Clinical aspects of Arteriovenous fistula use in a haemodialysis population. Results based on retrospective and internventional studies

Abstract: When a patient suffers from end stage renal disease, the vascular access becomes the lifeline to perform regular haemodialysis (HD) treatment. The recommended first choice is the surgically created native Arteriovenous Fistula (AVF). The AVF is exposed for repeated needling when connecting the dialysis machine several times a week. The AVF patency is limited caused by stenosis, aneurysm, and infections. This requires additive interventions, in-hospital care, and sometimes abandonment of the AVF. The effect of access complications is uraemia progression, which jeopardizes patient survival. The overall aim of this thesis was to evaluate risk factors associated with AVF complications, and to analyse interventions that might prevent AVF dysfunction. Far Infrared illumination (FIR) is an unrecognized method used by a few centres as an attempt to improve AVF flow. Study I was a prospective study that included 30 patients with a native AVF in the forearm with the patient as his/ her own control. The primary aim was to evaluate if one single treatment with FIR of the AVF changed AVF blood flow (BF) velocity, diameter, or inflammatory markers. FIR increased BF velocity of the AVF from 2.1 to 2.3 m/s (p=0.02). The diameter of the arterialized vein increased from 0.72 to 0.80 cm (p=0.006). The change in AVF blood characteristics correlated with plasma-urate (p=0.004) and serum-orosomucoid levels (p=0.005). In Study II, the primary aim was to evaluate conditions that might lead to a dysfunctional AVF in a retrospective study of patients in regular HD treatment (33 Cases with AVF dysfunction, 33 Controls without) during a two-year follow-up. Cases had higher weekly doses of Erythropoiesis stimulating agent (ESA) than Controls both before (mean 8312 vs 4348 IU/w, p=0.005) and after (7656 vs 4477 IU/w, p=0.018) radiological AVF investigation/follow-up. In Study III, the primary aim was to evaluate to what extent end-stage renal disease (ESRD) was related to a specific diagnosis, and how radiological intervention affected the AVF dysfunction. This was a retrospective study of 174 patients with clinically suspected dysfunction of the AVF. AVF venous stenoses were most frequent and were located mostly close to the anastomosis and less frequent at the puncture sites. Arterial stenosis was significantly more frequent among patients with diabetic nephropathy (p<0.001) and interstitial nephritis (p<0.001). In Study IV, the primary aim was to determine risk factors that could explain the occurrence of AVF dysfunction. This was a retrospective analysis of 205 HD patients from two hospitals. The main finding was a higher weekly dose of ESA among Cases with AVF dysfunction versus Controls without dysfunction (median 8000 vs 5000 IU, p<0.001). In patients with DM, HbA1c was higher among Cases than Controls (50 vs 38 mmol/mol, p<0.001). In conclusion, the AVF patency among HD patients is limited. Risk factors for AVF dysfunction are high doses of ESA and iron and for arterial lesions those with diabetic nephropathy and interstitial nephritis. FIR light may improve the maturation and patency of the AVF as prevention, and readiness for repeated radiological interventions helps to prolong AVF patency.