Combination of the electrocardiographic strain pattern and albuminuria for the prediction of new-onset heart failure in hypertensive patients: the LIFE study

Association of Urine Albumin Excretion With Incident Heart Failure Hospitalization in Community-Dwelling Adults

OBJECTIVES

This study examined the association between urinary albumin excretion and incident heart failure (HF) hospitalization.

BACKGROUND

Excess urinary albumin excretion is more strongly associated with incident stroke and coronary heart disease risk in black than in white individuals. Whether similar associations extend to HF is unclear.

METHODS

This study examined the associations between the urinary albumin-to-creatinine ratio (ACR) and incident hospitalization for HF overall in 24,433 REGARDS (Reasons for Geographic and Racial Differences in Stroke) study participants free of suspected HF at baseline; findings were stratified by race and HF subtype (preserved vs. reduced ejection fraction). Models were adjusted for sociodemographic, clinical, and laboratory variables including estimated glomerular filtration rate, and multiple imputation was used to account for missing covariate data.

RESULTS

After a median follow-up of 9.2 years, 881 incident HF events (332 preserved ejection fraction, 447 reduced ejection fraction, 102 unspecified) were observed. Compared to the lowest ACR category (<10 mg/g), the risk of incident HF increased with increasing ACR categories (10 to 29 mg/g hazard ratio [HR]: 1.49; 95% confidence interval [CI]: 1.26 to 1.78; 30 to 300 mg/g HR: 2.32; 95% CI: 1.93 to 2.78; >300 mg/g HR: 4.42; 95% CI: 3.36 to 5.83) in the fully adjusted model. Results did not differ by race. The magnitude of the association between ACR and HF with preserved ejection fraction was greater than with HF with reduced ejection fraction (HR comparing highest vs. lowest ACR category: 6.20; 95% CI: 4.15 to 9.26 vs. HR: 4.37; 95% CI: 3.00 to 6.25, respectively; p = 0.05).

CONCLUSIONS

Higher ACR was associated with greater risk of incident HF hospitalization in community-dwelling black and white adults.

Cardiorenal Syndrome in Hypertensive Rats: Microalbuminuria, Inflammation and Ventricular Hypertrophy

The aim of our study was to evaluate a possible association between microalbuminuria (MA), several low-grade inflammation factors and left ventricular hypertrophy (LVH) by using a pharmacological approach. This may provide new insights into the pathophysiologic mechanisms of the cardiorenal syndrome (CRS) linking early renal impairment with elevated cardiovascular risk. Two kidney-one clip (2K-1C) renovascular hypertension was induced in 24 male Wistar rats (220-250 g). After the development of hypertension, rats were divided into four groups: 2K-1C (untreated), calcium channel blocker (amlodipine-treated), angiotensin receptor blocker (losartan-treated) and peripheral vasodilator (hydralazine-treated), which were treated for 10 weeks. Rats in the 2K-1C group had all developed hypertension, a significant increase in plasma levels of tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), brain natriuretic peptide (BNP) and C-reactive protein (CRP). Moreover MA and creatininaemia underwent a significant increase. Under treatment decreases were observed in systolic blood pressure (SBP), TNF-α, CRP, IL-6, BNP concentrations and creatininaemia. These results were related to the absence of MA which was significantly associated with reductions in cardiac mass and hypertrophy markers (BNP and β-MHC gene expression) as well as renal interstitial inflammation. In conclusion, our results suggest that the reduction of MA is correlated with the decrease of the inflammatory components and seems to play an important role in protecting against cardiac hypertrophy and renal injury.

Diminished renal function and the incidence of heart failure

Heart failure is one of the most common, costly, disabling and deadly diseases. During the last decade, several different indices reflecting renal function such as creatinine-based glomerular filtration rate, circulating levels of cystatin C and low-grade albuminuria have been demonstrated to be independent risk factors for heart failure. This review summarizes our current knowledge of the relationship between diminished renal function and the incidence of heart failure in the community, and also in individuals with increased risk of heart failure such as patients with overt cardiovascular disease, hypertension or diabetes. This review will also put forward important areas of future research in this field.

The progressive pathway of microalbuminuria: from early marker of renal damage to strong cardiovascular risk predictor

There is clear evidence that urinary albumin excretion levels, even below the cut-off values currently used to diagnose microalbuminuria, are associated with an increased risk of cardiovascular events. The relationships of microalbuminuria with a variety of risk factors, such as hypertension, diabetes and metabolic syndrome and with several indices of subclinical organ damage, may contribute, at least in part, to explain the enhanced cardiovascular risk conferred by microalbuminuria. Nonetheless, several studies showed that the association between microalbuminuria and cardiovascular disease remains when all these risk factors are taken into account in multivariate analyses. Therefore, the exact pathophysiological mechanisms explaining the association between microalbuminuria and cardiovascular risk remain incompletely understood. The simple search for microalbuminuria in hypertensive patients may enable the clinician to better assess absolute cardiovascular risk, and its identification may induce physicians to encourage patients to make healthy lifestyle changes and perhaps would prompt to more aggressive modification of standard cardiovascular risk factors.

High-normal albuminuria and risk of heart failure in the community

BACKGROUND

Albuminuria has been associated with cardiovascular risk, but the relationship of high-normal albuminuria to subsequent heart failure has not been well established.

STUDY DESIGN

Prospective observational study, the Atherosclerosis Risk in Communities (ARIC) Study.

SETTING & PARTICIPANTS

10,975 individuals free from heart failure were followed up from the fourth ARIC Study visit (1996-1998) through January 2006.

PREDICTOR

Urinary albumin-creatinine ratio (UACR), analyzed continuously and categorically as optimal (<5 mg/g), intermediate-normal (5-9 mg/g), high-normal (10-29 mg/g), microalbuminuria (30-299 mg/g), and macroalbuminuria (≥300 mg/g).

OUTCOMES & MEASUREMENTS

Incident heart failure was defined as a heart failure-related hospitalization or death. Cox proportional hazard models were used to calculate the HR of heart failure after adjustment for age, race, sex, estimated glomerular filtration rate (eGFR), and other cardiovascular risk factors.

RESULTS

Individuals were followed up for a median of 8.3 years and experienced 344 heart failure events. Compared with normal UACR, albuminuria was associated with a progressively increased risk of heart failure from intermediate-normal (adjusted HR, 1.54; 95% CI, 1.12-2.11) and high-normal UACR (adjusted HR, 1.91; 95% CI, 1.38-2.66) to microalbuminuria (adjusted HR, 2.49; 95% CI, 1.77-3.50) and macroalbuminuria (adjusted HR, 3.47; 95% CI, 2.10-5.72). Results were similar in secondary analyses of participants censored at the time of coronary heart disease event and along a range of eGFRs.

LIMITATIONS

UACR was measured as a single random sample.

CONCLUSIONS

Albuminuria is associated with subsequent heart failure, even in individuals with few cardiovascular risk factors and UACR within the normal range. Our results suggest that the association between albuminuria and heart failure may not be mediated fully by ischemic heart disease or kidney disease, measured using eGFR.

Should targeting albuminuria be part of a cardiovascular risk reduction paradigm?

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in the United States as well as the rest of the world. Chronic kidney disease (CKD) is considered a CVD risk equivalent. The development of albuminuria has been identified as an additional possible risk marker that is almost unique to patients with CKD and a marker for predicting CVD risk. This review focuses on clinical and epidemiologic evidence regarding the role of albuminuria in the context of CVD development. It reviews the association of albuminuria with other comorbidities associated with increased cardiovascular risk and the modalities aimed at the reduction of albuminuria and maximizing of cardiovascular risk reduction.

Proteinuria and clinical outcomes in hypertensive patients

This narrative review focuses on outcomes related to proteinuria in hypertension (HT), and also examines the role of current and future therapeutic strategies. Proteinuria is an independent marker of renal and cardiovascular (CV) disease in hypertensive populations, particularly in high-risk groups such as diabetic patients. Effective blood pressure (BP) control and proteinuria management are associated with significant improvements in the risk of key adverse outcomes, although a causative relationship needs careful assessment. Available antihypertensives have varying effects on proteinuria reduction. Drugs affecting the renin system offer antiproteinuric and renoprotective effects that are probably at least partially independent of their BP effects. Economic evaluations of these interventions confirm their cost-saving benefits relative to other antihypertensives, but outcomes-based research is needed in some settings.

The role of urate and xanthine oxidase in vascular oxidative stress: future directions

Vascular oxidative stress has been shown to be a potent factor in the pathophysiology of endothelial dysfunction. Despite current optimal evidence-based therapy, mortality from various cardiovascular disorders remains high. The search for newer, novel ways of attenuating endothelial dysfunction has yielded several new and exciting possibilities, one of which is the manipulation of urate levels using xanthine oxidase inhibitors. Agents such as allopurinol have shown marked improvements in vascular endothelial function in various cohorts at risk of cardiovascular events. Most of the evidence so far comes from smaller mechanistic studies. The few large randomized controlled trials have failed to show any significant mortality benefit using these agents. This article highlights the potential avenues of further research such as dose-response, and the potential for these agents to regress left ventricular hypertrophy. The role of newer agents such as febuxostat and oxypurinol are discussed as well as potential reasons why some of the current newer agents have failed to live up to the promising early-phase data. It is crucial that these remaining questions surrounding urate, xanthine oxidase and the role of various agents that affect this important oxidative stress-generating system are answered, and therefore these promising agents should not be discarded prematurely.

Albuminuria in heart failure: what do we really know?

PURPOSE OF THE REVIEW

To describe the role of albuminuria as a risk marker for heart failure and a predictor for treatment effect on heart failure prognosis.

RECENT FINDINGS

The level of albumin in the urine is a predictor of heart failure in the general population and in patients with cardiovascular risk, such as those with diabetes. Mild elevations of albuminuria, in the microalbuminuria range, appear to be associated with impaired systemic endothelial function. This increases the chance of developing hypertension, diabetes and cardiovascular disease, ultimately leading to heart failure. Higher levels of albuminuria, in the proteinuric range, reflect marked renal pathology, which increases cardiovascular risk due to renal function decline. In patients with established heart failure, microalbuminuria is highly prevalent (30%). Although more frequent in diastolic than systolic dysfunction, it appears to indicate a worse prognosis in the latter class. Diabetes is a multiplier of risk, probably due to bidirectional relationship between diabetes and heart failure. Treatment with drugs that intervene in the renin-angiotensin-aldosterone system (RAAS) lowers albuminuria and is associated with prevention of the onset and worsening of heart failure and other cardiovascular disorders.

SUMMARY

Albuminuria is associated with increased heart failure risk. Lowering of albuminuria using RAAS inhibitors appears to lower the risk for heart failure.