Buddy Catheter Technique: A Method of Guiding the Mo.Ma Ultra into a Left Common Carotid Artery That Branches off the Aortic Arch at a Steep Angle

OBJECTIVE: The Mo.Ma Ultra is an embolic protection device used in carotid artery stenting (CAS). In cases of left internal carotid artery stenosis (ICS) in which the common carotid artery (CCA) branches off the aortic arch at a steep angle, insertion of the Mo.Ma Ultra into the CCA is sometimes difficult. We introduce a “buddy catheter technique” that helps guide the Mo.Ma Ultra into the CCA, with an additional 4 Fr catheter into the external carotid artery. CASE PRESENTATION: An 84-year-old man with left ICS whose CCA also branched off the aortic arch at a steep angle also underwent CAS. The “buddy catheter technique” was used, and the Mo.Ma Ultra was inserted smoothly. The buddy catheter technique displaces the left CCA upward. Displacement straightens the vessels anatomically, and the ledge effect can be prevented by aligning the course of the vessels with the wire. Nevertheless, this technique requires bilateral femoral puncture, and so, complications can occur. CONCLUSION: The buddy catheter technique may be considered in cases in which the left CCA branches off the aortic arch at a steep angle.