Buddy Wire-Supported Distal Access Catheter Advancement Technique (B-DAT) for Difficult Vertebral Artery Access: A Technical Note.

OBJECTIVE: Endovascular treatment (EVT) of posterior circulation lesions can be technically challenging when access to the vertebral artery (VA) is difficult because of tortuosity, stenosis, or a narrow caliber. Stable advancement of the distal access catheter (DAC) is often required for safe and effective EVT; however, selective VA cannulation with a guiding catheter (GC) may increase the risk of vascular injury or compromise flow in an unfavorable anatomy. We developed a buddy wire-supported DAC advancement technique (B-DAT) to facilitate direct DAC advancement into the VA. We evaluated the feasibility and safety of B-DAT in contemporary posterior circulation EVT practice, building on the modified buddy wire concept. METHODS: We retrospectively reviewed consecutive posterior circulation EVT cases performed at our hospital between April 2020 and September 2025, and identified cases in which B-DAT was used. In B-DAT, the GC is positioned in the subclavian artery and stabilized using a stiff buddy wire advanced into the ipsilateral brachial artery, enabling direct advancement of the DAC into the VA. The patient characteristics, VA anatomy, procedural details, technical success, and procedure-related complications were assessed. RESULTS: B-DAT was used in 10 of the 122 posterior circulation EVT cases. Indications included intracranial aneurysm embolization, percutaneous transluminal angioplasty and stenting, mechanical thrombectomy with adjunctive treatment, and transarterial embolization for arteriovenous malformations. Direct DAC advancement was successful in all cases, and all planned procedures were completed without procedure-related complications. CONCLUSION: B-DAT is a feasible and practical approach for facilitating direct DAC advancement in cases of difficult VA access during posterior circulation EVT.