Operator learning curve for transradial liver cancer embolization: Implications for the initiation of a transradial access program

PURPOSE We aimed to analyze transradial access (TRA) learning curve on patients undergoing hepatic chemoembolization, investigating the relationship between procedural volumes and various benchmarks of procedural success. METHODS We enrolled 60 consecutive patients who received two unilobar hepatic chemoembolizations within a 4-week interval performed by a single interventional radiologist, highly-trained in conventional transfemoral access (TFA) procedures, but without any previous practical experience in TRA procedures and with a preliminary 2-day theoretical training only. Consecutive patients were prospectively enrolled and analyzed in 3 groups: A (cases 1 to 20), B (cases 21 to 40), and C (cases 41 to 60). All patients underwent one hepatic chemoembolization using TRA and the other one using TFA in random order. All TFA procedures performed by the same operator in the same series of patients were considered as the control group. Primary endpoint was to analyze the relationship between TRA procedure operator experience and benchmarks of procedural success, to define the optimal procedural learning curve. RESULTS Technical success was obtained in all patients, with a crossover rate (radial to femoral access) of 0%. An association between incremental TRA operator experience (in terms of performed procedures) and decrease of preparation, puncture, fluoroscopy, and total examination times was observed. Similarly, inverse associations between incremental TRA operator experience and contrast medium (CM) volumes (P < 0.001) and radiation dose (RD) values (in terms of RAK - Reference Air Kerma) (P < 0.001) were also observed. Compared with TFA, CM volumes and RD values were significantly higher only in group A (cases 1-20). Procedure success remained high in all TRA groups and no significant association between TRA incremental experience and postprocedural outcomes was found. Higher postprocedural complaints at the access route and more limitations in performing basic activities were recorded after TFA vs. TRA (P < 0.001). CONCLUSION TRA catheterizations can be safely performed in patients treated for liver cancer embolization after a relatively short training in controlled conditions and with a better performance in comparison with TFA. Operator proficiency improves with greater TRA experience, with a threshold needed to overcome the learning curve represented by about 20 procedures.