Brief description of the design and results of 21 eligible studies included in the systematic analysis
| Sample size | Indications | Laterality | Anterior/posterior | Crossover to TFA | Complications | |
| Almallouhi et al 7 | 19 | Aneurysm embolization (ruptured (n=3) and unruptured (n=8)), tumor embolization (n=2), CAS (n=2), balloon occlusion test (n=1), vertebral artery sacrifice (n=1), and AVM embolization (n=2) | Right 14 Left 4 Bilateral 1 | 17/2 | None | Minor complications 7, major complications 0 |
| Chen et al 8 | 49 | Flow diversion for aneurysms | Right 17 Left 32 | 37/12 | 2 patients due to radial artery spasm, 8 patients due to tortuosity of aorta | No complications reported |
| Chen et al 9 | 18 | Challenging vascular anatomy for mechanical thrombectomy of anterior circulation | N/A | 18/0 | None | No complications reported |
| Eskioglu et al 10 | 8 | Aneurysms (n=5), basilar stenosis (n=1), dural AV fistula (n=1), high flow AVM (n=1) | N/A | 1/7 | None | No complications reported |
| Gao et al 11 | 58 | Severe intracranial atherosclerotic vertebrobasilar stenosis. Of the 58 patients, 19 (32.8%) used the transradial approach due to poor iliofemoral artery access, 28 (48.3%) due to unfavorable brachiocephalic or subclavian artery anatomy, 11 (19%) due to unfavorable vertebral artery anatomy | N/A | 0/58 | None | 4 periprocedural minor complications of which one was asymptomatic |
| Goland et al 12 | 40 | Flow diverters (n=5) and coil embolization (n=35). Seven of these aneurysms were asymptomatic, whereas 33 had already ruptured | Right 24 Left 16 | 39/1 | None | No complications reported |
| Hanaoka et al 13 | 20 | CAS (n=11) and coil embolization of cerebral aneurysms (n=9) | N/A | 20/0 | None | One patient had asymptomatic RAO |
| Lee et al 14 | 30 | Balloon angioplasty and/or stent placement (n=18), aneurysm treatment (n=6), tumor embolization (n=3), mechanical thrombectomy (n=2), embolization of DAVF (n=1) | Right 26 Left 4 | 13/17 | None | 2 cases had minor puncture site hematoma |
| Lee et al 15 | 38 | 38 patients with documented internal carotid artery stenosis were selected for CAS via a sheathless TRA and compared with 61 patients who received CAS via the brachial artery: overall 99 patients | N/A | 38/0 | None | 1 patient in TRA group had TIA, no access site complications |
| Maud et al 16 | 10 | Mechanical thrombectomy for posterior circulation strokes | Right 9 Left 1 | 0/10 | None | No complications reported |
| Mendiz 17 | 79 | All patients underwent CAS, 46 patients were symptomatic and 34 were asymptomatic | Right 47 Left 41 Bilateral 1 | 79/0 | In 1 patient whounderwent ipsilateral TRA-CAS, right carotid artery had a steep angulation,with sheath kinking and stent delivery system fracture during withdrawal afterstent deployment. Sheath and stent delivery systems were completely removed andexchanged for a regular 6F hydrophilic radial sheath over the 0.014 wire, keeping distal protection filter in position. Balloon postdilatation wasthen performed and filter successfully removed with no guiding catheter or longsheath support and exchanged for a diagnostic catheter for final angiographicimaging. | There were no deaths, myocardial infarction, or radial access site complications. In all, 2 patients sustained a stroke, 1 hemorrhage, and 1 ischemia |
| Folmar et al 18 | 42 | CAS for stenosis greater than 80% and comorbid conditions increasing the risk of CEA | Right 29 Left 13 | 42/0 | 7 patients crossed over to TFA | 1 patient had a minor site-related complication |
| Ruzsa et al 19 | 130 | The clinical and angiographic outcomes of 265 consecutive patients with high risk for CEA treated by CAS with cerebral protection were evaluated in a prospective randomized multicenter study between 2010 and 2012. 130 of these patients underwent CAS through a TRA | N/A | 130/0 | 2 patients due to failure to access radial artery and 11 due to inability to engage the target artery | 1 patient with a known history of Buerger’s disease had a major access site-related complication. The patient had a symptomatic RAO. Minor access site complications occurred in 9 patients (7%) in the TRA group. The cause of minor vascular complications was small forearm hematoma in 1 patient (0.8%), and asymptomatic RAO in 8 patients (6.8%) |
| Montorosi et al 20 | 214 | 214 patients had CAS procedure with either Mo.MA proximal protection (n=61) or distal filter protection (n=153) | Right 112 Left 102 | 214/0 | 12 patients crossed over to TFA due to failure to engage the target vessel | Chronic RAO was detected by Doppler ultrasound in 2/30 (6.6%) Mo.MA patients and in 4/124 (3.2%) filter patients by clinical assessment (p=0.25) at 8.1±7.5 month follow-up |
| Pinter et al 21 | 20 | All patients underwent CAS, 7 patients were symptomatic and 13 were asymptomatic | Right 12 Left 8 | 20/0 | Procedural success was achieved in 18 patients (90%). Intense radial artery vasospasm resulted in one failure, and the second failure occurred in a patient with a left-sided carotid lesion and type I arch | The 30-day incidence of stroke, TIA, myocardial infarction, and death was 0%. RAO only occurred in the one patient because of the development of intense vasospasm during the procedure. One patient had persistent local pain requiring intravenous medication for relief |
| Snelling et al 22 | 105 | Mechanical thrombectomy (n=29), intracranial aneurysm treatments (n=33), and interventions such as angioplasty, balloon test occlusion, chemotherapy delivery, and thrombolysis (n=33) | Right 63 Left 42 | 81/24 | 2 patients developed radial artery spasm following sheath placement recalcitrant to antispasmodic medications, resulting in crossover to TFA. No occlusion, hand ischemia, or other sequelae were seen in these patients. 1 patient crossed over due to aortic arch tortuosity | Minor access site complications were seen in 2.85% (3/105) of patients. One patient had RAO on post-procedure testing following use of a 0.088 inch sheathless guide catheter (NeuronMax, Penumbra), despite anti-spasmolytics and patent hemostasis. However, no hand ischemia was seen. The patient eventually failed TFA due to significant aortic arch tortuosity |
| Sur et al 23 | 11 | 11 patients were identified who underwent a TRA for mechanical thrombectomy for anterior circulation occlusions | Right 7 Left 4 | 11/0 | None | No complications reported |
| Crockett et al 24 | 403 | 163 intracranial aneurysm treatments, 125 stroke interventions, 55 internal carotid artery stents, 26 vasospasm, 11 intracranial stenting/ angioplasty, 13 DAVF and AVM, 4 VA stent, 4 head and neck tumors, 2 MMA embolizations | N/A | N/A | None | 2 cases with RAO were reported, 1 following 6Fr sheath insertion and 1 following 8Fr sheath insertion. Both occlusions were asymptomatic, were identified on clinical examination and confirmed on ultrasound. 1 spontaneously recanalized after 36 hours |
| Chivot et al 26 | 64 | 62 patients with 64 aneurysms treated with TRA, 33 were treated on an emergency basis for a ruptured aneurysm and 29 underwent scheduled embolization for an unruptured aneurysm. Two patients had a second embolization after recanalization: One procedure was performed with coils and the other with flow diverters | Right 31 Left 33 | 56/8 | 2 patients had crossover to TFA, 1 due to the angle of origin ofthe left common carotid artery and the other due to subclavian occlusion | No complications reported |
| Catapano et al 25 | 58 | Retrospective chart review comparing standard TFA approach with TRA, with the primary outcome of complications analyzed via a propensity-adjusted analysis. 35 aneurysms treated, 9 thrombectomy, thrombolysis, CAS, or stent for stenosis/stroke, 12 embolizations other than aneurysms, 2 other treatments | N/A | N/A | 1 patient crossed over to TFA | 1 major access site complication (thromboembolic event) and 3 minor (forearm hematomas) were noted |
| Sweid Ahmad et al 27 | 18 | Retrospective analysis of aneurysms treated with flow diverters from 2010 to 2019. Also performed a logistic regression analysis to compare outcomes of aneurysms treated by TRA compared with TFA | N/A | N/A | 1 patient crossed over to TFA due to need for more support | No complications reported |
AV, arteriovenous; AVM, arteriovenous malformation; CAS, carotid artery stenting; RAO, radial artery occlusion; TFA, transfemoral approach; TIA, transient ischemic attack; TRA, transradial approach.