The association between congestive heart failure and chronic renal disease

Carvedilol prevents and reverses hypertrophy-induced cardiac dysfunction

BACKGROUND/AIMS

Histological studies have provided evidence that carvedilol can prevent cardiac hypertrophy in spontaneously hypertensive-stroke prone rats (SP) fed a high-fat and -salt diet. However, the effects of carvedilol on cardiac function have not been studied in these animals. In addition, the ability of carvedilol to reverse established cardiac hypertrophy and dysfunction under these conditions remains to be determined. Here we have evaluated the ability of carvedilol to prevent and reverse cardiac hypertrophy and progressive dysfunction using echocardiography.

METHODS

Two echocardiology studies were conducted to determine the effects of carvedilol treatment on cardiac hypertrophy and dysfunction. In the first prevention study, four groups of rats were evaluated. SP were fed a high-fat (24.5% in food) and high-salt (1% in water) diet (SFD) without (SP-SFD control group) or with carvedilol (SP-SFD carvedilol group; carvedilol concentration 2,400 parts per million) for 18 weeks. Carvedilol was administered in the food at an optimum concentration (i.e. known to provide clinically relevant blood concentrations and reduce cardiac hypertrophy determined from previous studies). In addition, SP and WKY rats were fed a normal diet (SP normal diet group and WKY normal diet group). These groups are known to not develop the same significant cardiac hypertrophy and dysfunction within this limited time of study, and provided two more normal control groups for comparison. In the second reversal study, one group of SP was fed SFD for 12 weeks (SP-SFD pretreatment period) to induce cardiac hypertrophy. Carvedilol (2,400 parts per million) was then added to the diet for an additional 6 weeks (SP-SFD carvedilol treatment period).

RESULTS

In the first prevention study, carvedilol prolonged longevity (p < 0.05) and prevented left-ventricular hypertrophy and dysfunction (p < 0.05; SP-SFD control vs. SP-SFD carvedilol group). M-mode-measured and -calculated parameters demonstrated that carvedilol treatment in the SP-SFD carvedilol group prevented increases in left-ventricular wall thickness (p < 0.05) and decreases in diastolic chamber diameter and volume, stroke volume, ejection fraction and cardiac output (all p < 0.05) that occurred in the SP-SFD control group. Further, cardiac measurements in the SP-SFD carvedilol group were normalized to levels similar to those in the SP and WKY normal diet groups. All SFD-fed groups exhibited similar, significantly elevated blood pressure during the study. In the second reversal study, carvedilol treatment for 6 weeks reversed the cardiac hypertrophy and dysfunction that developed in SP-fed SFD for 12 weeks prior to carvedilol intervention. Under these conditions, carvedilol improved/normalized left-ventricular wall thickness, diastolic ventricular-chamber diameter and volume, stroke volume, ejection fraction and cardiac output (all p < 0.05).

CONCLUSIONS

These data indicate that carvedilol provides protection from and facilitates reversal of progressive cardiac remodeling and dysfunction in this SP-SFD model of cardiac hypertrophy/heart failure. Since these effects occurred in the absence of effects on blood pressure, other known actions of carvedilol, especially its antioxidant activity, for example, may explain this significant cardiac protection. In addition, research using this SP-SFD model of cardiac hypertrophy/end-organ injury appears to translate well to human cardiovascular disease.

Prevalence, predictors and prognostic value of acute impairment in renal function during intensive unloading therapy in a community population hospitalized for decompensated heart failure

BACKGROUND AND METHODS

Chronic heart failure (CHF) is often associated with impaired renal function. Diuretics and vasodilators may lead to aggravated renal dysfunction (ARD), particularly among patients with decompensated CHF. Although the prevalence of ARD has been evaluated in patients awaiting heart transplantation, little is known about ARD in the community sample of CHF patients. Accordingly, we prospectively assessed the prevalence, predictors and prognostic value of ARD in 79 consecutive patients admitted to our general community hospital for decompensated CHF undergoing intensive unloading therapy (intravenous nitroprusside and furosemide). ARD was defined as a >or= 25% increase in serum creatinine between admission and maximal value of >or= 2 mg/dl.

RESULTS

Sixteen patients (20%) developed ARD with a mean increase in serum creatinine of 31% (from 1.74 +/- 0.6 to 2.27 +/- 0.9 mg/dl). ARD persisted at 8-day evaluation in seven of 16 subjects (44%) whereas it was reversible in nine (56%). Lower creatinine clearance at baseline [exp beta = 0.93, 95% confidence interval (CI)=0.87-0.99] and the higher dose of furosemide (exp beta=1.02, 95% CI=1.01-1.03) emerged as independent predictors of ARD. During a follow-up of 11 +/- 8 months, death and hospitalization for worsening CHF occurred more frequently in ARD than non-ARD patients (69% versus 17%, P=0.0001; 69% versus 29%, P=0.003, respectively). Persistent ARD was a powerful independent predictor of long-term adverse outcome (odds ratio=11.1; 95% CI=1.12-36.1; P=0.04).

CONCLUSIONS

Intensive unloading therapy is associated with the development of ARD in one-fifth of the community population hospitalized for decompensated CHF. The magnitude of this phenomenon is not greater than that observed in younger selected populations with advanced CHF, and depends on baseline renal function and increased diuretic dosage. ARD persisting after 8 days from starting intensive unloading is a powerful predictor of subsequent worsened clinical outcome.

Importancia del estudio de la función renal en cardiología

Main cardiopathies, heart failure and ischaemic heart disease, share common risk factors with renal insufficiency and these clinical entities are often present in the same patient. This association has important implications in primary prevention as well as in cardiological patients and this is why the prevention, diagnosis and treatment of renal insufficiency and common risk factors are a relevant strategy in current cardiologic practise.

Relationship between erythropoietin administration and alterations of renin-angiotensin-aldosterone

The effect of erythropoietin (EPO) administration on the responsiveness of the renin-angiotensin-aldosterone system (RAAS) has not been established. Because patients with chronic kidney disease (CKD) require EPO for their management as CKD progresses, it is important to ascertain whether EPO treatment alters the RAAS. If EPO administration stimulates renin-angiotensin or aldosterone (ALDO) this intervention would mediate cardiovascular and renal injury, and consequently promote cardiovascular events and/or exacerbate the progression of renal disease. We reviewed the available publications investigating the effects of EPO on the RAAS. In CKD patients following EPO administration plasma renin activity (PRA) was unchanged in all three and ALDO was not altered in the two studies in which it was determined. In end-stage renal disease (ESRD) patients undergoing dialysis following EPO administration, four studies reported a decrease in PRA levels whereas the remaining nine disclosed no change in PRA levels. The changes in ALDO levels after EPO administration in ESRD patients were discrepant with two studies reporting an increase, two reporting a decrease and the remaining three disclosing no change.

The confounding issue of comorbid renal insufficiency

The United States is currently beleaguered by twin epidemics, heart failure (HF) and renal insufficiency (RI). HF and RI frequently coexist in the same patient, and this conjunction, often called the "cardiorenal syndrome," has important therapeutic and prognostic implications. Approximately 60% to 80% of patients hospitalized for HF have at least stage III renal dysfunction as defined by the National Kidney Foundation (NKF), and this comorbid RI is associated with significantly increased morbidity and mortality risk. Numerous studies have demonstrated that in patients with HF, indices of renal function are the most powerful independent mortality risk predictors. Comorbid RI can result from both intrinsic renal disease and inadequate renal perfusion. Atherosclerosis, renal vascular disease, diabetes mellitus, and hypertension are significant precursors of both HF and RI. Moreover, diminished renal perfusion is frequently a consequence of the hemodynamic changes associated with HF and its treatment. Both HF and RI stimulate neurohormonal activation, increasing both preload and afterload and reducing cardiac output. Inotropic agents augment this neurohormonal activation. In addition, diuretics can produce hypovolemia and intravenous vasodilators can cause hypotension, further diminishing renal perfusion. Management of these patients requires successfully negotiating the delicate balance between adequate volume reduction and worsening renal function. Despite this, few evidence-based data are available to guide management decisions, indicating a compelling need for additional studies in this patient population.

Vitamin D insufficiency in congestive heart failure: why and what to do about it?

This article gives an overview of the current knowledge on vitamin D status in patients with congestive heart failure (CHF). A serum 25-hydroxyvitamin D level below 50 nmol/l (20 ng/ml) is generally regarded as insufficient. Available data indicate that the majority of CHF patients have 25-hydroxyvitamin D levels in the insufficiency range. Skin synthesis of vitamin D after solar ultraviolet B exposure is the most important vitamin D source for humans. However, CHF patients have relatively low outdoor activities. Consequently, a disease-related sedentary lifestyle is an important cause for the insufficient vitamin D status in CHF patients. There is also evidence from a recently performed case-controlled study that indicators of ultraviolet B exposure are already reduced in CHF patients during childhood, adolescence, and early adulthood compared to healthy controls. We present results indicating that an insufficient vitamin D status may contribute to the etiology/pathogenesis of CHF. Data include a vitamin D-mediated reduction of elevated blood pressure as well as a vitamin D-mediated prevention of enhanced parathyroid hormone levels, a pathophysiological state that contributes to cardiovascular disease. Based on population attributable risks, hypertension and cardiovascular disease have a high impact, accounting for the majority of CHF events.Theoretically, vitamin D status can be improved by adequate skin synthesis of vitamin D and/or adequate oral vitamin D intake. At present, daily oral intake of 50-100 microg vitamin D seems to be the most effective way to improve vitamin D status in CHF patients.

Underuse of Standard Care and Outcome of Patients with Acute Myocardial Infarction and Chronic Renal Insufficiency

OBJECTIVES

To investigate characteristics, management and outcome of patients with acute myocardial infarction (AMI) and chronic renal insufficiency (CRI).

BACKGROUND

Patients with AMI and CRI are considered to be at high risk of complications and death. Physicians may be reluctant to prescribe life-saving medications to patients with concomitant CRI.

METHODS

We compared clinical characteristics, management and outcome of 1,683 consecutive AMI patients in three categories of renal function: (1) normal renal function (<1.5 mg/dl) (n = 1,559), (2) mild to moderate CRI (1.5-3.5 mg/dl) (n = 77), and (3) severe CRI (>3.5 mg/dl) (n = 47).

RESULTS

CRI patients were older and were more likely to have other co-morbidities such as hypertension, diabetes mellitus, prior AMI, stroke, angina and heart failure. Compared with patients with normal renal function, standard therapy for AMI including thrombolysis, aspirin, angiotensin-converting-enzyme inhibitors, beta-blockers and lipid lowering agents was underutilized in CRI patients and these patients were more likely to have in-hospital complications such as heart failure, atrial or ventricular fibrillation, cardiogenic shock, sepsis, worsening of renal function and death within 30 days [odds ratio (OR) = 3.3; 95% confidence interval (CI) = 2.0-4.8]. After adjustment for age and co-morbidities, the association between mild to moderate CRI and 30-days mortality declined, whereas severe CRI remained an independent determinant of mortality (OR = 4.8; 95% CI = 2.0-11.4). Adjustment for aspirin, angiotensin-converting-enzyme inhibitors and beta-blocker therapy weakened the association between CRI and death within 30 days after AMI.

CONCLUSIONS

CRI patients are more likely to experience serious complications and death early after AMI. Underutilization of standard care, particularly beta-blocker therapy, contributes to increased mortality risk in these patients.

Renal impairment and outcomes in heart failure: systematic review and meta-analysis

OBJECTIVES

We estimated the prevalence of renal impairment in heart failure (HF) patients and the magnitude of associated mortality risk using a systematic review of published studies.

BACKGROUND

Renal impairment in HF patients is associated with excess mortality, although precise risk estimates are unclear.

METHODS

A systematic search of MEDLINE (through May 2005) identified 16 studies characterizing the association between renal impairment and mortality in 80,098 hospitalized and non-hospitalized HF patients. All-cause mortality risks associated with any renal impairment (creatinine >1.0 mg/dl, creatinine clearance [CrCl] or estimated glomerular filtration rate [eGFR] <90 ml/min, or cystatin-C >1.03 mg/dl) and moderate to severe impairment (creatinine > or =1.5, CrCl or eGFR <53, or cystatin-C > or =1.56) were estimated using fixed-effects meta-analysis.

RESULTS

A total of 63% of patients had any renal impairment, and 29% had moderate to severe impairment. After follow-up > or =1 year, 38% of patients with any renal impairment and 51% with moderate to severe impairment died versus 24% without impairment. Adjusted all-cause mortality was increased for patients with any impairment (hazard ratio [HR] = 1.56; 95% confidence interval [CI] 1.53 to 1.60, p < 0.001) and moderate to severe impairment (HR = 2.31; 95% CI 2.18 to 2.44, p < 0.001). Mortality worsened incrementally across the range of renal function, with 15% (95% CI 14% to 17%) increased risk for every 0.5 mg/dl increase in creatinine and 7% (95% CI 4% to 10%) increased risk for every 10 ml/min decrease in eGFR.

CONCLUSIONS

Renal impairment is common among HF patients and confers excess mortality. Renal function should be considered in risk stratification and evaluation of therapeutic strategies for HF patients.

Skeletal muscle dysfunction in chronic renal failure: effects of exercise

A number of chronic illnesses such as renal failure (CRF), obstructive pulmonary disease, and congestive heart failure result in a significant decrease in exercise tolerance. There is an increasing awareness that prescribed exercise, designed to restore some level of physical performance and quality of life, can be beneficial in these conditions. In CRF patients, muscle function can be affected by a number of direct and indirect mechanisms caused by renal disease as well as various treatment modalities. The aims of this review are twofold: first, to briefly discuss the mechanisms by which CRF negatively impacts skeletal muscle and, therefore, exercise capacity, and, second, to discuss the available data on the effects of programmed exercise on muscle function, exercise capacity, and various other parameters in CRF.

Osmolality not predictive of mannitol-induced acute renal insufficiency

OBJECT

Mannitol is commonly used for acute insults to the central nervous system; acute renal insufficiency is one of its side effects. The cause of mannitol-induced acute renal insufficiency (MI-ARI) is unknown, although elevated osmolality has been implicated as a risk factor. The goal of this study was to determine risk factors and outcomes of MI-ARI and to determine whether osmolality is associated with MI-ARI.

METHODS

The authors retrospectively reviewed the cases of 95 patients treated with mannitol to determine if MI-ARI (an increase in the creatinine level of > 0.5 mg/dl if the baseline value is < 2 mg/dl or an increase > 1 mg/dl if the baseline value is > 2 mg/dl) is linked to elevated osmolality. The 11 patients (11.6%) in whom MI-ARI developed did not exhibit significant differences in patient age, sex, or race; history of cerebrovascular disease or smoking; baseline renal function; or Glasgow Coma Scale score from those in whom MI-ARI did not occur. Cumulative fluid balance, exposure to nephrotoxic drugs, and the peak osmolality and osmotic gap before onset of renal insufficiency were also similar in the two groups. Factors predictive of the onset of MI-ARI included a higher Acute Physiology and Chronic Health Evaluation (APACHE) II score on admission and a history of diabetes, coronary artery disease, congestive heart failure, and hypertension. The presence of congestive heart failure and a high APACHE II score were the only factors independently associated with a higher likelihood of MI-ARI according to a multivariate analysis. Renal function spontaneously returned to baseline in all patients. With maintenance of normovolemia and monitoring of the osmotic gap, MI-ARI appears to be associated with chronic insults to the kidneys such as a history of diabetes or hypertension, not mannitol dose, or osmolality.

CONCLUSIONS

Use of osmolality to limit mannitol use and thus prevent MI-ARI may be unwarranted. Prospective studies are needed.

Preserving cardiac function in the hypertensive patient: why renal parameters hold the key

The relationship between cardiovascular and renal pathologies is well recognized in advanced nephropathy and heart failure, but in early disease it has received less attention. Consequently, microalbuminuria screening and interventions that treat early nephropathy remain under-utilized cardioprotective strategies in the hypertensive patient. Agents that delay the progression of renal disease are likely to be cardioprotective by lessening the systemic consequences of renal dysfunction and may have additional cardioprotective effects by exerting beneficial effects on endothelia elsewhere in the body and within the heart. A critical driving factor within both renal and wider cardiovascular pathologies is overactivation of the renin-angiotensin-aldosterone system (RAAS). Accordingly, RAAS-directed antihypertensive agents including both angiotensin converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) have been demonstrated to have renoprotective effects. In major prospective trials, two ARBs, losartan and irbesartan, have been demonstrated to be renoprotective in patients with frank proteinuria, and one ARB, irbesartan, has been shown to have renoprotective properties in patients with microalbuminuria. For patients with incipient or frank renal dysfunction, an aggressive RAAS-based approach to hypertension management, combining potent blood pressure control with proven renoprotection, may therefore constitute a key component of therapy targeted towards long-term cardioprotection.

Bundle branch block patterns, age, renal dysfunction, and heart failure mortality

BACKGROUND

The determinants of bundle block patterns and their relationship to mortality in heart failure patients is not completely understood.

METHODS

We evaluated 2907 consecutive patients admitted to an intensive care unit with decompensated heart failure over 8 years. Clinical and echocardiographic factors were analyzed using multivariate techniques. All-cause mortality was available on greater than 99.0% of patients at a median of 23 months after discharge.

RESULTS

Right and left bundle branch blocks occurred in 211 (7.3%) and 386 (13.2%), p<0.0001. Older age, decreased left ventricular ejection fraction, and renal dysfunction were all found to be independently associated with bundle branch block patterns. Mortality rates for the subgroups of QRS<120 ms, right bundle branch block and left bundle branch block, over a mean follow-up of 23.4+/-2.6 months were 46.1%, 56.8% and 57.7%, p<0.0001 for comparison of QRS<120 ms versus either bundle pattern. Cox proportional hazards model adjusting for age, sex, ejection fraction, and renal function demonstrated graded decrements in survival in those with QRS<120 ms, right bundle branch block and left bundle branch block, p=0.03.

CONCLUSIONS

In patients hospitalized with severe heart failure, age, left ventricular dysfunction, and renal dysfunction are associated with bundle branch block patterns. When controlling for these factors, bundle branch block patterns are independently associated with slightly higher all cause mortality after discharge.