Since heparin is an anticoagulant commonly used in hemodialysis and the patients on hemodialysis are repeatedly exposed to heparin, heparin may be the cause of the development of heparin-dependent antibodies and thrombotic complications in patients on hemodialysis. The purpose of this study was to determine the prevalence and the clinical significance of the antibodies against heparin-platelet factor 4 complexes as determined by enzyme immunoassay in patients on maintenance hemodialysis. The prevalence of anti-heparin-platelet factor 4 antibodies was higher in hemodialysis patients than in normal subjects (8.8 vs 0.0%, p<0.05). The number of past episodes of vascular access obstruction per year was significantly higher in the anti-heparin-platelet factor 4 antibody positive group than antibody negative group. Anti-heparin-platelet factor 4 antibody positive patients experienced more frequent vascular access obstructions than control subjects. In conclusion, anti-heparin-platelet factor 4 antibody might be a risk factor for vascular access obstructions in patients with end-stage renal disease on maintenance hemodialysis.
Adult ; Autoantibodies/immunology* ; Autoimmune Diseases/immunology* ; Catheters, Indwelling* ; Enzyme-Linked Immunosorbent Assay ; Female ; Heparin/immunology* ; Human ; Kidney Failure, Chronic/blood ; Kidney Failure, Chronic/immunology ; Kidney Failure, Chronic/therapy* ; Male ; Middle Aged ; Platelet Factor 4/immunology* ; Recurrence ; Renal Dialysis* ; Risk Factors ; Thrombophilia/immunology* ; Thrombosis/epidemiology* ; Thrombosis/immunology ; Thrombosis/prevention & control

PURPOSE: Although warfarin is an effective oral anticoagulation (OAC) drug to reduce the risk of thromboembolism in patients with non-valvular atrial fibrillation (NVAF), long term follow-up data are scarce to be certain whether the target INR level is maintained in warfarin-treated patients in Korea. The aim of this study was to evaluate how well INRs are maintained within the target range using a new index, INR stability (= 100 x number of INRs within target range/total number of INR measurements) which we made, and to find out any correlation between thromboembolic events and INR stability. MATERIALS AND METHODS: This study was an observational analysis of retrospectively collected data of 129 patients with NVAF from April 2000 to December 2005 at a single tertiary hospital. All patients were registered at the anticoagulation service. RESULTS: The median duration of follow up was 2.03 years (interquartile range 1.35 - 2.96). During the follow-up period, 60.9 +/- 14.9% of the INR were within the target INR range. INR stability was not significantly different between patients without and with stroke (61.2 +/- 15.0% vs 53.3 +/- 4.9%). Among the known factors affecting fluctuations of the INR value, the most frequent factor was noncompliance (41.8%). CONCLUSION: The present study showed that it was not enough to maintain INR values within the target range in warfarin-treated patients with NVAF even at a tertiary hospital. Noncompliance is an important problem which interferes with maintaining target INR range.
Adult ; Age Factors ; Aged ; Aged, 80 and over ; Anticoagulants/*therapeutic use ; Atrial Fibrillation/*drug therapy/epidemiology/etiology ; Drug Monitoring/methods ; Female ; Follow-Up Studies ; Heart Valves ; Humans ; *International Normalized Ratio ; Male ; Middle Aged ; Patient Compliance ; Retrospective Studies ; Risk Factors ; Thrombosis/*blood/epidemiology/*prevention & control ; Warfarin/*therapeutic use