Primary vascular access.

Primary vascular access is usually achievable by a distal autogenous arterio-venous fistula (AVF). This article describes the approach to vascular access planning, the usual surgical options and the factors affecting patency.     

Direct access surgery.

Evolving surgical practice in the UK is imposing increasing pressures on surgical outpatient clinics. A Direct Access Surgery (DAS) programme was evaluated in which otherwise healthy patients with simple surgical conditions presenting little diagnostic difficulty were referred directly to hospital for surgical operation without attending the outpatient department. Specific referral criteria for DAS were devised. Appropriate surgical conditions or procedures included hernias, vasectomies, cystic scrotal swellings, subcutaneous lumps and skin lesions, symptomatic gallstones, varicose veins and ingrowing toenails. Over a 12 month period, 105 patients were referred for DAS and 102 underwent operation. There was a low incidence of inaccurate diagnosis (< 2%) and inappropriate referral (< 1%). DAS was well received by both General Practitioners (GPs) and patients. Implementation of such programmes may result in considerable savings of outpatient time and resources.     

Monitoring vascular access flow.

Blood flow in peripheral arterio-venous fistulae and grafts as used for hemodialysis access can be derived from measurements of the amount of access recirculation induced by reversing the dialysis blood lines and a knowledge of dialyzer blood flow rates. Furthermore, low or falling access blood flow rates are predictive of access dysfunction from the development of an intraluminal stenosis, which may be reversible, or of access thrombosis. The monitoring of access blood flow rates in hemodialysis populations is therefore suggested. Technologies including ultrasound dilution, hematocrit dilution (or concentration) differential conductivity, and thermodilution used for such monitoring are described.     

Ureteral access for upper urinary tract disease: the access sheath.

Ureteral access with the flexible ureteroscope remains a challenge for the urologist. The routine use of a newly developed, site-specific ureteral access sheath facilitates entry into the ureter for fragmentation and basket extraction of ureteral and renal calculi. The step-by-step technique of ureteral access with the Access Sheath is described.     

Implementation of a vascular access quality programme improves vascular access care.

INTRODUCTION: In the Netherlands an access quality improvement plan (QIP) was introduced by vascular access coordinators (VAC) with the aim to decrease vascular access-related complications by preemptive intervention of malfunctioning accesses. A vascular access QIP was established in 24 centres (46% of all Dutch facilities) and a structural multidisciplinary vascular access meeting was instituted. In these centres, including 2300 patients, a protocol for enhancement of fistula creation and access surveillance programme was implemented, with instruction of physicians and nurses, and rounds to discuss complications and evaluate vascular access interventions. The number and type of vascular access, permanent catheters, thrombosis rates and number of interventions were evaluated at the start and end of the study period. RESULTS: After the surveillance programme, the number of autogenous arterio-venous fistulas (AVFs) had increased significantly from 69 to 77% (P < 0.01), while the use of temporary subclavian vein catheters declined (34% vs 11%) (P < 0.01), with a substantially higher percentage of jugular vein catheters (from 23 to 35%). Interventional treatment of malfunctioning accesses by percutaneous transluminal angioplasty (PTA) (from 0.39 to 0.50 patient/year; P < 0.001)) and surgical revisions (from 0.06 to 0.12 per patient/year; P < 0.001) also increased. CONCLUSION: These data demonstrate that a vascular access QIP resulted in placement of more autogenous AVFs, increased number of PTAs and surgical interventions. These findings suggest that a vascular access care QIP is worthwhile to improve dialysis patients' care and access morbidity.     

The function of permanent vascular access.

BACKGROUND: Complications arising from vascular access (VA) are major causes of morbidity in patients on renal replacement therapy (RRT). They contribute to frustration of health care providers and to high medical cost. To prevent failures in the future it will be helpful to identify the factors that are related to VA malfunction. METHODS: In a retrospective analysis we analysed the types, duration and primary rate of patency of 1033 permanent vascular accesses in 544 consecutive patients established during a 13-year period in a tertiary care hospital. Patient characteristics, incidence, and risk factors related to VA failure were registered. In addition, VA outcomes in patients who started haemodialysis with a catheter and in whom initial VA failure occurred were analysed separately. RESULTS: Forty-five per cent of patients required a central catheter at the start of HD, but 92% of them were being dialysed with an a-v fistula at the last observation. The total number of complications was 0.24 episodes per patient per year at risk and the rate of thrombosis 0.1. A total of 52% of patients were dialysed throughout the observation period with their initial a-v fistula; 9.3% had more than three episodes of VA failure. The radiocephalic a-v fistula was the VA with the best median duration, exceeding 7 years, but also the type that had the highest initial failure rate, i.e. 25% of patients and 13% of the events. The brachiocephalic a-v fistula was the second most frequent type of VA, with a median duration of function of 3.6 years, in contrast to the humerobasilic a-v fistula, which exceeded 5 years. Average patency of the different types of grafts did not exceed 1 year, with the exception of the autologous saphenous graft with a median duration of function of 1.4 years. Patients with glomerulonephritis had the best function rates for their VA, the median exceeding the duration of the study, whereas in half of the diabetic patients it was less than 1 year. The duration of patency of the VA was twice in patients below age 65 years and in elderly males compared to elderly females. Patients who started HD with a catheter, as well as those with initial VA failure, had a higher rate of VA failure in the subsequent course on RRT. CONCLUSION: The radiocephalic and the humerobasilic a-v fistulae are the two types of VA with the longest duration of function, although a high rate of initial failure is seen with the radiocephalic a-v fistula. Age, female gender, presence of diabetic nephropathy, start of dialysis with a catheter, and failure to wait for initial maturation of the VA are risk factors, and account for the majority of VA failures during RRT.     

History of vascular access for haemodialysis.

The history of vascular access is a history of vascular surgery as well as a history of dialysis therapy. This survey is a personal view on the history of vascular access without the ambition to cover every detail, but with an effort to mention the major steps in a fascinating panorama.     

Population requirements for vascular access surgery.

The native arterio-venous fistula provides the best access for haemodialysis. The dialysis population is growing in number, becoming more elderly, and has increasingly complex medical co-morbidity. The ability to establish and maintain optimal haemodialysis access in this population requires the planning and commissioning of operating and diagnostic facilities and the training of sufficient suitable surgical specialists. This article outlines the major factors that influence the demand for and requirements of a vascular access service for the renal failure population.     

Nondialysis uses for vascular access procedures.

Chemotherapeutic agents, blood products and hyperalimentation solutions have been administered and recurrent diabetic ketoacidosis has been treated via vascular access procedures in 13 patients during the period from 1972 through 1977. Bovine heterograft, saphenous vein graft and the direct arteriovenous fistulae have been successfully utilized in the construction of arteriovenous fistulae in patients requiring vascular access for nonhemodialysis purposes. Operative techniques and therapeutic usefulness are discussed.     

Infectious complications of the hemodialysis access.

Infectious complications of the vascular access are a major source of morbidity and mortality among hemodialysis (HD) patients. Numerous reports implicate the vascular access in up to 48 to 73% of all bacteremias in HD patients. The incidence of vascular access-related infection is highest when central venous dialysis catheters are employed. Native arteriovenous fistulas carry the lowest risk of infection. Unfortunately, prosthetic arteriovenous grafts, which represent the most common type of HD access in the United States, have been repeatedly shown to be a risk factor for bacteremic and nonbacteremic infections. Silent infection in old nonfunctional clotted prosthetic arteriovenous grafts has recently been recognized as a frequent cause of bacteremia and morbidity among HD patients. High proportions of infections related to the vascular access are caused by staphylococcal organisms, which carry high rates of mortality, recurrence, and metastatic complications. Management of vascular access-related infection has two aspects: The first relates to the choice, duration, and mode of administration of antibiotic therapy. Empiric antibiotic therapy, guided by demographic data and severity of illness, should be employed when the causative organisms are unknown. Prolonged administration of specific parenteral antibiotics is crucial in decreasing complications of infection, especially in cases of staphylococcal bacteremia. The second aspect relates to management of the vascular access. Efforts directed toward bacteriological cure should be concurrent with efforts to preserve native venous access sites whenever possible. Efforts to prevent vascular access-related infection should focus on increasing placement of arteriovenous fistulas and minimizing insertion of central venous dialysis catheters. Careful inspection and monitoring of the vascular access is of paramount importance in early detection of vascular access site-related infections. Several new approaches aimed at preventing catheter and prosthetic graft-related infection are being explored.