Distal versus conventional radial large-bore access for percutaneous coronary intervention of complex coronary lesions: Rationale and design of the DISCO COMPLEX randomized superiority trial.

Rationale Distal radial access (DRA) has emerged as a promising alternative to conventional transradial access (TRA) for coronary angiography and percutaneous coronary intervention (PCI). However, existing randomized evidence on DRA primarily involves low-risk patients undergoing diagnostic angiography or non-complex PCI using ≤6 French (Fr) introducer sheaths. The clinical benefits of DRA among patients undergoing PCI for complex coronary lesions using large-bore guide catheters remain therefore uncertain.Design DISCO COMPLEX is an investigator-initiated, prospective, multicenter, international, open-label, randomized, controlled trial with a blinded outcome assessment and superiority design. The trial will compare in a 1:1 ratio large-bore DRA versus conventional TRA using a 7-Fr introducer sheath in 708 patients undergoing PCI for complex coronary lesions (chronic total occlusions, left main disease, heavily calcified lesions, or complex bifurcations) with a 7-Fr guide catheter. The primary hypothesis is that large-bore DRA is superior to conventional TRA with respect to the incidence of forearm radial artery occlusion (RAO) assessed by Doppler ultrasound at hospital discharge. The prespecified DISCOPHILE COMPLEX hand function substudy is a non-inferiority trial evaluating whether large-bore DRA is not inferior to conventional TRA with respect to change in full-Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire score from baseline to 12 months in participants of the DISCO COMPLEX trial.Enrolment Status The trial aims to recruit a total of 708 patients from 10 to 15 participating centers across Europe. The first patient was enrolled on August 31, 2023. As of August 20, 2025, 385 patients have been included.Conclusion DISCO COMPLEX is the first randomized clinical trial designed to test the superiority of large-bore DRA over conventional TRA in reducing RAO rates among patients undergoing complex PCI with 7-Fr guide catheters.