Corelation of arteriovenous fistula flow efficiency indicator with KT/ V ratio in dialysis patients

Aim: In this study, we aimed to evaluate the correlation of flow rate measured by doppler ultrasonography of patients undergoing dialysis via arteriovenous fistula with the kt / V ratio, which is the dialysis efficiency indicator. Material – Method: Between April 2019 and September 2019, 58 patients who applied to Van Yüzüncü Yıl University Medical Faculty Hospital Radiology Department and who had previously opened arteriovenous hemodialysis fistula were included in the study. Ultrasonography examinations were performed with the patient in a supine position. In the area starting from the subclavian region to the distal forearm, respectively; arterial structures, fistula anostomosis line and venous structures were evaluated. It was evaluated whether there was significant thrombus or stenosis in the arterial structures. The anastomosis diameter and the flow rate were measured by color doppler ultrasonography (RDUS) with gray mode examination performed at the level of fistula anostomosis. The flow rate of the delivery vascular structure (vein) was measured and compared with the flow measured at the level of anostomosis. In addition, presence of phlebitis and / or thrombosis, degree of thrombosis and anatomical localization were recorded. Patients with fistula flow rate above 250 ml / min (active fistula) were accepted as sufficient flow in RDUS examinations, and fistula flow rate was compared with kt / V ratios. Patients with fistula flow rate of 250 ml / min and less were evaluated as insufficient flow, and the kt / V ratios of patients with fistula total thrombosis were not calculated. After the fistula flow rate of the patients was measured, kt / V ratios were calculated. Diagnosis: We found a highly positive and statistically significant correlation between fistula flow rate and kt / V r = 0.72 (p = 0.001). We found a highly positive and statistically significant correlation between the fistula level and delivery vein flow rates of patients without phlebitis or thrombosis in the delivery vein and r = 0.871 (p <0.05). Patients with a fistula flow rate above 400 ml / min were found to have a vein diameter of 5 mm and above, and patients with a fistula flow rate below 250 ml / min and / or thrombosed of the fistula were less than 4 mm. We found a moderately positive and statistically significant correlation between the flow rate and the diameter of the delivery vein r = 0.66 (p = 0.001) (p <0.05). The carrier vein was evaluated as cephalic vein in 30 of the patients with fistula flow rate over 250 ml / min and the carrier vein was the basilic vein in 11. It was evaluated in favor of dysfunction related to the selection of the cephalic vein of the vascular access site in 6 of the patients with a carrier basilic vein and it was referred to us. Result: Flow rate measurement can be done from the anostomosis level and the delivery vein. When measuring from the delivery vein, more than 50% thrombosis, segment phlebitis longer than 4 cm, aneurysmatic dilatation should be considered in the localization where measurement is made and should be specified. In fistula measurements, especially in proximal radiocephalic fistulas, the carrier vein should be indicated on the arm and forearm. Fistula flow rate can ideally be determined as 500-1500 ml / min, but in patients with lower or higher flow rates, it can undergo long-term dialysis without problems. Those with a fistula flow rate below 250 ml / min can be considered as insufficient flow. RDUS is the first thing to be done in the patient who is considered fistula dysfunction. There is a positive correlation between fistula flow rate and kt / V ratio. In addition, there is a positive correlation between the fistula flow rate and the diameter of the delivery vein. Key-Words: Arterio-venous fistula, doppler ultrasonography, fistula flow