, TT, adiponectin, and NAFLD.

RESULTS

Median SHBG was highest among HIV+/NAFLD- men and lowest among HIV-/NAFLD+ men. Adjusted for demographics, HIV, visceral adiposity, HOMA-IR, TT, and PNPLA3 genotype, higher SHBG was associated with lower odds of NAFLD (odds ratio [OR], 0.52 per doubling; 95% confidence interval [CI], 0.34-0.80). In separate multivariable models without SHBG, HIV (OR, 0.46; 95% CI, 0.26-0.79) and higher adiponectin (OR, 0.66 per doubling; 95% CI, 0.49-0.89) were associated with lower NAFLD odds, whereas TT was not significantly associated (OR, 0.74 per doubling; 95% CI, 0.53-1.04). Adjusting for SHBG attenuated the associations of HIV (OR, 0.61; 95% CI, 0.34-1.08) and adiponectin (OR, 0.74; 95% CI, 0.54-1.02) with NAFLD.

CONCLUSIONS

SHBG levels were higher among HIV+ men, were independently associated with lower NAFLD, and could partially explain the associations of HIV and higher adiponectin with lower NAFLD in our cohort. These findings suggest that SHBG may protect against NAFLD, supporting further prospective and mechanistic studies.

HIV Infection Is Associated With Variability in Ventricular Repolarization: The Multicenter AIDS Cohort Study (MACS)

BACKGROUND

People living with human immunodeficiency virus (HIV+) have greater risk for sudden arrhythmic death than HIV-uninfected (HIV-) individuals. HIV-associated abnormal cardiac repolarization may contribute to this risk. We investigated whether HIV serostatus is associated with ventricular repolarization lability by using the QT variability index (QTVI), defined as a log measure of QT-interval variance indexed to heart rate variance.

METHODS

We studied 1123 men (589 HIV+ and 534 HIV-) from MACS (Multicenter AIDS Cohort Study), using the ZioXT ambulatory electrocardiography patch. Beat-to-beat analysis of up to 4 full days of electrocardiographic data per participant was performed using an automated algorithm (median analyzed duration [quartile 1-quartile 3]: 78.3 [66.3-83.0] hours/person). QTVI was modeled using linear mixed-effects models adjusted for demographics, cardiac risk factors, and HIV-related and inflammatory biomarkers.

RESULTS

Mean (SD) age was 60.1 (11.9) years among HIV- and 54.2 (11.2) years among HIV+ participants (P<0.001), 83% of whom had undetectable (<20 copies/mL) HIV-1 viral load (VL). In comparison with HIV- men, HIV+ men had higher QTVI (adjusted difference of +0.077 [95% CI, +0.032 to +0.123]). The magnitude of this association depended on the degree of viremia, such that in HIV+ men with undetectable VL, adjusted QTVI was +0.064 (95% CI, +0.017 to +0.111) higher than in HIV- men, whereas, in HIV+ men with detectable VL, adjusted QTVI was higher by +0.150 (95% CI, 0.072-0.228) than in HIV- referents. Analysis of QTVI subcomponents showed that HIV+ men had: (1) lower heart rate variability irrespective of VL status, and (2) higher QT variability if they had detectable, but not with undetectable, VL, in comparison with HIV- men. Higher levels of C-reactive protein, interleukin-6, intercellular adhesion molecule-1, soluble tumor necrosis factor receptor 2, and soluble cluster of differentiation-163 (borderline), were associated with higher QTVI and partially attenuated the association with HIV serostatus.

CONCLUSIONS

HIV+ men have greater beat-to-beat variability in QT interval (QTVI) than HIV- men, especially in the setting of HIV viremia and heightened inflammation. Among HIV+ men, higher QTVI suggests ventricular repolarization lability, which can increase susceptibility to arrhythmias, whereas lower heart rate variability signals a component of autonomic dysfunction.

Rare Genetic Variants Associated With Sudden Cardiac Death in Adults

BACKGROUND

Sudden cardiac death occurs in ∼220,000 U.S. adults annually, the majority of whom have no prior symptoms or cardiovascular diagnosis. Rare pathogenic DNA variants in any of 49 genes can pre-dispose to 4 important causes of sudden cardiac death: cardiomyopathy, coronary artery disease, inherited arrhythmia syndrome, and aortopathy or aortic dissection.

OBJECTIVES

This study assessed the prevalence of rare pathogenic variants in sudden cardiac death cases versus controls, and the prevalence and clinical importance of such mutations in an asymptomatic adult population.

METHODS

The authors performed whole-exome sequencing in a case-control cohort of 600 adult-onset sudden cardiac death cases and 600 matched controls from 106,098 participants of 6 prospective cohort studies. Observed DNA sequence variants in any of 49 genes with known association to cardiovascular disease were classified as pathogenic or likely pathogenic by a clinical laboratory geneticist blinded to case status. In an independent population of 4,525 asymptomatic adult participants of a prospective cohort study, the authors performed whole-genome sequencing and determined the prevalence of pathogenic or likely pathogenic variants and prospective association with cardiovascular death.

RESULTS

Among the 1,200 sudden cardiac death cases and controls, the authors identified 5,178 genetic variants and classified 14 as pathogenic or likely pathogenic. These 14 variants were present in 15 individuals, all of whom had experienced sudden cardiac death-corresponding to a pathogenic variant prevalence of 2.5% in cases and 0% in controls (p < 0.0001). Among the 4,525 participants of the prospective cohort study, 41 (0.9%) carried a pathogenic or likely pathogenic variant and these individuals had 3.24-fold higher risk of cardiovascular death over a median follow-up of 14.3 years (p = 0.02).

CONCLUSIONS

Gene sequencing identifies a pathogenic or likely pathogenic variant in a small but potentially important subset of adults experiencing sudden cardiac death; these variants are present in ∼1% of asymptomatic adults.

Plasma Tryptophan-Kynurenine Metabolites Are Altered in Human Immunodeficiency Virus Infection and Associated With Progression of Carotid Artery Atherosclerosis

Background

It is unknown whether disrupted tryptophan catabolism is associated with cardiovascular disease (CVD) in human immunodeficiency virus (HIV)-infected individuals.

Methods

Plasma tryptophan and kynurenic acid were measured in 737 women and men (520 HIV+, 217 HIV-) from the Women's Interagency HIV Study and the Multicenter AIDS Cohort Study. Repeated B-mode carotid artery ultrasound imaging was obtained from 2004 through 2013. We examined associations of baseline tryptophan, kynurenic acid, and kynurenic acid-to-tryptophan (KYNA/TRP) ratio, with risk of carotid plaque.

Results

After a 7-year follow-up, 112 participants developed carotid plaque. Compared to those without HIV infection, HIV-infected participants had lower tryptophan (P < .001), higher KYNA/TRP (P = .01), and similar kynurenic acid levels (P = .51). Tryptophan, kynurenic acid, and KYNA/TRP were correlated with T-cell activation (CD38+HLA-DR+) and immune activation markers (serum sCD14, galectin-3) but had few correlations with interleukin-6, C-reactive protein, or CVD risk factors (blood pressure, lipids). Adjusted for demographic and behavioral factors, each standard deviation (SD) increment in tryptophan was associated with a 29% (95% confidence interval [CI], 17%-38%) decreased risk of carotid plaque (P < .001), while each SD increment in kynurenic acid (P = .02) and KYNA/TRP (P < .001) was associated with a 34% (6%-69%) and a 47% (26%-73%) increased risk of carotid plaque, respectively. After further adjustment for CVD risk factors and immune activation markers, these associations were attenuated but remained significant.

Conclusions

Plasma tryptophan-kynurenine metabolites are altered in HIV infection and associated with progression of carotid artery atherosclerosis.

Association of High-Sensitivity Troponin with Cardiac CT Angiography Evidence of Myocardial and Coronary Disease in a Primary Prevention Cohort of Men: Results from MACS

BACKGROUND

High-sensitivity cardiac troponin (hs-cTn) elevations are associated with incident cardiovascular disease events in primary prevention samples. However, the mechanisms underlying this association remain unclear.

METHODS

We studied 458 men without known cardiovascular disease who participated in the cardiovascular disease substudy of the Multicenter AIDS Cohort Study and had cardiac CT angiography. We used multivariable linear and logistic regression models to examine the cross-sectional associations between coronary artery stenosis, coronary artery plaque, indexed left ventricular mass (LVMi), and the outcome of hs-cTnI. We also evaluated the associations between HIV serostatus or use of highly active antiretroviral therapy (HAART) and hs-cTnI.

RESULTS

The mean age was 54 years, 54% were white, and 61% were HIV infected. In multivariable-adjusted logistic models, comparing the highest quartile of LVMi with the lowest quartile, the odds ratio (OR) of hs-cTnI ≥75th percentile was 2.59 (95% CI, 1.20-5.75). There was no significant association between coronary stenosis severity or plaque type and hs-cTnI in linear models; however, in logistic regression models, coronary artery stenosis ≥70% (8% of sample) was marginally associated with a higher likelihood (OR, 2.75 [95% CI, 1.03, 7.27]) of having hs-cTnI ≥75th percentile. There were no associations between HIV serostatus or HAART use and hs-cTnI in either linear or logistic models.

CONCLUSION

Among primary prevention men with or at risk for HIV, hs-cTnI concentrations were strongly associated with LVMi but were not associated with HIV infection or treatment status or with coronary plaque type or stenosis until the extremes of severity (≥70% stenosis).

HDAC9 is implicated in atherosclerotic aortic calcification and affects vascular smooth muscle cell phenotype

Aortic calcification is an important independent predictor of future cardiovascular events. We performed a genome-wide association meta-analysis to determine single nucleotide polymorphisms (SNPs) associated with the extent of abdominal (AAC, n = 9,417) or descending thoracic (TAC, n = 8,422) aortic calcification. Two genetic loci, HDAC9 and RAP1GAP, were associated with AAC at a genome-wide level (P < 5.0 × 10⁻⁸). No SNPs were associated with TAC at the genome-wide threshold. Increased expression of HDAC9 in human aortic smooth muscle cells (HASMCs) promoted calcification and reduced contractility, while inhibition of HDAC9 in HASMCs inhibited calcification and enhanced cell contractility. In matrix Gla protein (MGP)-deficient mice, a model of human vascular calcification, mice lacking HDAC9 had a 40% reduction in aortic calcification and improved survival. This translational genomic study identifies the first genetic risk locus associated with calcification of the abdominal aorta and describes a novel role for HDAC9 in the development of vascular calcification.

Genome-wide analyses identify variants near HDAC9 associated with abdominal aortic calcification and other cardiovascular phenotypes. Functional work shows that HDAC9 promotes an osteogenic vascular smooth muscle cell phenotype, enhancing calcification and reducing contractility.

Associations between subcutaneous fat density and systemic inflammation differ by HIV serostatus and are independent of fat quantity

OBJECTIVES

Adipose tissue (AT) density measurement may provide information about AT quality among people living with HIV. We assessed AT density and evaluated relationships between AT density and immunometabolic biomarker concentrations in men with HIV.

DESIGN

Cross-sectional analysis of men enrolled in the Multicenter AIDS Cohort Study.

METHODS

Abdominal visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) density (Hounsfield units, HU; less negative = more dense) were quantified from computed tomography (CT) scans. Multivariate linear regression models described relationships between abdominal AT density and circulating biomarker concentrations.

RESULTS

HIV+ men had denser SAT (-95 vs -98 HU HIV-, P < 0.001), whereas VAT density was equivalent by HIV serostatus men (382 HIV-, 462 HIV+). Historical thymidine analog nucleoside reverse transcriptase inhibitor (tNRTI) use was associated with denser SAT but not VAT. In adjusted models, a 1 s.d. greater SAT or VAT density was associated with higher levels of adiponectin, leptin, HOMA-IR and triglyceride:HDL cholesterol ratio and lower hs-CRP concentrations in HIV- men. Conversely, in HIV+ men, each s.d. greater SAT density was not associated with metabolic parameter improvements and was significantly (P < 0.05) associated with higher systemic inflammation. Trends toward higher inflammatory biomarker concentrations per 1 s.d. greater VAT density were also observed among HIV+ men.

CONCLUSIONS

Among men living with HIV, greater SAT density was associated with greater systemic inflammation independent of SAT area. AT density measurement provides additional insight into AT density beyond measurement of AT quantity alone, and may have implications for metabolic disease risk.

Associations between QT interval subcomponents, HIV serostatus, and inflammation

Background

The total QT interval comprises both ventricular depolarization and repolarization currents. Understanding how HIV serostatus and other risk factors influence specific QT interval subcomponents could improve our mechanistic understanding of arrhythmias.

Methods

Twelve‐lead electrocardiograms (ECGs) were acquired in 774 HIV‐infected (HIV+) and 652 HIV‐uninfected (HIV−) men from the Multicenter AIDS Cohort Study. Individual QT subcomponent intervals were analyzed: R‐onset to R‐peak, R‐peak to R‐end, JT segment, T‐onset to T‐peak, and T‐peak to T‐end. Using multivariable linear regressions, we investigated associations between HIV serostatus and covariates, including serum concentrations of inflammatory biomarkers such as interleukin‐6 (IL‐6), and each QT subcomponent.

Results

After adjustment for demographics and risk factors, HIV+ versus HIV− men differed only in repolarization phase durations with longer T‐onset to T‐peak by 2.3 ms (95% CI 0–4.5, p < .05) and T‐peak to T‐end by 1.6 ms (95% CI 0.3–2.9, p < .05). Adjusting for inflammation attenuated the strength and significance of the relationship between HIV serostatus and repolarization. The highest tertile of IL‐6 was associated with a 7.3 ms (95% CI 3.2–11.5, p < .01) longer T‐onset to T‐peak. Age, race, body mass index, alcohol use, and left ventricular hypertrophy were each associated with up to 2.2–12.5 ms longer T‐wave subcomponents.

Conclusions

HIV seropositivity, in combination with additional risk factors including increased systemic inflammation, is associated with longer T‐wave subcomponents. These findings could suggest mechanisms by which the ventricular repolarization phase is lengthened and thereby contribute to increased arrhythmic risk in men living with HIV.

Gut Microbial-Related Choline Metabolite Trimethylamine-N-Oxide Is Associated With Progression of Carotid Artery Atherosclerosis in HIV Infection

We examined associations of 5 plasma choline metabolites with carotid plaque among 520 HIV-infected and 217 HIV-uninfected participants (112 incident plaque cases) over 7 years. After multivariable adjustment, higher gut microbiota-related metabolite trimethylamine-N-oxide (TMAO) was associated with an increased risk of carotid plaque in HIV-infected participants (risk ratio = 1.25 per standard deviation increment; 95% confidence interval, 1.05-1.50; P = .01). TMAO was positively correlated with biomarkers of monocyte activation and inflammation (sCD14, sCD163). Further adjustment for these biomarkers attenuated the association between TMAO and carotid plaque (P = .08). Among HIV-infected individuals, plasma TMAO was associated with carotid atherosclerosis progression, partially through immune activation and inflammation.

Change in left atrial function predicts incident atrial fibrillation: the Multi-Ethnic Study of Atherosclerosis

AIMS

Longitudinal change in left atrial (LA) structure and function could be helpful in predicting risk for incident atrial fibrillation (AF). We used cardiac magnetic resonance (CMR) imaging to explore the relationship between change in LA structure and function and incident AF in a multi-ethnic population free of clinical cardiovascular disease at baseline.

METHODS AND RESULTS

In the Multi-Ethnic Study of Atherosclerosis (MESA), 2338 participants, free at baseline of clinically recognized AF and cardiovascular disease, had LA volume and function assessed with CMR imaging, at baseline (2000-02), and at Exam 4 (2005-07) or 5 (2010-12). Free of AF, 124 participants developed AF over 3.8 ± 0.9 years (2015) following the second imaging. In adjusted Cox regression models, an average annualized change in all LA parameters were significantly associated with an increased risk of AF. An annual decrease of 1-SD unit in total LA emptying fractions (LAEF) was most strongly associated with risk of AF after adjusting for clinical risk factors for AF, baseline LA parameters, and left ventricular mass-to-volume ratio (hazard ratio per SD = 1.91, 95% confidence interval = 1.53-2.38, P < 0.001). The addition of change in total LAEF to an AF risk score improved model discrimination and reclassification (net reclassification improvement = 0.107, P = 0.017; integrative discrimination index = 0.049, P < 0.001).

CONCLUSION

In this multi-ethnic study population free of clinical cardiovascular disease at baseline, a greater increase in LA volumes and decrease in LA function were associated with incident AF. The addition of change in total LAEF to risk prediction models for AF improved model discrimination and reclassification of AF risk.

Endogenous Sex Hormones and Incident Cardiovascular Disease in Post-Menopausal Women

BACKGROUND

Higher androgen and lower estrogen levels are associated with cardiovascular disease (CVD) risk factors in women. However, studies on sex hormones and incident CVD events in women have yielded conflicting results.

OBJECTIVES

The authors assessed the associations of sex hormone levels with incident CVD, coronary heart disease (CHD), and heart failure (HF) events among women without CVD at baseline.

METHODS

The authors studied 2,834 post-menopausal women participating in the MESA (Multi-Ethnic Study of Atherosclerosis) with testosterone, estradiol, dehydroepiandrosterone, and sex hormone binding globulin (SHBG) levels measured at baseline (2000 to 2002). They used Cox hazard models to evaluate associations of sex hormones with each outcome, adjusting for demographics, CVD risk factors, and hormone therapy use.

RESULTS

The mean age was 64.9 ± 8.9 years. During 12.1 years of follow-up, 283 CVD, 171 CHD, and 103 HF incident events occurred. In multivariable-adjusted models, the hazard ratio (95% confidence interval [CI]) associated with 1 SD greater log-transformed sex hormone level for the respective outcomes of CVD, CHD, and HF were as follows: total testosterone: 1.14 (95% CI: 1.01 to 1.29), 1.20 (95% CI: 1.03 to 1.40), 1.09 (95% CI: 0.90 to 1.34); estradiol: 0.94 (95% CI: 0.80 to 1.11), 0.77 (95% CI: 0.63 to 0.95), 0.78 (95% CI: 0.60 to 1.02); and testosterone/estradiol ratio: 1.19 (95% CI: 1.02 to 1.40), 1.45 (95% CI: 1.19 to 1.78), 1.31 (95% CI: 1.01 to 1.70). Dehydroepiandrosterone and SHBG levels were not associated with these outcomes.

CONCLUSIONS

Among post-menopausal women, a higher testosterone/estradiol ratio was associated with an elevated risk for incident CVD, CHD, and HF events, higher levels of testosterone associated with increased CVD and CHD, whereas higher estradiol levels were associated with a lower CHD risk. Sex hormone levels after menopause are associated with women's increased CVD risk later in life.

Performance of glomerular filtration rate estimating equations in a community-based sample of Blacks and Whites: the multiethnic study of atherosclerosis

Background

The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations are recommended for glomerular filtration rate (GFR) estimation in the general population. They have not been evaluated in community-based populations, including Blacks at higher levels of GFR, but are commonly applied in such populations.

Methods

In an ancillary study of Multi-Ethnic Study of Atherosclerosis conducted at one site, we evaluated the performance of the CKD-EPI equations for creatinine (eGFRcr), cystatin C (eGFRcys) or the combination (eGFRcr-cys) compared with GFR measured as plasma clearance of iohexol.

Results

Among 294 participants, the mean age was 71 (SD 9) years, 47% were Black, 48% were women and the mean measured GFR (mGFR) was 72.6 (SD 18.8) mL/min/1.73 m2. The CKD-EPI equations overestimated mGFR with a larger median bias for eGFRcr and eGFRcr-cys than eGFRcys [-8.3 (95% confidence interval -9.7, -6.5), -7.8 (-9.2, -6.2) and -3.7 (-5.0, -1.8) mL/min/1.73 m2, respectively], with smaller bias for those with lower compared with higher eGFR and by race compared with sex.

Conclusion

The small differential bias of the CKD-EPI equation between races suggests that they can be used in Blacks as well as Whites in older community-based adults. The large differential bias in women versus men in all equations is in contrast to other studies and is unexplained. Further studies are required in multiracial and multiethnic community-based cohorts, taking into account differences in GFR measurement methods.

HIV Infection Is Associated with Greater Left Ventricular Mass in the Multicenter AIDS Cohort Study

HIV infection has been associated with diastolic heart failure and atrial fibrillation. The purpose of this study is to determine whether HIV infection is associated with differences in left ventricular mass (LVM), left ventricular end-diastolic volume (LVEDV), and left atrial volume (LAV) indexed to body surface area (left ventricular mass index, left ventricular end-diastolic volume index [LVEDVI], and left atrial volume index [LAVI], respectively). Cross-sectional study of 721 men [425 HIV-infected (HIV+), 296 HIV-uninfected (HIV-) enrolled in the cardiovascular substudy of the Multicenter AIDS Cohort Study (MACS). Participants underwent cardiac computed tomography imaging. A blinded reader measured LVM, LVEDV, and LAV. We used multivariable linear regression models to evaluate whether LVEDVI, left ventricular mass index (LVMI), and LAVI differed by HIV serostatus, adjusting for demographics and cardiovascular disease risk factors. LVMI was significantly greater in HIV+ compared with HIV- men, with adjusted difference of 2.65 g/m2 (95% confidence interval 0.53-4.77, p < .001). Left ventricular end-diastolic index and LAVI did not differ significantly between the two groups. HIV-related factors (nadir CD4 count, clinical AIDS diagnosis, cumulative antiretroviral therapy use, and cumulative protease inhibitor use) were not significantly associated with LVMI, LVEDVI, or LAVI. LVM was significantly higher in HIV+ than HIV- men, which may contribute to the observed increased risk for diastolic heart failure associated with HIV infection. Although HIV infection has been associated with an increased risk for atrial fibrillation, we did not find any difference in LAV by HIV serostatus.

Admixture mapping identifies novel loci for obstructive sleep apnea in Hispanic/Latino Americans

Obstructive sleep apnea (OSA) is a common disorder associated with increased risk of cardiovascular disease and mortality. Its prevalence and severity vary across ancestral background. Although OSA traits are heritable, few genetic associations have been identified. To identify genetic regions associated with OSA and improve statistical power, we applied admixture mapping on three primary OSA traits [the apnea hypopnea index (AHI), overnight average oxyhemoglobin saturation (SaO2) and percentage time SaO2 < 90%] and a secondary trait (respiratory event duration) in a Hispanic/Latino American population study of 11 575 individuals with significant variation in ancestral background. Linear mixed models were performed using previously inferred African, European and Amerindian local genetic ancestry markers. Global African ancestry was associated with a lower AHI, higher SaO2 and shorter event duration. Admixture mapping analysis of the primary OSA traits identified local African ancestry at the chromosomal region 2q37 as genome-wide significantly associated with AHI (P < 5.7 × 10-5), and European and Amerindian ancestries at 18q21 suggestively associated with both AHI and percentage time SaO2 < 90% (P < 10-3). Follow-up joint ancestry-SNP association analyses identified novel variants in ferrochelatase (FECH), significantly associated with AHI and percentage time SaO2 < 90% after adjusting for multiple tests (P < 8 × 10-6). These signals contributed to the admixture mapping associations and were replicated in independent cohorts. In this first admixture mapping study of OSA, novel associations with variants in the iron/heme metabolism pathway suggest a role for iron in influencing respiratory traits underlying OSA.

Characteristics, Prevention, and Management of Cardiovascular Disease in People Living With HIV: A Scientific Statement From the American Heart Association

As early and effective antiretroviral therapy has become more widespread, HIV has transitioned from a progressive, fatal disease to a chronic, manageable disease marked by elevated risk of chronic comorbid diseases, including cardiovascular diseases (CVDs). Rates of myocardial infarction, heart failure, stroke, and other CVD manifestations, including pulmonary hypertension and sudden cardiac death, are significantly higher for people living with HIV than for uninfected control subjects, even in the setting of HIV viral suppression with effective antiretroviral therapy. These elevated risks generally persist after demographic and clinical risk factors are accounted for and may be partly attributed to chronic inflammation and immune dysregulation. Data on long-term CVD outcomes in HIV are limited by the relatively recent epidemiological transition of HIV to a chronic disease. Therefore, our understanding of CVD pathogenesis, prevention, and treatment in HIV relies on large observational studies, randomized controlled trials of HIV therapies that are underpowered to detect CVD end points, and small interventional studies examining surrogate CVD end points. The purpose of this document is to provide a thorough review of the existing evidence on HIV-associated CVD, in particular atherosclerotic CVD (including myocardial infarction and stroke) and heart failure, as well as pragmatic recommendations on how to approach CVD prevention and treatment in HIV in the absence of large-scale randomized controlled trial data. This statement is intended for clinicians caring for people with HIV, individuals living with HIV, and clinical and translational researchers interested in HIV-associated CVD.

Association of myocardial fibrosis and cardiovascular events: the multi-ethnic study of atherosclerosis

Aims

We used contrast-enhanced cardiac magnetic resonance (CMR) to evaluate differences in myocardial fibrosis measured at the year-10 examination between participants with and without cardiovascular (CV) events accrued in a large population based study over the preceding 10-year follow-up period in this retrospective study.

Methods and results

The MESA study enrolled 6814 participants free of CV disease at baseline (2000-2002). We included MESA participants who underwent contrast-enhanced CMR at the MESA year-10 exam (N = 1840). We defined a composite CV endpoint of coronary heart disease, heart failure, atrial fibrillation, stroke, and peripheral artery disease. Using CMR, we characterized myocardial fibrosis with late-gadolinium enhancement for scar and T1 mapping indices of diffuse fibrosis. Demographic and CV-risk adjusted logistic (presence of scar) and linear regression (pre-contrast T1, T1 at 12 and 25 min post-contrast, and extracellular volume fraction or ECV) models were used to assess the relationship between fibrosis and events. The mean values of T1 indices were-pre-contrast T1: 977 ± 45 ms; T1 at 12': 456 ± 40 ms; T1 at 25': 519 ± 41 ms; ECV: 27.1 ± 3.2%. One-hundred and forty-six (7.9%) participants had myocardial scar. The presence of scar was strongly associated with prior CV events (adjusted coeff: 1.36, P < 0.001). Lower post-contrast T1 times and higher ECV, indicative of greater diffuse fibrosis were strongly associated with CV events (T1 at 12': coeff = -10.0 ms, P = 0.004; T1 at 25': coeff =-9.2 ms, P = 0.008; ECV: coeff = 1.31%, P < 0.001).

Conclusion

Individuals who suffered prior CV events have greater likelihood of diffuse myocardial fibrosis when compared with event-free individuals living in the same community.

Exome sequencing of 20,791 cases of type 2 diabetes and 24,440 controls

Protein-coding genetic variants that strongly affect disease risk can yield relevant clues to disease pathogenesis. Here we report exome-sequencing analyses of 20,791 individuals with type 2 diabetes (T2D) and 24,440 non-diabetic control participants from 5 ancestries. We identify gene-level associations of rare variants (with minor allele frequencies of less than 0.5%) in 4 genes at exome-wide significance, including a series of more than 30 SLC30A8 alleles that conveys protection against T2D, and in 12 gene sets, including those corresponding to T2D drug targets (P = 6.1 × 10-3) and candidate genes from knockout mice (P = 5.2 × 10-3). Within our study, the strongest T2D gene-level signals for rare variants explain at most 25% of the heritability of the strongest common single-variant signals, and the gene-level effect sizes of the rare variants that we observed in established T2D drug targets will require 75,000-185,000 sequenced cases to achieve exome-wide significance. We propose a method to interpret these modest rare-variant associations and to incorporate these associations into future target or gene prioritization efforts.

Lung Function, Coronary Artery Disease, and Mortality in HIV

Rationale: Impaired lung function is a potent independent predictor of coronary artery disease (CAD) in individuals without human immunodeficiency virus (HIV) infection; however, the relationship between lung function and CAD in HIV remains undefined. Objectives: To examine the relationship between lung function, CAD, mortality, and circulating biomarkers in HIV. Methods: Spirometry, diffusing capacity of the lung for carbon monoxide (DlCO), emphysema, coronary artery calcium, mortality, cause of death, and biomarkers were examined in HIV-infected and uninfected individuals enrolled in a cohort study at the University of Pittsburgh. Results were then validated in the Multicenter AIDS Cohort Study (MACS) cohort. Results: We examined data on 234 participants in the Pittsburgh cohort. The mean ± standard deviation age was 49.5 ± 10.2 years old, 82.1% were male, and 67.5% were ever smokers. Among the 177 of 234 individuals with HIV infection, lower DlCO (not forced expiratory volume in 1 second or emphysema) was independently associated with greater coronary artery calcium (odds ratio, 1.43 per 10% lower DlCO; 95% confidence interval, 1.14-1.81). HIV-infected individuals with both reduced DlCO and coronary artery calcium had a much higher mortality than those with either low DlCO or coronary calcium alone or with neither condition. Endothelin-1, a circulating biomarker of endothelial dysfunction, was associated with both lower DlCO and greater coronary artery calcium in those with HIV infection. Results were reproducible in 144 individuals enrolled in the MACS cohort; intercellular adhesion molecule 1 was the biomarker of endothelial dysfunction assessed in the MACS cohort. Conclusions: Impaired DlCO and CAD were associated with each other and with higher mortality in individuals with HIV infection.

Progression of calcium density in the ascending thoracic aorta is inversely associated with incident cardiovascular disease events

Aims

Little is known regarding the risk of atherosclerotic cardiovascular disease (ASCVD) conferred by changes in the volume and density of ascending thoracic aorta calcium (ATAC) over time. We evaluated changes in ATAC volume and density scores and incident ASCVD events.

Methods and results

The Multi-Ethnic Study of Atherosclerosis is a prospective cohort study of individuals without baseline clinical ASCVD. Ascending thoracic aorta calcium was measured from baseline and follow-up (mean interval 2.4 years) cardiac computed tomography (CT). Cox proportional hazard regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) per standard deviation for events after the follow-up exam adjusted for ASCVD risk factors, baseline ATAC and coronary artery calcium (CAC) volume and density, and changes in CAC volume and density. Among 5887 participants, 296 (5.0%) had detectable ATAC at baseline, follow-up, or both exams. A total of 403 events occurred over 9.5 years. An increase in ATAC volume was associated with coronary heart disease (CHD) (HR 1.90, 95% CI 1.14-3.16), ASCVD (HR 1.93, 95% CI 1.26-2.94), and ischaemic stroke (HR 2.14, CI 1.21-3.78). An increase in ATAC density was inversely associated with CHD (HR 0.29, 95% CI 0.14-0.60) and ASCVD (HR 0.42, 95% CI 0.23-0.76), but not stroke (HR 0.61, CI 0.23-1.61).

Conclusion

Ascending thoracic aorta calcium is uncommon on serial cardiac CT. However, changes in ATAC volume and density are both associated with incident ASCVD events, but in opposite directions. Serial assessments in those with baseline ATAC may provide insight into an individual's trajectory of ASCVD risk.