Ethylene-vinyl alcohol copolymer dialyzer membrane reduces protein oxidation in hemodialysis patients.

BACKGROUND: Oxidative stress has been implicated in the cardiovascular complications that affect hemodialysis (HD) patients. Ethylene-vinyl alcohol copolymer (EVAL) dialyzer membrane induces less production of reactive oxygen species as compared to conventional dialyzers. We evaluated the impact of EVAL membrane on plasma protein oxidation in HD patients. METHODS: HD patients treated with cellulose triacetate (CTA) dialyzers were selected. In the first study performed in a 2-month crossover design alternating between CTA and EVAL, nonmercaptalbumin and advanced oxidation protein products levels were measured in the predialysis blood from 10 subjects. In the second study, predialysis plasma myeloperoxidase levels were measured before and after a 2-week EVAL treatment on 12 patients. RESULTS: Plasma advanced oxidation protein products levels were reduced after a 2-month EVAL treatment and increased again after CTA treatment, although the nonmercaptalbumin proportions were not affected significantly by the change in dialyzer membranes. The following study, a 2-week EVAL treatment, showed the decrease in myeloperoxidase levels immediately before HD. CONCLUSION: The frequent use of EVAL dialyzers has been shown to reduce protein oxidation, possibly through the suppression of circulating phagocytes. This novel biocompatible dialyzer is expected to protect cardiovascular mortality in HD patients.

Long-term low-dose spironolactone therapy is safe in oligoanuric hemodialysis patients.

The Randomized Aldactone Evaluation Study showed that low-dose spironolactone treatment dramatically reduced mortality in patients with heart failure. However, the clinical use of this drug may be limited due to its tendency to cause life-threatening hyperkalemia in hemodialysis (HD) patients. We assessed whether low-dose spironolactone could be safely administered to HD patients for a long period. The study design comprised 2-month baseline and 6-month treatment periods. Sixty-one oligoanuric HD patients were administered a spironolactone dose of 25 mg/day. Serum potassium levels at baseline were compared with those during the treatment. Eleven patients discontinued the treatment because of adverse events other than hyperkalemia or for other reasons. The remaining 50 patients completed the trial, and none of them showed a potassium level of >6.8 mEq/l or required additional ion exchange resin therapy throughout the study period. The mean potassium levels during the treatment were higher than those at baseline; the differences were statistically significant, but only marginally. The safety of spironolactone should be examined in larger trials. However, from this study, we conclude that long-term low-dose spironolactone treatment is clinically safe for many HD patients. A more extensive treatment may help in determining whether spironolactone can reduce cardiovascular mortality in HD patients.

Changes in QTc interval in long-term hemodialysis patients.

BACKGROUND: Cardiovascular diseases, including sudden cardiac death (SCD), are the leading cause of death in hemodialysis (HD) patients. A prolonged QT interval on the electrocardiogram (ECG) is a risk factor for SCD in HD patients. This study investigated whether the heart rate-corrected QT (QTc) interval becomes prolonged along with dialysis vintage. METHODS: A total of 102 HD patients were retrospectively studied. Their ECG data were analyzed at 1, 4, and 7 years after HD initiation. The control group comprised 68 age-matched individuals who had normal renal function and two available ECG reports at an interval of more than 4 years. QTc was measured according to the Bazett formula. The association between QTc interval and dialysis vintage was studied. Additionally, clinically relevant variables related to QTc duration at 1 year after HD initiation were assessed. RESULTS: Average QTc interval at 4 and 7 years after HD initiation was significantly longer than that at 1 year after HD initiation (443, 445, and 437 ms) (p<0.05). On the other hand, QTc interval in the control group was 425 ms in the first year and 426 ms after an average of 6 years. They had no significant differences, although they were much shorter than that in HD patients. Multivariate regression analysis of baseline variables revealed that the corrected calcium levels (p = 0.041) and diabetes (p = 0.043) were independently associated with longer QTc interval. CONCLUSIONS: The QTc interval at 1 year after HD initiation was longer than in the control subjects and was prolonged over several years of HD treatment. Providing clinical management with a focus on QTc interval may be helpful for reducing the incidence of SCD in HD patients.

Spironolactone reduces cardiovascular and cerebrovascular morbidity and mortality in hemodialysis patients.

OBJECTIVES: This study sought to assess whether spironolactone treatment reduces the high incidence of cardiovascular and cerebrovascular (CCV) morbidity and mortality in hemodialysis (HD) patients. BACKGROUND: Aldosterone receptor blockers reduce cardiac-related events, but the efficacy of the agents in HD patients is unclear. METHODS: A 3-year randomized trial involving 5 clinics was performed. Of the 309 oligoanuric HD patients enrolled in the study, 157 patients were randomly assigned to receive 25 mg/day of spironolactone without any restriction on dietary potassium intake (treatment group), and 152 patients were assigned to a control group. The primary outcome was a composite of death from CCV events or hospitalization for CCV events, and the secondary outcome was death from all causes. RESULTS: During the 3-year follow-up, the primary outcome occurred in 5.7% of patients in the treatment group and in 12.5% of patients in the control group. Hazard ratios (HRs) for the primary outcome for treatment were 0.404 (95% confidence interval [CI]: 0.202 to 0.809; p = 0.017) and 0.379 (95% CI: 0.173 to 0.832; p = 0.016) before and after adjustment, respectively. The secondary outcome was significantly reduced in the treatment group compared with the control group (6.4% vs. 19.7%; HRs: 0.355 [95% CI: 0.191 to 0.662; p = 0.002] and 0.335 [95% CI: 0.162 to 0.693; p = 0.003] before and after adjustment, respectively). Gynecomastia or breast pain was reported in 16 patients (10.2%) in the treatment group. Serious hyperkalemia led to treatment discontinuation in 3 patients (1.9%). CONCLUSIONS: Aldosterone receptor blockade using spironolactone may substantially reduce the risk of both CCV morbidity and death among HD patients; however, larger-scale studies are recommended to further confirm its efficacy. (Effects of Spironolactone on Cardio- and Cerebrovascular Morbidity and Mortality in Hemodialysis Patients; NCT01687699).