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Background: Frequent hemodialysis (HD) may be associated with an increased risk of vascular access complications. Studies addressing vascular access outcomes in frequent HD show conflicting results. Methods: We searched Medline for trials looking at vascular access outcomes in frequent HD. Results: Nineteen studies met the inclusion criteria; only studies with a control group were included for analysis (n = 15). The vascular access event rate was higher in intensive HD as compared to conventional HD (difference of 6.7 events per 100 patient-years, p = 0.009). Overall event rates were not significantly different between conventional and intensive HD when stratified for access type, but were notably higher in the arteriovenous grafts and catheter group as compared to the arteriovenous fistula (AVF) group. Conclusion: Intensive HD is associated with an increased risk of vascular access complications. Overall reported event rates were lower in the AVF group. Further controlled studies should investigate whether a ‘fistula first' strategy may be recommended also for intensive HD.

Today, a growing activity to improve patient safety in all domains of medicine is reality. This chapter deals with patient safety research in general, but is also about strategies to implement this evidence in the daily clinical work treating patients on dialysis. Good clinical research practice has been well established for some years. In the domain of dialysis access, further basic, clinical, epidemiological and health service research will be important to further improve patient safety as a whole.

Stenotic intimal thickening at the venous end of prosthetic arteriovenous (AV) fistulas for hemodialysis has been associated with perianastomotic mismatch in elastic properties between prosthesis and vein and high flow velocities. In a prospective study, we investigated the role of flow velocity on the occurrence of intimal hyperplasia in prosthetic AV fistulas in hemodialysis patients. In 24 patients, the flow velocities were assessed in the distal graft and the outflow vein postoperatively, with the use of vessel wall Doppler tracking, a noninvasive ultrasound technique. The initial velocity in the venous anastomoses was correlated with the occurrence of stenoses during follow-up (2 years). The detection of a stenosis was performed with both Duplex ultrasound and angiography. In 4 cases a stenosis developed in the venous anastomosis, in 8 cases in the venous outflow segment, and in 4 cases at both sites. Higher flow velocities around the venous anastomosis was observed in fistulas developing a stenosis at this site as compared with the nonstenotic fistulas (p < 0.05). The occurrence of stenoses in prosthetic AV fistulas in or adjacent to the venous anastomosis is not associated with a mismatch in elastic properties, but with high flow velocity.

A dialysis arteriovenous fistula caused life-threatening high-output cardiac failure in a 66-year-old patient. Excessive shunting through the dialysis fistula was demonstrated by invasive measurement of cardiac output, systemic arterial blood pressure, systemic vascular resistance, and oxygen consumption before and after temporary occlusion of the dialysis fistula. Noninvasive echocardiographic evaluation of the influence of fistula compression on cardiac output and noninvasive duplex measurement of the fistula flow also confirmed the diagnosis. Following surgical closure of the fistula, the patient's condition improved, and signs of congestive heart failure subsided. High-output cardiac failure is a rare complication of dialysis arteriovenous fistulas. The diagnosis may remain unrecognized for longer periods. Noninvasive methods for estimation of the hemodynamic importance of a fistula may be of help in the establishment of the proper diagnosis.