Factors affecting the physical characteristics of arterio-venous fistula in patients with renal failure

Abstract: Background and PurposeA patent access is vital for a dialysis patient. The arterio-venous fistula (AVF), the most important access for haemodialysis (HD), is frequently affected by extensive complications such as stenosis and occlusions.Study I: To investigate whether the dimensions of AVFs used for performing haemodialysis were affected by the original disease.Study II: To investigate if the diameter of the distal radiocephalic fistula could influence left ventricular variables in stable haemodialysis patients.Study III: To investigate whether a single Far Infrared (FIR) light treatment could alter blood velocity, AVF diameter or inflammatory markers.Study IV: To evaluate in what extent the renal diagnosis and radiological interventions affected the dysfunction of AVF and results of percutaneous transluminal angioplasty (PTA).Materials and methodsStudy I: The lumen diameter of the AVF was studied by ultrasound in 19 patients with autosomal dominant polycystic kidney disease (ADPKD) and in 19 control patients. The monitoring was performed along the forearm part of the vein, the maximal diameter was measured. The diameters of the two needle insertion sites were also measured.Study II: Nineteen patients were investigated with echocardiography, using M-mode recordings and measurements in the 2D image. Ultrasound and doppler ultrasound were performed. Transsonic measurements were performed after the ultrasound investigation. Measurements of the diameter of the AVF were performed in four locations. Heart variables were analysed regarding left ventricular (LV) criteria.Study III: Thirty patients with native AVF in the forearm were included. Each patient was his/her own control. Ultrasound examinations of the AVF diameter and blood flow velocity were performed before and after a single Far Infrared light (FIR) treatment.Study IV: 522 radiological investigations and endovascular treatments between January 1, 2006 and December 31, 2014 were analysed in 174 patients, retrospectively. All investigations had been performed due to clinical suspicion of impaired AVF function. All stenoses were evaluated and the number, degree, length, location and relation to anastomosis were recorded. After PTA the remaining stenoses were evaluated again and complications were recorded.ResultsStudy I: The diameter of the AVF at the maximal site in patients with ADPKD was significantly wider than that for the control patients.Study II: A larger AVF mean and maximal diameter worsened left ventricular characteristics.Study III: A single FIR treatment resulted in a significant increase in blood velocity over the AV fistula from a mean of 2.1±1.0 m/s to 2.3±1.0 m/s. The diameter of the arterialized vein became wider, i.e. 0.72±0.02 to 0.80±0.02 cm. The increase in fistula blood velocity correlated positively with baseline serum-urate and the increase in venous diameter correlated positively with the baseline plasma orosomucoid concentration.Study IV: The degree of AVF stenosis before PTA correlated significantly with the degree of remaining stenosis after intervention. Arterial stenosis was significantly more frequent among patients with diabetic nephropathy and interstitial nephritis. A shorter life span between PTAs was related to diabetic nephropathy.ConclusionsStudy I: The receiving veins of AVF in patients with ADPKD have an abnormality that causes a greater than normal dilatation in response to the arterialization.Study II: The maximal diameter of the distal AVF seems to be a sensitive marker of LV impairment in stable haemodialysis patients.Study III: A single FIR treatment increased AVF blood velocity and vein diameter. Thus, one FIR treatment can help maturation of AVF in the early postoperative course.Study IV: Repeated PTA was performed significantly more often in patients with diabetic nephropathy. Clinically significant stenosis should be dilated as soon as possible. Occlusion of the AVF should be thrombolyzed and/or dilated when diagnosed.