SAT-217 COMPLICATIONS OF ARTERIO-VENOUS FISTULA AS A VASCULAR ACCESS IN HEMODIALYSIS PATIENTS- A HOSPITAL BASED STUDY

Abstract

Vascular access is required for hemodialysis and arterio-venous fistula is the preferred access. It is the life line for patients on hemodialysis. Various guidelines have recommended monitoring and surveillance of arterio-venous fistula as a standard of care. Clinical examination can detect most of the complications. This study looked into various complications of arterio-venous fistula as a vascular access in hemodialysis patients. The study was conducted in the hemodialysis unit of a Teaching Hospital in Central Nepal from January 2017 till December 2017. Ethical clearance was taken from IRC, Nepal Medical College. Patients undergoing hemodialysis for at least 3 months were enrolled in the study. After informed and written consent, clinical examination and colour doppler ultrasound of the arterio-venous fistula was done. The physicians performing the clinical examination and the colour doppler examination were blinded to remove bias. Clinical, socio-demographic and biochemical parameters were recorded. Statistical analysis was done using Statistical Package for the Social Sciences software version 20 and Epi-info software version 7. Total study population was 102. The patency of arterio-venous fistula was seen in 91%. Primary failure was present in 15.7%. The different complications observed were pseudoaneurysm (16.7%), thrombus formation (17.6%), venous outflow stenosis (9.8%), juxta-anastomostic stenosis (8.8%), central vein stenosis (8.8%), extravascular hematoma (4.9%), megafistula (4.9%) and infection (2.9%). Sensitivity and specificity of clinical examination as compared to colour doppler ultrasound was 88% and 95% which varied with different complications. Secondary failure rate of arterio-venous fistula was 13.7%. The average blood flow rate across the AVF in the complications group was much higher (2183 ml/min) and was statistically significant (p=0.002). Female sex, high venous pressure, history of primary failure of AVF, Tuberculosis, higher pre dialysis systolic and diastolic blood pressure, low BMI and secondary AVF failure were statistically significant for complications associated with AVF. Presence of strong palpable pulsations on clinical examination of AVF was statistically significant parameter which identified complications of AVF.TableShowing Validity of clinical examination as compared to colour doppler ultrasound examination in detecting complications of AVF.ComplicationsSensitivity (%)(95% CI)Specificity (%)(95% CI)Positive Predictive Value (%) (95% CI)Negative Predictive Value (%) (95% CI)Thrombus87.5 (61.6-98.4)95.3 (88.5-98.7)77.7 (56.9-90.2)97.6 (91.8-99.3)Pseudoaneurysm71.4 (47.8-88.7)97.5 (91.3-99.7)88.2 (65.0-96.0)92.9 (87.1-96.2)Stenosis95.4 (77.1-99.8)91.2 (82.8-96.4)75 (59.5-85.9)98.6 (91.4-99.8)Infection40 (5.27-85.3)98.9 (94.3-99.7)66.6 (17.7-94.8)96.9 (93.9-98.5)Hematoma40 (5.3-85.4)96.9 (91.2-99.3)40 (12.4-75.8)96.9 (93.8-98.4) Open table in a new tab Arterio-venous fistula is associated with higher rate of complications. Clinical examination is highly sensitive and specific but underutilized tool to detect the complications of arterio-venous fistula. Colour doppler ultrasonographic examination should also be done to look into hemodynamics of associated AVF and managed accordingly. Monitoring and surveillance of AVF should be performed as a standard of care in every hemodialysis centre.