Пользуясь правилами форума- тема о протезах уже есть.... Dipyridamole Plus Aspirin May Improve Hemodialysis Graft Patency
Laurie Barclay, MD
May 20, 2009 — Treatment with dipyridamole plus aspirin improves hemodialysis graft patency, according to the results of a randomized, double-blind, placebo-controlled trial reported in the May 21 issue of the New England Journal of Medicine.
"Arteriovenous graft stenosis leading to thrombosis is a major cause of complications in patients undergoing hemodialysis," write Bradley S. Dixon, MD, from the University of Iowa and the Veterans Affairs Medical Center in Iowa City and colleagues from the Dialysis Access Consortium Study Group. "Procedural interventions may restore patency but are costly. Although there is no proven pharmacologic therapy, dipyridamole may be promising because of its known vascular antiproliferative activity."
This trial evaluated the combination of extended-release dipyridamole (200 mg) and aspirin (25 mg) administered twice daily after the placement of a new arteriovenous graft until the main endpoint of the study was reached. That primary outcome was loss of primary unassisted patency, defined as patency without thrombosis or requirement for intervention, and secondary outcomes were cumulative graft failure and mortality. A Cox proportional-hazards regression with adjustment for prespecified covariates was used to analyze primary and secondary outcomes.
The study sample consisted of 649 patients who were recruited from 13 centers in the United States and randomly assigned to receive dipyridamole plus aspirin (n = 321) or placebo (n = 328) during a period of 4.5 years and who were observed for 6 additional months. At 1 year, the incidence of primary unassisted patency was 23% in the placebo group (95% confidence interval [CI], 18% - 28%) vs 28% in the dipyridamole-aspirin group (95% CI, 23% - 34%), yielding an absolute difference of 5 percentage points.
Compared with the placebo group, the dipyridamole plus aspirin group had less stenosis and a significantly longer duration of primary unassisted patency (hazard ratio
, 0.82; 95% CI, 0.68 - 0.98; P = .03). The study groups were not significantly different in the incidences of cumulative graft failure, mortality, the composite of graft failure or death, or serious adverse events including bleeding. "Treatment with dipyridamole plus aspirin had a significant but modest effect in reducing the risk of stenosis and improving the duration of primary unassisted patency of newly created grafts," the study authors write. "As is consistent with the known antiproliferative effects of extended-release dipyridamole plus aspirin, the results suggest that strategies targeting neointimal hyperplasia may be an important area for future research."
Limitations of this study include failure to meet the enrollment goal, limiting the applicability of the subgroup analyses. Furthermore, the possible benefit of continuing treatment with dipyridamole plus aspirin on cumulative graft patency could not be determined because the study drug was stopped once the primary outcome was reached.
In an accompanying editorial, Charmaine E. Lok, MD, from the University of Toronto in Ontario, Canada, notes that this study may also help clarify the issue of whether intra-access flow in grafts should be monitored routinely.
"The study by Dixon et al. is unique in reporting on an intervention that provides an improvement, albeit modest, in graft outcomes without an excessive risk of adverse events," Dr. Lok writes. "Though a formal cost-effectiveness analysis is lacking and the cumulative effect of ongoing therapy on graft survival is unknown, dipyridamole-aspirin therapy appears to be a low-risk, broadly applicable intervention that may prolong access patency among patients undergoing hemodialysis whose arteriovenous graft is a lifeline."
The National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, and Boehringer Ingelheim Pharmaceuticals supported this study. Boehringer Ingelheim Pharmaceuticals also provided the extended-release dipyridamole plus aspirin and matched placebo. Some of the study authors have disclosed various financial relationships with Proteon Therapeutics, Pervasis Therapeutics, Renal Advantage, Boehringer Ingelheim Pharmaceuticals, Abbott Laboratories, Genzyme, Angiotech, Bellus Health (formerly Neurochem), Novartis, GlaxoSmithKline, Merck, Ortho Biotech, GE Healthcare, Amgen-Research Triangle Institute, Eli Lilly, Pfizer, and DeCode Genetics.