Association of low-grade albuminuria with adverse cardiac mechanics: findings from the hypertension genetic epidemiology network (HyperGEN) study

Myocardial Microvascular Inflammatory Endothelial Activation in Heart Failure With Preserved Ejection Fraction

OBJECTIVES

The present study investigated whether systemic, low-grade inflammation of metabolic risk contributed to diastolic left ventricular (LV) dysfunction and heart failure with preseved ejection fraction (HFpEF) through coronary microvascular endothelial activation, which alters paracrine signalling to cardiomyocytes and predisposes them to hypertrophy and high diastolic stiffness.

BACKGROUND

Metabolic risk is associated with diastolic LV dysfunction and HFpEF.

METHODS

We explored inflammatory endothelial activation and its effects on oxidative stress, nitric oxide (NO) bioavailability, and cyclic guanosine monophosphate (cGMP)-protein kinase G (PKG) signalling in myocardial biopsies of HFpEF patients and validated our findings by comparing obese Zucker diabetic fatty/Spontaneously hypertensive heart failure F1 hybrid (ZSF1)-HFpEF rats to ZSF1-Control (Ctrl) rats.

RESULTS

In myocardium of HFpEF patients and ZSF1-HFpEF rats, we observed the following: 1) E-selectin and intercellular adhesion molecule-1 expression levels were upregulated; 2) NADPH oxidase 2 expression was raised in macrophages and endothelial cells but not in cardiomyocytes; and 3) uncoupling of endothelial nitric oxide synthase, which was associated with reduced myocardial nitrite/nitrate concentration, cGMP content, and PKG activity.

CONCLUSIONS

HFpEF is associated with coronary microvascular endothelial activation and oxidative stress. These lead to a reduction of NO-dependent signalling from endothelial cells to cardiomyocytes, which can contribute to the high cardiomyocyte stiffness and hypertrophy observed in HFpEF.

Association of chronic kidney disease with abnormal cardiac mechanics and adverse outcomes in patients with heart failure and preserved ejection fraction

AIMS

Chronic kidney disease (CKD) is associated with worse outcomes in heart failure with preserved ejection fraction (HFpEF). Whether this association is due the effect of CKD on intrinsic abnormalities in cardiac function is unknown. We hypothesized that CKD is independently associated with worse cardiac mechanics in HFpEF.

METHODS AND RESULTS

We prospectively studied 299 patients enrolled in the Northwestern University HFpEF Program. Using the creatinine-based CKD-Epi equation to calculate estimated glomerular filtration rate (eGFR), study participants were analysed by CKD status (using eGFR <60 mL/min/1.73 m(2) to denote CKD). Indices of cardiac mechanics (longitudinal strain parameters) were measured using speckle-tracking echocardiography. Using multivariable-adjusted linear and Cox regression analyses, we determined the association between CKD and echocardiographic parameters and clinical outcomes (cardiovascular hospitalization or death). Of 299 study participants, 48% had CKD. CKD (dichotomous variable) and reduced eGFR (continuous variable) were both associated with worse cardiac mechanics indices including left atrial (LA) reservoir strain, LV longitudinal strain, and right ventricular free wall strain even after adjusting for potential confounders, including co-morbidities, EF, and volume status. For example, for each 1-SD decrease in eGFR, LA reservoir strain was 3.52% units lower (P < 0.0001) after multivariable adjustment. Reduced eGFR was also associated with worse outcomes [adjusted hazard ratio (HR) 1.28, 95% confidence interval (CI) 1.01-1.61 per 1-SD decrease in eGFR; P = 0.039]. The association was attenuated after adjustment for indices of cardiac mechanics (P = 0.064).

CONCLUSION

In HFpEF, CKD is independently associated with worse cardiac mechanics, which may explain why HFpEF patients with CKD have worse outcomes.

TRIAL REGISTRATION

NCT01030991.

Discordant associations of lipid parameters with albuminuria and chronic kidney disease: a population-based study

Background

Although dyslipidemia is related to the pathogenesis of renal insufficiency, which routinely available lipid measure is more applicable in estimation of kidney function is still uncertain. Our objective was to evaluate inconsistent associations of lipid profiles with both albuminuria and chronic kidney disease (CKD).

Methods

We performed a population-based study in 9730 subjects aged 40 years or older. Definitions of abnormalities in albumin excretion were according to the latest guidelines of American Diabetes Association’s Standards of Medical Care. CKD was defined as estimated glomerular filtration rate (eGFR) < 60 mL/min per 1.73 m² or the presence of albuminuria.

Results

There were 2274 (23.4 %) participants categorized as low-grade albuminuria, 639 (6.6 %) participants categorized as increased urinary albumin excretion and 689 (7.1 %) participants categorized as CKD. Triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), Non HDL-C to HDL-C ratio, TG to HDL-C ratio were significantly correlated with urinary albumin to creatinine ratio (ACR), serum creatinine and eGFR (all P < 0.0001). Compare with other lipid parameters, TG to HDL-C ratio have shown the strongest correlation with increased odds of both increased urinary albumin excretion and CKD. No significant associations between lipid parameters and low-grade albuminuria were observed after adjustments for potential confounding factors.

Conclusion

Our study lends support to discordant associations of lipid parameters with albuminuria and renal function. TG to HDL-C ratio is a better marker than other routine lipid measures for identifying renal insufficiency and should be given more consideration in the clinical practice.

Influence of chronic kidney disease on cardiac structure and function

Chronic kidney disease (CKD), the presence of kidney dysfunction and/or damage, is a worldwide public health issue. Although CKD is independently associated with various subtypes of cardiovascular diseases, a recent international collaborative meta-analysis demonstrates that CKD is particularly strongly associated with heart failure, suggesting its critical impact on cardiac structure and function. Although numerous studies have investigated the association of CKD and cardiac structure and function, these studies substantially vary regarding source populations and methodology (e.g., measures of CKD and/or parameters of cardiac structure and function), making it difficult to reach universal conclusions. Nevertheless, in this review, we comprehensively examine relevant studies, discuss potential mechanisms linking CKD to alteration of cardiac structure and function, and demonstrate clinical implications as well as potential future research directions. We exclusively focus on studies investigating both CKD measures, kidney function (i.e., glomerular filtration rate [GFR], creatinine clearance, or levels of filtration markers), and kidney damage represented by albuminuria, since current international clinical guidelines of CKD recommend staging CKD and assessing its clinical risk based on both GFR and albuminuria.

Urine Albumin Excretion Is Associated with Cardiac Troponin T Detected with a Highly Sensitive Assay in a Community-Based Population

Background

Urine albumin excretion is an important predictor of adverse cardiovascular events. Minimally elevated levels of serum cardiac troponin T (cTnT), a marker of cardiomyocyte micronecrosis, can be detected with high sensitivity cTnT (hs-cTnT) assays. The purpose of this study was to investigate the relationship between alterations in albuminuria and serum hs-cTnT levels in a community-based population.

Methods

We examined the association between the urine albumin/creatinine ratio (UACR) and hs-cTnT levels in 1354 participants without overt cardiovascular disease in a community-based, cross-sectional study in Beijing, China.

Results

With the highly sensitive assay, cTnT levels were detectable in 90.5% of our subjects. The median (interquartile range) concentrations of hs-cTnT were 7 (5–10) pg/mL. After adjustment for several factors, UACR (odds ratio: 1.40; 95% confidence interval: 1.08–1.65; P = 0.002) was associated with a higher likelihood of elevated hs-cTnT (≥14 pg/ mL), whereas the relationship between UACR and a higher presence of detectable hs-cTnT (≥ 3 pg/ mL) was not significant. In addition, a fully adjusted logistic regression analysis revealed that compared with participants in the lowest UACR quartile, those in the highest quartile had a 2.43- fold (95% CI: 1.25–5.08; P = 0.006) increased risk of elevated hs-cTnT.

Conclusions

Higher urine albumin excretion is associated with elevated hs-cTnT among persons without clinically evident cardiovascular disease, suggesting that albuminuria may be a potential risk factor for subclinical cardiovascular disease in the general population.

Clinical features of subclinical left ventricular systolic dysfunction in patients with diabetes mellitus

Background

Left ventricular (LV) longitudinal systolic dysfunction has been identified even in asymptomatic patients with diabetes mellitus (DM) and preserved LV ejection fraction (LVEF). However, its relevant clinical features have not been fully evaluated.

Methods

We studied 144 asymptomatic DM patients without coronary artery disease. Their mean age was 57 ± 15 years, 79 (55%) were female, and mean LVEF was 66 ± 4% (all ≥50%). Global longitudinal strain (GLS) was determined as the average peak strain of 18 segments from the three standard apical views, and was expressed as an absolute value. With the pre-defined cutoff for subclinical LV systolic dysfunction in DM patients with preserved LVEF set at GLS < 18%, this dysfunction was detected in 53 patients (37%).

Results

Multivariate logistic regression analysis revealed that type 2 DM, hypertriglyceridemia, overweight/obesity, nephropathy and neuropathy were independently associated with GLS < 18%, with nephropathy being the highest risk factor (OR: 5.26; 95% CI 2.111-13.12, p < 0.001). For sequential logistic regression models, a model based on clinical variables including gender, type 2 DM and DM duration (χ² = 24.1) was improved by addition of overweight/obesity and hypertriglyceridemia (χ² = 45.6, p < 0.001), and further improved by addition of nephropathy and neuropathy (χ² = 70.2, p < 0.001) as variables. Furthermore, albuminuria significantly correlated with GLS (r = −0.51, p < 0.001), and a multivariate regression model showed it to be the factor most closely associated with GLS (β = −0.33, p < 0.001).

Conclusions

Diabetic complications, hypertriglyceridemia and overweight/obesity were closely associated with early stage of LV systolic longitudinal myocardial dysfunction in asymptomatic DM patients with preserved LVEF. Our findings can be clinically noticeable for the management of DM patients.

Association between low-grade albuminuria and cardiovascular risk in Korean adults: the 2011-2012 Korea National Health and Nutrition Examination Survey

Background

Recent studies have indicated that low UACR levels (<30 μg/mg) previously considered to be in the normal range (‘low-grade albuminuria’) are associated with cardiovascular morbidity and mortality in the general population.

Methods

We studied 9,736 participants with albuminuria in the normal range from the 2011–2012 Korea National Health and Nutrition Examination Survey (KNHANES).

Results

The weighted prevalences of metabolic syndrome (MS) and the 10-year risk for coronary heart disease measured using the Framingham risk score (FRS) ≥ 20% (high risk) were 22.5 ± 0.7% and 14.5 ± 0.7%, respectively, in males and 23.3 ± 0.8% and 8.5 ± 0.4%, respectively in females. Weighted comparisons among the tertiles of UACR revealed that the prevalences of MS and high-risk FRS increased with increasing UACR (MS: males, 15.9 ± 1.1, 20.2 ± 1.2, 32.4 ± 1.5%, respectively; P < 0.001; and females, 17.6 ± 1.0, 22.7 ± 1.0, 30.2 ± 1.4%, respectively; P < 0.001. High-risk FRS: males, 9.5 ± 0.7, 12.3 ± 0.9, 22.5 ± 1.2, respectively; P < 0.001; and females, 5.8 ± 0.6, 7.9 ± 0.7, 12.0 ± 0.9%, respectively; P < 0.001). The positive association persisted after adjusting for hypertension and diabetes. The weighted comparisons among the deciles of UACR revealed that the prevalences of MS and high-risk FRS began to increase at the ranges of 3.89–5.15 and 5.16–7.36 mg/g Cr, respectively.

Conclusion

Low-grade albuminuria was significantly associated with estimated cardiovascular risk and MS in a nationally representative sample of Koreans.

Association between low-grade albuminuria and hearing impairment in a non-diabetic Korean population: The Korea National Health and Nutrition Examination Survey (2011-2013)

INTRODUCTION

The objective of the present study was to examine the association between low-grade albuminuria and hearing impairment in the non-diabetic population.

MATERIALS AND METHODS

Data from the Korean National Health and Nutrition Examination Survey 2011-2013 were used in the analyses. Participants were excluded from this study if they were younger than 19 years old, or had urine albumin/creatinine ratio (UACR) ≥ 30 mg/g or diabetes mellitus. There were 10,608 participants included in this study. The participants were divided into three groups according to their UACR tertiles.

RESULTS

There were 1560; 1561; and 1552 male and 1982; 1975; and 1978, female participants in the low, middle, and high tertile groups, respectively. The results indicated the association between low-grade albuminuria and the numbers of metabolic syndrome (MetS) components or Framingham risk score, and the presence of MetS or the proportions of participants at high cardiovascular risk. Univariate and multivariate linear regression analyses demonstrated an association between the UACR and average hearing threshold (AHT) that was observed in both sexes. Multivariate analyses showed that mean AHTs in the low, middle, and high tertile groups were, respectively, 16.127 dB, 17.139 dB, and 18.604 dB for men, and 14.842 dB, 15.100 dB, and 16.353 dB, respectively, for women. Low-frequency, mid-frequency, and high-frequency hearing thresholds according to UACR tertiles showed similar trends. In both sexes, multivariate logistic regression analyses revealed that participants in the low and middle tertile groups had a decreased risk for hearing loss compared to participants in the high tertile group.

CONCLUSION

Low-grade albuminuria was associated with hearing impairment in the non-diabetic participants of this study.

Serum gamma - glutamyltransferase is associated with albuminuria: a population-based study

Background

Serum γ - glutamyltransferase (GGT) is implicated in the pathogenesis of endothelial dysfunction and atherosclerosis. Albuminuria is a marker of endothelial damage and correlated with structural and functional integrity of the vasculature. Our objective was to evaluate the association between serum GGT level and prevalence of albuminuria in a Chinese population.

Materials and Methods

We conducted a population-based cross-sectional study in 9,702 subjects aged 40 years or older. Increased urinary albumin excretion was defined according to the urinary albumin-to-creatinine ratio (ACR) ranges greater or equal than 30 mg/g. Low-grade albuminuria was defined according to the highest quartile of ACR in participants without increased urinary albumin excretion.

Results

The prevalence of low-grade albuminuria and increased urinary albumin excretion were respectively 23.4% and 6.6% in this population and gradually increased across the sex-specific serum GGT quartiles (all P for trend <0.05). In logistic regression analysis, compared with subjects in the lowest quartile of serum GGT level, the adjusted odds ratios (ORs) in the highest quartile was 1.22 [95% confidence interval (CI), 1.04–1.43] for low-grade albuminuria and 1.55 (95% CI, 1.18–2.04) for increased urinary albumin excretion. In subgroup analysis, significant relationship of serum GGT level with both low-grade albuminuria and increased urinary albumin excretion were detected in women, younger subjects, overweight subjects and in those with hypertension or glomerular filtration rate greater than 90 (all P <0.05).

Conclusion

Serum GGT level is associated with urinary albumin excretion in middle-aged and elderly Chinese.

Diastolic wall strain: a simple marker of abnormal cardiac mechanics

BACKGROUND

Diastolic wall strain (DWS), defined using posterior wall thickness (PWT) measurements from standard echocardiographic images (DWS = [PWT(systole)-PWT(diastole)]/PWT(systole)), has been proposed as a marker of left ventricular (LV) diastolic stiffness. However, the equation for DWS is closely related to systolic radial strain, and whether DWS is associated with abnormal cardiac mechanics (reduced systolic strains and diastolic tissue velocities) is unknown. We sought to determine the relationship between DWS and systolic and diastolic cardiac mechanics.

METHODS

We calculated DWS and performed speckle-tracking analysis in a large population- and family-based study (Hypertension Genetic Epidemiology Network [HyperGEN]; N=1907 after excluding patients with ejection fraction [EF] <50% or posterior wall motion abnormalities). We measured global longitudinal, circumferential, and radial strain (GLS, GCS, and GRS, respectively) and early diastolic (e') tissue velocities, and we determined the independent association of DWS with cardiac mechanics using linear mixed effects models to account for relatedness among study participants. We also prospectively performed receiver-operating characteristic (ROC) analysis of DWS for the detection of abnormal cardiac mechanics in a separate, prospective validation study (N=35).

RESULTS

In HyperGEN (age 51 ± 14 years, 59% female, 45% African-American, 57% hypertensive), mean DWS was 0.38 ± 0.05. DWS decreased with increasing comorbidity burden (β-coefficient -0.013 [95% CI -0.015, -0.011]; P<0.0001). DWS was independently associated with GLS, GCS, GRS, and e' velocity (adjusted P<0.05) but not LV chamber compliance (EDV20, P=0.97). On prospective speckle-tracking analysis, DWS correlated well with GLS, GCS, and GRS (R=0.61, 0.57, and 0.73, respectively; P<0.001 for all comparisons). C-statistics for DWS as a diagnostic test for abnormal GLS, GCS, and GRS were: 0.78, 0.79, and 0.84, respectively.

CONCLUSIONS

DWS, a simple parameter than can be calculated from routine 2D echocardiography, is closely associated with systolic strain parameters and early diastolic (e') tissue velocities but not LV chamber compliance.

Albuminuria is independently associated with cardiac remodeling, abnormal right and left ventricular function, and worse outcomes in heart failure with preserved ejection fraction

OBJECTIVES

The purpose of this study was to determine the relationship between albuminuria and cardiac structure/function in heart failure with preserved ejection fraction (HFpEF).

BACKGROUND

Albuminuria, a marker of endothelial dysfunction, has been associated with adverse cardiovascular outcomes in HFpEF. However, the relationship between albuminuria and cardiac structure/function in HFpEF has not been well studied.

METHODS

We measured urinary albumin-to-creatinine ratio (UACR) and performed comprehensive echocardiography, including tissue Doppler imaging and right ventricular (RV) evaluation, in a prospective study of 144 patients with HFpEF. Multivariable-adjusted linear regression was used to determine the association between UACR and echocardiographic parameters. Cox proportional hazards analyses were used to determine the association between UACR and outcomes.

RESULTS

The mean age was 66 ± 11 years, 62% were female, and 42% were African American. Higher UACR was associated with greater left ventricular mass, lower preload-recruitable stroke work, and lower global longitudinal strain. Higher UACR was also significantly associated with RV remodeling (for each doubling of UACR, RV wall thickness was 0.9 mm higher [95% confidence interval: 0.05 to 0.14 mm; p = 0.001, adjusted p = 0.01]) and worse RV systolic function (for each doubling of UACR, RV fractional area change was 0.56% lower [95% confidence interval: 0.14 to 0.98%; p = 0.01, adjusted p = 0.03]. The association between UACR and RV parameters persisted after the exclusion of patients with macroalbuminuria (UACR >300 mg/g). Increased UACR was also independently associated with worse outcomes.

CONCLUSIONS

In HFpEF, increased UACR is a prognostic marker and is associated with increased RV and left ventricular remodeling and longitudinal systolic dysfunction. (Classification of Heart Failure With Preserved Ejection Fraction; NCT01030991).

Association of comorbidity burden with abnormal cardiac mechanics: findings from the HyperGEN study

Background

Comorbidities are common in heart failure (HF), and the number of comorbidities has been associated with poor outcomes in HF patients. However, little is known about the effect of multiple comorbidities on cardiac mechanics, which could impact the pathogenesis of HF. We sought to determine the relationship between comorbidity burden and adverse cardiac mechanics.

Methods and Results

We performed speckle‐tracking analysis on echocardiograms from the HyperGEN study (n=2150). Global longitudinal, circumferential, and radial strain, and early diastolic (e') tissue velocities were measured. We evaluated the association between comorbidity number and cardiac mechanics using linear mixed effects models to account for relatedness among subjects. The mean age was 51±14 years, 58% were female, and 47% were African American. Dyslipidemia and hypertension were the most common comorbidities (61% and 58%, respectively). After adjusting for left ventricular (LV) mass index, ejection fraction, and several potential confounders, the number of comorbidities remained associated with all indices of cardiac mechanics except global circumferential strain (eg, β=−0.32 [95% CI −0.44, −0.20] per 1‐unit increase in number of comorbidities for global longitudinal strain; β=−0.16 [95% CI −0.20, −0.11] for e' velocity; P≤0.0001 for both comparisons). Results were similar after excluding participants with abnormal LV geometry (P<0.05 for all comparisons).

Conclusions

Higher comorbidity burden is associated with worse cardiac mechanics, even in the presence of normal LV geometry. The deleterious effect of multiple comorbidities on cardiac mechanics may explain both the high comorbidity burden and adverse outcomes in patients who ultimately develop HF.