Dilated cardiomyopathy in dialysis patients--beneficial effects of carvedilol: a double-blind, placebo-controlled trial

β-Blockers for prevention of sudden cardiac death in patients on hemodialysis: a propensity score analysis of the HEMO Study

BACKGROUND

Hemodialysis patients have an elevated risk of sudden cardiac death. Although the efficacy of β-blockers for the prevention of sudden cardiac death has been proven in the general population, little evidence exists in patients with kidney failure.

STUDY DESIGN

Post hoc analysis of the Hemodialysis (HEMO) Study.

SETTING & PARTICIPANTS

Participants enrolled in the HEMO Study from May 1995 to February 2001.

INTERVENTION

β-Blocker use ascertained through self-reported questionnaires and dialysis clinic charts.

OUTCOMES

Sudden cardiac death adjudicated by a committee as a secondary outcome of interest.

MEASUREMENTS

We used Cox proportional hazards regression models, competing risk survival analysis, propensity score matching, and covariate adjustment to study the association of β-blockers with sudden cardiac death.

RESULTS

1,747 patients were included in this study, and 521 were on β-blocker therapy at baseline. Mean age was 58 years, 57% were women, and 39% had ischemic heart disease (IHD) at baseline. Baseline β-blocker use was not associated with lower risk of sudden cardiac death in univariate (cause-specific HR, 0.89; 95% CI, 0.64-1.24), multivariable (cause-specific HR, 0.87; 95% CI, 0.62-1.22), or propensity-matched (cause-specific HR, 0.91; 95% CI, 0.55-1.50) analyses. There was a significant interaction between β-blocker use and sudden cardiac death (interaction P = 0.03) in patients with (cause-specific HR, 0.65; 95% CI, 0.42-1.01) and without IHD (cause-specific HR, 1.61; 95% CI, 0.92-2.80).

LIMITATIONS

Observational nature of the study.

CONCLUSIONS

In hemodialysis patients without preexisting IHD, β-blocker use was not associated with lower risk of sudden cardiac death. However, there was a trend toward benefit in those with IHD.

Beta-blockers and cardiovascular outcomes in dialysis patients: a cohort study in Ontario, Canada

BACKGROUND

Beta-blockers may be cardioprotective in patients receiving chronic dialysis. We examined cardiovascular outcomes among incident dialysis patients receiving beta-blocker therapy.

METHODS

We conducted a retrospective cohort study employing linked healthcare databases in Ontario, Canada. We studied all consecutive chronic dialysis patients aged≥66 years who initiated dialysis between 1 July 1991 and 31 July 2007. Patients were divided into three groups according to new medication use after the initiation of chronic dialysis. The three groups were patients initiated on beta-blockers, calcium channel blockers and statins only. Patients in the beta-blocker and calcium channel blocker groups could also be concurrently receiving a statin. The primary outcome was time to a composite endpoint of death, myocardial infarction, stroke or coronary revascularization.

RESULTS

There were a total of 1836 patients (504 beta-blocker, 570 calcium channel blocker and 762 statin-only users). Compared to statin-only use, beta-blocker use was not associated with improved cardiovascular outcomes [adjusted hazard ratio (aHR) 1.07, 95% confidence interval (CI) 0.92-1.23]. As expected, calcium channel blocker use was also not associated with improved cardiovascular outcomes (aHR 0.91, 95% CI 0.79-1.06). Among all subgroup analyses by beta-blocker attributes, only high-dose beta-blocker therapy was associated with better cardiovascular outcomes as compared to low-dose beta-blockers (aHR 0.50, 95% CI 0.29-0.88).

CONCLUSIONS

We observed no beneficial effect of beta-blocker use among patients receiving chronic dialysis relative to our comparator groups. Given current uncertainty around the cardioprotective benefits of beta-blockers in patients receiving dialysis, a large randomized clinical trial is warranted.

Major pathways of the reno-cardiovascular link: the sympathetic and renin-angiotensin systems

Chronic kidney disease is often characterized by enhanced activity of the renin-angiotensin system (RAS) and the sympathetic nervous system. Independent of their effect on blood pressure, these systems also contribute to the pathogenesis of both structural and functional cardiovascular abnormalities and contribute importantly to clinical outcome. There is much evidence that the diseased kidneys are of central importance in the pathogenesis of both abnormalities. Inhibitors of the RAS also reduce sympathetic overactivity. Future research should be aimed at addressing the pathophysiological mechanisms causing the enhanced activities. Given the fact that even a small kidney lesion can cause enhanced activity of the RAS and the sympathetic nervous system, it is likely that these pathophysiological mechanisms are operational in more disease conditions, including essential hypertension, heart failure, and obesity/metabolic syndrome.

Heart failure in long-term peritoneal dialysis patients: a 4-year prospective analysis

BACKGROUND AND OBJECTIVES

Heart failure occurs frequently in end-stage renal disease patients. However, there are no prospective, longitudinal follow-up data on its prevalence, severity, and risk factors in long-term peritoneal dialysis (PD) patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A prospective observational study was conducted in 220 long-term PD patients followed up for 4 years or until death. Echocardiography was obtained at baseline. Primary study end points were heart failure and mortality.

RESULTS

Eighty-six patients had a previous history of heart failure at study entry. The cumulative 4-year survival probability was 37.4% and 64.7% for patients with and without previous heart failure, respectively (P<0.0001). During follow-up, 87 patients (40.9%) developed heart failure, of which 53 were recurrence and 34 were new-onset heart failure. Diabetes, background atherosclerotic vascular disease, systolic hypertension, left ventricular (LV) mass index, systolic dysfunction, and hypoalbuminemia were significant risk factors predicting heart failure in the entire cohort. Diabetes and LV mass and volume index were significant predictors of new-onset heart failure. Systolic hypertension, LV volume index, and hypoalbuminemia were significant predictors of recurrent heart failure.

CONCLUSIONS

Heart failure is a highly prevalent complication in long-term PD patients and predicts adverse clinical outcomes. More attention should be focused on improving BP and volume control and identifying treatment strategies that effectively lower atherosclerotic burden and reverse LV hypertrophy, remodeling, and systolic dysfunction in PD patients.

Treatment of heart failure in long-term dialysis patients: a reappraisal

Heart failure is one of the most frequent cardiac complications in patients with end-stage renal disease receiving long-term hemodialysis or peritoneal dialysis and is associated strongly with a poor prognosis. Despite the significant morbidity and mortality associated with heart failure, there are very limited therapeutic options proved to prevent and treat heart failure in dialysis patients. This limitation largely reflects the paucity of adequately powered prospective randomized clinical trials that have examined the efficacy of different therapeutic options in long-term dialysis patients with heart failure. In this article, the second in a series discussing the management of heart failure in dialysis patients, current therapeutic options for heart failure in the maintenance dialysis population are reviewed and potential novel therapeutic options are discussed.

Effects of telmisartan added to Angiotensin-converting enzyme inhibitors on mortality and morbidity in hemodialysis patients with chronic heart failure a double-blind, placebo-controlled trial

OBJECTIVES

the aim of this study was to determine whether telmisartan decreases all-cause and cardiovascular mortality and morbidity in hemodialysis patients with chronic heart failure (CHF) and impaired left ventricular ejection fraction (LVEF) when added to standard therapies with angiotensin-converting enzyme inhibitors.

BACKGROUND

in hemodialysis patients, CHF is responsible for a high mortality rate, but presently very few data are available with regard to this population.

METHODS

A 3-year randomized, double-blind, placebo-controlled, multicenter trial was performed involving 30 Italian clinics. Hemodialysis patients with CHF (New York Heart Association functional class II to III; LVEF ≤ 40%) were randomized to telmisartan or placebo in addition to angiotensin-converting enzyme inhibitor therapy. A total of 332 patients were enrolled (165 telmisartan, 167 placebo). Drug dosage was titrated to a target dose of telmisartan of 80 mg or placebo. Mean follow-up period was 35.5 ± 8.5 months (median: 36 months; range: 2 to 40 months). Primary outcomes were: 1) all-cause mortality; 2) cardiovascular mortality; and 3) CHF hospital stay.

RESULTS

at 3 years, telmisartan significantly reduced all-cause mortality (35.1% vs. 54.4%; p < 0.001), cardiovascular death (30.3% vs. 43.7%; p < 0.001), and hospital admission for CHF (33.9% vs. 55.1%; p < 0.0001). With Cox proportional hazards analysis, telmisartan was an independent determinant of all-cause mortality (hazard ratio [HR]: 0.51; 95% confidence interval [CI]: 0.32 to 0.82; p < 0.01), cardiovascular mortality (HR: 0.42; 95% CI: 0.38 to 0.61; p < 0.0001), and hospital stay for deterioration of heart failure (HR: 0.38; 95% CI: 0.19 to 0.51; p < 0.0001). Adverse effects, mainly hypotension, occurred in 16.3% of the telmisartan group versus 10.7% in the placebo group.

CONCLUSIONS

addition of telmisartan to standard therapies significantly reduces all-cause mortality, cardiovascular death, and heart failure hospital stays in hemodialysis patients with CHF and LVEF ≤ 40%. (Effects Of Telmisartan Added To Angiotensin Converting Enzyme Inhibitors On Mortality And Morbidity In Haemodialysed Patients With Chronic Heart Failure: A Double-Blind Placebo-Controlled Trial; NCT00490958).

Antihypertensive agents in hemodialysis patients: a current perspective

Hypertension affects most hemodialysis patients and is often poorly controlled. Adequate control of blood pressure is difficult with conventional hemodialysis alone but is important to improve cardiovascular outcomes. Nonpharmacologic interventions to improve blood pressure include educating patients about limiting sodium intake, ensuring adequate sodium solute removal during hemodialysis, and achieving target "dry weight." However, most patients require a number of antihypertensive medications to achieve an appropriate blood pressure. First-line antihypertensive agents include angiotensin converting enzyme inhibitors and angiotensin receptor blockers given their safety profile and demonstrated benefit on cardiovascular outcomes in clinical trials. beta-blockers and combined alpha- and beta-blockers should also be used in patients with cardiovascular disease or congestive heart failure and may improve outcomes in these populations. Calcium channel blockers and direct vasodilators are also effective for controlling blood pressure. Many blood pressure agents can be dosed once daily and should preferentially be administered at night to control nocturnal blood pressure and minimize intradialytic hypotension. In patients who are noncompliant with therapy, renally eliminated agents (such as lisinopril and atenolol) can be given thrice weekly following hemodialysis. Older antihypertensive agents which require thrice daily dosing ought to be avoided given the high pill burden with these regimens and the concern for noncompliance resulting in rebound hypertension. Newer antihypertensive agents, such as direct renin inhibitors, may provide alternative options to improve blood pressure but require testing for efficacy and safety in hemodialysis patients.

Decreased pulse pressure during hemodialysis is associated with improved 6-month outcomes

Pulse pressure is a well established marker of vascular stiffness and is associated with increased mortality in hemodialysis patients. Here we sought to determine if a decrease in pulse pressure during hemodialysis was associated with improved outcomes using data from 438 hemodialysis patients enrolled in the 6-month Crit-Line Intradialytic Monitoring Benefit Study. The relationship between changes in pulse pressure during dialysis (2-week average) and the primary end point of non-access-related hospitalization and death were adjusted for demographics, comorbidities, medications, and laboratory variables. In the analyses that included both pre- and post-dialysis pulse pressure, higher pre-dialysis and lower post-dialysis pulse pressure were associated with a decreased hazard of the primary end point. Further, every 10 mm Hg decrease in pulse pressure during dialysis was associated with a 20% lower hazard of the primary end point. In separate models that included pulse pressure and the change in pulse pressure during dialysis, neither pre- nor post-dialysis pulse pressure were associated with the primary end point, but each 10 mm Hg decrease in pulse pressure during dialysis was associated with about a 20% lower hazard of the primary end point. Our study found that in prevalent dialysis subjects, a decrease in pulse pressure during dialysis was associated with improved outcomes. Further study is needed to identify how to control pulse pressure to improve outcomes.

Efficacy and safety of nebivolol in elderly heart failure patients with impaired renal function: insights from the SENIORS trial

AIM

To determine the safety and efficacy of nebivolol in elderly heart failure (HF) patients with renal dysfunction.

METHODS AND RESULTS

SENIORS recruited patients aged 70 years or older with symptomatic HF, irrespective of ejection fraction, and randomized them to nebivolol or placebo. Patients (n = 2112) were divided by tertile of estimated glomerular filtration rate (eGFR). Mean age of patients was 76.1 years, 35% of patients had an ejection fraction of >35%, and 37% were women resulting in a unique cohort, far more representative of clinical practice than previous trials. eGFR was strongly associated with outcomes and nebivolol was similarly efficacious across eGFR tertiles. The primary outcome rate (all-cause mortality or cardiovascular hospital admission) and adjusted hazard ratio for nebivolol use in those with low eGFR was 40% and 0.84 (95% CI 0.67-1.07), 31% and 0.79 (0.60-1.04) in the middle tertile, and 29% and 0.86 (0.65-1.14) in the highest eGFR tertile. There was no interaction noted between renal function and the treatment effect (P = 0.442). Nebivolol use in patients with moderate renal impairment (eGFR <60) was not associated with major safety concerns, apart from higher rates of drug-discontinuation due to bradycardia.

CONCLUSION

Nebivolol is safe and has a similar effect in elderly HF patients with mild or moderate renal impairment.

Vascular endothelial growth factor, left ventricular dysfunction and mortality in hemodialysis patients

OBJECTIVES

Vascular endothelial growth factor induces nitric oxide-dependent angiogenic effects and participates in the inflammatory response. This cytokine is over-expressed in the myocardium in experimental models of pressure overload and renal mass ablation, and vascular endothelial growth factor is increased in end-stage renal disease. We investigated the relationship between vascular endothelial growth factor, left ventricular function (by midwall fractional shortening) and mortality in a prospective cohort study in 228 hemodialysis patients.

RESULTS

Serum vascular endothelial growth factor concentration was associated directly with interleukin-6 and tumor necrosis factor-alpha (P < 0.01) and inversely with albumin (P = 0.007) but was independent of the endogenous inhibitor of nitric oxide synthesis, asymmetric dimethylarginine. Vascular endothelial growth factor was inversely related with midwall fractional shortening (P = 0.002) and predicted mortality (P = 0.02). In multivariate analyses testing the involvement of this angiogenic cytokine in left ventricular dysfunction and death, these links remained substantially unmodified after adjustment for Framingham risk factors, risk factors peculiar to end-stage renal disease (Hb, Ca, P) and previous cardiovascular complications. However, these links became weaker and not significant when biomarkers of inflammation and asymmetric dimethylarginine were sequentially introduced into the multivariate models. In crude and adjusted analyses, left ventricular function was lowest in patients who displayed both high vascular endothelial growth factor and high asymmetric dimethylarginine, intermediate in patients with either high vascular endothelial growth factor or high asymmetric dimethylarginine and highest in those with low asymmetric dimethylarginine and low vascular endothelial growth factor (P = 0.001).

CONCLUSION

Vascular endothelial growth factor is associated with left ventricular systolic dysfunction and mortality in hemodialysis patients. Vascular endothelial growth factor appears to be in the pathway whereby inflammation and nitric oxide inhibition lead to cardiomyopathy and death in hemodialysis patients.

Effects of carvedilol on left ventricular function and oxidative stress in infants and children with idiopathic dilated cardiomyopathy: a 12-month, two-center, open-label study

OBJECTIVES

This study was conducted to determine the effects of carvedilol adjunct to standard treatment on left ventricular function (LVF), estimated as ejection fraction (EF) and fractional shortening (FS) on echocardiography, in children with idiopathic dilated cardiomyopathy (DCM). A secondary end point was to characterize the antioxidant potential of carvedilol.

METHODS

Hospitalized children aged <or=16 years with clinically stable DCM and advanced congestive heart failure (HF) with modified New York Heart Association Classification for Children (NYHAC) functional classes II to IV and EF <40% were enrolled in this prospective, 12-month, 2-center, open-label study. Oral carvedilol was added to a standard regimen of an angiotensin-converting enzyme inhibitor, a diuretic, and digoxin in a dose-escalation design. Systolic and diastolic blood pressure (BP), heart rate (HR), and modified NYHAC were assessed before (baseline) and at 1, 3, 6, and 12 months of adjunct carvedilol treatment. EF and FS were analyzed before and at 6 and 12 months of carvedilol treatment. At each study visit, tolerability was assessed in terms of adverse events (AEs), treatment emergent signs and symptoms, physical examination including vital sign measurement (BP, HR, and body temperature), and laboratory analysis. Antioxidative enzyme activity was evaluated by measuring erythrocyte copper/zinc superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and glutathione reductase (GR) activity at baseline and 1, 3, 6, and 12 months of adjunct carvedilol treatment. For assessment of antioxidative enzyme activity, a control group comprised 29 age-matched healthy children.

RESULTS

Twenty-one children (12 boys, 9 girls; age range, 7 months to 16 years; 100% white) completed the study. Four patients discontinued carvedilol at the beginning of the study due to severe arrhythmia which required amiodarone therapy (2 patients), bradycardia and hypotension (1), and bronchospasm (1). Carvedilol (0.4 mg/kg/d in children <or=62.5 kg or 25 mg/d in children >62.5 kg) was associated with significant decreases from baseline in systolic BP (130 [4] vs 123 [3] mm Hg; P<0.05), diastolic BP (85 [4] vs 77 [4] mm Hg; P<0.05), and HR (81 [4] vs 65 [4] bpm; P<0.001) after the first month of addition to standard therapy. At 6 months, there were significant improvements from baseline in EF (37.2% [2.4%] vs 50.2% [2.3%]; P<0.001) and FS (18.37% [2.00%] vs 23.58% [0.90%]; P<0.001). Modified NYHAC class was significantly improved in 80% of children (2.9 vs 2.3; P<0.001) at 12 months. The highest dose of carvedilol (0.8 mg/kg/d in children <or=62.5 kg or 50 mg/d in children >62.5 kg) was well tolerated in all 21 children. No serious AEs that necessitated study drug discontinuation (tiredness, headache, vomiting) were observed. At baseline, mean (SE) erythrocyte SOD activity (2781 [116] vs 2406 [102] U/g Hb; P<0.05) and GR activity (5.3 [0.3] vs 3.0 [0.2] micromol nicotinamide adenine dinucleotide phosphate [NADPH]/min/g Hb; P<0.001) were significantly higher in children with DCM who received standard therapy compared with healthy controls.CAT activity (12.7[0.9] vs 18.5 [1.0]U/g Hb; P<0.001) was significantly lower, while GSH-Px was unchanged. At 6 and 12 months of therapy, carvedilol plus standard treatment was associated with significant decreases from baseline in SOD (2516 [126] and 2550 [118], respectively, vs 2781 [116] U/g Hb; both, P<0.001) and GR (4.7 [0.3] and 4.1 [0.2], respectively, vs 5.3 [0.2] micromol NADPH/min/g Hb; P<0.05 and P<0.001) and increased CAT (16.9 [1.0] and 16.4 [0.7], respectively, vs 12.7 [0.9] U/g Hb; both, P<0.001).

CONCLUSIONS

These pediatric patients with DCM treated for 12 months with carvedilol (up to 0.8 mg/kg/d in children <or=62.5 kg or 50 mg/d in children >62.5 kg) were found to have significant improvements in LVF and symptoms of HF. Twelve months of carvedilol therapy was associated with antioxidant enzyme activities near those observed in healthy children.

Left Atrial Volume Monitoring and Cardiovascular Risk in Patients with End-Stage Renal Disease: A Prospective Cohort Study

Left atrial volume (LAV), as indexed by height(2.7), has recently emerged as an useful echocardiographic measurement to refine the estimate of cardiovascular (CV) risk in ESRD. Whether progression or regression in LAV has prognostic value in patients with ESRD is still unknown. The prognostic value for CV events of changes in LAV was tested in a cohort of 191 dialysis patients. Echocardiography was performed twice, 17 +/- 2 mo apart. Changes in LAV that occurred between the second and the first echocardiographic studies were used to predict CV events during the ensuing 27 +/- 13 mo. During the follow-up, there was a significant increase in LAV (from 10.5 +/- 5.0 to 11.6 +/- 5.6 ml/m(2.7); P < 0.001). After the second echocardiographic study, 76 patients died (52 [68%] of CV causes) and 33 had nonfatal CV events. The independent association between changes in LAV and CV events was analyzed in a multiple Cox regression model taking into account a series of potential confounders, including baseline LAV and left ventricular mass and geometry. In these models, a 1-ml/m(2.7) per yr increase in LAV was associated with a 12% increase in the relative risk for fatal and nonfatal CV events (P < 0.001). Changes in LAV predict incident CV events in dialysis patients independent of the corresponding baseline measurement and of left ventricular mass. Monitoring LA size by echocardiography is useful for monitoring CV risk in patients with ESRD.

Effect of beta-blocker therapy on functional status in patients with heart failure - A meta-analysis

BACKGROUND

The results of randomised control trials (RCTs) evaluating the effect of beta-blockers on functional status in patients with chronic heart failure are conflicting.

AIM

To perform a systematic review and meta-analysis of RCTs evaluating the effect of beta-blockers on New York Heart Association (NYHA) classification and exercise tolerance in chronic heart failure.

METHODS AND RESULTS

We selected 28 RCTs evaluating beta-blocker versus placebo in addition to ACE inhibitor therapy. Combined results of 23 RCTs showed that beta-blockers improved NYHA class by at least one class with odds ratio (OR) 1.80 (1.33-2.43) p<0.0001. Meta-analysis of 10 RCTs showed a significant prolongation of exercise time by 44.19 (6.62-81.75) s p=0.021. Combining 8 RCTs evaluating the maximal peak oxygen uptake and 9 RCTs evaluating 6-min walk distance showed that beta-blockers had no significant effect compared with placebo, p=0.484, and p=0.730, respectively. Combined results of the 23 RCTs showed significant reducing effect on all cause mortality with OR=0.69 (0.59-0.82) p<0.0001.

CONCLUSION

Chronic use of a beta-blocker in conjunction with ACE inhibitor therapy improves dyspnoea and prolongs exercise tolerance time, but has no significant effect on 6-min walk test or maximal oxygen uptake in patients with heart failure.

Characteristics of sudden death in hemodialysis patients

Hemodialysis (HD) is an intermittent procedure during which large fluid and electrolyte shifts occur. We hypothesized that sudden death occurrences in HD patients are related to the timing of HD, and that they occur more frequently in the 12 h period starting with dialysis and in the 12 h period at the end of the dialysis-free weekend interval. In a retrospective study, 228 patient deaths were screened to determine if they met the criteria for sudden death. Information was obtained from clinic charts, dialysis center records, and interview of witnesses of the death event. There were 80 HD patients who met the criteria for sudden death. A bimodal distribution of death occurrences was present, with a 1.7-fold increased death risk occurring in the 12 h period starting with the dialysis procedure and a threefold increased risk of death in the 12 h before HD at the end of the weekend interval (P=0.011). Patients with sudden death had a high prevalence of congestive heart failure and coronary artery disease. Only 40% of patients experiencing sudden death were receiving beta-blockers, and the prior monthly serum potassium value was less than 4 mEq/l in 25%. Sudden death is temporally related to the HD procedure. Every other day HD could be beneficial in preventing sudden death. Careful attention to the usage of beta-blockers and to the maintenance of normal serum potassium values is indicated in HD patients at risk for sudden death.

The effect of carvedilol on mortality risk in heart failure patients with diabetes: results of a meta-analysis

BACKGROUND

Although beta-blocker therapy has been shown to improve survival in patients with chronic heart failure, this class of drugs tends to be underutilized in diabetic patients due to concerns about adverse metabolic effects, especially on glycemic control. No randomized clinical trial has specifically evaluated the effect of beta-blocker therapy on mortality in diabetic patients with heart failure. Previous meta-analyses combining results of heart failure trials with pharmacologically diverse beta-blockers suggest that the survival benefit in diabetic patients may be diminished compared to benefits in non-diabetic patients. However, some trial results indicate that carvedilol, which blocks beta1-, beta2-, and alpha1-receptors and is a potent antioxidant, may produce at least comparable effects in both patient groups.

OBJECTIVES

To evaluate the effect of carvedilol in patients with heart failure and diabetes, specifically to determine if the survival benefit of carvedilol demonstrated in heart failure trials was as great in the subgroups of patients with diabetes.

METHODS

A meta-analysis was performed that included 5757 patients with heart failure, 25% of whom had diabetes, from seven large placebo-controlled randomized trials with carvedilol. All large (> 100 patients) placebo-controlled, randomized trials with carvedilol in heart failure were included. The endpoint of all-cause mortality was examined in the overall population, patients without diabetes, and patients with diabetes. The number of patients needed to treat (NNT) for 1 year to prevent one death associated with carvedilol use in diabetic versus non-diabetic patients was also calculated. The log-rank test and the Cox proportional hazards regression were used to compare the event time distributions of carvedilol versus placebo with respect to the outcome of mortality.

RESULTS

Similar survival benefits were seen with carvedilol use in diabetic and non-diabetic patients (relative risk reductions of 28% [95% confidence interval (CI) 3-46%; p = 0.03] and 37% [95% CI 22-48%; p < 0.001], respectively). There were no significant differences between the relative mortality risk reductions or the NNT with carvedilol use in diabetic versus non-diabetic patients. The NNT for 1 year to prevent one death was 23 for all patients, as well as for non-diabetic patients, and 25 for the diabetic group.

CONCLUSIONS

This meta-analysis provides evidence that the same survival benefit may occur with carvedilol in heart failure patients with and without diabetes. The low NNT in the severe heart failure trial, COPERNICUS, and the diabetic subgroup in this meta-analysis suggests that severe heart failure patients and heart failure patients with diabetes may particularly derive benefit from therapy with carvedilol.

Clinical and pathologic characteristics of dilated cardiomyopathy in hemodialysis patients

BACKGROUND

Some dialysis patients have impaired left ventricular (LV) function without coronary artery disease. The pathologic changes and prognoses of these patients have not been well described.

METHODS

We performed LV endomyocardial biopsies on 40 hemodialysis patients with dilated cardiomyopathy (DCM; an ejection fraction <50% and a left ventricular end-diastolic volume index >90 mL/m(2) without coronary artery disease), and on 50 nondialysis patients with idiopathic DCM as the control group. Following LV biopsies, the patients were followed-up for a mean of 3.1 +/- 2.3 years.

RESULTS

The pathologic characteristics of the dialysis group were severe myocyte hypertrophy (the mean myocyte diameter across the nucleus: 37.6 +/- 10.5 mum vs. 25.6 +/- 7.7 mum, P= 0.001), myocyte disarray (30%), and extensive fibrosis (the mean percent area of left ventricular fibrosis: 22.3 +/- 18.4% vs. 21.3 +/- 14.6%, P= NS). These pathologic characteristics resembled the dilated phase of hypertrophic cardiomyopathy. In the dialysis group, a high percent area of LV fibrosis was the only significant predictor of cardiac death by multivariate analysis (P= 0.02). The 3-year cumulative event-free survival rate for cardiac death in dialysis patients with severe fibrosis (more than 30%) was 42%, while that for patients without severe fibrosis was 82% (P= 0.03).

CONCLUSION

The pathologic characteristics of the heart in dialysis patients with DCM are interstitial fibrosis and severe myocyte hypertrophy with occasional disarray. The extent of LV fibrosis is a strong predictor of cardiac death. Careful follow-up and treatment are necessary for dialysis patients with a high percent area of LV fibrosis.

Cardiovascular risk in chronic renal disease and transplantation prevention and management

Cardiovascular disease (CVD) is the single best predictor of mortality in patients with chronic kidney disease and in kidney transplant recipients. These populations are considered to be at extraordinarily high risk for CVD and its complications. On the other hand, renal dysfunction should be considered as a CVD risk factor. The management of CVD in patients with chronic kidney disease is a special challenge for clinicians. In this article, major risk factors for CVD are presented, as well as diagnosis of coronary artery disease, acute coronary syndromes, its treatment modalities (pharmacological therapy and coronary revascularisation procedures), and outcomes in patients with chronic renal failure and kidney allograft recipients.

Critical differences among beta-adrenoreceptor antagonists in myocardial failure: debating the MERIT of COMET

In the United States, carvedilol and metoprolol (tartrate or succinate) are the most commonly employed beta-adrenoreceptor antagonists for the treatment of heart failure. However, use of these agents in patients with heart failure remains extremely low despite overwhelming evidence of their beneficial short- and long-term effects. Because the myocardial pathophysiology associated with heart failure involves not only beta-1 adrenoreceptors but also beta-2 and alpha-1 adrenoreceptors, this indicates a more complex disease process that may require pan-receptor antagonism to provide optimal clinical benefit. Relative to metoprolol (tartrate or succinate), carvedilol represents an extremely complex molecular entity that not only possesses the ability to antagonize all of the principle adrenoreceptors involved in heart failure but also reduces oxidative stress and provides an antiarrhythmic benefit independent of beta-adrenoreceptor antagonism. Taken together, an interesting pharmacologic premise for the superiority of carvedilol relative to metoprolol (tartrate) may exist, but the lack of clinical trials comparing an optimal dose of either extended-release metoprolol (ie, succinate) or immediate-release metoprolol (ie, tartrate) to carvedilol limits the clinical application of the pharmacologic differences between the agents.

Drug therapy for hypertension in hemodialysis patients

The majority of end-stage renal disease (ESRD) patients are hypertensive. Drug therapy for hypertension in hemodialysis (HD) patients includes all classes of antihypertensive drugs, with the sole exception of diuretics. Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers may decrease morbidity and mortality by reducing the mean arterial pressure (MAP), aortic pulse wave velocity, and aortic systolic pressure augmentation, as well as left ventricular hypertrophy (LVH) and probably reduction of C-reactive protein (CRP) and oxidant stress. Potential risk factors include hyperkalemia, anaphylactoid reaction with AN69 membranes (particularly ACE inhibitors), and aggravation of renal anemia. beta-blockers decrease not only mortality, blood pressure (BP), and ventricular arrhythmias, but also improve left ventricular function in ESRD patients. Nonselective beta-blockers can cause an increase in serum potassium (particularly during fasting or exercise). Lisinopril and atenolol have a predominant renal excretion and therefore a prolonged half life in ESRD patients. Thus thrice-weekly supervised administration of these drugs after HD can enhance BP control. The use of calcium channel blockers is also associated with lower total and cardiovascular-specific mortality in HD patients. Minoxidil is a very potent vasodilator that is generally reserved for dialysis patients with severe hypertension. Hypertensive dialysis patients who are noncompliant with their medications may benefit from transdermal clonidine therapy once a week. The majority of dialysis patients need a combination of several antihypertensive drugs for adequate BP control.

HYPERTENSION IN HEMODIALYSIS PATIENTS: Cardiac Disease in Chronic Uremia: Can it Explain the Reverse Epidemiology of Hypertension and Survival in Dialysis Patients?

Definitive randomized trials are rare in the dialysis literature. Treatment decisions are often based on extrapolation from trials in other populations and observational studies in dialysis patients. "Reverse epidemiology" is a term increasingly applied to classic cardiovascular risk factors in studies of dialysis patients. The term is used when outcome associations are the opposite of those seen in general population studies. Hypertension is an archetypal example, with several studies showing inverse associations with mortality. As a term, "reverse epidemiology" is intellectually unsatisfactory because validation of the real direction of an association is only possible with experimental designs. In contrast, blood pressure (BP) is associated with typical association patterns for outcomes other than death, including left ventricular hypertrophy and cardiac failure, which are dominant entities in dialysis populations. There is a strong suspicion that current analytical approaches may partly explain the paradox. For example, it is possible that unmeasured comorbidities are associated with lower BP levels. In addition, few studies use BP as a time-integrated parameter, which is problematic given the variability of this parameter. Several recent studies suggest that using pulse pressure as a BP parameter may normalize associations with mortality. BP, extracellular blood volume, residual renal function, and vasoactive medications are interlinked. Time-integrated analysis that examines all these parameters concurrently makes sense, but has rarely been attempted. A large burden of cardiac disease and insensitive analytical approaches may go a long way toward explaining the reverse epidemiology of hypertension and survival in dialysis patients.

The role of ultrasound in molecular imaging

Ultrasound has received less attention than other imaging modalities for molecular imaging, but has a number of potential advantages. It is cheap, widely available and portable. Using Doppler methods, flow information can be obtained easily and non-invasively. It is arguably the most physiological modality, able to image structure and function with less sedation than other modalities. This means that function is minimally disturbed, and multiple repeat studies or the effect of interventions can easily be assessed. High frame rates of over 200 frames a second are achievable on current commercial systems, allowing for convenient cardiac studies in small animals. It can be used to guide interventional or invasive studies, such as needle placement. Ultrasound is also unique in being both an imaging and therapeutic tool and its value in gene therapy has received much recent interest. Ultrasound biomicroscopy has been used for in utero imaging and can guide injection of virus and cells. Ultrahigh frequency ultrasound can be used to determine cell mechanical properties. The development of microbubble contrast agents has opened many new opportunities, including new functional imaging methods, the ability to image capillary flow and the possibility of molecular targeting using labelled microbubbles.

Traditional and emerging cardiovascular risk factors in end-stage renal disease

Patients with end-stage renal disease face a particularly high risk of cardiovascular disease and total mortality. Part of their increased risk is due to a higher prevalence of established risk factors, such as arterial hypertension, diabetes, smoking, and anemia. Hypertension and diabetes have a very high prevalence in dialysis patients and play a major role in their high mortality and morbidity. Hyperparathyroidism, hyperhomocysteinemia and disordered lipid metabolism represent factors that are peculiarly altered by the uremic state. Inflammatory processes, high sympathetic activity, and the accumulation of an endogenous inhibitor of NO synthase (ADMA), have recently emerged as cardiovascular risk factors of paramount importance. Sleep apnea has been linked with nocturnal hypertension and could be implicated in the high prevalence of concentric hypertrophy of the left ventricle in these patients. Hypertension control, as well as appropriate treatment of anemia and cessation of smoking, constitutes a fundamental area of intervention in dialysis patients. It appears possible that, in the near future, control of chronic inflammatory processes of high sympathetic activity and endothelial dysfunction will further help to curb the exceedingly high cardiovascular mortality of patients on chronic dialysis treatment.

Carvedilol increases two-year survivalin dialysis patients with dilated cardiomyopathy: a prospective, placebo-controlled trial

OBJECTIVES

We sought to evaluate the effects of carvedilol on mortality and morbidity in dialysis patients with dilated cardiomyopathy.

BACKGROUND

Several lines of evidence support the concept that therapy with beta-blocking agents reduces morbidity and mortality in patients with congestive heart failure (HF), but the demonstration of such a survival benefit in dialysis patients with dilated cardiomyopathy is still lacking.

METHODS

A total of 114 dialysis patients with dilated cardiomyopathy were randomized to receive either carvedilol or placebo in addition to standard therapy. A first analysis was performed at one year and was followed by an additional follow-up period of 12 months.

RESULTS

Two-year echocardiographic data revealed a significant attenuation of pathologic remodeling, with smaller cavity diameters and higher ejection fractions in the active treatment group than in the placebo group. At two years, 51.7% of the patients died in the carvedilol group, compared with 73.2% in the placebo group (p < 0.01). Furthermore, there were significantly fewer cardiovascular deaths (29.3%) and hospital admissions (34.5%) among patients receiving carvedilol than among those receiving a placebo (67.9% and 58.9%, respectively; p < 0.00001). The exploratory analyses revealed that fatal myocardial infarctions, fatal strokes, and hospital admissions for worsening HF were lower in the carvedilol group than in the placebo group. A reduction in sudden deaths and pump-failure deaths was also observed, though it did not reach statistical significance.

CONCLUSIONS

Carvedilol reduced morbidity and mortality in dialysis patients with dilated cardiomyopathy. These data suggest the use of carvedilol in all dialysis patients with chronic HF.

Diagnosis and therapy of coronary artery disease in renal failure, end-stage renal disease, and renal transplant populations

Even though cardiovascular disease is the leading cause of death in patients with CRF and end-stage renal disease (ESRD), ill-conceived notions have led to therapeutic nihilism as the predominant strategy in the management of cardiovascular disease in these populations. The recent data clearly support the application of proven interventions in the general population, such as angiotensin-converting enzyme inhibitors and statins to patients with CRF and ESRD. The advances in coronary stents and intracoronary irradiation have decreased the restenosis rates in renal failure patients. Coronary artery bypass with internal mammary graft might be the procedure of choice for coronary revascularization in these patients. The role of screening for asymptomatic coronary disease is established as a pretransplant procedure, but it is unclear whether this will be applicable to all patients with ESRD. Future studies need to focus on unraveling the mechanisms by which uremia leads to increased cardiovascular events to design optimal therapies targeted toward these mechanisms and improve cardiovascular outcomes.

Congestive heart failure in patients with chronic kidney disease and on dialysis

CHF is highly prevalent in ESRD and is a leading cause of death in such patients. Hypertension, renal anemia, and comorbid conditions such as coronary artery disease are particularly important risk factors for CHF in ESRD. Dialysis hypotension may be a marker of poor prognosis in such persons. Recent studies suggest that lipid peroxidation and L-carnitine deficiency may contribute to CHF in some patients with ESRD. All forms of renal replacement therapy are capable of ameliorating symptoms of CHF, but their effect on cardiovascular mortality has not been firmly established. Drug therapy, particularly angiotensin-converting enzyme inhibitors and beta-adrenergic receptor blockers, is under-used in patients with ESRD and CHF. Heart/kidney transplantation may be a viable option for some patients with advanced CHF and ESRD.

Why is coronary heart disease of uraemic patients so frequent and so devastating?

On September 6, 2001, Professor Fernando Valderrabano (Hospital Gregorio Marañon, Madrid) died at the age of 59 years. He was a leading figure in Spanish nephrology, a full professor of Medicine/Nephrology at the University Complutense of Madrid, and an outstanding scientist who published more than 300 articles in medical journals. He was a very intelligent and cultured person, and a man of great style who enjoyed a wide range of hobbies and interests in addition to his medical work. All his colleagues and friends mourn his passing.

The pharmacokinetics and pharmacodynamics of angiotensin-receptor blockers in end-stage renal disease

Angiotensin-converting enzyme (ACE) inhibitors and more recently angiotensin-receptor blockers (ARBs) have become popular therapies in the end-stage renal disease (ESRD) patient. The ability of either of these drug classes to reduce blood pressure in the ESRD patient is well accepted; however, there is considerably less information available to guide the clinician in the safe and effective use of these drugs in the ESRD patient with congestive heart failure and/or coronary artery disease. Head-to-head studies in the ESRD patient are lacking for both drug classes. Several pharmacokinetic factors can influence the selection of these drugs, including dialysability and the propensity for systemic accumulation. ACE inhibitors (ACE-Is) and ARBs are recognised as having a range of nonpressor effects that are pertinent to patients with ESRD. Such effects include their ability to decrease both thirst drive and erythropoiesis. These drug classes, though, are distinguishable by the unique adverse effect profile for ACE-Is. As is the case in patients without renal failure, ESRD patients can experience cough and, less frequently, angioneurotic oedema with ACE-Is. In the ESRD population, so-called anaphylactoid dialyser reactions can occur in conjunction with ACE-I use. The use of a drug from within the ARB class carries both less risk and permits a compound with a preferred pharmacokinetic profile limited dialysability and minimal systemic accumulation to be administered. These attributes would favour the increased use of ARBs in this population.

Blood pressure and long-term mortality in United States hemodialysis patients: USRDS Waves 3 and 4 Study

BACKGROUND

The long-term prognostic associations of pre- and post-dialysis blood pressures, interdialytic weight gain, and antihypertensive use in hemodialysis patients are unclear.

METHODS

The United States Renal Data System (USRDS) Dialysis Morbidity and Mortality Waves 3 and 4 Study, a randomly generated sample of 11,142 subjects receiving hemodialysis on December 31, 1993, was examined, with vital status followed until May 2000.

RESULTS

Pre- and post-dialysis blood pressure values, interdialytic weight gain and number of antihypertensives averaged 151.8/79.7, 137.0/74, 3.6% and 0.76, respectively. Prognostic discrimination was maximized by considering pre- and post-systolic and diastolic blood pressure values simultaneously, in a pattern suggesting that wide pulse pressures were associated with mortality (P < 0.0001). Comorbidity adjustment markedly affected associations, with low pre-dialysis diastolic (P < 0.05), low post-dialysis dialysis diastolic pressure (P < 0.05), high post-dialysis dialysis systolic pressure (P < 0.05), and high interdialytic weight gains (P = 0.005) associated with mortality. Each class of antihypertensive drug, except angiotensin-converting enzyme (ACE)-inhibitors, was associated with lower mortality in unadjusted models, an effect most pronounced for beta-blockers (hazards ratio 0.72, 95% CI 0.66 to 0.79, P < 0.0001). Comorbidity adjustment eliminated survival associations for each antihypertensive class except beta-blockers.

CONCLUSIONS

Pre- and post-dialysis blood pressure values have independent associations with mortality, in a way that implicates wide pulse pressures. Much of the adverse prognosis of wide pulse pressures probably reflects older age and cardiovascular comorbidity. Large interdialytic weight gains are associated with shorter survival when comorbidity is taken into account. Beta-blocker use shows a robust association with survival, and may be protective.