Cannulation Challenges and Flow Variability of Arteriovenous Fistulae Among Hemodialysis Patients

Introduction/ Objectives Difficult cannulation of Arteriovenous Fistulae (AVF) remains a significant challenge, potentially affecting dialysis adequacy and increasing the risk of vascular access complications. This study aimed to assess the prevalence and describe AVF complications and Doppler-derived flow patterns among affected hemodialysis patients. Methods This retrospective observational study included adult maintenance hemodialysis patients treated at a single center in Tirana, Albania, between February 2024 and February 2025. Medical records and Doppler ultrasound findings were reviewed. Categorical variables were compared using Fisher’s exact test. Doppler analyses were descriptive because comparable measurements were unavailable for patients without difficult cannulation. Results : Of 141 screened patients, 96 had native AVFs, and 33 met the difficult-cannulation definition, representing 23.4% of the screened cohort and 34.4% of patients with native AVFs. Among these 33 patients, 99 Doppler measurements were analyzed: 17.2% showed low flow, 48.5% adequate flow, and 34.3% high flow. Thrombosis occurred in 19 patients (57.6%). AVFs aged 5-10 years had higher odds of calcification than AVFs aged less than 1 year (OR 15.00, 95% CI 1.60–140.20; p = 0.0096). Aneurysm or varicosity was also more frequent in the older group (p = 0.018). Discussion Doppler abnormalities were frequent among affected patients, but no association with difficult cannulation can be inferred without a comparison group. Conclusion Difficult cannulation was common in this cohort. The observed associations with AVF vintage are exploratory and require confirmation in prospective studies with standardized Doppler protocols and multivariable analysis.