Comparing Transradial and Transfemoral Access for Acute Ischemic Stroke Thrombectomy

Transradial access (TRA) is gaining traction as an alternative to transfemoral access (TFA) in mechanical thrombectomy (MT) for acute ischemic stroke (AIS). However, uncertainties persist regarding optimal sheath sizing, procedural adaptability, and the prevalence of access route failure rates. An improved understanding of the technical nuances and interventional challenges of different access approaches is essential to inform decision making in the field of neurointervention. This systematic review evaluates the range of vascular sheath and guide catheter sizes, procedural variations in thrombectomy technique, and failure rates between radial and femoral access in MT for AIS. A comprehensive search strategy was implemented in Nested Knowledge via PubMed, OVID, Springer and Cochrane databases until July 2025. The primary outcome was a comparison of access failure leading to crossover: TRA converting to TFA or vice versa. Other outcomes assessed were procedural technique variations, base catheter diameter, thrombectomy approaches (ADAPT, stent retriever and co‐aspiration), and the use of balloon guide catheters (BGC). Comparisons between TRA and TFA groups were made using a Welch's two‐sided T‐test, assuming no equal variance, in R‐studio. 343 articles were screened and 16 (1 RCT, 15 retrospective observational) were included, representing 1288 TRA and 5019 TFA cases. TRA crossover trended higher (6.99% [6.60, 7.37] vs 2.18% [2.13, 2.23], p=0.24), indicating a 3‐fold higher potential for TRA to fail and cross over to TFA compared to the opposite. Most common reasons for TRA failure were severe vascular tortuosity, radial vasospasm, or inability to advance devices distally. Reasons for TFA failure were unfavourable femoral and aortic arch anatomy. Radial access utilized predominantly 6F and 7F base catheters, with the 6F Glidesheath Slender (2.62mm outer diameter [OD]) being the most widely used, where 4/16 studies (n=311) utilized 7F and 8F base catheters (2.77‐2.95mm OD), demonstrating feasibility with larger‐bore radial options. Femoral access showed broader use of 8F‐9F base catheters (2.6‐3.5mm OD). 5/16 studies (n=201) measured the radial artery diameter with ultrasound to select access approach, taken together these data indicate a diameter range of >2.5 ‐ 2.7mm is suitable for radial entry. Substantial variability was seen in thrombectomy technique for TRA and TFA, where ADAPT, stent retrievers, and co‐aspiration were used variably across both access routes. However, BGCs were more frequently used in TFA than TRA (10.4% vs. 3.5%). The TFA approach is associated with more versatility—larger base catheters, more use of flow arrest, and no need to measure the arterial diameter. However, the TRA approach can accommodate a similar range of techniques (ADAPT, stent‐retriever, co‐aspiration) utilizing 1F smaller base catheters, and it is common to measure the radial artery diameter before sheath introduction. Despite this, TRA tends to fail about 3‐fold more often mostly due to anatomical challenges, forcing a conversion to TFA, indicating safety outcomes such as complications with TRA may need to be similarly multiplied to better compare the rates with TFA. Therefore, careful pre‐procedural assessment of arterial diameter, tortuosity, and technique selection is essential to maximize access and procedural success in MT for AIS treatment.