TCAR Direct Access Carotid Stenting Lowers Stroke Risk

December 23, 2019

A new approach to carotid stenting, in which the carotid artery is accessed directly instead of by use of a catheter that is guided through the circulation from the groin, has shown lower rates of periprocedural complications compared with the traditional approach.

The technique, known as transcarotid artery revascularization (TCAR), involves making a small incision above the clavicle and entering the carotid artery directly.

In a propensity score–matched analysis of data from patients with carotid artery stenosis, TCAR was associated with about half the risk for periprocedural stroke/death than traditional transfemoral carotid artery stenting (1.6% vs 3.1%).

The study was published online December 17 in JAMA.

Carotid stenting has fallen out of favor in recent years following several trials that showed high periprocedural stroke rates with the intervention. Most carotid stenosis patients now undergo carotid endarterectomy surgery; stenting is generally reserved for those considered too high risk for surgery.

"But the low rates of stroke and death seen in this study with the TCAR approach suggest that this strategy may be an attractive option going forward," lead author Marc Schermerhorn, MD, Beth Israel Deaconess Medical Center, Boston, Massachusetts, told | Medscape Cardiology.

The TCAR procedure is designed to reduce the risk for periprocedural stroke in two ways, he explained. With the traditional femoral approach, the catheter has to traverse the aortic arch ― a site in which there is a large amount of debris that can be dislodged. Then the catheter also has to cross the lesion in the carotid artery to set up the embolic protection device, and this can cause particles from the lesion to break off. Both these actions can cause periprocedural strokes.

"But with TCAR, the catheter is inserted above the aortic arch, so that hazard is avoided. Then the carotid artery is clamped to stop forward flow and the blood flows backwards through the side arm in the sheath and a filter to collect any debris," Schermerhorn said. "Any debris that escapes the filter flows back to the femoral vein and not to the brain. We keep the blood pressure high and the brain recruits its blood flow from its other side."

Schermerhorn describes TCAR as a hybrid surgical/interventional procedure, being less invasive than carotid endarterectomy but slightly more invasive than femoral stenting. The learning curve for the procedure is fairly short; those who perform the procedure become skilled at it quite quickly.

"It is less invasive than carotid endarterectomy surgery, has a lower rate of cranial nerve complications, and is a shorter procedure," he said. "Given the outcomes in this study, I think its use would increase quite dramatically if the procedure was given reimbursement.

"I think this new approach could rejuvenate the whole field of carotid stenting," he added. "Based on these results, we have petitioned the FDA to allow expansion of TCAR to patients who are not high risk for surgery."

Current Analysis

Using data from the Vascular Quality Initiative Transcarotid Artery Surveillance Project and Carotid Stent Registry, the researchers identified asymptomatic and symptomatic patients who underwent TCAR (n = 5251) or transfemoral carotid artery stenting (n = 6640) in the United States and Canada from September 2016 to April 2019.

After propensity-score matching, 3286 pairs of patients who underwent TCAR or transfemoral carotid artery stenting were identified.

Results showed that TCAR was associated with a lower risk for in-hospital stroke or death (1.6% vs 3.1%; P < .001), stroke (1.3% vs 2.4%; P = .001), and death (0.4% vs 1.0%; P = .008).

The biggest difference was seen in the symptomatic patients ― those who had recently had a stroke or transient ischemic attack. "This is probably because there is a much higher event rate in these patients, so it is easier to show a difference," Schermerhorn suggested.

Among the 1829 pairs of patients with symptomatic carotid disease, the in-hospital stroke/death rate was 2.1% with TCAR vs 4.2% with transfemoral carotid stenting. Stroke rates were 2.0% vs 3.1%, and death rates were 0.5% vs 1.5%.

In a risk-adjusted analysis of all patients, TCAR was associated with a lower risk for ipsilateral stroke or death at 1 year (5.1% vs 9.6%; hazard ratio, 0.52; 95% confidence interval, 0.41 – 0.66).

The theoretical benefits with TCAR were first confirmed clinically in the single-group ROADSTER trial, which showed a stroke rate of 1.4% at 30 days and 95% stroke-free survival at 1 year, the authors note.

"This study found a similar but slightly lower perioperative stroke rate of 1.2% following TCAR compared with the ROADSTER trial," they state.

Several trials have shown a reduction in perioperative myocardial infarctions (MI) with transfemoral carotid artery stenting compared with endarterectomy, likely attributable to its more minimally invasive approach, the researchers report.

With TCAR, there was no significant difference in perioperative MI as compared with transfemoral carotid artery stenting in both asymptomatic and symptomatic patients in the current study, they add.

TCAR was associated with higher risk for access site complication resulting in interventional treatment (1.3% vs 0.8%), whereas transfemoral carotid artery stenting was associated with more exposure to radiation (median fluoroscopy time, 5 minutes vs 16 minutes) and use of more contrast (median, 30 mL vs 80 mL).

Two studies comparing TCAR with carotid endarterectomy surgery showing similar stroke/death rates are expected to be published soon, Schermerhorn said.

Femoral Results Improving

Another study published this week, the CREST-2 Registry, has shown lower rates of periprocedural stroke for the femoral approach than previously reported.

Commenting on the results, Schermerhorn said: "I do think the femoral approach is improving. There have been technological improvements, operators are becoming more skilled, and patient selection is better than in the past."

But he pointed out that the CREST-2 registry selected interventionalists who could participate. "If you have to be a CREST-2 investigator to get good results, this can't be duplicated across whole of clinical practice.

"And in our study, the femoral results were also quite good, but the TCAR results were better," Schermerhorn added.

Commenting for | Medscape Cardiology, lead author of the CREST-2 registry analysis, Brajesh K. Lal, MD, said TCAR is a new stenting strategy in the "early stages" of adoption, and although more than half of procedures are performed under deeper anesthesia, ultimately it can be performed under local anesthesia.

"There is in incision made with TCAR, so there is a risk of carotid artery dissection, but the short circuit of the entire aorta pathway gives less risks of atherothrombosis," he said.

"The data from this new analysis on TCAR are encouraging, but without a randomized trial, it is very difficult to prove that one is better than the other (femoral vs TCAR)," added Lal, who is professor of vascular surgery at the University of Maryland, Baltimore.

The study was conducted with support from Harvard Catalyst–the Harvard Clinical and Translational Science Center, the National Center for Research Resources, and the National Center for Advancing Translational Sciences, National Institutes of Health and by financial contributions from Harvard University and its affiliated academic healthcare centers. Schermerhorn reported personal fees for provision of consultancy services from Silk Road Medical, Abbott, Cook, Endologix, and Medtronic. Lal reports no relevant financial relationships.

JAMA. Published online December 17, 2019. Abstract

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