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Long-term outcomes of arteriovenous snuffbox fistulas for hemodialysis

OBJECTIVE

Autologous arteriovenous fistulas in the arm have been shown to be superior to all other types of arteriovenous access and should be placed as far distally as possible. The aim of the present study was to delineate the advantages of snuffbox fistulas (SBFs).

METHODS

From January 2007 through April 2017, first time or new arteriovenous fistula surgery was performed in 375 patients. If feasible, an SBF was chosen. The observation period ended in December 2019. The focus of the present study was on the patency rates, redo surgery, complications, and mortality rates.

RESULTS

SBFs were created in 236 patients (92 women and 144 men; mean age, 67 years; 46% with diabetes). Within the first 6 weeks, 11% of the fistulas had failed. The primary patency rates were 75%, 69%, 64%, 61%, 60%, and 58% after 1, 2, 3, 5, 7, and 9 years, respectively. The secondary patency rates were 86%, 83%, 80%, and 77% after 1, 2, 3, and 5 years, respectively. Age, sex, and the presence of diabetes mellitus had no effect on the primary patency rates. Patients with a right-sided SBF had significantly worse primary patency. Of the 236 patients, 154 (65%) had died during the observation period. The incidence of surgical site infection within the first 30 days and access-related ischemia during the observation period was <1%.

CONCLUSIONS

The results from the present study have shown that with suitable anatomic conditions, a SBF is a good choice for the creation of dialysis access. The patency rates were encouraging, and it offers the longest puncturable segment of the cephalic vein. Also, the rate of perioperative complications was low.

[Vascular access for shunt devices]

In Germany approximately 70,000 patients with a renal insufficiency are treated by hemodialysis. The most frequent reasons for the need for dialysis are currently diabetic nephropathy and nephrosclerosis. Due to the increasing average age and the resulting multimorbidity of dialysis patients, the difficulties of medical care have also increased. Therefore, an interdisciplinary treatment of these patients is of great importance. An important point in the treatment is the choice of vascular access. This depends on the patient's concomitant diseases and on the urgency of hemodialysis. Vascular access is a prerequisite for dialysis and thus for the survival of the patient. A well-functioning dialysis access not only ensures the patient's survival but it is also important for the quality of life. The surgeon's task is therefore to create the optimal vascular access at the right time together with the treating nephrologist.

Organisation of a Radiological Vascular access Unit

An interventional vascular access unit is usually part of an interdisciplinary centre, including departments of nephrology, vascular surgery, angiology and interventional radiology. We present recommendations on quality control, equipment and diagnostic and interventional techniques for the treatment of vascular access insufficiency.

[Central venous catheters as access for acute and long-term dialysis]

Central venous dialysis catheters are indispensible as a rapid large lumen access to the blood compartment. If such a central venous catheter is necessary for longer than 2-3 weeks it is better to implant a tunnelled cuffed catheter initially or to switch early from the non-tunnelled acute catheter to a tunnelled cuffed catheter. Tunnelled cuffed catheters can be used for many weeks or even years and the complication rate is less than that of non-tunnelled acute catheters. The proportion of dialysis patients with long-term dialysis using tunnelled cuffed catheters has increased rapidly in recent years and now stands at approximately 20 % in Germany. These catheters are, however, prone to more infectious complications and more thromboses than native arteriovenous fistulas or prosthetic shunts. The mortality of patients with long-term dialysis catheters is also higher than those with arteriovenous shunts. For these reasons central venous catheters will always be regarded as the third choice dialysis access when arteriovenous fistulas are not possible. Catheters are available in a wide variety of designs but the individual advantages are still unclear. In order to avoid short-term and long-term complications a variety of measures for implantation and use during dialysis treatment have been developed which make the use safer.

Endovascular Treatment of Dysfunctional Hemodialysis Catheters

Hemodialysis-catheter dysfunction is a common clinical condition in nephrology. Like other central venous devices, hemodialysis-catheters show a disposition for partial or complete thrombotic obstruction and fibrin sleeve formation. Thrombolytic infusion is recommended as therapy of first choice. Alternative interventional strategies include over-the-wire catheter exchange, mechanical fibrin sleeve stripping with a snare and angioplastic sleeve disruption. Those approaches show extremely variable results with mediocre long-term patency rates. Therefore, catheter-avoiding strategies should be considered in detail and AV-fistula creation preferred.

[Hemodialysis fistulas: possibilities of vascular ultrasound]

Vascular ultrasound is an established technique in shunt diagnostics for hemodialysis fistulas that allows non-invasive diagnosis of vascular morphology and hemodynamics. Early detection of shunt stenoses in hemodialysis fistulas or thrombotic occlusions facilitates an interventional decision. High occlusion rates of up to 45% within 1 year in hemodialysis fistulas due to reduced flow volume justify follow up with vascular ultrasound examination. The use of high resolution transducers in vascular ultrasound enables complications, such as stenoses and occlusions to be recognized early therefore allowing preemptive therapy. In the present review the examination technique and strategy, the most important complications and treatment options will be discussed.