Radial artery access with a sheathless 0.087” inner diameter balloon guide catheter (Walrus) for neurointerventional procedures: Technique and clinical outcomes

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Korean J Cerebrovasc Surg. 2024;.jcen.2024.E2024.05.003

Publication date (electronic) : 2024 September 23

doi : https://doi.org/10.7461/jcen.2024.E2024.05.003

Simon Levinson, Arjun Pendharkar, Andrew Gauden, Benjamin Pulli

Department of Neurosurgery and Department of Radiology, Stanford University, CA, United States

Correspondence to Benjamin Pulli Stanford Neuroimaging and Neurointervention, 300 Pasteur Dr Rm S031E MC 5105 Stanford CA 94305 Tel +1-650-724-1140 Fax +1-650-736-1523 E-mail benjamin.pulli@stanford.edu

Received 2024 May 6; Revised 2024 August 8; Accepted 2024 August 14.

Abstract

INTRODUCTION

There is a growing preference among neurointerventionalists for transradial access (TRA) over transfemoral access (TFA). This shift is driven by evidence suggesting that TRA enhances patient satisfaction, enables early ambulation, and reduces access site complications, aligning with trends in interventional cardiology [1,2,9]. Several case series have demonstrated the safety and effectiveness of TRA for various neurointerventions, including aneurysm coiling, flow diverting stent placement, and diagnostic cerebral angiography [4,17,20].

However, using large bore catheters commonly used in neurointerventional procedures can be challenging considering the smaller size of the radial artery compared to the common femoral artery. This is especially true for balloon guide catheters (BGCs) that require 8 or even 9-french sheaths. The outer diameter of these sheaths is larger than the size of the average radial artery (estimated at 2.68±0.24 mm in adult males and 2.27±0.27 in adult females) [22], and such size relationship has been found to correlate with post-procedure radial artery occlusion [8]. This may in part explain the approximately 10% crossover rate from transradial to transfemoral in a recent randomized trial of carotid stenting [22]. Hence, it seems advantageous to minimize device size for transradial interventions. Previously, Dossani et al. [7] published a case series where they used the Walrus BGC (Q’Apel Medical, Fremont, California, USA) without an additional sheath in acute ischemic stroke patients treated with thrombectomy. In this report, we expand on their findings by reporting on our experience using this BGC sheathless for neurointerventional procedures other than thrombectomy in which BGC use and TRA may have favorable characteristics (e.g., proximal flow-arrest to minimize thrombo-embolic events, and reduced access site complications in patients on antiplatelet medications).

METHODS

Radial access and ballon guide catheter technique

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.

Table 1.

Patient cohort, outcomes, and case logs

RESULTS

Illustrative cases

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.

Fig. 1.

Patient #3 with symptomatic high-grade left internal carotid artery stenosis. (A) Roadmap angiogram of the right radial artery after access. (B-C) Walrus catheter tracking over the wire within the common carotid artery (yellow arrows) and advancement to final position. (D) Pretreatment angiogram of the left common carotid artery, yellow arrows showing the site of severe focal stenosis at the carotid bifurcation. (E) Inflated balloon as the lesion is crossed with the microwire to minimize thromboembolic events. (F) Balloon used as anchor during stent advancement to prevent balloon guide catheter prolapse into the aortic arch. (G) Post intervention angiogram of the left common carotid artery demonstrates no significant residual stenosis after stent placement.

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.

Fig. 2.

Patient #7 with acutely symptomatic left internal carotid dissection. (A-B) Walrus catheter tracking within the left common carotid artery over the diagnostic catheter and wire. (C) Left common carotid angiogram demonstrates left ICA dissection with intramural thrombus resulting in occlusion of the left Internal Carotid Artery (ICA). (D) Pretreatment angiogram of left ICA circulation demonstrates no intracranial large vessel occlusion. (E) Walrus catheter inflation to increase the stability of the balloon guide catheter for stent delivery and deployment. (F) Native view of stent construct. (G, H) Post treatment left common carotid angiogram demonstrates widely patent stent construct with reconstitution of left ICA, no significant residual stenosis, and brisk intracranial flow without distal thromboembolic complication.

DISCUSSION

In summary, we report our experience with using the Walrus BGC via a sheathless transradial approach for carotid artery stenting and intracranial balloon angioplasty/stenting. We were able to successfully complete the procedure in all patients with zero vascular access or immediate target organ complications.

A common issue with TRA is that the radial artery is too small to allow for the placement of large catheter system, such as BGCs, that are used in the treatment of neuromuscular diseases. However, considering results from ST-elevation myocardial infarction patients undergoing percutaneous coronary intervention that require antiplatelet therapy, TRA resulted in reduced vascular complications and improved overall survival [10,19]. Therefore, decreasing the diameter of the device entering the radial artery should allow for a transradial approach in patients who may not be able to tolerate the placement of an 8Fr sheath. Our patient cohort had a mean radial artery size of 2.51 mm, which is comparable to what has been reported in the literature [22], and the smallest radial diameter we were able to successfully access with this technique was only 1.7 mm. This suggests that this particular BGC can likely be used in the majority of patients. Furthermore, TRA should minimize access site bleeding complications, especially in patients who require antiplatelet therapy.

Utilizing a BGC for treatment of ischemic disease has three main advantages. First, balloon inflation allows for temporary flow arrest, which should minimize distal thromboembolic events, particularly with intracranial balloon angioplasty/stenting, where a DEP device cannot be used. Second, balloon inflation can be used to anchor the BGC in place (Fig. 1E and 2E), which prevents movement or even prolapse of the catheter construct into the aortic arch. This is particularly helpful for left carotid stenting from a right radial approach, considering the unfavorable anatomy and stiffness of currently available carotid stent systems. Third, when treating traumatic carotid injury (e.g., patient #9), balloon inflation can provide proximal control in case of intra-operative hemorrhage.

Additional advantages of TRA in neurointervention include aortic arch anatomy (e.g., bovine arch configuration with right radial to left carotid artery approach), or patients with common femoral artery (CFA) access difficulty including peripheral artery disease, prior CFA access, or prior stent or bypass involving the CFA. It is well established that TRA is superior to TFA regarding patient satisfaction, decreased access site complication, early ambulation and overall shortened length of patient stay [1,11].

In all cervical carotid artery stenting cases except for patient #7 (cervical and petrous ICA dissection that did not allow for DEP placement), a DEP was utilized as is standard-of-care at our center. For these patients, the BGC was utilized to potentially provide flow arrest during the initial crossing of the lesion, and to prevent catheter prolapse during stent delivery. While a detailed discussion of the evidence behind DEP is outside the scope of this report, it is noteworthy that the initial crossing of the stenotic segment is completed before the DEP device can be deployed. Arresting/reversing flow during this process may reduce the risk of distal emboli, though this study was not designed or powered to investigate this point. A large retrospective review has shown no significant difference in adverse events for BGC-mediate flow arrest versus DEP in transfemoral carotid stenting [14]. Moreover, Cappuzzo and colleagues [3] have demonstrated the safety of using the Walrus BGC to achieve flow arrest/reversal prior to crossing the stenotic segment in a series of 105 patients (DEP use in 85% of cases) without any periprocedural strokes or transient ischemic attacks.

Previous generations of BGC via TRA have been associated with an approximately 20% incidence of catheter kinking [15]. We did not experience any kinking with the Walrus catheter and in two other recent series of TRA BGC Walrus use (either sheathless or via a short 8-Fr sheath), no kinking was reported either [7,16]. Tracking the entire BGC through the radial artery could theoretically increase the risk of vasospasm and mechanical injury to the artery. We mitigated this risk by lubricating the balloon guide tip and shaft with saline and minimizing the movement of the BGC once in the correct position. In our opinion, the polyurethane balloon construction of Walrus BGC appears more robust than comparable contemporary BGCs. In both our series and Dossani et al. 2022 [7] (for a total of 22 patients), there were no instances of radial artery injury, severe vasospasm, or balloon damage with the use of this technique.

As with many aspects of the rapidly advancing neurointerventional field, the lack of direct comparison studies limits definitive conclusions. For example, there are no direct comparison studies between contemporary BGCs [23], and no randomized data that establishes BGC superiority over other techniques for stroke thrombectomy [8]. Retrospective registry studies point to a benefit of BGCs for thrombectomy, but heterogeneity in technique and BGC positioning may have affected the outcomes of these studies [9,13,18,21]. Fortunately, at least one RCT (proFATE) is currently underway in the UK, which should help answer some of these questions [6]. In a single-arm study, the Walrus BGC was safe and effective in stroke thrombectomy with high reperfusion rates [5]. Baig and colleagues have recently shown a benefit of Walrus in patients undergoing urgent carotid stenting for tandem strokes [2]. Since sheathless TRA of contemporary BGCs other than Walrus has not been reported, our study cannot provide comparative data. Furthermore, the low incidence of thromboembolic complications with carotid stenting also generally precludes single-center studies of technical nuances, device use, and access routes. Additional limitations of this study include its limited sample size and retrospective design. While no immediate access site complications were found, we did not follow patients for longer than 3 months to know if there were any delayed ischemic complications with TRA nor obtain any follow-up imaging of the radial artery to assess patency.

CONCLUSIONS

The Walrus 0.087″ ID BGC is an effective tool that can safely be used via the radial artery using a sheathless approach which helps to maximize the size of the catheter that can be used. This is the first instance to our knowledge of this technique being utilized for neurointerventions other than stroke thrombectomy and therefore could be used to expand the indications for TRA to a wider range of procedures.

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