Carotid artery stenosis (CAS) is a highly prevalent condition, and is implicated as the etiology of 15% of stroke [1]. Thus, when discovered incidentally or due to symptomatology, CAS is treated in appropriate patients with medical and surgical therapies. Historically, carotid endarterectomy (CEA) was the primary treatment modality and did not require fluoroscopy, however, with the advent of endovascular technology, transfemoral carotid artery stenting (TFCAS) grew in popularity. In the last decade, transcarotid artery stenting (TCAR) emerged as a novel method of stent deployment, requiring a surgical exposure of the proximal carotid artery, and then endovascular deployment of a stent with flow reversal via the common carotid artery [2]. TCAR has been demonstrated to reduce overall fluoroscopy time compared to TFCAS [3]. The mean dose area product of a TCAR in the vascular quality initiative was 93.1 Gy.cm2; about 2/3 of the mean dose area product for endovascular aneurysm repair (131.34 Gy.cm2]) [4,5]. However, in TFCAS, it is possible to step out of the room and use an automatic injector to perform digital subtraction angiography (DSA), however, the workflow of TCAR mandates at least two manual hand-runs with at least one operator in the room [6]. Thus, although patient dose may be comparable, one could hypothesize that the surgeon’s radiation dose may be elevated in TCAR due to more direct exposure to DSA, which has 100x the radiation dose of plain fluoroscopy although as yet, no direct dosimetry data has been made available to substantiate this [7]. Thus, compared to CEA, which is radiation-free, and TFCAS, with less operator proximity to radiation, TCAR represents an area of carotid surgery that is ripe for the application of radiation sparing techniques.

Radiation safety is a pressing issue in vascular surgery as new endovascular therapies such as TCAR take the place of previous non-irradiative procedures, and although fluoroscopic technologic and personal protective equipment improve, it nonetheless remains imperative that vascular surgeons strive to reduce radiation use wherever viable alternatives exist. Excess radiation exposure is common in vascular surgery [8]. There is high variability in exposure between institutions and surgeons, and there are many short- and long-term health sequelae for the operator who receives excess radiation [9]. In addition to occupational exposure for the surgeon, vascular surgery patients often have disease in multiple vascular beds and receive high cumulative medical radiation doses for diagnostic and interventional imaging [10]. Compared to CEA, which does not require CT scan prior to surgery, TCAR instructions-for-use mandate cross sectional imaging of the carotids to determine patient eligibility. Though the primary motivation for our work on radiation sparing methods is the reduction of operator dose, a beneficial side effect of this work may be curtailing patient radiation exposure.

Various methods have been proposed to incorporate radiation sparing methods in carotid surgery, borrowed from advancements in aortic surgery, which we will review here. However, we posit that ultrasound is a uniquely applicable adjunct in the carotid space because the carotid is superficial and imaging windows are typically excellent. This has been little explored as a radiation-sparing adjunct due to its limited applicability in aortic surgery, but there have been areas of peripheral intervention and inferior vena cava filter placement where ultrasound has been shown to be successful, although ultimately it has met with limited adoption in the face of the widespread adoption and availability of fluoroscopy.

Therefore, we aim to review radiation-sparing methods in carotid surgery, discuss a novel proposed method of ultrasound guidance in TCAR, and explore areas for future investigation.