Transcarotid artery revascularization

Abstract

Transcarotid artery revascularization (TCAR) is a hybrid procedure that involves stenting of the common and internal carotid arteries via remote surgical access to the common carotid artery.The United States Food and Drug Administration (FDA) approved TCAR in 2015 as an additional endovascular procedural option to treat patients with carotid artery stenosis.Approval was authorized without supporting evidence from a randomized clinical trial (RCT), under the stipulation that all procedures be entered into the Vascular Quality Initiative (VQI) registry, which captures more than 95 per cent of TCARs performed in the US.Despite a lack of level 1 evidence, TCAR has been rapidly adopted in the US, with approximately 21 000 implants across nearly 500 centres.In 2022 the FDA expanded the indications for a TCAR system (Enroute; Silk Road Medical, Sunnyvale, California, USA) to include patients at standard risk.Previously, TCAR was approved for use only in patients with anatomical or physiological criteria that put them at higher risk of procedural complications with other carotid revascularization options (standard carotid stenting (CAS) or carotid endarterectomy (CEA)).In Europe, the availability of TCAR was limited to a small number of centres and, recently, Silk Road Medical decided to completely withdraw TCAR from the European market.To understand the rationale for TCAR it is necessary to review the underlying scientific evidence.Transfemoral carotid artery stenting (TFCAS) is associated with higher 30-day stroke rates than CEA in both symptomatic and asymptomatic patients 1 .TFCAS is also associated with a four times higher procedural risk of new ischaemic brain lesions measured by diffusionweighted MRI (DW-MRI) 1,2 .Of importance, without exception, all large randomized trials have consistently shown that, beyond the 30-day period, the long-term risk of any stroke following either TFCAS or CEA appears to be virtually the same 1 .The key message, therefore, is that the magnitude of the initial procedural risk remains the key factor in determining the optimal revascularization technique 3 .The higher procedural stroke risk after CAS is believed to be secondary to intraprocedural embolization, because of surface thrombus and aortic arch manipulation.TCAR was initially developed to reduce the number of embolic complications associated with transfemoral access.TCAR was designed to avoid aortic arch manipulation, by using direct carotid exposure paired with cerebral blood flow reversal to minimize the embolic potential 4 .Several cohort series and two single-arm trials have claimed favourable procedural stroke and death rates for TCAR, as

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