Distal versus proximal transradial access and radial artery occlusion: a meta-analysis and trial sequential analysis

Distal radial access (DRA) has been proposed as a physiologically superior alternative to conventional proximal transradial access (TRA) for coronary angiography and percutaneous coronary intervention, with the potential to preserve radial artery patency. This systematic review and meta-analysis evaluated the comparative safety and efficacy of DRA versus TRA. PubMed/MEDLINE, Embase, Cochrane CENTRAL, and Web of Science were searched from inception to January 2026. Randomized controlled trials comparing DRA (anatomical snuffbox or dorsal distal radial puncture) with proximal TRA in adults undergoing diagnostic or interventional cardiac catheterization were included. Two reviewers independently performed study selection, data extraction, and risk-of-bias assessment using the Cochrane RoB 2 tool. Random-effects meta-analysis using the restricted maximum likelihood (REML) estimator with Knapp-Hartung adjustment was performed to pool odds ratios (ORs) and mean differences (MDs) with 95% confidence intervals (CIs) and 95% prediction intervals. Pre-specified subgroup analyses, meta-regression, trial sequential analysis (TSA), and GRADE certainty assessment were conducted. Twenty randomized trials enrolling 8,718 patients (3,966 randomized to DRA and 4,752 to TRA) were included. DRA significantly reduced radial artery occlusion (RAO) compared with TRA (OR 0.26, 95% CI 0.18-0.36; prediction interval 0.12-0.56; I² = 21.3%; NNT = 27). DRA also significantly reduced bleeding (OR 0.53, 95% CI 0.35-0.80; prediction interval 0.12-2.26; I² = 67.9%) and hematoma formation (OR 0.42, 95% CI 0.30-0.58). Access-site crossover was significantly higher with DRA (OR 2.28, 95% CI 1.27-4.08), and procedural success was lower (OR 0.53). There were no statistically significant differences between DRA and TRA in time to hemostasis, access time, total procedural time, fluoroscopy time, radial artery spasm, or number of puncture attempts. Subgroup analyses demonstrated consistent benefit of DRA on RAO across clinical settings, imaging guidance, sheath sizes, trial sizes, and follow-up durations. Trial sequential analysis confirmed that the evidence for RAO reduction is conclusive, while the evidence for bleeding has approached the required information size. In this updated meta-analysis of 20 randomized trials, distal radial access significantly reduced radial artery occlusion and bleeding compared with conventional proximal transradial access. These benefits were achieved at the cost of greater technical demand, as evidenced by higher crossover rates and lower procedural success with DRA. Distal radial access should be preferred when preservation of the radial artery is a clinical priority.