Pulmonary vascular dysfunction among people aged over 65 years in the community in the Atherosclerosis Risk In Communities (ARIC) Study: A cross-sectional analysis

Metabolomic Association and Risk Prediction With Heart Failure in Older Adults

BACKGROUND

Older adults have markedly increased risks of heart failure (HF), specifically HF with preserved ejection fraction (HFpEF). Identifying novel biomarkers can help in understanding HF pathogenesis and improve at-risk population identification. This study aimed to identify metabolites associated with incident HF, HFpEF, and HF with reduced ejection fraction and examine risk prediction in older adults.

METHODS

Untargeted metabolomic profiling was performed in Black and White adults from the ARIC study (Atherosclerosis Risk in Communities) visit 5 (n=3719; mean age, 75 years). We applied Cox regressions to identify metabolites associated with incident HF and its subtypes. The metabolite risk score (MRS) was constructed and examined for associations with HF, echocardiographic measures, and HF risk prediction. Independent samples from visit 3 (n=1929; mean age, 58 years) were used for replication.

RESULTS

Sixty metabolites (hazard ratios range, 0.79-1.49; false discovery rate, <0.05) were associated with incident HF after adjusting for clinical risk factors, eGFR, and NT-proBNP (N-terminal pro-B-type natriuretic peptide). Mannonate, a hydroxy acid, was replicated (hazard ratio, 1.36 [95% CI, 1.19-1.56]) with full adjustments. MRS was associated with an 80% increased risk of HF per SD increment, and the highest MRS quartile had 8.7× the risk of developing HFpEF than the lowest quartile. High MRS was also associated with unfavorable values of cardiac structure and function. Adding MRS over clinical risk factors and NT-proBNP improved 5-year HF risk prediction C statistics from 0.817 to 0.850 (∆C, 0.033 [95% CI, 0.017-0.047]). The association between MRS and incident HF was replicated after accounting for clinical risk factors (P<0.05).

CONCLUSIONS

Novel metabolites associated with HF risk were identified, elucidating disease pathways, specifically HFpEF. An MRS was associated with HF risk and improved 5-year risk prediction in older adults, which may assist at at-risk population identification.

Changes in Pulmonary Artery Pressure Late in Life: The Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

Although the prognostic implications of higher pulmonary artery systolic pressure (PASP) are well established, few data exist regarding longitudinal change in pulmonary pressure in late life.

OBJECTIVES

The aim of this study was to quantify changes in PASP over 6 years and determine the relative contributions of cardiac and pulmonary dysfunction.

METHODS

Among 1,420 participants in the ARIC (Atherosclerosis Risk in Communities) study with echocardiographic measures of PASP at both the fifth (2011-2013) and seventh (2018-2019) visits, longitudinal changes in PASP over about 6.5 years were quantified. Multivariable regression was used to determine the extent to which cardiac and pulmonary dysfunction were associated with changes in PASP and to define the relationship of changes in PASP with dyspnea development.

RESULTS

The mean age was 75 ± 5 years at visit 5 and 81 ± 5 years at visit 7, 24% of subjects were Black adults, and 68% were women. Over the 6.5 years, PASP increased by 5 ± 8 mm Hg, from 28 ± 5 to 33 ± 8 mm Hg. PASP increased more in older participants. Predictors of greater increases in PASP included worse left ventricular (LV) systolic and diastolic function, pulmonary function, and renal function. Increases in PASP were associated with concomitant increases in measures of LV filling pressure, including E/e' ratio and left atrial volume index. Each 5 mm Hg increase was associated with 16% higher odds of developing dyspnea (OR: 1.16; 95% CI: 1.07-1.27; P < 0.001).

CONCLUSIONS

Pulmonary pressure increased over 6.5 years in late life, was associated with concomitant increases in LV filling pressure, and predicted the development of dyspnea. Interventions targeting LV diastolic function may be effective at mitigating age-related increases in PASP.

Association of Right Ventricular Afterload With Atrial Fibrillation Risk in Older Adults: The Atherosclerosis Risk in Communities Study

BACKGROUND

Atrial fibrillation (AF) is widely perceived to originate from the left atrium (LA). Whether increases in right ventricular (RV) afterload in older adults play an etiological role in AF genesis independent of LA and left ventricular (LV) remodeling is unknown.

RESEARCH QUESTION

Is higher RV afterload associated with greater AF risk independent of LA and LV remodeling?

STUDY DESIGN AND METHODS

In this observational prospective study, we included 2,246 community-dwelling older adults (mean age, 75 years) without known cardiovascular disease, with LV ejection fraction > 50%, LA volume index < 34 mL/m2, and E/e' ratio < 14 and a measurable functional tricuspid regurgitation jet velocity. From 2D-echocardiograms, we estimated pulmonary artery systolic pressure (PASP) and pulmonary vascular resistance (PVR). We ascertained incident AF (through 2018) from hospital discharge codes and death certificates. We estimated hazard ratios (HR) by Cox regression.

RESULTS

During follow-up (median, 6.3 years; interquartile interval, 5.5-6.9 years), 215 participants developed AF. AF risk was significantly higher in the third (vs first) tertile of PASP (HR, 1.65; 95% CI, 1.08-2.54) and PVR (HR, 1.38; 95% CI, 1.00-2.08) independent of LA and LV structure and function, heart rate, BMI, prevalent sleep apnea, systemic BP, antihypertensive medications, and lung, kidney, and thyroid function. These associations persisted after further exclusion of participants with tricuspid regurgitation jet velocity > 2.8 m/s and lateral and septal mitral annular velocity above age- and sex-specific reference limits.

INTERPRETATION

In older adults, higher RV afterload is associated with greater AF risk independent of LA and LV remodeling. Future research should focus on confirming this novel association and elucidate underlying mechanisms.

Imaging in Pulmonary Vascular Disease-Understanding Right Ventricle-Pulmonary Artery Coupling

The right ventricle (RV) and pulmonary arterial (PA) tree are inextricably linked, continually transferring energy back and forth in a process known as RV-PA coupling. Healthy organisms maintain this relationship in optimal balance by modulating RV contractility, pulmonary vascular resistance, and compliance to sustain RV-PA coupling through life's many physiologic challenges. Early in states of adaptation to cardiovascular disease-for example, in diastolic heart failure-RV-PA coupling is maintained via a multitude of cellular and mechanical transformations. However, with disease progression, these compensatory mechanisms fail and become maladaptive, leading to the often-fatal state of "uncoupling." Noninvasive imaging modalities, including echocardiography, magnetic resonance imaging, and computed tomography, allow us deeper insight into the state of coupling for an individual patient, providing for prognostication and potential intervention before uncoupling occurs. In this review, we discuss the physiologic foundations of RV-PA coupling, elaborate on the imaging techniques to qualify and quantify it, and correlate these fundamental principles with clinical scenarios in health and disease. © 2022 American Physiological Society. Compr Physiol 12: 1-26, 2022.

Hypoxia and hemorheological properties in older individuals

Hypoxia is caused by insufficient oxygen availability for the organism leading to reduced oxygen delivery to tissues and cells. It has been regarded as a severe threat to human health and it is indeed implicated in pathophysiological mechanisms involved in the development and progression of many diseases. Nevertheless, the potential of controlled hypoxia interventions (i.e. hypoxia conditioning) for improving cardio-vascular health is gaining increased attention. However, blood rheology is often a forgotten factor for vascular health while aging and hypoxia exposure are both suspected to alter hemorheological properties. These changes in blood rheology may influence the benefits-risks balance of hypoxia exposure in older individuals. The benefits of hypoxia exposure for vascular health are mainly reported for healthy populations and the combined impact of aging and hypoxia on blood rheology could therefore be deleterious in older individuals. This review discusses evidence of hypoxia-related and aging-related changes in blood viscosity and its determinants. It draws upon an extensive literature search on the effects of hypoxia/altitude and aging on blood rheology. Aging increases blood viscosity mainly through a rise in plasma viscosity, red blood cell (RBC) aggregation and a decrease in RBC deformability. Hypoxia also causes an increase in RBC aggregation and plasma viscosity. In addition, hypoxia exposure may increase hematocrit and modulate RBC deformability, depending on the hypoxic dose, i.e, beneficial effect of intermittent hypoxia with moderate dose vs deleterious effect of chronic continuous or intermittent hypoxia or if the hypoxic dose is too high. Special attention is directed toward the risks vs. benefits of hemorheological changes during hypoxia exposure in older individuals, and its clinical relevance for vascular disorders.

Depressive Symptoms, Cardiac Structure and Function, and Risk of Incident Heart Failure With Preserved Ejection Fraction and Heart Failure With Reduced Ejection Fraction in Late Life

Background Depressive symptoms are associated with heightened risk of heart failure (HF), but their association with cardiac function and with HF with preserved ejection fraction (HFpEF) and HF with reduced ejection fraction (HFrEF) in late life is unclear. We aimed to determine the prevalence of depression in HFpEF and in HFrEF in late life, and the association of depressive symptoms with cardiac function and incident HFpEF and HFrEF. Methods and Results We studied 6025 participants (age, 75.3±5.1 years; 59% women; 20% Black race) in the ARIC (Atherosclerosis Risk in Communities) study at visit 5 who underwent echocardiography and completed the Center for Epidemiologic Studies Depression Scale questionnaire. Among HF-free participants (n=5086), associations of Center for Epidemiologic Studies Depression Scale score with echocardiography and incident adjudicated HFpEF and HFrEF were assessed using multivariable linear and Cox proportional hazards regression. Prevalent HFpEF, but not HFrEF, was associated with a higher prevalence of depression compared with HF-free participants (P<0.001 and P=0.59, respectively). Among HF-free participants, Center for Epidemiologic Studies Depression Scale score was not associated with cardiac structure and function after adjusting for demographics and comorbidities (all P>0.05). Over 5.5-year follow-up, higher Center for Epidemiologic Studies Depression Scale score was associated with heightened risk of incident HFpEF (hazard ratio [HR] [95% CI], 1.06 [1.04-1.12]; P=0.02), but not HFrEF (HR [95% CI], 1.02 [0.96-1.08]; P=0.54), independent of echocardiographic measures, NT-proBNP (N-terminal pro-B-type natriuretic peptide), troponin, and hs-CRP (high-sensitivity C-reactive protein) (HR [95% CI], 1.06 [1.00-1.12]; P=0.04). Conclusions Worse depressive symptoms predict incident HFpEF in late life, independent of common comorbidities, cardiac structure and function, and prognostic biomarkers. Further studies are necessary to understand the mechanisms linking depression to risk of HFpEF.

Mildly elevated pulmonary artery systolic pressure on echocardiography: bridging the gap in current guidelines

Pulmonary hypertension is associated with increased morbidity and mortality, and growing evidence suggests that even mild elevations in pulmonary artery pressure estimated with echocardiography are linked to increased mortality. In healthy individuals who undergo right heart catheterisation, the average pulmonary artery systolic pressure ranges from 17 mm Hg to 25 mm Hg; on echocardiography, estimated pulmonary artery systolic pressure of more than 30 mm Hg is outside the normal range for most healthy individuals. Increased pulmonary artery systolic pressure (>30 mm Hg) is reported on more than 40% of clinically indicated echocardiograms, often in the presence of metabolic and cardiopulmonary comorbidities, and is associated with a 5-year mortality of 25-40%. However, current guidelines do not sufficiently highlight risk and risk-reduction approaches for the sizable patient population with elevated pulmonary artery pressure who do not have underlying severe pulmonary vascular disease such as pulmonary arterial hypertension. Increased awareness of this frequently reported high-risk echocardiographic finding, and multidisciplinary risk-reduction approaches for patients with metabolic and cardiopulmonary comorbidities and elevated pulmonary artery pressure, are urgently needed.