We performed a retrospective chart review that identified thirteen consecutive patients who underwent non-emergent treatment of symptomatic cervical or intracranial carotid artery stenosis, or traumatic carotid artery injury via a sheathless transradial approach with the Walrus BGC at our institution between March 2023 and February 2024. All data were obtained and processed in accordance with an institution data and safety protocol (IRB# 37209).

We collected data on patient demographics, type and location of lesions, admission and discharge National Institutes of Health Stroke Scale (NIHSS), modified Ranken Scale (mRS) on discharge, radial artery diameter, device(s) used, anticoagulation, and complications. The median and interquartile range (IQR) were calculated for numerical data.

All patients that presented were considered for radial access. The primary operator in this series (BP) had switched his neurointerventional practice to a radial-first approach in 2022, based on accumulating data that transradial neuroangiography and neurointervention is thought to be safer and preferred by most patients, especially in patients who require dual-antiplatelet therapy [11,12]. The decision to choose a ballon guide was driven by the possible benefit of proximal flow control in patients with cervical carotid artery stenosis, intracranial artery stenosis, or traumatic carotid artery injury [15,16].

Under sonographic guidance, the radial artery was accessed with a 22-gauge Angiocath needle using a double-wall puncture technique. The Angiocath was then exchanged over a 45 mm 0.021″ microwire or 0.018″ Nitrex wire (Medtronic, Minneapolis, MN, USA) for a 7-Fr Slender Glidesheath (Terumo, Tokyo, Japan). Next, approximately 15 mL of blood was aspirated into a 20 mL syringe containing 3000-5000 IU heparin, 100-200 mcg nitroglycerine, and 2.5 mg verapamil. The blood-medication mix was slowly injected into the radial artery. Next, under roadmap guidance, an exchange-length 0.035″ Glidewire advantage (Terumo, Tokyo, Japan) was advanced into the aortic arch, and the 7-Fr Slender Glidesheath was exchanged for a 90 cm Walrus BGC loaded with a 6-Fr 125 cm Simmons or VER catheter (Penumbra, Alameda, CA, USA). The Glidewire advantage was removed, and the Simmons catheter was reshaped in the descending aorta. The Simmons/VER catheter and a 0.035 Glidewire (Terumo, Tokyo, Japan) were then used to selectively catheterize the vessel of interest. The Walrus BGC was then tracked over the diagnostic catheter and/or Glidewire, depending on the patient’s anatomy, and positioned appropriately in the distal common carotid artery for carotid stenting, or in the distal cervical internal carotid artery for intracranial angioplasty/stenting. The Walrus BGC was inflated 1) during the initial crossing of the lesion with the microwire, 2) during balloon angioplasty/stent deployment, and 3) in case of cervical carotid stenting, while advancing the carotid stent from the access site to the site of stenosis. Approximately 10 mL of blood was briskly aspirated before balloon deflation. Carotid stenting or intracranial angioplasty/stenting was otherwise performed in the usual fashion with devices as seen in Table 1. Upon conclusion of the procedure, the Walrus BGC was removed, and a TR band was applied to achieve patent hemostasis.

Thirteen patients underwent TRA carotid stenting (CAS) or intracranial angioplasty/stenting via a sheathless transradial approach with the Walrus BGC. Eight of the patients were male and the median age was 63 years (range 19-84, IQR 52-74 yrs).

The mean radial artery diameter was 2.51 mm (SD 0.47, range 1.7-3.2 mm). No patients were excluded from attempting TRA based on preprocedural radial artery size measurements.

Procedures were all performed under general anesthesia with neuromonitoring as indicated. There were zero cases of TRA conversion to TFA. Median admission NIHSS was 2 (IQR 0-8), median discharge NIHSS was 1 (IQR 0-2) and median mRS was 1 (IQR 0-3). All interventions were successfully performed (Table 1).

There were zero cases of significant access site complications and no known ischemic complications of TRA. Mild swelling, ecchymosis, or pain at the puncture site was noted in a small number of patients, none of which required additional monitoring or intervention. No intraprocedural complications were encountered. Patient #10 suffered from post-operative thrombosis of the left internal carotid artery stent, and this resulted in a large left Middle Cerebral Artery (MCA) territory stroke with significant disability (mRS 5). Patients were evaluated between four- and six-week post procedure and then again at three months. At those time points, there were also no incidences of radial artery complications noted, although we did not obtain imaging to confirm radial artery patency.

Patient #3 (Fig. 1) presented with a symptomatic high-grade left Internal Cerebral Artery (ICA) stenosis. TRA was obtained with the sheathless 8F Walrus BGC following the technique outlined in the methods section. Initial angiographic images showed severe focal stenosis at the carotid bifurcation on the left. Prior to deployment of the distal embolic protection device (DEP), the ballon guide catheter was inflated and the stenosis crossed with the DEP wire followed by the DEP. The BGC was particularly helpful in this case as it served as an anchor point in torturous anatomy to prevent catheter prolapse into the aortic arch during delivery of the carotid stent (1F). The patient was discharged the next day with a NIHSS of 0.

Patient #7 (Fig. 2) presented with acutely symptomatic left ICA dissection that resulted in left cerebral hemisphere hypoperfusion. While the initial admission NIHSS was 3, the patient subsequently worsened to an NIHSS of 8 with severe aphasia and right arm plegia. The right radial artery was accessed as described above, and a cervical angiogram demonstrated left ICA dissection with an intramural thrombus resulting in occlusion of the left ICA. Again, the balloon was inflated prior to crossing the stenosis. No DEP could be used due to the location of the dissection extending into the horizontal petrous ICA segment. No intracranial large vessel occlusion was seen after the dissection site had been crossed with a microcatheter and microwire. The inflated balloon also provided additional support for subsequent stent reconstruction with a Surpass evolve 4×30 mm, Surpass evolve 4×25 mm, Onyx Frontier 4×22 mm Drug-eluting stent, and Acculink 6-8×30 mm carotid stent. Post stent angiogram demonstrated successful reconstruction of the left ICA with a widely patent stent construct spanning the entire length of the cervical ICA to the horizontal petrous segment, and no evidence of distal thrombo-embolic complication. The patient made an excellent recovery with a discharge NIHSS of 0 and a 90-day follow-up mRS of 0.