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Permanent vascular access: a nephrologist's view
1Department of Medicine, Washington University School of Medicine, St Louis, MO.
Insights
Vascular access complications, primarily thrombosis and stenosis in prosthetic grafts, significantly impact hemodialysis patients. Improved screening and treatment strategies are crucial for managing these common issues.
Area of Science:
- Nephrology
- Vascular Surgery
- Medical Engineering
Background:
- Vascular access complications are a leading cause of morbidity in US hemodialysis patients.
- Prosthetic graft fistulas are common, despite recommendations for arteriovenous fistulas.
- Thrombosis and stenosis are the most frequent complications of prosthetic grafts.
Purpose of the Study:
- To review current understanding and management of vascular access complications in hemodialysis.
- To highlight challenges and future directions in preventing and treating graft-related issues.
Main Methods:
- Review of current literature on vascular access complications, pathogenesis, screening, and treatment.
- Discussion of diagnostic techniques including recirculation measurements, pressure monitoring, and Doppler ultrasound.
- Evaluation of existing and emerging treatment modalities such as surgery, angioplasty, and thrombolysis.
Main Results:
- Hospitalization rates for fistula complications are higher in patients with diabetes and of black race.
- Intimal hyperplasia, driven by growth factors and endothelial injury, contributes to complications.
- Current screening combines multiple techniques for optimal fistula evaluation.
Conclusions:
- Effective long-term pharmacologic prevention of thrombosis and stenosis in graft fistulas remains elusive.
- Future research should focus on improving primary fistula creation, graft materials, and complication prevention strategies.
- A multidisciplinary approach integrating surgical, interventional, and pharmacological strategies is needed.
Abstract:
Vascular access complications are the greatest cause of morbidity in hemodialysis patients in the United States. Although arteriovenous fistulas have been recommended as the preferred mode of vascular access, recent data indicate that the majority of patients on hemodialysis in the United States have prosthetic graft fistulas. The most frequent complications of prosthetic graft fistulas are thrombosis and stenosis. Hospitalization rates for fistula complications are higher in patients with diabetes mellitus and of black race. Pathogenesis of intimal hyperplasia may include elaboration of platelet-derived growth factor and mechanical endothelial injury. Screening for stenosis and impaired blood flow in fistulas can be carried out with recirculation measurements, venous and intra-access pressure measurements, and Doppler ultrasound. A combination of the techniques is probably the best current strategy for fistula screening and further evaluation. Surgical thrombectomy and fistula revision remain the standard for comparison of newer approaches to management of complications. Percutaneous angioplasty with or without stent placement, thrombolysis, and use of atherectomy devices may play an increasing role in the treatment of complications, although comparative trials of these modalities need to be performed. No satisfactory long-term pharmacologic means of preventing thrombosis, stenosis, or restenosis have been found for graft arteriovenous fistulas. It is hoped that future directions in the field of vascular access placement and management will include better strategies for allowing primary arteriovenous fistula development, advances in graft materials, improved understanding of the pathogenesis of thrombosis and stenosis, and development strategies to prevent complications.