Coronary and Systemic Vasodilator Responsiveness of Patients Receiving Conventional Intermittent or Nocturnal Hemodialysis

BACKGROUND

Nocturnal hemodialysis (nHD) restores the attenuated brachial artery vasodilator responsiveness of patients receiving conventional intermittent hemodialysis (iHD). Its impact on coronary vasodilatation is unknown.

METHODS

We evaluated 25 patients on hemodialysis who fulfilled transplant criteria: 15 on iHD (4-hour sessions, 3 d/wk) and 10 on nHD (≈40 h/wk over 8-10-hour sessions) plus 6 control participants. Following diagnostic angiography, left anterior descending (LAD) coronary flow reserve and mean luminal diameter were quantified at baseline and during sequential intracoronary administration of adenosine (infusion and bolus), nitroglycerin (bolus), acetylcholine (infusion), acetylcholine coinfused with vitamin C, and, finally, sublingual nitroglycerin.

RESULTS

Coronary flow reserve in those receiving nHD was augmented relative to iHD (3.28±0.26 versus 2.17±0.12 [mean±SEM]; P<0.03) but attenuated, relative to controls (4.80±0.63; P=0.011). Luminal dilatations induced by intracoronary adenosine and nitroglycerin were similar in nHD and controls but blunted in the iHD cohort (P<0.05 versus both). ACh elicited vasodilatation in controls but constriction in both dialysis groups (both P<0.05, versus control); vitamin C coinfusion had no effect. Sublingual nitroglycerin increased mid-left anterior descending diameter and reduced mean arterial pressure in controls (+15.2±2.68%; -16.00±1.60%) and in nHD recipients (+14.78±5.46%; -15.82±1.32%); iHD responses were markedly attenuated (+1.9±0.86%; -5.89±1.41%; P<0.05, all comparisons).

CONCLUSIONS

Coronary and systemic vasodilator responsiveness to both adenosine and nitroglycerin is augmented in patients receiving nHD relative to those receiving iHD, whereas vasoconstrictor responsiveness to acetylcholine does not differ. By improving coronary conduit and microvascular function, nHD may reduce the cardiovascular risk of patients on dialysis.

Experimental renal transplantation in rats improves cardiac dysfunction caused by chronic kidney disease while LVH persists

Background

Chronic kidney disease (CKD) causes congestive heart failure (CHF) with systolic dysfunction and left ventricular hypertrophy (LVH), which is a major contributor to increased mortality in CKD patients. It remains unclear whether cardiovascular changes that occur during the course of CKD can be reversed when renal function is restored by transplantation.

Methods

To investigate this, chronic kidney disease was established in F344 rats by subtotal nephrectomy (SNx) for 8 weeks, followed by transplantation of a functional kidney from an isogenic F344 donor. SNx rats without transplantation and sham-operated animals served as controls. Renal function was assessed before and throughout the experiment. In addition, cardiac ultrasound was performed at weeks 0, 8, 12 and 16. At the end of the experiment, intra-arterial blood pressure was measured and kidneys and hearts were histologically and molecularly examined.

Results

Eight weeks after SNx, rats developed marked renal dysfunction associated with significant glomerulosclerosis and tubulointerstitial fibrosis, but also an increase in left ventricular mass. After transplantation, renal function normalized but relative heart weight and ventricular mass as assessed by ultrasound scans showed no reduction compared with SNx controls. However, left ventricular wall thickness, fractional shortening and ejection fraction was normalized by renal transplantation. At 8 weeks after kidney transplantation, cardiac expression of BNP and FGF23 was also at levels comparable to healthy controls, whereas these factors were significantly increased in SNx rats. Cardiac fibrosis, as measured by fibronectin mRNA expression, was completely normalized, whereas cardiac fibronectin protein was still slightly but not significantly increased in transplanted animals compared to controls. In addition, the myofibroblast marker collagen 1, as assessed by immunohistochemistry, was significantly increased in SNx rats and also normalized by renal transplantation. Interestingly, CD68+ macrophages were significantly reduced in the hearts of SNx rats and in transplanted animals at slightly higher levels compared to controls.

Conclusion

Restoration of renal function by kidney transplantation normalized early cardiac changes at most functional and molecular levels, but did not completely reverse LVH. However, further studies are needed to determine whether restoration of renal function can also reverse LVH at a later time point.

Treatment rationale for coronary heart disease in advanced CKD

Chronic kidney disease (CKD) is accompanied by coronary artery disease (CAD) in most patients. In this article we describe differences in the pathogenesis, diagnosis, and treatment of CAD compared with patients without kidney impairment. The histological phenotype as well as the clinical presentation of acute and chronic coronary syndromes differ from those of patients with normal kidney function. The risk of cardiovascular events including death is strikingly increased with higher stages of CKD. Traditional but even more nontraditional cardiovascular risk factors are contributing to this increase. Screening and diagnostic procedures show limited sensitivity and specificity. Lifestyle modification is important for reducing the progression of both CKD and CAD. A special emphasis should be placed on physical exercising. Equally important is a strict antihypertensive therapy due to the very high incidences of hypertension in CKD patients. Blockade of the renin-angiotensin-system is imperative providing that adverse effects can be managed. Target blood pressure should be at 130 mm Hg systolic. Antiglycemic treatment should be implemented with metformin and SGLT2-inhibitors as first-line therapy, and glomerular filtration rate thresholds must be respected for both drugs. The risk of hypoglycemia is increased with worsening kidney function. Statins are indicated for up to stage 5 CKD. When a revascularization procedure is indicated (percutaneous intervention or bypass grafting), higher rates or peri-interventional morbidity and mortality must be anticipated. Taken together, the available literature on patients with CKD and CAD is clearly restricted compared with that on CAD patients with preserved kidney function. Mechanisms of arteriosclerosis and atheromatosis in CKD deserve more attention in the future. One major innovation in the field is SGLT2-inhibitor treatment with its concordant advantages for kidney and cardiac protection.

Pretransplant NT-proBNP, Dialysis Vintage, and Posttransplant Mortality in Kidney Transplant Recipients

BACKGROUND

End-stage kidney disease and dialysis vintage are characterized by accelerated atherosclerosis, volume overload, and progressive left ventricular hypertrophy, leading to elevated N-terminal probrain natriuretic peptide (NT-proBNP) levels. Pretransplant dialysis vintage is associated with excess mortality after transplantation. We want to study whether pretransplant NT-proBNP is associated with posttransplantation mortality and if it explains the association of dialysis vintage with posttransplantation mortality in kidney transplant recipients (KTR).

METHODS

We measured plasma NT-proBNP on arrival at the hospital before kidney transplantation in 658 KTR between January 1995 and December 2005 in our center. Multivariable Cox regression analyses, adjusted for potential confounders, were used to prospectively study the associations of dialysis vintage and NT-proBNP with all-cause mortality.

RESULTS

During median 12.7 (7.8-15.6) years of follow-up after transplantation, 248 (37.7%) KTR died. Dialysis vintage was associated with an increased risk of posttransplant mortality in the fully adjusted model (hazard ratio [HR], 1.22; 95% confidence interval [CI], 1.03-1.43; P = 0.02), independent of potential confounders. The association weakened materially and lost significance after further adjustment for NT-proBNP (HR, 1.14; 0.96-1.34; P = 0.14). NT-proBNP was independently associated with all-cause mortality in the fully adjusted model (HR, 1.34; 1.16-1.55; P < 0.001). The association remained independent of adjustment for dialysis vintage (HR, 1.31; 1.13-1.52; P < 0.001).

CONCLUSIONS

Our study shows that longer dialysis vintage is associated with a higher mortality risk in KTR, and this association might be explained for a considerable part by variation in pretransplant NT-proBNP at the time of transplantation.

Abdominal aortic calcification on a plain X-ray and the relation with significant coronary artery disease in asymptomatic chronic dialysis patients

Background

Coronary artery disease (CAD) is common in asymptomatic chronic dialysis patients and plays an important role in their poor survival. Early identification of these high-risk patients could improve treatment and reduce mortality. Abdominal aortic calcification (AAC) has previously been associated with CAD in autopsy studies. Since the AAC can be quantified easily using a lateral lumbar X-ray we hypothesized that the extent of AAC as assessed on a lateral lumbar X-ray might be predictive of the presence of significant CAD in dialysis patients.

Methods

All patients currently enrolled in the ICD2 trial without a history of CABG or a PCI with stent implantation were included in this study. All patients underwent CT-angiography (CTA) and a lateral X-ray of the abdomen. AAC on X-ray was quantified using a previously validated scoring system whereupon the association between AAC and the presence of significant CAD was assessed.

Results

A total of 90 patients were included in this study (71% male, 67 ± 7 years old). Forty-six patients were found to have significant CAD. AAC-score was significantly higher in patients with CAD (10.1 ± 4.9 vs 6.3 ± 4.6 (p < 0.05). Multivariate regression analysis revealed that AAC score is an independent predictor for the presence of CAD with a 1,2 fold higher risk per point increase (p < 0.01). The AAC score has a sensitivity of 85% and a specificity of 57% for the presence of significant CAD.

Conclusion

This study shows that abdominal aortic calcification as assessed on a lateral lumbar X-ray is predictive for the presence of significant coronary artery disease in asymptomatic dialysis patients. This simple, non-invasive and cheap screening method could contribute to early identification of patients eligible for further screening of CAD.

Trial registration

NTR948, registered 10-4-2007 ; ISRCTN20479861, registered 2-5-2007

Dealing with prognostic signature instability: a strategy illustrated for cardiovascular events in patients with end-stage renal disease

Background

Identification of prognostic gene expression markers from clinical cohorts might help to better understand disease etiology. A set of potentially important markers can be automatically selected when linking gene expression covariates to a clinical endpoint by multivariable regression models and regularized parameter estimation. However, this is hampered by instability due to selection from many measurements. Stability can be assessed by resampling techniques, which might guide modeling decisions, such as choice of the model class or the specific endpoint definition.

Methods

We specifically propose a strategy for judging the impact of different endpoint definitions, endpoint updates, different approaches for marker selection, and exclusion of outliers. This strategy is illustrated for a study with end-stage renal disease patients, who experience a yearly mortality of more than 20 %, with almost 50 % sudden cardiac death or myocardial infarction. The underlying etiology is poorly understood, and we specifically point out how our strategy can help to identify novel prognostic markers and targets for therapeutic interventions.

Results

For markers such as the potentially prognostic platelet glycoprotein IIb, the endpoint definition, in combination with the signature building approach is seen to have the largest impact. Removal of outliers, as identified by the proposed strategy, is also seen to considerably improve stability.

Conclusions

As the proposed strategy allowed us to precisely quantify the impact of modeling choices on the stability of marker identification, we suggest routine use also in other applications to prevent analysis-specific results, which are unstable, i.e. not reproducible.

The heart and vascular system in dialysis

The heart and the vascular tree undergo major structural and functional changes when kidney function declines and renal replacement therapy is required. The many cardiovascular risk factors and adaptive changes the heart undergoes include left ventricular hypertrophy and dilatation with concomitant systolic and diastolic dysfunction. Myocardial fibrosis is the consequence of impaired angio-adaptation, reduced capillary angiogenesis, myocyte-capillary mismatch, and myocardial micro-arteriopathy. The vascular tree can be affected by both atherosclerosis and arteriosclerosis with both lipid rich plaques and abundant media calcification. Development of cardiac and vascular disease is rapid, especially in young patients, and the phenotype resembles all aspects of an accelerated ageing process and latent cardiac failure. The major cause of left ventricular hypertrophy and failure and the most common problem directly affecting myocardial function is fluid overload and, usually, hypertension. In situations of stress, such as intradialytic hypotension and hypoxaemia, the hearts of these patients are more vulnerable to developing cardiac arrest, especially when such episodes occur frequently. As a result, cardiac and vascular mortality are several times higher in dialysis patients than in the general population. Trials investigating one pharmacological intervention (eg, statins) have shown limitations. Pragmatic designs for large trials on cardio-active interventions are mandatory for adequate cardioprotective renal replacement therapy.

Predictors of Arrhythmic Events Detected by Implantable Loop Recorders in Renal Transplant Candidates

BACKGROUND

The recording of arrhythmic events (AE) in renal transplant candidates (RTCs) undergoing dialysis is limited by conventional electrocardiography. However, continuous cardiac rhythm monitoring seems to be more appropriate due to automatic detection of arrhythmia, but this method has not been used.

OBJECTIVE

We aimed to investigate the incidence and predictors of AE in RTCs using an implantable loop recorder (ILR).

METHODS

A prospective observational study conducted from June 2009 to January 2011 included 100 consecutive ambulatory RTCs who underwent ILR and were followed-up for at least 1 year. Multivariate logistic regression was applied to define predictors of AE.

RESULTS

During a mean follow-up of 424 ± 127 days, AE could be detected in 98% of patients, and 92% had more than one type of arrhythmia, with most considered potentially not serious. Sustained atrial tachycardia and atrial fibrillation occurred in 7% and 13% of patients, respectively, and bradyarrhythmia and non-sustained or sustained ventricular tachycardia (VT) occurred in 25% and 57%, respectively. There were 18 deaths, of which 7 were sudden cardiac events: 3 bradyarrhythmias, 1 ventricular fibrillation, 1 myocardial infarction, and 2 undetermined. The presence of a long QTc (odds ratio [OR] = 7.28; 95% confidence interval [CI], 2.01-26.35; p = 0.002), and the duration of the PR interval (OR = 1.05; 95% CI, 1.02-1.08; p < 0.001) were independently associated with bradyarrhythmias. Left ventricular dilatation (LVD) was independently associated with non-sustained VT (OR = 2.83; 95% CI, 1.01-7.96; p = 0.041).

CONCLUSIONS

In medium-term follow-up of RTCs, ILR helped detect a high incidence of AE, most of which did not have clinical relevance. The PR interval and presence of long QTc were predictive of bradyarrhythmias, whereas LVD was predictive of non-sustained VT.

Sudden cardiac death in haemodialysis patients: preventative options

Sudden cardiac death (SCD) is the most common cause of death in haemodialysis patients, accounting for 25% of all-cause mortality. There are many potential pathological precipitants as most patients with end-stage renal disease have structurally or functionally abnormal hearts. For example, at initiation of dialysis, 74% of patients have left ventricular hypertrophy. The pathophysiological and metabolic milieu of patients with end-stage renal disease, allied to the regular stresses of dialysis, may provide the trigger to a fatal cardiac event. Prevention of SCD can be seen as a legitimate target to improve survival in this patient group. In the general population, this is most effective by reducing the burden of ischaemic heart disease. However, the aetiology of SCD in haemodialysis patients appears to be different, with myocardial fibrosis, vascular calcification and autonomic dysfunction implicated as possible causes. Thus, the range of therapies is different to the general population. There are potential preventative measures emerging as our understanding of the underlying mechanisms progresses. This article aims to review the evidence for therapies to prevent SCD effective in the general population when applied to dialysis patients, as well as promising new treatments specific to this population group.

Influence of hemodialysis duration on mid-term clinical outcomes in hemodialysis patients with coronary artery disease after drug-eluting stent implantation

Accelerated atherosclerosis in prolonged maintenance hemodialysis (HD) has been recognized; however, whether HD duration is associated with poor clinical outcome in HD patients with coronary artery disease (CAD) after drug-eluting stent (DES) implantation is unknown. We evaluated the impact of HD duration on clinical outcomes in HD patients with CAD after DES implantation. Between April 2007 and December 2012, 168 angina pectoris patients (320 de novo lesions) on HD were treated with DES. Major adverse cardiovascular events (MACE) and target lesion revascularization (TLR) were investigated at 3 years according to the HD duration (≤ 3 years, 83 patients; >3 years, 85 patients). The incidence of MACE was significantly higher in the long HD duration group (25.3 vs. 50.6 %; P = 0.001). Especially, sudden cardiac death (SCD) was significantly higher in the long HD duration group (3.6 vs. 16.5 %; P = 0.006). On the other hand, the rates of TLR were similar between the two groups (12.0 vs. 14.1 %; P = 0.69). Cox's proportional hazard analysis revealed that HD duration (HR 1.08 per year, 95 % CI 1.03-1.13, P = 0.002), β-blocker use (0.28, 0.17-0.46, P < 0.001), and diabetes mellitus (2.10, 1.23-3.56, P = 0.007) were independent predictors of MACE. Longer HD duration did not affect TLR; however, SCD was significantly higher in the long HD duration group.

Echocardiographical determinants of an abnormal spatial QRS-T angle in chronic dialysis patients

BACKGROUND

The spatial QRS-T angle describes the relation between ventricular depolarization and repolarization. Having a wide (abnormal) angle is considered an important predictor of arrhythmic events. Given the high incidence of sudden cardiac death in dialysis patients, this parameter is of particular interest in this patient group. The objective of this study was to assess the association of (modifiable) echocardiographic parameters and an abnormal spatial QRS-T angle in dialysis patients.

METHODS

A total of 94 consecutive dialysis patients were included. In all patients a 12-lead electrocardiogram (ECG), a two-dimensional echocardiogram and routine blood samples were obtained. The spatial QRS-T angle was then calculated from the 12-lead ECG. An abnormal spatial QRS-T angle was defined as ≥130° in males and ≥116° in females.

RESULTS

An abnormal spatial QRS-T angle was present in 27 (29%) patients. Patients with an abnormal spatial angle had a lower left ventricular ejection fraction (LVEF) of 47 ± 7 versus 55 ± 6% (P < 0.001) and had a higher left ventricular (LV) dyssynchrony, with a septal to lateral (S-L) delay of peak systolic velocity of 70 inter quartile range (iIQR) (40, 100) ms versus 30 IQR (10, 70) ms (P = 0.001), respectively. Multivariate logistic regression analysis controlling for possible confounders demonstrated that LVEF [odds ratio (OR) 0.82; 95% confidence interval (CI) 0.72-0.93, P = 0.001] and LV dyssynchrony (OR 1.19 per 10 ms; 95% CI 1.03-1.38, P = 0.02) were independent determinants of an abnormal spatial QRS-T angle in this patient group.

CONCLUSIONS

LVEF and dyssynchrony are echocardiographic determinants of an abnormal spatial QRS-T angle in dialysis patients and might therefore represent a potential target for the prevention of sudden cardiac death in these patients.

CKD and sudden cardiac death: epidemiology, mechanisms, and therapeutic approaches

Multiple studies demonstrate a strong independent association between CKD and cardiovascular events including death, heart failure, and myocardial infarction. This review focuses on recent clinical studies that expand this spectrum of adverse cardiovascular events to include ventricular arrhythmias and sudden cardiac death. In addition, experimental models suggest structural remodeling of the heart and electrophysiologic changes in this population. These processes may explain the increased arrhythmic risk in kidney disease and aid in identifying patients who are at higher risk for sudden cardiac death. Finally, we review here the data to support the use of pharmacologic and device-based therapies for both the primary and secondary prevention of sudden cardiac death.

Sudden cardiac arrest and sudden cardiac death on dialysis: Epidemiology, evaluation, treatment, and prevention

Sudden cardiac death is the most common cause of death in dialysis patients and is usually preceded by sudden cardiac arrest due to ventricular tachycardia or ventricular fibrillation. A variety of risk factors have been identified that predispose the sudden cardiac arrest and sudden cardiac death in dialysis patients. Primary prevention of sudden cardiac arrest in dialysis patients may be accomplished by avoiding the use of low potassium dialysate. Pharmacotherapy with beta-blockers angiotensin converting enzyme inhibitors and angiotensin receptor blockers and use of implantable cardioverter defibrillators (ICDs) may also prevent sudden cardiac arrest and sudden cardiac death in high-risk dialysis patients. Secondary prevention of sudden cardiac death may be accomplished by similar pharmacotherapy and by the use of ICDs. Indications for ICD use in dialysis patients are similar to those for nondialysis patients; however, survival rates following ICD implantation in dialysis patients are substantially lower than in non-dialysis patients.

Left ventricular diastolic dysfunction in dialysis patients assessed by novel speckle tracking strain rate analysis: prevalence and determinants

Background. Diastolic dysfunction is common among dialysis patients and is associated with increased morbidity and mortality. Novel echocardiographic speckle tracking strain analysis permits accurate assessment of left ventricular diastolic function, independent of loading conditions and taking all myocardial segments into account. The aim of the study was to evaluate the prevalence of diastolic dysfunction in chronic dialysis patients using this novel technique, and to identify its determinants among clinical and echocardiographic variables. Methods. Patients currently enrolled in the ICD2 study protocol were included for this analysis. Next to conventional echo measurements diastolic function was also assessed by global diastolic strain rate during isovolumic relaxation (SRIVR). Results. A total of 77 patients were included (age 67 ± 8 years, 74% male). When defined as E/SRIVR ≥236, the prevalence of diastolic dysfunction was higher compared to more conventional measurements (48% versus 39%). Left ventricular mass (OR 1.02, 95% CI 1.00–1.04, P = 0.014) and pulse wave velocity (OR 1.34, 95% CI 1.07–1.68, P = 0.01) were independent determinants of diastolic dysfunction. Conclusion. Diastolic dysfunction is highly prevalent among dialysis patients and might be underestimated using conventional measurements. Left ventricular mass and pulse wave velocity were the only determinants of diastolic dysfunction in these patients.

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.

Impact of moderate to severe renal impairment on mortality and appropriate shocks in patients with implantable cardioverter defibrillators

Background. Due to underrepresentation of patients with chronic kidney disease (CKD) in large Implantable-Cardioverter Defibrillator (ICD) clinical trials, the impact of ICD remains uncertain in this population. Methods. Consecutive patients who received ICD at Creighton university medical center between years 2000–2004 were included in a retrospective cohort after excluding those on maintenance dialysis. Based on baseline Glomerular filtration rate (GFR), patients were classified as severe CKD: GFR < 30 mL/min; moderate CKD: GFR: 30–59 mL/min; and mild or no CKD: GFR ≥ 60 mL/min. The impact of GFR on appropriate shocks and survival was assessed using Kaplan-Meier method and Generalized Linear Models (GLM) with log-link function. Results. There were 509 patients with a mean follow-up of 3.0 + 1.3 years. Mortality risk was inversely proportional to the estimated GFR: 2 fold higher risk with GFR between 30–59 mL/min and 5 fold higher risk with GFR < 30 mL/min. One hundred and seventy-seven patients received appropriate shock(s); appropriate shock-free survival was lower in patients with severe CKD (GFR < 30) compared to mild or no CKD group (2.8 versus 4.2 yrs). Conclusion. Even moderate renal dysfunction increases all cause mortality in CKD patients with ICD. Severe but not moderate CKD is an independent predictor for time to first appropriate shock.

Vitamin D deficiency is associated with sudden cardiac death, combined cardiovascular events, and mortality in haemodialysis patients

Aims

Dialysis patients experience an excess mortality, predominantly of sudden cardiac death (SCD). Accumulating evidence suggests a role of vitamin D for myocardial and overall health. This study investigated the impact of vitamin D status on cardiovascular outcomes and fatal infections in haemodialysis patients.

Methods and results

25-hydroxyvitamin D [25(OH)D] was measured in 1108 diabetic haemodialysis patients who participated in the German Diabetes and Dialysis Study and were followed up for a median of 4 years. By Cox regression analyses, we determined hazard ratios (HR) for pre-specified, adjudicated endpoints according to baseline 25(OH)D levels: SCD (n = 146), myocardial infarction (MI, n = 174), stroke (n = 89), cardiovascular events (CVE, n = 414), death due to heart failure (n = 37), fatal infection (n = 111), and all-cause mortality (n = 545). Patients had a mean age of 66 ± 8 years (54% male) and median 25(OH)D of 39 nmol/L (interquartile range: 28–55). Patients with severe vitamin D deficiency [25(OH)D of≤ 25 nmol/L] had a 3-fold higher risk of SCD compared with those with sufficient 25(OH)D levels >75 nmol/L [HR: 2.99, 95% confidence interval (CI): 1.39–6.40]. Furthermore, CVE and all-cause mortality were strongly increased (HR: 1.78, 95% CI: 1.18–2.69, and HR: 1.74, 95% CI: 1.22–2.47, respectively), all persisting in multivariate models. There were borderline non-significant associations with stroke and fatal infection while MI and deaths due to heart failure were not meaningfully affected.

Conclusion

Severe vitamin D deficiency was strongly associated with SCD, CVE, and mortality, and there were borderline associations with stroke and fatal infection. Whether vitamin D supplementation decreases adverse outcomes requires further evaluation.

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.