Aldosterone and cortisol affect the risk of sudden cardiac death in haemodialysis patients

BACKGROUND

Sudden cardiac death is common and accounts largely for the excess mortality of patients on maintenance dialysis. It is unknown whether aldosterone and cortisol increase the incidence of sudden cardiac death in dialysis patients.

METHODS AND RESULTS

We analysed data from 1255 diabetic haemodialysis patients participating in the German Diabetes and Dialysis Study (4D Study). Categories of aldosterone and cortisol were determined at baseline and patients were followed for a median of 4 years. By Cox regression analyses, hazard ratios (HRs) were determined for the effect of aldosterone, cortisol, and their combination on sudden death and other adjudicated cardiovascular outcomes. The mean age of the patients was 66 ± 8 years (54% male). Median aldosterone was <15 pg/mL (detection limit) and cortisol 16.8 µg/dL. Patients with aldosterone levels >200 pg/mL had a significantly higher risk of sudden death (HR: 1.69; 95% CI: 1.06-2.69) compared with those with an aldosterone <15 pg/mL. The combined presence of high aldosterone (>200 pg/mL) and high cortisol (>21.1 µg/dL) levels increased the risk of sudden death in striking contrast to patients with low aldosterone (<15 pg/mL) and low cortisol (<13.2 µg/dL) levels (HR: 2.86, 95% CI: 1.32-6.21). Furthermore, all-cause mortality was significantly increased in the patients with high levels of both hormones (HR: 1.62, 95% CI: 1.01-2.62).

CONCLUSIONS

The joint presence of high aldosterone and high cortisol levels is strongly associated with sudden cardiac death as well as all-cause mortality in haemodialysed type 2 diabetic patients. Whether a blockade of the mineralocorticoid receptor decreases the risk of sudden death in these patients must be examined in future trials.

Prevention of sudden cardiac death in patients with chronic kidney disease

Cardiovascular deaths account for about 40% of all deaths of patients with chronic kidney disease (CKD), particularly those on dialysis, while sudden cardiac death (SCD) might be responsible for as many as 60% of SCD in patients undergoing dialysis. Studies have demonstrated a number of factors occurring in hemodialysis (HD) that could lead to cardiac arrhythmias. Patients with CKD undergoing HD are at high risk of ventricular arrhythmia and SCD since changes associated with renal failure and hemodialysis-related disorders overlap. Antiarrhythmic therapy is much more difficult in patients with CKD, but the general principles are similar to those in patients with normal renal function - at first, the cause of arrhythmias should be found and eliminated. Also the choice of therapy is narrowed due to the altered pharmacokinetics of many drugs resulting from renal failure, neurotoxicity of certain drugs and their complex interactions. Cardiac pacing in elderly patients is a common method of treatment. Assessment of patients’ prognosis is important when deciding whether to implant complex devices. There are reports concerning greater risk of surgical complications, which depends also on the extent of the surgical site. The decision concerning implantation of a pacing system in patients with CKD should be made on the basis of individual assessment of the patient.

Optimal fluid control can normalize cardiovascular risk markers and limit left ventricular hypertrophy in thrice weekly dialysis patients

Increased hemodialysis frequency can make fluid overload easier to treat, although most patients are still treated thrice weekly. Chronic fluid overload is associated with left ventricular hypertrophy and elevated serum cardiac biomarkers, recognized as mortality risk factors. Serum cardiac troponin T (cTnT), N-terminal prohormone brain natriuretic peptide (NT-proBNP), left ventricular mass index by cardiac magnetic imaging, and ambulatory blood pressure was measured in 30 thrice weekly hemodiafiltration patients. Time-averaged fluid overload (TAFO) was quantified by bioimpedance spectroscopy. In the study group, left ventricular hypertrophy was found to be 26% by cardiac magnetic resonance. Ambulatory blood pressure was 130 mmHg (112-151) requiring a low equivalent dose of medication of 0.25 units (0-1). Significantly, lower levels of left ventricular mass index (P < 0.05) were associated in those patients with TAFO <1 L or NT-proBNP <1200 pg/mL or cTnT <0.1 ug/L. In the subgroups, 16 patients had normal cTnT (<0.03 ug/L), 16 patients had NT-proBNP <400 pg/mL, and 20 patients had TAFO <1 L. Nine patients had both cTnT <0.03 ug/L and NT-proBNP <400 pg/mL. Normally hydrated thrice-weekly hemodiafiltration patients can have cardiac biomarker and TAFO levels indistinguishable from the normal healthy population. Obtaining TAFO by bioimpedance monitoring can offer a practical alternative to serum cardiac biomarkers.

Are dialysate sodium levels too high?

Universal lower dialysate [Na+] is often advocated as a means of improving the dire cardiovascular plight of our dialysis patients. However, there is evidence associating lower dialysate [Na+] and increased morbidity and mortality especially in frailer patients, probably as a result of more frequent intra-dialytic hypotension. In this editorial, we summarize arguments for and against lower dialysate [Na+], and provide recommendations around selecting the most appropriate dialysate [Na+] for specific clinical subsets that may benefit from manipulation of salt and water balance. The lack of overall clarity on relative benefits and risks of lower dialysate [Na+] does not support the case for empirical "across the board" change, and experimental testing in clinical trials is required to determine safe and effective use.

Modifiable practices associated with sudden death among hemodialysis patients in the Dialysis Outcomes and Practice Patterns Study

BACKGROUND AND OBJECTIVES

Sudden death is common in hemodialysis patients, but whether modifiable practices affect the risk of sudden death remains unclear.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This study analyzed 37,765 participants in 12 countries in the Dialysis Outcomes and Practice Patterns Study to explore the association of the following practices with sudden death (due to cardiac arrhythmia, cardiac arrest, and/or hyperkalemia): treatment time [TT] <210 minutes, Kt/V <1.2, ultrafiltration volume >5.7% of postdialysis weight, low dialysate potassium [K(D) <3]), and prescription of Q wave/T wave interval-prolonging drugs. Cox regression was used to estimate effects on mortality, adjusting for potential confounders. An instrumental variable approach was used to further control for unmeasured patient-level confounding.

RESULTS

There were 9046 deaths, 26% of which were sudden (crude mortality rate, 15.3/100 patient-years; median follow-up, 1.59 years). Associations with sudden death included hazard ratios of 1.13 for short TT, 1.15 for large ultrafiltration volume, and 1.10 for low Kt/V. Compared with K(D) ≥3 mEq/L, the sudden death rate was higher for K(D) ≤1.5 and K(D)=2-2.5 mEq/L. The instrumental variable approach yielded generally consistent findings. The sudden death rate was elevated for patients taking amiodarone, but not other Q wave/T wave interval-prolonging drugs.

CONCLUSIONS

This study identified modifiable dialysis practices associated with higher risk of sudden death, including short TT, large ultrafiltration volume, and low K(D). Because K(D) <3 mEq/L is common and easy to change, K(D) tailoring may prevent some sudden deaths. This hypothesis merits testing in clinical trials.

Sudden cardiac death in hemodialysis patients: a comprehensive care approach to reduce risk

Sudden cardiac death is a major problem in hemodialysis patients, and our understanding of this disease is underdeveloped. The lack of a precise definition tailored for use in the hemodialysis population limits the reliability of epidemiologic reports. Efforts should be directed toward an accurate classification of all deaths that occur in this vulnerable population. The traditional paradigm of disease pathophysiology based on known cardiac risk factors appears to be inadequate to explain the magnitude of sudden cardiac death risk in chronic kidney disease, and numerous unique cofactors and exposures appear to determine risk in this population. Well-designed cohort studies will be needed for a basic understanding of disease pathophysiology and risk factors, and randomized intervention trials will be needed before best management practices can be implemented. This review examines available data to describe the characteristics of the high-risk patient and suggests a comprehensive common sense approach to prevention using existing cardiovascular medications and reducing and monitoring potential dialysis-related arrhythmic triggers. Other unproven cardiovascular therapies such as implantable cardioverter defibrillators should be used on a case-by-case basis, with recognition of the associated hazards that these devices carry among hemodialysis patients.

Homoarginine, heart failure, and sudden cardiac death in haemodialysis patients

AIMS

Sudden cardiac death (SCD) is a major contributor to the excess mortality of patients on maintenance dialysis. Homoarginine deficiency may lead to decreased nitric oxide availability and endothelial dysfunction. Based on this rationale we assessed whether homoarginine deficiency is a risk factor for SCD in dialysis patients.

METHODS AND RESULTS

This study examined the association of homoarginine with cardiovascular outcomes in 1255 diabetic haemodialysis patients from the German diabetes and dialysis study. During a median of 4 years of follow-up, hazard ratios (HR) (95% CI) for reaching the following pre-specified, adjudicated endpoints were determined: SCD, myocardial infarction, stroke, death due to heart failure, and combined cardiovascular events. There was a strong association of low homoarginine concentrations with the presence of congestive heart failure and left ventricular hypertrophy as well as increased levels of brain natriuretic peptide. Per unit decrease in homoarginine, the risk of SCD increased three-fold (HR 3.1, 95% CI 2.0-4.9), attenuating slightly in multivariate models (HR 2.4; 95% CI 1.5-3.9). Patients in the lowest homoarginine quintile experienced a more than two-fold increased risk of SCD, and more than three-fold increased risk of heart failure death than patients in the highest quintile, which accounted for the high incidence of combined cardiovascular events. Low homoarginine showed a trend towards increased risk of stroke, however, myocardial infarction was not meaningfully affected.

CONCLUSION

Low homoarginine is a strong risk factor for SCD and death due to heart failure in haemodialysis patients. Further studies are needed to elucidate the underlying mechanisms, offering the potential to develop new interventional strategies.

Left ventricular morphology and function in diabetic and nondiabetic hemodialyzed patients

Morbidity in end-stage renal disease (ESRD) diabetic patients is worse than in patients without diabetes mellitus (DM). This study aims to compare clinical, laboratory, and echocardiographic features between the ESRD patients with and without DM. Fifty-eight ESRD patients on dialysis were prospectively divided into two groups according to the presence of DM. Demographic, clinical, laboratory, and echocardiographic features (ejection fraction and wall motion score index) were compared between the two groups. Overall, 20 out of 58 patients (37.8%) with ESRD had DM. There were no significant differences between the patients with DM and those without DM when it comes to age (60.6 ± 10.6 vs. 59.0 ± 10.6 years, P = 0.665), ejection fraction (52.6% ± 12.8% vs. 54.2% ± 12.8%, P = 0.59), and wall motion score index (1.21 ± 0.3 vs.1.15 ± 0.3, P = 0.37). In multivariant analysis of the interventricular septum, posterior wall thickness and left atrium size correlated positively with DM. There was also no statistical difference in myocardial perfusion disturbances on real-time contrast echocardiography between the groups with and without DM (12 (60%) patients vs. 14 patients (36.8%), P = 0.079). Among diabetics 77.8% had significant atherosclerotic changes, while in the group without DM, only 38.1%, P = 0.01. From the laboratory parameters ferritin and high-sensitivity C-reactive protein levels were significantly higher in the group with DM, P = 0.014 and P = 0.026, respectively. Patients with ESRD and DM have significantly bigger left atrial size, thicker left ventricular walls, and higher serum ferritin and high-sensitivity C-reactive protein levels than the patients without DM. The aforementioned features may be possible risk factors for the development of adverse cardiac events in patients on hemodialysis.

Improving ascertainment of sudden cardiac death in patients with end stage renal disease

BACKGROUND AND OBJECTIVES

Data collected by the US Renal Data System (USRDS) identify sudden cardiac death (SCD) as the leading cause of death among hemodialysis patients. However, evidence suggests that clinical events captured on the USRDS death notification form may be inaccurate. A new method for classifying SCD was recently developed to enhance the accuracy of SCD classification. This study examined the performance characteristics of this refined definition using a cohort of hemodialysis patients who experienced a witnessed SCD as the reference standard.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This is a retrospective cohort study of 363 patients who experienced a witnessed SCD in US Gambro (DaVita) outpatient dialysis clinics. Sensitivity of SCD defined by death notification forms and SCD defined using additional administrative sources was compared. Clinical data recorded near time of death were also examined.

RESULTS

Existing USRDS death notification forms reported 70.8% of witnessed SCD as "cardiac arrest/cause unknown" or "arrhythmia." The refined definition significantly improved identification to 83.8% of witnessed SCD events (P<0.001). Verified SCD cases that were not identified by either definition were more likely to be reported on the death notification form as death due to myocardial infarction, hyperkalemia, sepsis, malignancy, or unknown cause.

CONCLUSIONS

Compared with the death notification form alone, the refined SCD definition significantly improves the sensitivity of reporting of witnessed SCD occurring within outpatient hemodialysis clinics. More accurate reporting of cardiac events by clinicians and refinements to existing death notification forms may further improve recognition and understanding of SCD.

Phosphate: the new cholesterol? The role of the phosphate axis in non-uremic vascular disease

Higher serum phosphate levels within the normal range are associated with substantially increased risk of cardiovascular disease events. Whether this reflects a causative relationship is unknown. Phosphate-responsive hormones (fibroblast growth factor-23, parathyroid hormone and calcitriol) are also predictors of cardiovascular mortality in populations without kidney disease or recognised disturbances of bone mineral metabolism. The high bioavailable phosphate content of Western diets may contribute to this apparent discrepancy between 'normal' and optimal phosphate axis parameters. Although uremic hyperphosphatemia is recognised to cause vascular medial calcification, this does not readily explain the association of higher-normal phosphate with common athero-occlusive phenomena. The phosphate axis may in fact play a role in atherogenesis; observational data link higher levels of phosphate and fibroblast growth factor-23 with coronary atheroma burden, whilst dietary phosphate supplementation accelerates atherosclerosis in a mouse model. In vitro studies show adverse effects of phosphate increases on both vascular smooth muscle cells and endothelium, though these observations have not yet been extended to phosphate increments within the normal range. Receptors for phosphate-responsive hormones are present throughout the cardiovascular system and may mediate atherogenic effects. Since interventions are already available to manipulate the phosphate axis, this is an important issue. If an atherogenic role for phosphate exposure is demonstrated then phosphate binders could become the new statins.

Noninvasive imaging for assessment of calcification in chronic kidney disease

Vascular calcification is highly prevalent in patients with chronic kidney disease and has a progressive course. Several cardiovascular and uremia-related risk factors, such as abnormalities in mineral metabolism, contribute to the development of vascular calcification, although the pathophysiological mechanisms are still unclear. The presence and extent of vascular calcification is associated with an increased risk of cardiovascular events and mortality. By contrast, patients who do not have calcification seem to have a good prognosis, with minimal or no calcification progression over an extended period of time. A number of noninvasive imaging methods are available to detect vascular calcification and may help clinicians to make therapeutic decisions. Cardiac CT remains the reference standard to detect and quantify coronary artery, aortic and cardiac valve calcification. However, the high cost of equipment, the inability to perform in-office testing and the expertise required limit its use on a routine basis. Other imaging methods, such as planar X-ray, ultrasound and echocardiography, are appropriate alternatives to evaluate vascular and valvular calcification. In this review, we discuss the noninvasive imaging methods most frequently used to assess vascular and valvular calcification, with their advantages and limitations.

Wasting and sudden cardiac death in hemodialysis patients: a post hoc analysis of 4D (Die Deutsche Diabetes Dialyse Studie)

BACKGROUND

Wasting is common in hemodialysis patients and often is accompanied by cardiovascular disease and inflammation. The cardiovascular risk profile meaningfully changes with the progression of kidney disease, and little is known about the impact of wasting on specific clinical outcomes. This study examined the effects of wasting on the various components of cardiovascular outcome and deaths caused by infection in hemodialysis patients.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

1,255 hemodialysis patients from 178 centers participating in Die Deutsche Diabetes Dialyse Studie (4D) in 1998-2004.

PREDICTOR

Moderate wasting was defined as body mass index, albumin, and creatinine values less than the median (26.7 kg/m(2), 3.8 g/dL, and 6.8 mg/dL, respectively) and C-reactive protein level less than the median (5 mg/L) at baseline. Severe wasting was defined as body mass index, albumin, and creatinine levels less than the median and C-reactive protein level greater than the median at baseline.

OUTCOMES & MEASUREMENTS

Risks of sudden cardiac death (SCD), myocardial infarction (MI), stroke, combined cardiovascular events, deaths due to infection, and all-cause mortality were determined using Cox regression analyses during a median of 4 years of follow-up.

RESULTS

196 patients had wasting (severe, n = 109; and moderate, n = 87). Overall, 617 patients died (160 of SCD and 128 of infectious deaths). Furthermore, 469 patients experienced a cardiovascular event, with MI and stroke occurring in 200 and 103 patients, respectively. Compared with patients without wasting (n = 1,059), patients with severe wasting had significantly increased risks of SCD (adjusted HR, 1.8; 95% CI, 1.1-3.1), all-cause mortality (adjusted HR, 1.8; 95% CI, 1.4-2.4), and deaths due to infection (adjusted HR, 2.3; 95% CI, 1.2-4.3). In contrast, MI was not affected. The increased risk of cardiovascular events (adjusted HR, 1.5; 95% CI, 1.0-2.1) was explained mainly by the effect of wasting on SCD.

LIMITATIONS

Selective patient cohort.

CONCLUSIONS

Wasting was associated strongly with SCD, but not MI, in diabetic hemodialysis patients. Nonatherosclerotic cardiac disease potentially has a major role to account for the increased cardiovascular events in patients with wasting, suggesting the need for novel treatment strategies.

Sudden cardiac death in patients with chronic kidney disease: prevention is the sine qua non

Despite developments in the technology of dialysis procedures and improvements in the understanding of systemic derangements related to chronic kidney disease (CKD), cardiovascular disease is the major cause of death. Unfortunately, the leading subset of cardiovascular disease death is sudden cardiac death (SCD). To date much effort has been exerted to figure out the clues pointing to the risk of future development of SCD in patients with CKD. However, none of these factors satisfactorily detects a truly vulnerable dialysis patient. Thus, recently, it has been advocated that a combination of noninvasive risk assessment methods, carefully chosen to reflect the different aspects of the underlying pathology and changes in the myocardial substrate in CKD, could help to identify patients at high risk of SCD within the CKD. In this review, we aimed to summarize what is known about risk stratification of patients with CKD and appropriate prevention strategies with a special emphasis on recent developments and the use of complimentary tests perhaps as a risk prediction rule.

Prevention of sudden cardiac arrest in dialysis patients: can we do more to improve outcomes?

Sudden cardiac arrest (SCA) is a leading cause of cardiac-associated mortality in dialysis patients. Risk factors unique to hemodialysis patients include abnormal electrolytes, large-volume ultrafiltration, and prior history of cardiac disease. Few randomized controlled trials of standard cardiac interventions have been completed in dialysis patients. Observational studies suggest that modification of the dialysis prescription may be one place to intervene. Prospective research is needed to determine mechanisms of SCA in hemodialysis patients.

The risks of high ultrafiltration rate in chronic hemodialysis: implications for patient care

As dialytic practice has evolved, hemodialysis (HD) adequacy has come to be defined in terms of small molecule clearance. A growing body of evidence suggests that fluid dynamics, specifically ultrafiltration rate (UFR), bear clinical and physiological significance and should perhaps play a more central role in titrating HD therapy. Three recent studies have shown an independent association between higher UFR and mortality. Further work is needed to determine whether this relationship represents a direct toxic effect of rapid fluid perturbations or whether this association is a consequence of confounding on the basis of large interdialytic weight gain, as each would prompt a different therapeutic response. This mounting evidence builds the case that fluid management should play a more central role in the dialytic prescription and that more individualized approaches to fluid management should be encouraged.

Copeptin levels associate with cardiovascular events in patients with ESRD and type 2 diabetes mellitus

In ESRD, the neurohormone arginine vasopressin (AVP) may act primarily through V1a and V1b receptors, which promote vasoconstriction, myocardial hypertrophy, and release of adrenocorticotropic hormone. The preanalytical instability of AVP limits the investigation of whether this hormone associates with cardiovascular events, but the stable glycopeptide copeptin may serve as a surrogate because it is co-secreted with AVP from the posterior pituitary. Here, we studied whether copeptin predicts cardiovascular risk and mortality in ESRD. We measured copeptin at baseline in 1241 hemodialysis patients with type 2 diabetes participating in the German Diabetes and Dialysis Study. The median copeptin level was 81 pmol/L (interquartile range, 81 to 122 pmol/L). In Cox regression analyses, compared with patients with copeptin levels in the lowest quartile (≤51 pmol/L), patients with copeptin levels in the highest quartile (>122 pmol/L) had a 3.5-fold increased risk for stroke (HR, 3.48; 95% CI: 1.71 to 7.09), a 73% higher risk for sudden death (HR, 1.73; 95% CI: 1.01 to 2.95), a 42% higher risk for combined cardiovascular events (HR, 1.42; 95% CI: 1.06 to 1.90), and a 48% higher risk for all-cause mortality (HR, 1.48; 95% CI: 1.15 to 1.90). In contrast, we did not detect significant associations between copeptin levels and risks for myocardial infarction or death caused by congestive heart failure. In conclusion, copeptin levels strongly associate with stroke, sudden death, combined cardiovascular events, and mortality in hemodialysis patients with type 2 diabetes. Whether vasopressin receptor antagonists will improve these outcomes requires further studies.

Abdominal obesity is the most significant metabolic syndrome component predictive of cardiovascular events in chronic hemodialysis patients

BACKGROUND

Five components of metabolic syndrome (MetS) have been identified as predictive of cardiovascular events (CVEs) in the general population: impaired fasting glucose, abdominal obesity, hypertriglyceridemia, hypertension and low high-density lipoprotein cholesterol. Whether MetS and its components are also predictive of CVEs in chronic hemodialysis (HD) patients remains unclear. We therefore investigated the role of MetS and its components in patients on chronic HD.

METHODS

MetS at baseline was diagnosed in 91 HD patients based on the American Heart Association/National Heart, Lung and Blood Institute (AHA/NHLBI) and the International Diabetes Federation (IDF) definitions. During a 3-year period, all hospitalizations, CVEs and deaths were recorded and analyzed using Kaplan-Meier survival analysis and Cox regression.

RESULTS

There were no differences in the number of CVEs, hospitalizations or deaths between patients with and without AHA/NHLBI-defined MetS; however, patients with IDF-defined MetS were found to be at a higher risk for CVEs (P = 0.006). Cox regression analysis showed that, of the MetS components, abdominal obesity was the single most significant predictor of CVEs (hazard ratio 6.25; 95% confidence interval: 1.65-23.6; P = 0.007).

CONCLUSIONS

IDF-defined MetS was more predictive of CVEs than AHA/NHLBI-defined MetS. Of the MetS components, abdominal obesity was the single most significant predictor of CVEs in chronic HD patients.

Sudden cardiac death in chronic kidney disease: epidemiology and prevention

Annual cardiovascular mortality in patients with chronic kidney disease (CKD) is much higher than in the general population. The rate of sudden cardiac death increases as the stage of CKD increases and could be responsible for 60% of cardiac deaths in patients undergoing dialysis. In hemodialysis units treating patients with CKD, cardiac arrest occurs at a rate of seven arrests per 100,000 hemodialysis sessions. Important risk factors for sudden cardiac death in patients with CKD include hospitalization within the past 30 days, a drop of 30 mmHg in systolic blood pressure during hemodialysis, duration of life on hemodialysis, time since the previous dialysis session, and the presence of concomitant diabetes mellitus. As a result of the adverse cardiomyopathic and vasculopathic milieu in CKD, the occurrence of arrhythmias, conduction abnormalities, and sudden cardiac death could be exacerbated by electrolyte shifts, divalent ion abnormalities, diabetes, sympathetic overactivity, in addition to inflammation and perhaps iron deposition. Impaired baroreflex effectiveness and sensitivity, as well as obstructive sleep apnea, might also contribute to the risk of sudden death in CKD. The likelihood of survival following cardiac arrest is very low in dialysis patients. Primary and secondary prevention of cardiac arrest could reduce cardiovascular mortality in patients with CKD. Cardioverter-defibrillator implantation decreases the risk of sudden death in patients with CKD. The decision to implant a cardioverter-defibrillator should be influenced by the patient's age and stage of CKD.

Cardiovascular disease in end-stage renal disease: the challenge of assessing and managing cardiac disease in dialysis patients

Cardiovascular disease (CVD) is the leading cause of mortality in end-stage renal disease (ESRD), approximating a 10- to 20-fold higher risk of death in dialysis patients than in the general population. Despite this, dialysis patients often undergo fewer investigations, receive less invasive procedures, and are prescribed fewer medications compared with age-matched non-ESRD patients. A lack of randomized control trials for evidence-based treatment strategies in this population may explain some of these discrepancies, but there is concern that an attitude of "therapeutic nihilism" may be impacting on the medical care of these patients. In this review, we will explore CVD in the ESRD population. Specifically, we will try to address the following issues in patients with ESRD: (1) mechanisms of CVD, (2) cardiac evaluation and the role of coronary revascularization with percutaneous or coronary artery bypass procedures, and (3) cardiac pharmacotherapy use.

Rapid fluid removal during dialysis is associated with cardiovascular morbidity and mortality

Patients receiving hemodialysis have high rates of cardiovascular morbidity and mortality that may be related to the hemodynamic effects of rapid ultrafiltration. Here we tested whether higher dialytic ultrafiltration rates are associated with greater all-cause and cardiovascular mortality, and hospitalization for cardiovascular disease. We used data from the Hemodialysis Study, an almost-7-year randomized clinical trial of 1846 patients receiving thrice-weekly chronic dialysis. The ultrafiltration rates were divided into three categories: up to 10 ml/h/kg, 10-13 ml/h/kg, and over 13 ml/h/kg. Compared to ultrafiltration rates in the lowest group, rates in the highest were significantly associated with increased all-cause and cardiovascular-related mortality with adjusted hazard ratios of 1.59 and 1.71, respectively. Overall, ultrafiltration rates between 10-13 ml/h/kg were not associated with all-cause or cardiovascular mortality; however, they were significantly associated among participants with congestive heart failure. Cubic spline interpolation suggested that the risk of all-cause and cardiovascular mortality began to increase at ultrafiltration rates over 10 ml/h/kg regardless of the status of congestive heart failure. Hence, higher ultrafiltration rates in hemodialysis patients are associated with a greater risk of all-cause and cardiovascular death.

Prognostic value of reduced left ventricular ejection fraction at start of hemodialysis therapy on cardiovascular and all-cause mortality in end-stage renal disease patients

BACKGROUND AND OBJECTIVES

Cardiac failure is directly affected by left ventricular (LV) dysfunction, and particularly LV systolic dysfunction is strongly associated with survival in ESRD patients. The aim of this study was to determine the prognostic value of reduced LV ejection fraction (LVEF) measured at the time of initiation of hemodialysis (HD) in incident HD patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

1254 consecutive ESRD patients who electively started HD therapy were screened by echocardiography within 1 month after its inception. They were divided into five groups according to LVEF levels with a decrease of 0.1 each and were followed up for up to 7 years. Survival was examined with the Kaplan-Meier method and compared using the log-rank test.

RESULTS

Among the 1254 patients, LVEF levels ≥0.6, 0.5 to 0.6, 0.4 to 0.5, 0.3 to 0.4, and <0.3 were seen in 842 (67.1%), 247 (19.7%), 107 (8.5%), 41 (3.3%), and 17 (1.4%) patients, respectively. On Kaplan-Meier analysis, 7-year event-free rates from cardiovascular death were 84.2, 83.7, 73.6, 59.4, and 30.9% in order of groups with decreasing LVEF of 0.1 each, respectively. Seven-year event-free rates from all-cause death were 69.2, 61.7, 57.1, 45.9, and 23.1% in the respective groups. Even after adjustment for other risk factors, decreasing LVEF was a strong independent predictor for cardiovascular death.

CONCLUSIONS

Reduced LVEF on starting HD therapy could stratify risk of cardiovascular and all-cause mortality in ESRD patients. Screening by echocardiography at start of HD therapy might be recommended to predict prognosis in patients with ESRD.

Did 20 years of technological innovations in hemodialysis contribute to better patient outcomes?

During the past two decades, impressive technological innovations have been introduced in the field of hemodialysis. This review analyzes whether these have been translated into better patient survival. The potential impacts of an increase in dialysis dosage, the preference of high-flux versus low-flux membranes, the choice between convection and diffusion as dialysis strategy, the chemical composition and biologic purity of dialysate, the effect of sodium, potassium, volume profiling, and the intradialytic volume monitoring aiming at improving hemodynamic stability are explored. Studies in which the dialysis dosage was increased were not associated with increased patient survival, whereas the superiority of high-flux over low-flux membranes is not convincingly demonstrated. Although strict evidence is lacking, observational data suggest an advantage of convective over pure diffusive strategies. Longer duration of the dialysis sessions and/or higher frequency of dialysis is probably beneficial, but the results of powerful randomized, controlled trials should be awaited. Sodium profiling has more disadvantages than advantages, whereas potassium profiling mainly in arrhythmia-prone patients with ventricular hypertrophy should be considered. Intradialytic blood volume monitoring has reduced intradialytic hypotension episodes, but hard evidence for improving patient survival is lacking. Overall, the major technological advances in dialysis have not yet been translated into longer patient survival. Optimal predialysis care in preventing the cardiovascular damage that accumulates before the start of dialysis and timely creation of an arteriovenous fistula as vascular access is a more effective and more economic strategy in the long-term outcome of the dialysis patient.

Left ventricular mass in chronic kidney disease and ESRD

Chronic kidney disease (CKD) and ESRD, treated with conventional hemo- or peritoneal dialysis are both associated with a high prevalence of an increase in left ventricular mass (left ventricular hypertrophy [LVH]), intermyocardial cell fibrosis, and capillary loss. Cardiac magnetic resonance imaging is the best way to detect and quantify these abnormalities, but M-Mode and 2-D echocardiography can also be used if one recognizes their pitfalls. The mechanisms underlying these abnormalities in CKD and ESRD are diverse but involve afterload (arterial pressure and compliance), preload (intravascular volume and anemia), and a wide variety of afterload/preload independent factors. The hemodynamic, metabolic, cellular, and molecular mediators of myocardial hypertrophy, fibrosis, apoptosis, and capillary degeneration are increasingly well understood. These abnormalities predispose to sudden cardiac death, most likely by promotion of electrical instability and re-entry arrhythmias and congestive heart failure. Current treatment modalities for CKD and ESRD, including thrice weekly conventional hemodialysis and peritoneal dialysis and metabolic and anemia management regimens, do not adequately prevent or correct these abnormalities. A new paradigm of therapy for CKD and ESRD that places prevention and reversal of LVH and cardiac fibrosis as a high priority is needed. This will require novel approaches to management and controlled interventional trials to provide evidence to fuel the transition from old to new treatment strategies. In the meantime, key management principles designed to ameliorate LVH and its complications should become a routine part of the care of the patients with CKD and ESRD.

Antibodies to platelet factor 4-heparin complex and outcome in hemodialysis patients with diabetes

BACKGROUND AND OBJECTIVES

Hemodialysis patients with type 2 diabetes exhibit an excessive cardiovascular risk and regularly receive heparin. We tested whether antibodies to the platelet factor 4-heparin complex (PF4-H-AB) contribute to outcome.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In 1255 hemodialysis patients with type 2 diabetes, the German Diabetes Dialysis Study evaluated the effect of atorvastatin (20 mg/d) versus placebo. In a post hoc analysis, the association among PF4-H-ABs, biochemistry, and prespecified, centrally adjudicated end points (combined cardiovascular end point [CVE], all-cause mortality, sudden death, myocardial infarction, stroke) was investigated.

RESULTS

During 4 years, 460 patients reached the CVE; 605 died, 159 of sudden death. Myocardial infarction and stroke occurred in 199 and 97 patients, respectively. Positive PF4-H-AB status was found in 231 (18.7%) of 1236 tested patients and was associated with lower albumin, higher C-reactive protein, and arrhythmia. In a multivariate model adjusted for demographics, comorbidities, and biochemistry, PF4-H-ABs were associated with sudden death. No significant association between PF4-H-ABs and all-cause mortality, myocardial infarction, stroke, or the CVE was observed. Detecting an interaction between acetylsalicylic acid and PF4-H-ABs regarding sudden death and mortality, we found that the association between PF4-H-ABs and outcomes was restricted to patients with acetylsalicylic acid use, most likely because of indication bias.

CONCLUSIONS

In hemodialysis patients who have type 2 diabetes and are treated with acetylsalicylic acid, PF4-H-ABs are associated with sudden and all-cause death. Further studies are needed to elucidate this association.

Glycemic control and cardiovascular events in diabetic hemodialysis patients

BACKGROUND

Patients on maintenance dialysis treatment experience an excess mortality, predominantly of sudden cardiac death. Poor glycemic control is associated with cardiovascular comorbidities in the general population. This study investigated the impact of glycemic control on cardiac and vascular outcomes in diabetic hemodialysis patients.

METHODS AND RESULTS

Glycohemoglobin A1c (HbA(1c)) was measured in 1255 hemodialysis patients with type 2 diabetes mellitus who participated in the German Diabetes and Dialysis Study (4D Study) and were followed up for a median of 4 years. Using Cox regression analyses, we determined hazard ratios to reach prespecified, adjudicated end points according to HbA(1c) levels at baseline: sudden cardiac death (n=160), myocardial infarction (n=200), stroke (n=103), cardiovascular events (n=469), death caused by heart failure (n=41), and all-cause mortality (n=617). Patients had a mean age of 66+/-8 years (54% male) and mean HbA(1c) of 6.7+/-1.3%. Patients with an HbA(1c) >8% had a >2-fold higher risk of sudden death compared with those with an HbA(1c) < or =6% (hazard ratio, 2.14; 95% confidence interval, 1.33 to 3.44), persisting in multivariate models. With each 1% increase in HbA(1c), the risk of sudden death rose significantly by 18%; similarly, cardiovascular events and mortality increased by 8%. There was a trend for higher risks of stroke and deaths resulting from heart failure, whereas myocardial infarction was not affected. The increased risks of both cardiovascular events and mortality were explained mainly by the impact of HbA(1c) on sudden death.

CONCLUSIONS

Poor glycemic control was strongly associated with sudden cardiac death in diabetic hemodialysis patients, which accounted for increased cardiovascular events and mortality. In contrast, myocardial infarction was not affected. Whether interventions achieving tight glycemic control decrease sudden death requires further evaluation. Clinical Trial Registration- URL: http://www.clinicalstudyresults.org. Unique identifier: CT-981-423-239.

Disordered aldosterone-volume relationship in end-stage kidney disease

INTRODUCTION

Sodium loading, and subsequent volume expansion, suppresses aldosterone levels in individuals with normal renal function. We hypothesised that loss of renal function impairs this volume-aldosterone relationship.

MATERIALS AND METHODS

With multifrequency bioimpedance spectroscopy, we measured total body water (TBW), extracellular volume (ECV), and intracellular volume in five haemodialysis patients at varied states of hydration and in five healthy volunteers during low-, normal-, and high-salt diets. Serum aldosterone, potassium, and C-reactive protein were measured simultaneously. Scatterplots and general estimating equations were used to examine the relationship among these variables.

RESULTS

In healthy volunteers with salt loading, and in haemodialysis subjects with increased inter-dialytic weight gain, expansion of ECV led to reciprocal declines in serum aldosterone concentrations. The relationship was more profound in healthy volunteers (p<0.001) than in haemodialysis subjects (p=0.1). Notably, haemodialysis subjects posted consistently higher levels of ECV (median 49.6% TBW, IQR 43.9-51.8% compared to 41.1%, 39.9-42.8% in volunteers) and serum aldosterone (median 26.7 ng/dl, IQR 19.8-29.6 compared to 12.4 ng/dl, 8.8-16.0 in volunteers). Serum potassium did not appear to influence aldosterone concentration (p=0.9).

CONCLUSIONS

The shift of the volume-aldosterone curve in haemodialysis subjects suggests that end-stage kidney disease is a state of high volume and inappropriately high aldosterone. These data have important clinical implications, as dialysis patients may benefit from both volume reduction and mineralocorticoid receptor blockade.

Chronic kidney disease is associated with increased risk of sudden cardiac death among patients with coronary artery disease

Sudden cardiac death is the most common cause of mortality among patients with end-stage kidney disease maintained on hemodialysis. To examine whether this increased risk is also seen with less advanced kidney disease, we studied the relationship between glomerular filtration rate and risk of sudden cardiac death in patients with moderate kidney disease and known coronary artery disease. This retrospective longitudinal study encompassed 19,440 consecutive patients who underwent cardiac catheterization at a single academic institution. There were 522 adjudicated sudden cardiac death events, yielding an overall rate of 4.6 events per 1000 patient years. This figure reflected rates of 3.8 events in 14,652 patients with estimated glomerular filtration rates (eGFR) > or =60 (stage 2 CKD or better) and 7.9 events in 4788 patients with glomerular filtration rates <60 (stage 3-5 CKD), all normalized to 1000 patient-years. After adjusting for differences in known cardiac risk factors and other covariates in a multivariate Cox proportional hazards model, the eGFR was independently associated with sudden cardiac death (hazard ratio (HR)=1.11 per 10 ml/min decline in the eGFR). Our analysis found that reductions in the eGFR in CKD stages 3-5 are associated with a progressive increase in risk of sudden cardiac death in patients with coronary artery disease. Additional studies are needed to better characterize the mechanisms by which reduced kidney function increases this risk.

Cardiac function in an African dialysis population with a low prevalence of pre-existing cardiovascular disease

Cardiac dysfunction is highly prevalent in dialysis patients in the developed world, and is a major cause of morbidity and mortality. The relative impact of pre-existing cardiac disease and dialysis/uremia on cardiovascular morbidity are not clear. We conducted a retrospective, cross-sectional analysis of cardiac function and mortality in 202 incident and prevalent dialysis patients over an 18-month period in a population with a low prevalence of cardiovascular disease at dialysis initiation. Systolic dysfunction was defined as an ejection fraction (EF) of <50%. Left ventricular hypertrophy (LVH) was determined by echocardiography or electrocardiogram. Clinical data was collected by chart review. Ninety-nine percent of patients were black, with a mean age of 41.7 +/- 10.1 years, and median follow up 28 months (range 1-216 months). Echocardiograms were available in 132 patients. Seventy-seven patients received hemodialysis, and 55 received peritoneal dialysis. Mean EF was 63.2 +/- 11.1. EF was not lower in patients with greater duration of dialysis, although LVH tended to increase (not statistically significant). In 39 patients who died during the study period, cardiac function was not different from survivors, and no patient died of ischemic heart disease or heart failure. In conclusion, in a population of patients with a low prevalence of cardiovascular disease at dialysis initiation, cardiac function appears preserved over time, and cardiac morbidity and mortality are low. This finding suggests that dialysis and uremia per se, in the absence of pre-existing cardiac disease, may not be major contributors to cardiovascular morbidity.

Electrocardiography and outcome in patients with diabetes mellitus on maintenance hemodialysis

BACKGROUND AND OBJECTIVES

In hemodialysis, applicable guidelines recommend regular electrocardiogram (ECG) recordings. However, respective systematic evaluations are absent. Thus, the authors investigated whether routine ECG findings add prognostic information to standard risk assessment in hemodialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The relationship between nine common baseline ECG variables and a combined cardiovascular endpoint (CVE; cardiac death, myocardial infarction, stroke), sudden death, stroke, MI, and all-cause death in 1253 patients from the German Diabetes and Dialysis Study was evaluated. All patients were on maintenance hemodialysis, had type 2 diabetes mellitus, and received randomized treatment with atorvastatin or placebo.

RESULTS

During 4 yr of follow-up (March 1998 to March 2004), 469 patients reached the CVE, and 617 died. After adjustment for demographics, comorbidities, and biomarkers in multivariate analysis, patients presenting without sinus rhythm were 89% more likely to die, and the risk of CVE and stroke increased by 75% and 164%, respectively, compared with patients with preserved sinus rhythm. Left ventricular hypertrophy was associated with >2-fold increase in the risk of stroke and a 60% increase in the risk of sudden death.

CONCLUSIONS

In hemodialysis patients with type 2 diabetes mellitus, the absence of sinus rhythm is a risk indicator for CVE, stroke, and all-cause death, and left ventricular hypertrophy is associated with stroke and sudden death. Thus, routine ECG recording adds prognostic information to standard risk assessment.