Abstract
Purpose
The objective of this study was to assess the efficacy and safety of transradial access for diagnostic angiography and interventional neuroradiology procedures.
Methods
This was a retrospective analysis of a single-center experience based on 225 patients attended between August 2015 and October 2019, in which transradial access was used for diagnostic angiography and endovascular interventions. Ultrasound-guided access was done at the level of the forearm or anatomical or snuffbox (distal transradial access). Conventional forearm transradial access was done in 179 procedures (right, left and bilateral in 169, 5 and 5, respectively), while distal transradial access was done in 46 cases (41 right and 5 left). Primary outcome measures included successful catheterization, need to change access, or technical complications.
Results
In the group of 131 diagnostic angiographies, the technique success rate was 100% to target the right vertebral artery, 97% for the right internal carotid, 93.5% for the left internal carotid, 82% for the left vertebral artery, and 100% for both common and external carotid arteries. All patients were discharged within 2–4 h after the procedure. A total of 94 interventional procedures were performed, including aneurysms in 39 cases, stroke in 34, and other procedures (carotid stents, arteriovenous malformations, carotid-cavernous fistula) in the remaining 21. The overall technical success in both diagnostic angiographies and interventional procedures was 97.7%. In four cases of diagnostic angiography and in 1 intervention, it was necessary to switch from transradial access to transfemoral access. Three cases of hematoma related to the access site were recorded.
Conclusions
In our experience, transradial access is an alternative approach for diagnostic angiography and neuro-interventions.
Keywords: Radial artery, transradial, thrombectomy, endovascular therapy, angiography
Introduction
There is a vast experience with the use of transfemoral access (TFA) in interventional neuroradiology, being the vascular approach most frequently used for catheterization of the supraaortic and intracranial vessels. In a review of 19,826 consecutive patients undergoing diagnostic cerebral angiography using TFA, groin hematoma was the most common complication, which was seen in 4.2% of patients.1 The use of the radial artery (transradial access, TRA) as the point of entry instead of TFA has gained popularity based on the mounting evidence of its clinical benefits in coronary angiography and percutaneous coronary intervention (PCI).2–4 Clinical outcomes of radial access for coronary interventions in patients with coronary artery disease (CAD) were examined in a meta-analysis of 24 studies, with a total of 22,843 patients.5 Compared with femoral access, radial access reduces mortality and major adverse cardiovascular events and improves safety, with reductions in major bleeding and vascular complications across the whole spectrum of patients with CAD.4 In the 2018 ESC/EACTS guidelines on myocardial revascularization, radial access is preferred for any PCI irrespective of clinical presentation, unless there are overriding procedural considerations.6
The radial artery approach has more recently been applied to neuroendovascular techniques, including diagnostic angiography, carotid artery stent placement, coil embolization of aneurysms, and intervention for acute ischemic stroke.7–9 Some studies have shown the feasibility and safety of TRA for diagnostic and interventional neuroangiographic procedures,7–10 but the clinical experience with catheterization of the supraaortic vessels is still limited. Vascular tortuosity, obese patients, marked atheromatosis or patients with high risk of bleeding may be precluded from TFA, and require alternative vascular access. Complications specific to TRA include radial artery spasm (RAS) and radial artery occlusion (RAO). RAO occurs in less than 5% of patients and RAS in 6–10% with appropriate prevention, including assessment of collateral circulation from the ulnar artery, radial artery size, and spasmolytic cocktail infusion.4 Also, the distal TRA (dTRA) at the anatomical snuffbox reduces the chance of RAO at the distal forearm and allows a more convenient position for the operator when a left radial access is required.11
The purpose of this study is to present our experience concerning the feasibility, efficacy, and safety of TRA for diagnostic angiography and complex interventional neuroradiology procedures.
Methods
Study design
This was a retrospective analysis of all consecutive patients undergoing diagnostic angiography and neurointerventional procedures at the Department of Neuroradiology of a 900-bed acute-care teaching hospital between August 2015 and October 2019. Patients were fully informed about the details of the procedure, and written informed consent was obtained in all cases. Local institutional review board approval was not required to review retrospectively our database for the purpose of this study.
Access and procedures
All patients underwent an ultrasound examination (Hockey stick transducer) in order to measure the diameter of the radial artery. Assessment of the collateral circulation to the hand via Allen’s test (time needed for maximal palmar blush after release of the ulnar artery compression with occlusive pressure of the radial artery) and the Barbeau (using pulse oximetry and plethysmography)12,13 test was used prior to TRA. Patients with a radial artery diameter of less than 1.8 mm were excluded. The preferred access was on the right arm, as it is more suitable for neuroradiology. An approach via the left or left dTRA was used when this was the only accessible site, a bilateral access was required or an interventional procedure in the vertebral artery was needed.
When distal access was performed, the patient’s hand was placed with dorsal flexion to help the progression of the wire. The artery was punctured under ultrasound. A 5F radial sheath (Terumo Medical, Somerset, New Jersey, USA or Merit Medical, Utah, USA) was used for diagnostic angiography and a 6F sheath for most of the interventional procedures. As the introducer sheath was placed within the artery, an intra-arterial injection of a mixture of heparin (2000–4000 IU) and verapamil (5 mg) was infused through the side-port of the introducer to prevent radial artery spasm and thrombosis.
In patients undergoing diagnostic angiography, Simmons type 1 or type 2 catheters were the most favorable for catheterizing the supraaortic trunks. In patients undergoing neurointerventional procedures, the decision to select TRA was based on the following considerations: (a) as a rescue vascular access when catheterization of the supraaortic vessels was unsuccessfully attempted through the femoral approach; (b) as a combined method with TFA in cases in which multiple vascular access were needed, particularly in patients with arteriovenous malformation (AVM); (c) as a primary access when CT angiography showed a favorable anatomy for TRA and there were contraindications for TFA; and (d) as the initial vascular access. The configuration for aortic arch and branching patterns was evaluated in stroke patients, as these were the only patients that had a previous CT angiography of the neck. Different combinations of introducer sheaths and intermediate catheters were used according to the type and site of the procedure.
When a Simmons 2 6F Envoy guiding catheter was used, we could catheterize and directly place the catheter in the desired vessel. This method was commonly used for both internal carotid arteries catheterization. To catheterize any of both vertebral arteries, a 5F or 6F intermediate catheter was normally used directly through a radial sheath. For posterior circulation thrombectomy, a distal aspiration catheter was directly placed with a 0.35 wire. In cases in which more inner working lumen was needed (double thicker microcatheters, larger stents) or vessel tortuosity required more support, a 6F 90 cm sheath (Cook Shuttle or Balt Ballast) was used. To use it, an exchange through a 0.35 guidewire was used from a short 6F radial sheath. In stroke patients with vascular tortuosity, a long sheath gave support to advance a distal aspiration catheter such as Sofia 6F (Microvention) or ACE 68 (Penumbra). Finally, in cases of anterior circulation stroke performed through a balloon occlusion catheter and aspiration, either a 6–7F radial sheath accompanied with a 6F Cello balloon (Medtronic) or a Flowgate 2 balloon (Stryker) sheathless were placed.
Results
During the study period, a total of 225 neuroradiological procedures were performed, 131 (58.2%) of which were diagnostic angiograms and the remaining 94 were interventional procedures. Conventional forearm TRA was used in 179 procedures (right, n = 169; left, n = 5; bilateral, n = 5) and dTRA in 46 cases (right, n = 41; left, n = 5). Diagnostic angiograms were either primary initial studies or control of previously treated patients, and included complete (both internal carotid arteries and both vertebral arteries were catheterized) and selective (catheterization of a single vessel) angiographies. In all cases, access through the radial artery was feasible, but four cases required crossover to TFA. In two cases, TRA was not possible due to vasospasm, even after intra-arterial injection of 200 µg nitroglycerin, one case due to a subclavia lusoria, and another due to impossibility to catheterize the left vertebral artery. In other four patients, a radial loop was encountered, two cases was crossed with a “j” bended 0.35″ wire and in the two other cases a 0.18″ guidewire was required to cross and rectify the loop, after which the progression of the catheter was adequate.
All patients undergoing diagnostic angiography were discharged after 2–4 h of the examination. The technical success rate was 100% to target the right vertebral artery, 97% for the right internal carotid, 93.5% for the left internal carotid, 82% for the left vertebral artery, and 100% for both common and external carotid arteries. Fluoroscopy time was recorded for diagnostic angiographies performed by one of the authors (RB) in 2018. Time for vessel catheterization, including centering was 3.8 min/vessel for TRA compared to 4.2 min/vessel for TFA. In cases with radial loop, TRA time increased to 4.7 min/vessel.
In the group of 94 interventional procedures involving selective catheterization of the vessel of interest, the success rate of the technique was 98.9%. The indications of interventional procedures were stroke thrombectomy in 34 patients, aneurysms in 39, and miscellaneous in 21. In the group of 34 stroke patients (Table 1), thrombectomy using TRA had a revascularization technical success rate of 88% (TICI 2b/3). TRA was used after failure of TFA in four patients and used as a first approach in the remaining 30 cases. No TFA was required as a crossover after TRA failure.
Table 1.
TRA stroke treatments performed in 34 patients.
| Localization | Total cases | Radial first (%) | TICI 2b-3 (%) |
|---|---|---|---|
| Right TICA | 3 | 3 (100%) | 2 (67%) |
| Right MCA | 7 | 6 (86%) | 6 (86%) |
| Left TICA | 7 | 7 (100%) | 7 (100%) |
| Left MCA | 13 | 11 (85%) | 8 (61%) |
| Basilar artery | 4 | 3 (75%) | 4 (100%) |
| Global | 34 | 30 (88%) | 27 (79%) |
MCA: middle cerebral artery; TICA: terminal internal carotid; TICI: thrombolysis in cerebral infarction.
In the group of 39 patients with aneurysms (Table 2), successful occlusion was achieved in all cases. Periprocedural complications occurred in two cases. Details of other interventional procedures performed in 21 patients are shown in Table 3.Patency of the radial artery at 30 days was not specifically registered in all patients until 2019. There were three cases of superficial local hematoma at the puncture site that resolved spontaneously without increase of hospital stay length.
Table 2.
Treatment of TRA aneurysms in 39 patients.
| Localization | Total cases | BAC | FD | Complications |
|---|---|---|---|---|
| Posterior circulation | 7 (18%) | 3 | 4 | – |
| Basilar artery | 6 | 3 (1+SAC) | 3 | – |
| Left PICA | 1 | – | 1 | – |
| Anterior circulation | 32 (82%) | 29 | 3 | 2 |
| ACoA | 7 | 7 | – | – |
| Left A1 | 1 | 1 | – | – |
| Left pericallosal | 3 | 3 | – | 1. Aneurysm rupture |
| Left ICA | 6 | 5 | 1 | – |
| Left PCoA | 3 | 3 | – | 1. coil migration, gooseneck snare |
| Left MCA | 3 | 3 | – | – |
| Right pericallosal | 1 | 0 | 1 | – |
| Right ICA | 4 | 3 | 1 | – |
| Right MCA | 1 | 1 | – | – |
| Right PCoA | 3 | 3 | – | – |
| Global | 39 | 32 | 7 | 2 |
BAC: balloon-assisted coiling; FD: flow diverter; PICA: postero-inferior cerebellar artery; ICA: internal cerebral artery; PCoA: posterior communicating artery; posterior communicating artery; MCA: middle cerebral artery.
Table 3.
TRA miscellaneous interventional procedures in 21 patients.
| Procedure | Cases | Technique | Complications |
|---|---|---|---|
| Left ICA stenosis | 4 | Carotid stenting with filter | No |
| Right ICA stenosis | 4 | Carotid stenting with filter | No |
| Carotid-cavernous fistula | 1 | Comaneci-assisted coiling | No |
| Torcular AVF | 1 | Phil + Onyx embolization | No |
| Right Tentorial AVF | 1 | Onyx embolization | No |
| Left Tentorial AVF | 1 | Phil + Onyx embolization | No |
| Ponto-cerebellar AVF | 1 | Phil embolization | No |
| Mesencephalic AVM | 1 | Glue embolization | No |
| Pericallosal AVM | 1 | Onyx embolization | No |
| Frontal AVM | 1 | Phil + Onyx embolization | No |
| Lumbar Cordoma | 1 | PVA embolization | No |
| Right common carotid artery and subclavian artery stent | 1 | Stenting + angioplasty+ filter | Filter entrapment. Use of gooseneck snare |
| Lingual artery bleeding | 1 | Coils embolization | No |
| Left carotid occlusion test | 1 | Balloon occlusion | No |
| Left ECA bleeding | 1 | Coils + glue embolization | Need crossover to TFA |
SAC: Stent-assisted coiling; AVM: arteriovenous fistula; ECA: external carotid artery; PVA: polyvinyl alcohol particles.
A total of 32 patients had both a diagnostic TRA and a prior diagnostic TFA, and telephone interviews were successfully conducted. Of patients who had experienced both TRA and TFA previously, 75% (24/32) would prefer TRA for their next procedure, with 15.6% (5/32) preferring TFA, and 3 declaring no preference.
Illustrative cases of interventional procedures using TRA are shown in Figures 1 to 3. Figure 4 shows the steps to solve the presence of a 360° radial loop.
Figure 1.
A 93-year-old women with M2 left superior division occlusion and moderate stroke severity (NIHSS scale score 12). (a) Type 3 arch and curvature of proximal left common carotid. Right transradial access is decided after transfemoral unsuccessful catheterization; (b) a 6F cook Shuttle is placed in left carotid artery; (c) M2 superior division occlusion on selective angiography; (d) thrombectomy is performed with a 6F ACE 68 catheter aspiration and 4 × 40 solitaire stent retrieval; (e) TICI 3 recanalization is achieved (radial puncture to recanalization in 33 min).
Figure 2.
A 74-year-old man with right amaurosis fugax and right internal carotid artery stenosis and incidental Silvian aneurysm. Carotid stenting and aneurysm embolization is decided. (a) 6F Envoy Simmons catheter is placed in right common carotid artery; (b) and (c) proximal internal carotid artery focal stenosis and 3 mm middle cerebral artery bifurcation aneurysm; (d) once the stent is deployed, the 6F guiding catheter is moved upwards with help of a 4F catheter; (e) balloon-assisted coiling is attempted, but finally embolization is done using double microcatheter technique; (f) and (g) final angiogram showing 6F guiding catheter positioned upper the stent.
Figure 3.
A 76-year-old woman with two incidental aneurysms, anterior communicating, and left cavernous. Double access was decided to perform occlusion test and an embolization of the anterior communicating aneurysm. (a) Left distal transradial access with diagnostic catheter and right radial access with guiding catheter; (b) crossing of the catheters at the aortic arch; (c) bilateral initial angiography; (d) balloon-assisted coiling of the anterior communicating aneurysm; (e) it was then decided to preserver left carotid artery and to perform partial occlusion of the cavernous aneurysm with coils.
Figure 4.
(a) 0.35″ guidewire and catheter resistance. Contrast injection shows catheterization of a muscular branch; (b) Catheter retrieval and contrast injection. Presence of a 360° radial loop; (c) Crossing of the loop with a 0.18″ guidewire; (d, e) Guidewire withdrawal maneuver to unbend the loop; (f) The 0.35″ guidewire and catheter could be advanced properly with a resolution of the loop.
Discussion
Safety of TRA in diagnostic arteriography has been extensively confirmed in numerous studies in the field of interventional cardiology, with a low rate of complications versus TFA.3,4 In agreement with other studies,7,9 vascular access via the right radial artery is feasible for diagnostic cerebral angiography. Through a right radial approach, the success rate of the technique is almost 100% for accessing carotid arteries and the right vertebral artery. Depending on the anatomy of each individual, the left vertebral artery is the most challenging vessel. In the largest series of 1240 cerebral angiographies performed via a TRA, the success rate for selective catheterization of the left vertebral artery was 52.2%,8 which is lower than 82% found in our study. In some cases, the use of 0.35″ Stiff or Half Stiff guidewire allowed successful progression of the catheter through the vertebral artery.
TRA is an attractive option in anticoagulated patients or those treated with antiplatelet agents due to the decreased risk of bleeding at the access site. The rates of post-procedural RAO remain an issue, and although rarely associated with immediate clinical sequelae, RAO can deny patients the benefits of TRA catheterization if future examinations or procedures are required. It has been shown that patent hemostasis using an inflated band is highly effective in preventing early RAO14 and has the benefits of cost savings especially with regard of the closure devices used for TFA and patients’ preference due to postprocedural immediate deambulation.15
In relation to endovascular treatment, without considering the access site, almost all interventions can be performed through a 6F sheath or guiding catheter, although a 7F may be useful when three microcatheters are needed. Aneurysms can be successfully treated with simple coiling technique, balloon remodeling, or stent-assisted coiling for which 6F guiding catheter is adequate (Envoy 6F in our experience). For carotid stenting and depending on the external diameter of the stent-carrying catheter, a 6F sheath of guiding catheter can be used. In our experience, the Cordis Precise RX could be delivered with an Envoy 6F catheter, whereas the Terumo RoadSaver required a 6F sheath (Cook shuttle), although in both cases filter-assisted stenting can be used.
When an intervention through left vertebral artery is needed (basilar thrombectomy, arteriovenous malformation embolization, treatment of a basilar aneurysm), it is preferable to use a left radial access, being in the forearm or the left dTRA variant. However, in some cases, left vertebral artery catheterization can be successfully performed via right TRA. When double access is needed, both right and left TRA or combined with TFA can be used. Patients undergoing scheduled interventional procedures are usually discharged after 24 h with one overnight hospital stay.
With regard to endovascular treatment for acute large-vessel occlusion for appropriately selected patients, the ability to gain vascular access and achieve reperfusion has a major impact on outcomes. There is little experience with the use of TRA in stroke patients. Sur et al.16 reported successful revascularization in 10 out of 11 acute ischemic stroke patients in whom the radial artery was chosen as the primary access site and treated with standard thrombectomy including stent retriever deployment with aspiration through the guide. In stroke treatment using direct thrombus aspiration (ADAPT) or distal aspiration combined with stent retriever, a 6F catheter is adequate, and in our center, this is the technique of choice for cases of posterior circulation thrombus. In case of anterior circulation thrombus, we use balloon occlusion and aspiration. The use of 8F sheath and an 8F balloon-guided catheter may be feasible in selected patients only.17 Saito et al.18 studied the feasibility of using guiding catheters equal to or greater than 7F in transradial coronary intervention and measured the inner diameter of the radial artery and its flow using two-dimensional ultrasound and Doppler examination before and after the procedure. The incidence of severe flow reduction in the radial artery after coronary intervention was 8.3% in patients with 8F sheaths used, which increased significantly to 13% if the ratio of the radial artery inner diameter/sheath outer diameter was less than 1.0. For balloon occlusion aspiration, feasible options include the use of a 6F Cello balloon (Medtronic) that requires a 7F sheath introducer, or a 6F slender sheath (Terumo) or the Preclude Ideal hydrophobic sheath (Merit) that allows 7F catheter diameters. An 8F balloon occlusion catheter may also be used sheatless.
The present findings should be interpreted taking into account the limitations of a single-center and retrospective characteristics of the study, and the fact that the study was focused on TRA, so that a comparison with TFA was not performed. In relation to the learning curve in the use of the radial artery as vascular access, we started with follow-up angiographies of one or two vessels (internal carotid or right vertebral artery) followed by complete angiographies in young patients and, then, in elderly patients with tortuous anatomy.
Regarding interventions, we recommend starting using TRA once catheterization skills have been achieved. Again, it is advisable to start with scheduled aneurysms and then move forward to more complex interventions. Regarding stroke treatment in which thrombectomy is limited by a narrow time window, in the first cases, we only used TRA as an alternative to TFA when the access was not feasible, but after gaining experience and in patients with favorable anatomy, TRA was used as the initial vascular access.
The use of radial access has been progressive, with 13 cases in 2015–2016, 49 cases in 2017, 95 cases in 2018, and 67 in January until October 2019. In the first three years period, most of the procedures were diagnostic angiographies. As the experience has been gained and seen the advantages for patients, familiarity with the use of ultrasound for vascular access is expected to reduce the learning curve associated with the transition from TFA to TRA. The use of ultrasound for conventional TRA can give the proper skills to move to dTRA easily. The present experience indicates that almost the full range of endovascular interventional procedures can be performed using the TRA.
Although radial access is preferred for any PCI according to the 2018 ESC/EACTS guidelines on myocardial revascularization,19 direct carotid artery puncture may be an alternative to TFA and TRA in cases of stroke of difficult anatomy including unfavorable arch type, carotid tortuosity, or an ostial lesion.20 Recent case reports20,21 and small case series22 have shown that direct carotid puncture could be an alternative for endovascular thrombectomy when TFA is not possible. Safety of radial access is supported by 2018 ESC/EACTS guidelines,19 but evidence regarding the safety of the transcarotid approach is currently limited and more studies on this alternative mode of access are needed.
Conclusions
In our experience, TRA is a useful approach for diagnostic angiography and the vast majority of interventional procedures. It is a valuable option in patients in whom TFA is challenging. We found that the learning curve is not too steep and that the radial access approach can be adopted smoothly for a large percentage of diagnostic and interventional neuroradiological procedures.
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Ethical approval
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. For this type of retrospective study, institutional review board approval is not required.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Informed consent
Informed consent was obtained from all individual participants included in the study.
ORCID iDs
Roger Barranco Pons https://orcid.org/0000-0001-5491-2687
Isabel Rodriguez Caamaño https://orcid.org/0000-0002-6377-6952
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