Thromboprophylactic effect of ticlopidine in arteriovenous fistulas for haemodialysis. Anti-platelet therapy in graft thrombosis: results of a prospective, randomized, double-blind study. Double-blind randomized trial of the effect of ticlopidine in arteriovenous fistulas for hemodialysis. Effects of ticlopidine in AV-fistula surgery in uremia. Fistula Study Group. Low-intensity warfarin is ineffective for the prevention of PTFE graft failure in patients on hemodialysis: a randomized controlled trial. Prevention of p.o. clotting of av. cimino fistulae with acetylsalicyl acid. Results of a prospective double blind study. Prevention of thrombosis in patients on hemodialysis by low-dose aspirin. Prophylaxis of hemodialysis graft thrombosis with fish oil: double-blind, randomized, prospective trial.
When constructing arteriovenous fistulas for haemodialysis in chronic renal failure patients, one of the main problems is still their clotting tendency. Ticlopidine is an effective inhibitor of platelet aggregation. In this randomized double-blind study placebo or ticlopidine 250 mg twice daily was given to chronic uremic patients up to 4 weeks after construction of an arteriovenous fistula. 42 patients were recruited and 36 completed the trial. The fistula clotted in 8 patients on placebo and in 2 patients on ticlopidine. The difference is significant. This effect was achieved without an increased frequency of side effects compared with placebo. It is concluded that ticlopidine has a function as a thromboprophylactic drug in chronic uremic patients. Hemodialysis (HD) vascular access thrombosis remains a major cause of morbidity, accounting for 17.4% of all HD patient hospital admissions in 1986. We initiated this prospective, randomized, double-blind, placebo-controlled, parallel group study to examine if dipyridamole and/or aspirin decreased the rate of thrombosis of expanded polytetrafluoroethylene (ePTFE) grafts in HD patients. Two patient groups were studied: Type I--with a new ePTFE graft; and Type II--with thrombectomy and/or revision of a previously placed ePTFE graft. One hundred and seven patients were followed for 18 months or until the first thrombotic episode. Actuarial analysis of Type I patients showed cumulative thrombosis rates (mean +/- SEM) of 21 +/- 9% on dipyridamole alone, compared with 25 +/- 11% on dipyridamole and aspirin combination, 42 +/- 13% on placebo, and 80 +/- 12% on aspirin alone. The relative risk of thrombosis with dipyridamole was 0.35 (P = 0.02) and that for aspirin was 1.99 (P = 0.18). In Type II patients, the rate of thrombosis was high in all study drug and placebo groups (overall 78% thrombosis) and actuarial analysis was not carried out because of the small number of patients enrolled. We conclude that dipyridamole is beneficial in patients with new ePTFE grafts and that aspirin does not improve the risk of thrombosis in ePTFE grafts. Neither dipyridamole nor aspirin has any beneficial effect in patients with prior thrombosis of ePTFE grafts. The antiplatelet drug ticlopidine was assessed as an agent for improving the patency of Brescia-Cimino arteriovenous fistulas as access for hemodialysis. In a double-blind randomized study over 1 month, two of six fistulas in the ticlopidine group and five of nine in the placebo group failed. A further one placebo and two ticlopidine patients still had functioning fistulas at the time of withdrawal for technical reasons from the trial. Ticlopidine appears, therefore, to enhance the efficacy of Brescia-Cimino fistulas, at least in the short term. Two hundred and fifty-eight patients with uremia who were offered surgery for placement of an arteriovenous fistula for hemodialysis were recruited in nine regional dialysis centers. The patients were randomized to receive the platelet aggregation inhibitory compound ticlopidine, 250 mg b.d., or matching placebo. Study medication was targeted at 7, minimum 3, days before scheduled surgery and continued for 28 days after surgery. The overall rate of occlusion was 41/260 evaluable operations (16%), 25/131 (19%) in the placebo group and 16/129 (12%) in the ticlopidine group. The risk of early occlusion was a non-significant 35% lower in the ticlopidine group. Limited risk factor analysis did not clearly identify any subgroup other than females at greater risk of early thrombosis nor any subgroup deriving particular benefit from ticlopidine treatment. Polytetrafluoroethylene (PTFE) dialysis grafts in patients with end-stage renal disease (ESRD) are prone to thrombotic failure. The objective of this multicenter, randomized, double-blind, placebo-controlled clinical trial was to determine if warfarin reduces the risk of failure of PTFE dialysis grafts. Patients with ESRD and newly placed PTFE grafts were studied at community and academic dialysis centers in Southwestern Ontario. Patients were allocated to receive warfarin or matching placebo, with the warfarin administered to achieve a target INR of 1.4 to 1.9. Time to graft failure was the main outcome measure. A total of 107 patients (56 allocated to warfarin) were randomized. The time-to-event analysis revealed no significant difference in the likelihood of graft survival between the two groups (odds ratio, 1.76 in favor of placebo; 95% confidence interval, 0.72 to 4.34). Six major bleeds occurred in five patients allocated to warfarin compared with none in the patients who received placebo (P = 0.03). In conclusion, low-dose warfarin was associated with an excess of clinically important major bleeding in patients with ESRD enrolled in this study. Furthermore, low-intensity, monitored-dose warfarin does not appear to prolong PTFE graft survival. nan Since platelet cyclo-oxygenase is much more sensitive to inactivation by aspirin than is the enzyme in the arterial wall and low doses of aspirin may prevent thrombosis by blocking thromboxane synthesis, we conducted a randomized, double-blind trial of aspirin (160 mg per day) vs. placebo in 44 patients on chronic hemodialysis. The study was continued until there were 24 patients with thrombi and both groups had been under observation for a mean of nearly five months. Thrombi occurred in 18 of 25 (72 per cent) of patients given placebo and 16 of 19 (32 per cent) of those given aspirin (P less than 0.01). The incidence of thrombosis was reduced from 0.46 thrombi per patient month in the placebo group to 0.16 thrombi per patient month in the aspirin group (p less than 0.005). A dose of 160 mg of aspirin per day is an effective, nontoxic antithrombotic regimen in patients on hemodialysis. Diets enriched with fish oil may favorably affect the vascular perturbations underlying synthetic graft thrombosis. Therefore, these studies were designed to test the hypothesis that diets enriched with fish oil would decrease the incidence of thrombosis in newly constructed polytetrafluorethylene grafts. A double-blind, randomized trial was conducted. Twenty-four patients were randomized to receive 4000 mg of fish oil or 4000 mg of control oil. Both preparations were enriched with antioxidants and deodorized with peppermint. Patients began therapy within 2 wk after graft placement and were monitored for 12 mo or until thrombosis developed. With a permuted-block randomization schedule, 12 patients received fish oil and 12 patients received control oil. The primary patency rates at 365 d were 14.9% for the control group and 75.6% for the fish oil-treated group. Survival analysis revealed a significant difference between fish oil-treated and untreated patients (P < 0.03, Mantel-Cox test), with a power of 90%. Moreover, analysis of covariables, including age of > or =50 yr, gender, race, body weight, diabetes mellitus, bleeding times, and lipid profiles, indicated that this effect occurred principally as a result of fish oil administration. Importantly, fish oil treatment also decreased venous outflow resistance and systemic BP, compared with control values. Fish oils possess unique biologic properties that favorably affect the incidence of polytetrafluorethylene graft thrombosis, and they thus represent a potential treatment strategy for the prevention of access thrombosis.