Distal radial artery approach is safe and effective for cerebral angiography and neuroendovascular treatment: A single-center experience with ultrasonographic measurement

Abstract

Background

The transradial artery approach to cerebral angiography can reduce both patient stress following examination and the risk of major complications due to hematoma. Recently, the distal radial artery approach (DRA) has garnered attention in cardiology as a minimally invasive method. DRA is also considered applicable to neurosurgery, although concerns about procedural difficulty and complications persist. Therefore, this study aimed to evaluate the efficacy of the DRA in cerebral angiography and neuroendovascular treatment.

Methods

We retrospectively selected 30 consecutive patients for whom the DRA was attempted for cerebral angiography at our hospital. The patients’ age, sex, height, weight, and medical history information was collected and correlated with successful puncture and complications. The diameter of the distal radial artery (RA) was measured using ultrasonography.

Results

The median patient age was 67 years (range, 32–87 years) and 21 (70%) were men. The median diameter of the distal RA was 2.3 mm (range, 1.7–3.2 mm). Distal RA puncture was successful in 23 patients (77%) and no complications were noted; however there was no significant correlation between successful puncture and any of the patient factors. Carotid artery stenting and preoperative tumor embolization were performed via DRA in six and three cases, respectively. Although puncture site hematoma occurred in only one case, all treatments were successful, and no major complications were observed.

Conclusion

DRA can be safely used for cerebral angiography and neuroendovascular treatment.

Introduction

The transfemoral artery approach is the standard route for cerebral angiography. While the advantages of this approach include easy puncture and good distal vessel selectability, it is often considered to be invasive for a diagnostic procedure because of the need for rest following examination and the risk of serious complications, such as puncture site and retroperitoneal hematoma.^1,2 The trans-radial artery approach (TRA) is already common in cardiology, and has a substantial advantage over the transfemoral artery approach since it results in significantly fewer complications.^1,2 Reportedly, in the cerebrovascular field, the TRA is sufficient for completing examinations and neuroendovascular treatment, except in cases where definitive selection of the branches of the external carotid artery or left vertebral artery is necessary.^3–5

Recently, the distal radial artery approach (DRA), which involves puncturing the radial artery (RA) running through the anatomical snuffbox, has garnered attention as a less invasive approach.^6–8 An additional advantage is that there is minimal restriction of patient movement after the test. Moreover, post-examination RA occlusion is reportedly lower than that with the TRA. ⁸ In light of the above-mentioned factors, the DRA may be safely indicated for neurosurgery; however, only a few studies have been published on this topic, and the degree of difficulty and the risk of complications remain largely unestablished. Since 2021, our hospital has been actively performing the DRA in patients who do not require vascular selection, with the intention of making cerebral angiography and endovascular treatment less invasive. We examined the puncture success rate and complications in cases where cerebral angiography was attempted with the DRA at our institution to evaluate the effectiveness and safety of the DRA in the cerebrovascular field. Furthermore, we evaluated the utility of the DRA in neuroendovascular treatment.

Methods

Study participants

We set our study period to commence from June 2021, when we introduced the DRA for diagnostic cerebral angiography, to February 2022. During this period, 137 diagnostic cerebral angiographies were performed at our hospital. We retrospectively selected 30 consecutive cases in which the DRA was attempted. We included patients in whom the RA was palpable in the anatomical snuffbox. We did not attempt the DRA in cases requiring left external carotid artery selection and in cases where left vertebral artery angiography was necessary. The patients’ age, sex, height, weight, and medical history were collected and examined for correlation with puncture success and complications as outcomes. The correlations between patient factors and successful puncture were analyzed. Moreover, we retrospectively collected information from nine patients who underwent neuroendovascular treatment via the DRA at our hospital between February 2021 and June 2022; during this period, we performed 83 procedures of neuroendovascular treatment in total. All treatments were reviewed in detail, and their efficacy and complications were evaluated. The study was approved by the institutional review board and performed in accordance with the ethical standards established in the 1964 Declaration of Helsinki and its subsequent amendments.

Technique of the distal radial artery approach for cerebral angiography

The details of the procedures, i.e., from puncture to hemostasis, are shown in Figure 1. The patient lay supine on the examination table and the upper arms were elevated with towels and cushions to the level of the femoral artery, in order to facilitate catheter manipulation after sheath insertion. Disinfection was performed from the palms and proximal dorsum of the hands to the distal forearm (Figure 1A). The diameters of the RA at the snuffbox, wrist, and brachial artery were measured using ultrasonography in all patients before puncture. Since arteries are visualized as circular to oval on ultrasonography, the average of the long and short diameters was used to calculate the vessel diameter (Figure 1B). After transvenous administration of diazepam 5 mg and pentazocine 15 mg, the patient was administered 1‒5 mL of 1% lidocaine as local anesthesia. Puncture was performed by neurosurgeons with 3–13 years of experience, including a board-certified neurointerventionalist Physicians performed punctures based on palpation of the distal RA and scaphoid bone underneath and also tried the echo-guided technique in case the RA pulsation was weak. After placing the puncture needle into the artery, a 4-French (Fr) 17-cm sheath (Medikit, Japan; Figure 1C) with an outer diameter of 1.80 mm was inserted using the Seldinger technique. Immediately after sheath insertion, nitroglycerin (1 mg) was injected into the arterial sheath for the prevention of vasospasm, and heparin (40 U/kg) was infused via the venous route for the prevention of procedure-related thrombosis. The procedure for cerebral angiography was similar to that of the TRA with a 4-Fr MS2 and/or Simmons C catheter (Medikit, Japan). After the procedure, STEPTYP (NICHIBAN, Japan) was placed over the puncture site, the sheath was removed, and waterproof skin tape (Tegaderm, 3M, USA) was applied to the wrist with compression over STEPTY, to ensure stable puncture site compression and wrist mobility (Figure 1D). There were no restrictions on patient activity after the procedure, and compression was continued for 5 h.

Figure 1.

Distal radial artery approach (DRA) for cerebral angiography. A. Patient lying supine on the examination table with the upper arms positioned using towels and cushions. B. Ultrasonography was used to measure the arterial diameters before the puncture procedures. The average of the short and long axes was adopted for calculating the vessel diameter. C. A 4-Fr 17-cm sheath (Medikit, Japan) with an 1.80-mm outer diameter was inserted into the radial artery in the anatomical snuffbox. D. After the examination, STEPTYP (NICHIBAN, Japan) was placed over the puncture site, the sheath was removed, and waterproof skin tape (Tegaderm, 3M) was applied to the wrist with compression over STEPTY.

Statistical analysis

Data were presented as the medians and ranges for continuous variables and frequencies for categorical variables. Patient characteristics were compared between cases with puncture success and failure using the Wilcoxon rank-sum test or chi-squared test. The diameter of the distal RA was analyzed using Pearson's correlation for continuous variables and the Wilcoxon rank-sum test for categorical variables. Statistical analyses were performed using JMP Pro 16 software (SAS Institute Inc., USA).

Results

DRA for cerebral angiography

The median age of the study population (N  =  30) was 67 years (range, 25–87 years), and 21 (70%) were men. The diseases for which examinations were performed included the following: cerebral arteriovenous malformations, eight patients (27%); cervical internal carotid artery stenosis, eight patients (27%); unruptured aneurysms, seven patients (23%); intracranial artery stenosis, four patients (13%); dural arteriovenous fistula, two patients (7%); and tumor, one patient (3%). When the DRA was unsuccessful, patients were examined using the TRA, and the scheduled examinations were completed for all patients. The median diameters of the distal RA and forearm RA differed significantly (p < 0.001) at 2.3 mm (range, 1.7–3.2 mm) and 2.7 mm (range, 1.5–3.5 mm), respectively. There was no significant correlation between successful puncture and any patient factor or medical history (Table 1). The procedural success rate was 53% for 15 patients examined in the first three months of the study, which rose significantly to 100% for 15 patients examined in the subsequent six months (p  =  0.003). There were no procedural complications, and RA pulsation at the puncture site was confirmed in all the patients at discharge. Of note, an aberrant right subclavian artery was observed in two patients. It was possible to navigate the catheter into the ascending aorta and form the Simmons-shape also in those patients.

Table 1.

Baseline characteristics of 30 patients who underwent cerebral angiography via the DRA.

Variables	Total (n  =  30)	Puncture success (n  =  23)	Puncture failure (n  =  7)	p-value
Median (range)				Wilcoxon rank-sum test
Age, year	67 [25–87]	68 [25–87]	59 [32–85]	0.461
Height, cm	166 [150–183]	165 [150–183]	167 [161–176]	0.607
Weight, kg	64 [49–96]	66 [49–96]	61 [51–78]	0.787
BSA (Du Bois), m2	1.71 [1.44–2.05]	1.75 [1.44–2.05]	1.71 [1.52–1.95]	0.980
Diameter, mm
Distal radial artery	2.3 [1.7–3.2]	2.3 [1.7–3.2]	2.0 [1.9–2.6]	0.241
Radial artery	2.7 [1.5–3.5]	2.7 [1.5–3.5]	2.8 [2.3–2.9]	0.558
Brachial artery	4.6 [2.5–8.0]	4.6 [2.5–8.0]	4.1 [3.6–5.1]	0.296
n [%]				chi-squared test
Male sex	21 [70]	15 [65]	6 [86]	0.300
Diagnosis
AVM	8 [27]	6 [26]	2 [29]	0.896
CICS	8 [27]	6 [26]	2 [29]	0.896
Aneurysm	7 [23]	6 [26]	1 [14]	0.518
ICAS	4 [13]	2 [9]	2 [29]	0.176
DAVF	2 [7]	2 [9]	0 [0]	0.419
Tumor	1 [3]	1 [4]	0 [0]	0.575
Anti-platelet drug	12 [40]	9 [39]	3 [43]	0.860
Anti-coagulant drug	1 [3]	1 [4]	0 [0]	0.575
Comorbidity
Hypertension	16 [53]	13 [57]	3 [43]	0.526
Dyslipidemia	15 [50]	13 [57]	2 [29]	0.195
Diabetes mellitus	8 [27]	7 [30]	1 [14]	0.398
Coronary disease	5 [7]	4 [17]	1 [14]	0.847
Malignancy	5 [17]	3 [13]	2 [29]	0.334
Smoking	11 [37]	9 [39]	2 [29]	0.612

AVM, arteriovenous malformation; BSA, body surface area; CICS, cervical internal carotid artery stenosis; DAVF, dural arteriovenous fistula; DRA, distal radial artery approach; ICAS, intracranial artery stenosis.

Pearson's correlation coefficients for the distal RA diameter were 0.16 (p  =  0.401) for age, 0.28 (p  =  0.140) for height, 0.36 (p  =  0.054) for weight, and 0.35 (p  =  0.063) for body surface area (Du Bois method), none of which was significant (Supplementary Digital Content 1, Supplementary Figure). The correlation coefficient between the diameters of the distal RA and forearm RA was 0.44 (p  =  0.018), and that of the brachial artery diameter was 0.41 (p  =  0.029), showing a moderate correlation. Moreover, the distal RA diameter did not differ significantly between the sexes [male: median 2.3 (1.9–3.2) mm versus female: median 2.2 (1.7–2.8) mm; p  =  0.741 (Wilcoxon's rank-sum test)]. None of the comorbidities was a statistically significant predictive factor for distal RA diameter (Supplementary Digital Content 2, Supplementary Table). None of the patients experienced distal RA or forearm RA occlusion on discharge.

DRA for neuroendovascular therapy

Neuroendovascular treatments via the DRA were performed for nine patients during the study period (Table 2). The patients’ ages ranged from 47 to 80 years, and seven (78%) were men. The treatment included six (67%) carotid artery stenting (CAS) procedures for cervical internal carotid artery stenosis and three (33%) tumor embolizations prior to meningioma resection. The treatment side was confined to the right in six cases (67%) and the left in three cases (33%). After insertion of a 4-Fr arterial sheath, a larger profile guiding system was inserted using an exchange maneuver. The guiding system used was a 6-Fr 90-cm FUBUKI Dilator Kit (Asahi Intecc, Japan) with an outer diameter of 2.70 mm, or an 8-Fr 90-cm Optimo EPD and TMP dilator (Tokai Medical Products, Japan) with an of outer diameter of 2.70 mm for CAS, while a 4-Fr 90-cm FUBUKI Dilator Kit (Asahi Intecc) with an outer diameter of 2.09 mm was used for tumor embolization. All guiding systems were navigated to the target artery using a 4-Fr MS2 or Simmons C catheter (Medikit, Japan) and Radifocus (TERUMO, Japan). All patients were successfully treated with the DRA, and no neurological complications nor distal RA occlusion were observed. Although one patient (patient 3) with idiopathic thrombocytopenic purpura experienced hematoma at the puncture site, no additional treatment or limitation of activities of daily living was needed.

Table 2.

Summary of patients treated with neuroendovascular therapy using the DRA

Case no.	Age	Sex	Side	Diagnosis	Treatment	Guide catheter/sheath	Target artery	Materials	Complications
1	71	M	Right	CICS	CAS	6 Fr, FUBUKI GS	ICA	Carotid Wallstent	-
2	70	M	Right	CICS	CAS	6 Fr, FUBUKI GS	ICA	Carotid Wallstent	-
3	76	M	Right	CICS	CAS	6 Fr, FUBUKI GS	ICA	Carotid Wallstent	hematoma*
4	67	F	Right	Meningioma	Tumor embolization	4 Fr, FUBUKI GS	ILT, MMA	Embosphere, coil	-
5	80	F	Left	CICS	CAS	8 Fr, Optimo	ICA	CASPER RX	-
6	54	M	Right	Meningioma	Tumor embolization	4 Fr, FUBUKI GS	IMA, ILT	NBCA, coil	-
7	47	M	Right	Meningioma	Tumor embolization	4 Fr, FUBUKI GS	MMA	Embosphere, coil	-
8	79	M	Left	CICS	CAS	8 Fr, Optimo	ICA	CASPER RX	-
9	72	M	Left	CICS	CAS	6 Fr, FUBUKI GS	ICA	Carotid Wallstent	-

CAS, carotid artery stenting; CICS, cervical internal carotid artery stenosis; DRA, distal radial artery approach; F, female; Fr, French; GS, guide sheath; ICA, internal carotid artery; ILT, inferolateral trunk; IMA, internal maxillary artery; M, male; MMA, middle meningeal artery; NBCA, N-butyl-2-cyanoacrylate.

*This patient had a low platelet count due to idiopathic thrombocytopenic purpura and a hematoma formed around the puncture site.

A representative case of DRA for CAS is shown in Figure 2 (patient 8 in Table 2). A 78-year-old man underwent CAS for a severely stenotic lesion in the left internal carotid artery. The DRA was considered a good option because of severe atherosclerosis in the abdominal aorta, the gentle angle of the right brachiocephalic artery and the aorta, and good palpation of the distal RA. The embolic protection technique entailed a combination of the flow reversal technique (8 Fr Optimo) and distal filter (Spider FX, Medtronic, USA). A 4-Fr 10-cm long MERIT MAK (Merit Medical Systems, USA), a micro-puncture kit, was inserted into the cephalic vein of the forearm to establish a blood-return circuit. The CASPER RX stent (TERUMO) was deployed after pre-dilation, and the procedure was completed with post-dilation. The hemostatic procedure was the same as that used for cerebral angiography. Mild sedation and analgesia ensured patient comfort, and no postoperative rest was required. Postoperative magnetic resonance imaging revealed no ischemic lesions.

Figure 2.

Illustrative case of carotid artery stenting with a forearm flow reversal circuit. A. Picture of the actual treatment procedure B. Schema of the flow reversal system and blood flow circuit. A balloon guide catheter (8 Fr Optimo EPD; Tokai Medical Products, Japan) was directly introduced via the DRA (white arrowhead) and a 4-Fr 10-cm long MERIT MAK (Merit Medical Systems, USA) was inserted into the cephalic vein of the forearm as a blood-return circuit (black arrowhead) with Optimo Chamber (Tokai Medical Products; white asterisk). The orange arrows indicate blood flow under the forearm flow reversal circuit system. A patient with left cervical internal carotid stenosis was treated with CASPER RX (Terumo) stenting. C. Under double protection of the distal filter (Spider FX, Medtronic; black arrowhead) and flow reversal circuit with Optimo inflation (white arrowhead), post-stenting balloon angioplasty with SHIDEN (Kaneka, Japan) was performed. D. Successful recanalization was confirmed with favorable dilatation of the stenotic internal carotid artery.

Discussion

This study is the first to explore the factors contributing to successful puncture and safety of the DRA in the initial stage of its application for cerebral angiography. Moreover, we have detailed the indications for the DRA for neuroendovascular treatment in Asian patients.

The DRA involving puncture of the anatomical snuffbox has found widespread application in cardiology examinations and percutaneous coronary intervention, since it was first reported by Kiemeneji in 2017. ⁶ The advantages of the DRA include reduced arm stress during the procedure, shorter hemostasis time, no activity limitation after the procedure, and lower frequency of RA occlusion.^7,8 This study found few puncture site complications resulting from the procedure, confirming the safety of the DRA. Conversely, the pre-concerned disadvantages of the DRA include long puncture time, need for technical proficiency, and poor catheter operability due to the distal puncture site. Additionally, previous studies have reported that procedural failure of the DRA or TRA is associated with the tortuosity and anatomical variations in the RA, such as abnormal origin and radial artery loop.^9–11 Furthermore, investigation of the relationship between distal RA diameter and body size revealed that a low body mass index is associated with the risk of puncture failure in the DRA.^12–14 Previous studies have reported that the distal RA diameter is thinner than the that of the forearm RA, consistent with the findings of this study. However, this study showed that distal RA diameter was not associated with puncture success, at least for 4-Fr arterial sheath insertions, and that there was no significant difference in the correlation between distal RA diameter and sex, height, or weight.

In our study, the time from the introduction of the DRA was related to successful puncture. The puncture success rate reached 100% three months after the introduction of the DRA when the RA was palpable in the anatomical snuffbox. Although the lack of routine ultrasound guided puncture may also contribute to the high failure rate initially, it was possible to achieve proficiency in the DRA puncture technique relatively early. Several previous studies have reported that the DRA is a feasible method for cerebral angiography. Patel et al. ¹⁵ performed 31 DRA cerebral angiographies and were able to select an average of 3.8 vessels and catheterize all of the inserted vessels. They revealed that the fluoroscopy time decreased with experience, and neurosurgeons’ proficiency in the DRA was considered important, akin to the present study. Saito et al. ¹⁶ selected 70 vessels for cerebral angiography from 47 DRAs. The vessels examined included the left vertebral artery and left internal carotid artery, suggesting that it is possible to reach the distal left vessels in selective cases. On the other hand, the left external carotid artery was not included, and failure was encountered in selecting the left internal carotid artery in some cases; therefore, further investigation of the target vessels for catheterization and approach selection is warranted. Moreover, aberrant right subclavian arteries were observed in two patients in this study. Although this variation may be one of the difficulties in performing cerebral angiography via the DRA, considering the possibility of right aberrant subclavian arteries in advance is important for smooth examination.

Several studies have reported the use of the DRA in neuroendovascular treatment, as shown in Table 3.^17–25 The DRA has been used to treat various diseases, including aneurysms, cerebral arteriovenous malformations, dural arteriovenous fistulas, carotid artery stenosis, and acute cerebral infarction. The guiding sheath is selected from amongst 4- to 6-Fr systems, except for one case where a 7-Fr system was used. Considering that the median distal RA diameter was 2.3 mm, a system with a 6-Fr sheath (outer diameter: 2.7 mm) may usually be the upper limit. Based on our finding that body measurements do not influence successful puncture, we performed the DRA with a 6-Fr guiding sheath (or an 8-Fr guiding catheter using a dilator sheath) when the preoperative distal RA diameter was at least 2.0 mm. Even if the distal RA is < 2 mm, a 4-Fr guiding sheath (outer diameter 2.09 mm) can be placed without difficulty. Consequently, measurement of the distal RA diameter can be useful for preoperative system discussions and selection of cases appropriate for DRA neuroendovascular treatment. In all previous studies, the procedural success rate ranged from 91–100%, and no major complications were reported. In general, the puncture point of the DRA is 3–5 cm distal to that of the TRA, which may result in poor support of the guiding catheter. Introducing to a 90-cm guide catheter sufficiently distally is considered impossible, especially for tall patients. Moreover, the sharp angulation of the brachiocephalic artery and aorta is sometimes problematic, making it difficult to establish the access route. Therefore, preparation of multiple guide catheter lengths and preoperative review of the treatment protocol are vital. The DRA can be reasonably adapted for neuroendovascular treatment after carefully weighing the ease of the access route against the complexity of the therapeutic procedure.

Table 3.

Previous studies on the distal radial artery approach for cerebral angiography and neuroendovascular treatment

Authors	N	Median age	Diagnosis	Sheath selection	Success rate	Compliation (Number of cases)
Weinberg et al. (2020) 11	9	NA	Aneurysm (1), AVM/CCF/DAVF (7), Othrer (1)	5 Fr or 6 Fr	100%	NA
Kinkori et al. (2020) 12	11	72	Aneurysm (6), AVM (1), CICS (3), Other (1)	4 Fr (50%), 5 Fr (10%), 6 Fr (40%)	91%	None
Kühn et al. (2020) 13	11	66	Aneurysm (11)	5 Fr (9%), 6 Fr (91%)	100%	None
Kühn et al. (2020) 14	48	64 (mean)	AIS (2), Aneurysm (18), AVM/DAVF (3), CICS (6), others (14)	6 Fr (100%)	90%	None
Kühn et al. (2021) 15	42	58 (mean)*	Aneurysm (42)	6 Fr (100%)	96%*	SAH (2), Stent clot (2)*
Kühn et al. (2021) 16	22	69 (mean)	CICS (22)	6 Fr (95%), 7 Fr (5%)	91%	None
Manzoor et al. (2021) 17	36	42 (mean)†	AIS (3), Aneurysm (13), AVM/DAVF (7), CICS (2), Tumor (4), others (7)	6 Fr (100%)	95%†	Hematoma (3) †
Rodriguez Caamaño et al. (2022) 18	47	58 (mean)†	AIS (14), Aneurysm (16), AVM/DAVF (4), CICS (3), others (10)	NA	96%†	Hematoma (2), Dissection of RA (1)
Present study	9	71	CICS (6), Tumor (3)	4 Fr (33%), 6 Fr (67%)	100%	hematoma (1)

AIS, acute ischemic stroke; AVM, arteriovenous malformation; CCF, carotid cavernous fistula; CICS, cervical internal carotid artery stenosis; DAVF, dural arteriovenous fistula; Fr, French; F/U, follow-up; m, month; N, number; NA, not available; RA, radial artery; SAH, subarachnoid hemorrhage.

*This study included 42 cases of distal radial artery access and 32 cases of radial artery access; the asterisk indicates that the figures includes cases of both.

†These studies included both diagnostic cerebral angiography and neuroendovascular treatment via the distal radial artery approach. The dagger indicates that the figures includes cases of both.

Limitations

There are two limitations of this study. First, the sample size of the study was not large (N  =  30). Second, there was selection bias for examination and treatment using DRA. Future studies are required to determine the degree of procedural difficulty in cases in which the distal branch of the left external carotid artery or left vertebral artery need to be selected.

Conclusions

The DRA is a safe and less invasive technique for cerebral angiography and neuroendovascular treatment, which causes few complications. The success rate of DRA puncture increases with proficiency over a short period, and it can also be applied for neuroendovascular treatment following ultrasonographic measurement of the diameter of the RA. Given that patients requiring left vertebral or external carotid angiographies were excluded from this study, further investigations are needed to expand the possible applications of the DRA.

Abbreviations

DRA

distal radial artery approach

RA

radial artery

TRA

trans-radial artery approach