Antithrombotic agents for primary and secondary prevention of cardiovascular events in patients with end-stage renal disease on chronic hemodialysis.

BACKGROUND AND AIMS: Cardiovascular disease (CVD) is common in patients with end-stage renal disease (ESRD) on hemodialysis (HD). However, antithrombotic therapy to prevent CVD increases the risk of bleeding. We aimed to investigate the prevalence of CVD and the practice patterns of antithrombotic agents in patients with ESRD on HD. METHODS: In a cross-sectional population based cohort of chronic HD patients (n = 626) from Vienna, Austria, the medical histories of patients and use of antithrombotic treatment were recorded, and the distribution of antithrombotic therapies for primary (n = 260, 41.5%) or secondary (n = 366, 58.5%) prevention of CVD was analyzed. RESULTS: Single antiplatelet therapy (SAPT) was used in 234 patients (37.4%), dual antiplatelet (DAPT) in 50 (8.0%), combination of anticoagulation and antiplatelet in 59 (9.4%), anticoagulation monotherapy in 78 (12.5%), and no antithrombotics in 205 patients (32.7%). The prevalence of CVD was 58.5%. In primary CVD prevention, 23.5% (n = 61) of patients were treated with SAPT. For secondary prevention, SAPT was used in 173 (47.3%), DAPT in 49 (13.4%), and dual antithrombotic therapies in 50 patients (13.7%), while 55 (15.0%) patients received no antithrombotics. Age (odds ratio [OR] per 1 year increase 0.96, 95%CI 0.94-0.99, p = 0.004) and hereditary nephropathy (OR 4.13, 95%CI 1.08-15.78, p = 0.038) were independently associated with the absence of antithrombotic therapy in secondary CVD prevention. CONCLUSION: The majority of patients did not receive antithrombotic therapy for primary prevention. Only 15% did not receive antithrombotic agents in the secondary prevention setting. The net-clinical benefit of antithrombotic therapy in ESRD needs to be determined.

Effect of high dose folic acid therapy on hyperhomocysteinemia in hemodialysis patients: results of the Vienna multicenter study.

Homocysteine is associated with atherosclerosis and enhanced cardiovascular risk. In previous studies, treatment with folic acid up to 15 mg/d failed to correct hyperhomocysteinemia in the majority of end-stage renal disease patients. A dose of 30 or 60 mg of folic acid per day was compared with 15 mg/d in an attempt to normalize hyperhomocysteinemia in 150 hemodialysis patients. In a randomized, double-blind, multicenter study, 144 patients completed the 4-wk treatment period and 121 patients completed the 6-mo follow-up. Total homocysteine plasma levels were reduced by 32.1% (15 mg/d), 29. 9% (30 mg/d), or 37.8% (60 mg/d) with no significant differences found between the three treatment groups. Baseline total homocysteine plasma concentration was an independent predictor of the response to folic acid therapy (P = 0.0001), whereas the 5, 10-methylenetetrahydrofolate reductase polymorphisms (MTHFR 677C --> T and 1298A --> C) had no influence. Nevertheless, patients with the MTHFR 677TT genotype more frequently attained normal total homocysteine plasma levels than patients with the CC or CT genotype (P = 0.025). In response to 60 mg of folic acid per day, TT genotype patients had lower folate plasma levels compared to CC or CT genotype patients (P = 0.016). After completion of the 4-wk treatment period with 30 or 60 mg of folic acid per day, there was a marked rebound of total homocysteine plasma levels at the end of the follow-up in patients with the MTHFR 677TT genotype, which even exceeded baseline values in several patients (P = 0.0001). This study clearly demonstrates that doses of 30 or 60 mg of folic acid per day are not more effective than 15 mg/d in reducing hyperhomocysteinemia in regular hemodialysis patients. Patients with the MTHFR 677TT genotype are more likely to realize normal total homocysteine plasma levels. Folic acid at 30 or 60 mg/d but not 15 mg/d results in a rebound of total homocysteine plasma concentrations when treatment is stopped.