Development and Validation of a Nomogram to Predict the Difficult Transradial Approach for Percutaneous Transluminal Angioplasty in Radiocephalic Arteriovenous Fistulas.

BACKGROUND:The transradial approach (TRA) is a critical access method for percutaneous transluminal angioplasty (PTA) in hemodialysis (HD) patients with arteriovenous fistula (AVF) dysfunction, yet its technical challenges remain unaddressed. Currently, no predictive tools exist to assess TRA feasibility. This study aimed to identify risk factors for difficult TRA and develop a predictive nomogram. METHODS:We retrospectively analyzed 160 HD patients undergoing ultrasound-guided TRA-PTA across three Chinese hospitals (May 2022-May 2024). A training cohort (n = 110) and validation cohort (n = 50) were established. Independent risk factors were identified via univariate and multivariate logistic regression. A nomogram was constructed and validated using ROC curves, calibration plots, and decision curve analysis (DCA). RESULTS:The cohort had a mean age of 59.7 ± 12.9 years, with 36.9% (59/160) experiencing difficult TRA. Radial artery diameter (OR = 2.1, p = 0.003), calcification (OR = 3.4, p < 0.001), and tortuosity (OR = 2.8, p = 0.002) were independent predictors. The nomogram demonstrated strong discrimination (AUC: 0.902), with sensitivity = 0.907 and specificity = 0.806 at a cutoff of 0.416. Calibration showed excellent agreement (mean absolute error = 0.022), and DCA confirmed clinical utility across threshold probabilities of 0.2-0.8. CONCLUSION:This nomogram demonstrates that for optimal puncture feasibility, the radial artery diameter should be ≥ 3 mm when both calcification and tortuosity are present, > 2.2 mm if either condition is present, and > 1.5 mm if neither is present. The nomogram effectively predicts difficult TRA during AVF-PTA in HD patients, offering clinicians a practical tool to preoperatively assess procedural feasibility and optimize vascular access planning.