Abstract Body (Do not enter title and authors here):
Background:
Chronic total occlusion (CTO) contributes to increased mortality because it is often revascularized by percutaneous coronary intervention (PCI). Traditionally, transfemoral (TF) access has been preferred in CTO-PCI owing to its high procedural complexity and ease of introduction of a large guide catheter. Transradial (TR) access is gaining popularity in PCI, but its efficacy in CTO-PCI has not been well investigated.

Methods:
We searched major databases to retrieve studies comparing TR and TF access in patients with CTO who underwent PCI. The DerSimonian and Laird random-effects model was used to pool the odds ratios (OR) and mean differences (MD) with 95% confidence intervals. Statistical significance was considered at p<0.05.

Results:
We included 18 studies with 30,286 CTO PCI cases (TR: 10921 and TF: 19365). For procedural outcomes, TR access was associated with a significantly lower total contrast volume requirement [MD: -19.57; 95% CI: -34.34, -4.81; p=0.009], with comparable procedural success [OR: 1.16; 95% CI: 0.97, 1.40] and total procedural time [MD: -5.30; 95% CI: -21.09, 10.48]. For clinical outcomes, TR was associated with significantly lower risks of in-hospital mortality [OR: 0.46; 95% CI: 0.25, 0.85; p=0.01], major adverse cardiovascular events [OR: 0.73; 95% CI: 0.59, 0.92; p=0.007], vascular complications [OR: 0.35; 95% CI: 0.25, 0.51; p<0.00001], and major bleeding [OR: 0.33; 95% CI: 0.20, 0.56; p<0.0001] compared with TF access.

Conclusion:
CTO PCI using TR access demonstrated favourable outcomes regarding lower contrast volume requirement, lower risks of in-hospital mortality, major adverse cardiovascular events, vascular complications, and major bleeding compared with TF access. The selection of appropriate arterial access varies on a case-to-case basis and according to operator preferences.