Subclinical myocardial disease by cardiac magnetic resonance imaging and spectroscopy in healthy HIV/Hepatitis C virus-coinfected persons

Myocardial steatosis across the spectrum of human health and disease

Preclinical data strongly suggest that myocardial steatosis leads to adverse cardiac remodelling and left ventricular dysfunction. Using 1 H cardiac magnetic resonance spectroscopy, similar observations have been made across the spectrum of health and disease. The purpose of this brief review is to summarize these recent observations. We provide a brief overview of the determinants of myocardial triglyceride accumulation, summarize the current evidence that myocardial steatosis contributes to cardiac dysfunction, and identify opportunities for further research.

Altered cardiac structure and function in newly diagnosed people living with HIV: a prospective cardiovascular magnetic resonance study after the initiation of antiretroviral treatment

HIV associated cardiomyopathy (HIVAC) is a poorly understood entity that may progress along a continuum. We evaluated a group of persons newly diagnosed with HIV and studied the evolution of cardiac abnormalities after ART initiation. We recruited a group of newly diagnosed, ART naïve persons with HIV and a healthy, HIV uninfected group. Participants underwent comprehensive cardiovascular evaluation, including cardiovascular magnetic resonance imaging. The HIV group was started on ART and re-evaluated 9 months later. The cardiovascular parameters of the study groups were compared at diagnosis and after 9 months. The ART naïve group's (n = 66) left- and right end diastolic volume indexed for height were larger compared with controls (n = 22) (p < 0.03). The left ventricular mass indexed for height was larger in the naïve group compared with controls (p = 0.04). The ART naïve group had decreased left- and right ventricular ejection fraction (p < 0.03) and negative, non-linear associations with high HIV viral load (p = 0.02). The left ventricular size increased after 9 months (p = 0.04), while the systolic function remained unchanged. The HIV group had a high rate of non-resolving pericardial effusions. HIV infected persons demonstrate structurally and functionally altered ventricles at diagnosis. High HIV viral load was associated with left- and right ventricular dysfunction. Cardiac parameters and pericardial effusion prevalence did not show improvement with ART. Conversely, a concerning trend of increase was observed with left ventricular size. These subclinical cardiac abnormalities may represent a stage on the continuum of HIVAC that can progress to symptomatic disease if the causes are not identified and addressed.

Association of HIV Infection With Cardiovascular Pathology Based on Advanced Cardiovascular Imaging: A Systematic Review

IMPORTANCE

HIV-associated cardiovascular disease is increasing in prevalence, but its mechanisms remain poorly understood.

OBJECTIVE

To systematically review data from advanced cardiovascular imaging studies evaluating computed tomographic coronary angiography, positron emission tomography (PET), and cardiac magnetic resonance (MR), in people living with HIV compared with uninfected individuals.

DATA SOURCES

Three databases and Google Scholar were searched for studies assessing cardiovascular pathology using computed tomographic coronary angiography, cardiac MR, PET, and HIV from inception to February 11, 2022.

STUDY SELECTION

Two reviewers selected original studies without any restrictions on design, date, or language, investigating HIV and cardiovascular pathology.

DATA EXTRACTION AND SYNTHESIS

One investigator extracted data checked by a second investigator. Prevalence ratios (PRs) and differences in inflammation among people living with HIV and uninfected individuals were qualitatively synthesized in terms of cardiovascular pathology. Study quality was assessed using the National Heart, Lung, and Blood Institute quality assessment tool for observational studies.

MAIN OUTCOMES AND MEASURES

Primary outcomes were computed tomographic coronary angiography-defined moderate to severe (≥50%) coronary stenosis, cardiac MR-defined myocardial fibrosis identified by late gadolinium enhancement, and PET-defined vascular and myocardial target to background ratio. Prevalence of moderate to severe coronary disease, as well as myocardial fibrosis, and PRs compared with uninfected individuals were reported alongside difference in vascular target to background ratio.

RESULTS

Forty-five studies including 5218 people living with HIV (mean age, 48.5 years) and 2414 uninfected individuals (mean age, 49.1 years) were identified. Sixteen studies (n = 5107 participants) evaluated computed tomographic coronary angiography; 16 (n = 1698), cardiac MRs; 10 (n = 681), vascular PET scans; and 3 (n = 146), both computed tomographic coronary angiography and vascular PET scans. No studies originated from low-income countries. Regarding risk of bias, 22% were classified as low; 47% moderate; and 31% high. Prevalence of moderate to severe coronary disease among those with vs without HIV ranged from 0% to 52% and 0% to 27%, respectively, with PRs ranging from 0.33 (95% CI, 0.01-15.90) to 5.19 (95% CI, 1.26-21.42). Prevalence of myocardial fibrosis among those with vs without HIV ranged from 5% to 84% and 0% to 68%, respectively, with PRs ranging from 1.01 (95% CI, 0.85-1.21) to 17.35 (95% CI, 1.10-274.28). Differences in vascular target to background ratio among those with vs without HIV ranged from 0.06 (95% CI, 0.01-0.11) to 0.37 (95% CI, 0.02-0.72).

CONCLUSIONS AND RELEVANCE

In this systematic review of studies of advanced cardiovascular imaging, the estimates of the associations between HIV and cardiovascular pathologies demonstrated large amounts of heterogeneity. The findings provide a summary of the available data but may not be representative of all individuals living with HIV, including those from low-income countries with higher HIV endemicity.

Progression of cardiac structure and function in people with human immunodeficiency virus

OBJECTIVE

People living with HIV (PLWH) are at increased risk for cardiac dysfunction. It is unknown how their global longitudinal cardiac function, cardiac structure, and other indices of function progress over time. We aimed to characterize the longitudinal trend in cardiac structure and function in PLWH.

DESIGN

Retrospective study of PLWH with clinically obtained echocardiograms at an academic medical center.

METHODS

We reviewed archived transthoracic echocardiograms (TTEs) performed between 2001 and 2012 on PLWH. The primary outcome measures were progression of global longitudinal strain (GLS, left and right ventricles), LV mass, E/e' ratio, LV end-systolic, and -diastolic volumes using hierarchical mixed model analysis as a function of CD4+ T cell count and HIV RNA suppression. Models were adjusted for clinical and demographic characteristics.

RESULTS

We analyzed 469 TTEs from 150 individuals (median age 46 years, 58% male). Median CD4+ T cell counts at nadir and proximal to first echocardiogram were 85 and 222 cells/mm3 , respectively. Over a median of 5 years, LV mass index increased regardless of nadir or proximal CD4+ T cell count or viral suppression status. PLWH with viral suppression at baseline had more normal GLS throughout the follow-up period. There were no significant trends in LV end-systolic volume index or E/e'.

CONCLUSIONS

In PLWH, HIV viral suppression is associated with early gains in echocardiographic indices of cardiac function that persist for up to >5 years. HIV disease control impacts routine echocardiographic measures with known impacts on long-term prognosis.

Cardiac adiposity as a modulator of cardiovascular disease in HIV

BACKGROUND

With the number of people living with human immunodeficiency virus (HIV) steadily increasing, cardiovascular disease has emerged as a leading cause of non-HIV related mortality. People living with HIV (PLWH) appear to be at increased risk of coronary artery disease and heart failure (HF), while the underlying mechanism appears to be multifactorial. In the general population, ectopic cardiac adiposity has been highlighted as an important modulator of accelerated coronary artery atherosclerosis, arrhythmogenesis and HF with preserved ejection fraction (HFpEF). Cardiac adiposity is also strongly linked with obesity, especially with visceral adipose tissue accumulation.

AIMS

This review aims to summarize the possible role of cardiac fat depositions, assessed by imaging modalities,as potential contributors to the increased cardiac morbidity and mortality seen in PLWH, as well as therapeutic targets in the current ART era.

MATERIALS & METHODS

Review of contemporary literature on this topic.

DISCUSSION

Despite antiretroviral therapy (ART), PLWH have evidence of persistent, HIV-related systemic inflammation and body fat alterations. Cardiac adiposity can play an additional role in the pathogenesis of cardiovascular disease in the HIV setting. Imaging modalities such as echocardiography, cardiac multidetector computed tomography and cardiac magnetic resonance have demonstrated increased adipose tissue. Studies show that high cardiac fat depots play an additive role in promoting coronary artery atherosclerosis and HFpEF in PLWH. Systemic inflammation due to HIV infection, metabolic adverse effects of ART, adipose alterations in the ageing HIV population, inflammation and immune activation are likely important mechanisms for adipose dysfunction and disproportionately occurrence of ectopic fat depots in the heart among PLWH.

CONCLUSIONS

High cardiac adiposity seems to plays an additive role in promoting coronary artery atherosclerosis and HFpEF in PLWH. The underlying mechanisms are multiple and warrant further investigation. Improved understanding of the regulating mechanisms that increase cardiovascular risk in HIV infection may give rise to more tailored therapeutic strategies targeting cardiac fat depots.

Extracellular volume-guided late gadolinium enhancement analysis for non-ischemic cardiomyopathy: The Women's Interagency HIV Study

BACKGROUND

Quantification of non-ischemic myocardial scar remains a challenge due to the patchy diffuse nature of fibrosis. Extracellular volume (ECV) to guide late gadolinium enhancement (LGE) analysis may achieve a robust scar assessment.

METHODS

Three cohorts of 80 non-ischemic-training, 20 non-ischemic-validation, and 10 ischemic-validation were prospectively enrolled and underwent 3.0 Tesla cardiac MRI. An ECV cutoff to differentiate LGE scar from non-scar was identified in the training cohort from the receiver-operating characteristic curve analysis, by comparing the ECV value against the visually-determined presence/absence of the LGE scar at the highest signal intensity (SI) area of the mid-left ventricle (LV) LGE. Based on the ECV cutoff, an LGE semi-automatic threshold of n-times of standard-deviation (n-SD) above the remote-myocardium SI was optimized in the individual cases ensuring correspondence between LGE and ECV images. The inter-method agreement of scar amount in comparison with manual (for non-ischemic) or full-width half-maximum (FWHM, for ischemic) was assessed. Intra- and inter-observer reproducibility were investigated in a randomly chosen subset of 40 non-ischemic and 10 ischemic cases.

RESULTS

The non-ischemic groups were all female with the HIV positive rate of 73.8% (training) and 80% (validation). The ischemic group was all male with reduced LV function. An ECV cutoff of 31.5% achieved optimum performance (sensitivity: 90%, specificity: 86.7% in training; sensitivity: 100%, specificity: 81.8% in validation dataset). The identified n-SD threshold varied widely (range 3 SD-18 SD), and was independent of scar amount (β = -0.01, p = 0.92). In the non-ischemic cohorts, results suggested that the manual LGE assessment overestimated scar (%) in comparison to ECV-guided analysis [training: 4.5 (3.2-6.4) vs. 0.92 (0.1-2.1); validation: 2.5 (1.2-3.7) vs. 0.2 (0-1.6); P < 0.01 for both]. Intra- and inter-observer analyses of global scar (%) showed higher reproducibility in ECV-guided than manual analysis with CCC = 0.94 and 0.78 versus CCC = 0.86 and 0.73, respectively (P < 0.01 for all). In ischemic validation, the ECV-guided LGE analysis showed a comparable scar amount and reproducibility with the FWHM.

CONCLUSIONS

ECV-guided LGE analysis is a robust scar quantification method for a non-ischemic cohort. Trial registration ClinicalTrials.gov; NCT00000797, retrospectively-registered 2 November 1999; NCT02501811, registered 15 July 2015.

Intramyocardial Triglycerides Among Women With vs Without HIV: Hormonal Correlates and Functional Consequences

CONTEXT

Women with HIV (WHIV) on anti-retroviral therapy (ART) are living longer but facing heightened vulnerability to heart failure.

OBJECTIVE

We investigated metabolic/hormonal/immune parameters relating to diastolic dysfunction-a precursor to heart failure-among WHIV without known cardiovascular disease (CVD).

DESIGN AND OUTCOME MEASURES

Nineteen ART-treated WHIV and 11 non-HIV-infected women without known CVD enrolled and successfully completed relevant study procedures [cardiac magnetic resonance spectroscopy (MRS) and cardiac MRI]. Groups were matched on age and body mass index. Primary outcome measures included intramyocardial triglyceride content (cardiac MRS) and diastolic function (cardiac MRI). Relationships between intramyocardial triglyceride content and clinical parameters were also assessed.

RESULTS

Among WHIV (vs non-HIV-infected women), intramyocardial triglyceride content was threefold higher [1.2 (0.4, 3.1) vs 0.4 (0.1, 0.5)%, P = 0.01], and diastolic function was reduced (left atrial passive ejection fraction: 27.2 ± 9.6 vs 35.9 ± 6.4%, P = 0.007). There was a strong inverse relationship between intramyocardial triglyceride content and diastolic function (ρ = -0.62, P = 0.004). Among the whole group, intramyocardial triglyceride content did not relate to chronologic age but did increase across the reproductive aging spectrum (P = 0.02). HIV status and reproductive aging status remained independent predictors of intramyocardial triglyceride content after adjusting for relevant cardiometabolic parameters (overall model R2 = 0.56, P = 0.003; HIV status P = 0.01, reproductive aging status P = 0.02).

CONCLUSIONS

For asymptomatic WHIV, increased intramyocardial triglyceride content is associated with diastolic dysfunction. Moreover, relationships between intramyocardial triglyceride accumulation and women's reproductive aging are noted.

Management of Long-Term Complications of HIV Disease: Focus on Cardiovascular Disease

HIV-infected individuals on effective antiretroviral therapy experience a number of non-AIDS noncommunicable diseases, such as cardiovascular disease, more frequently than uninfected individuals. Common pathways for such diseases are chronic immune activation and inflammation, including the prolonged inflammation associated with lower nadir CD4+ cell count. Prevention and treatment of non-AIDS conditions include treatment of traditional risk factors, lifestyle interventions, earlier initiation of antiretroviral therapy, and potentially therapies specifically targeting inflammation and immune activation (eg, statins). This article summarizes a presentation by Judith S. Currier, MD, at the IAS-USA continuing education program, Improving the Management of HIV Disease, held in New York, New York, in February 2017.