TCAR’s Huge Growth Outpaces Middling Safety Data

The newest and now most pervasive operation for patients with carotid artery stenosis, transcarotid artery revascularization (TCAR), has been associated with mixed safety relative to other carotid procedures since it entered real-world practice with limited data.

Based on the large Vascular Quality Initiative (VQI) registry, perioperative strokes and deaths after TCAR significantly exceeded those after carotid endarterectomy (CEA; 2.0% vs 1.7%) and trended nonsignificantly lower than those after transfemoral carotid artery stenting (CAS; 3.7%).

However, TCAR’s rates of stroke or death were no longer significantly worse than CEA’s at 1 year (6.4% vs 5.2%). By this metric, TCAR also gained a significant advantage against CAS at year’s end (9.7%), reported Jesse Columbo, MD, MS, of Dartmouth-Hitchcock Medical Center in Lebanon, New Hampshire, and colleagues.

Symptomatic patients with carotid stenosis were the ones for whom TCAR had the most attractive safety profile, with adjusted HRs of 1.30 for CEA compared with TCAR (95% CI 1.04-1.64) and 1.86 for CAS versus TCAR (95% CI 1.27-2.71).

“Although CEA remains the gold standard procedure for patients with carotid stenosis, TCAR appears to be a safe alternative to CEA and transfemoral CAS when used selectively and may be useful when treating symptomatic patients,” the researchers concluded in their report published in the Journal of the American Heart Association.

That may be reassuring news for some, given that TCAR has proliferated rapidly. Recently, a report showed that as of 2019, TCAR has already overtaken CEA and CAS to become the dominant carotid revascularization approach.

Yet no carotid artery procedure has proven effectiveness for patients with carotid stenosis who might otherwise take medical therapy alone without risking complications from an operation — however minimally invasive it may be.

“Guidelines worldwide already encourage use of carotid artery procedures in subgroups not shown to benefit compared with noninvasive medical intervention alone. This should be recognized and resisted, including for new procedural approaches, such as TCAR,” said neurologist Anne Abbott, MBBS, PhD, of Monash University in Melbourne, Australia, writing in an accompanying editorial.

“The fact that TCAR has become so popular in parts of the United States is very concerning,” Abbott wrote. “We can only hope that this inappropriate procedural intervention recedes and that, instead, patients are diverted into the studies that are so critically needed to establish what can now be achieved with current best practice, noninvasive medical intervention alone, and if any subgroups of carotid stenosis patients now benefit from the addition of a carotid artery procedure.”

To fill that gap, researchers are currently recruiting for the CREST-2 trial comparing CEA and CAS against intensive medical management alone.

FDA had approved the Enroute TCAR system in 2015, stipulating that postmarket surveillance be performed in the absence of a randomized trial.

The present study relied on the VQI registry, which captured the bulk of carotid revascularizations in the U.S., Canada, and Europe from 2016 to 2021. Included were 21,234 patients who underwent TCAR, 82,737 who underwent CEA, and 14,595 who underwent transfemoral CAS across 662 centers. Average age was around 70 years, and over one-third of patients were women.

Of the three groups, TCAR patients tended to be the oldest and were most likely to have coronary artery disease and be on preventive medications.

Approximately half of the procedures were performed in symptomatic patients.

Notably, Columbo’s group had employed instrumental variable analysis — with a center’s preference for TCAR relative to CEA or CAS as the instrument — to adjust for selection bias and other unmeasured confounding.

This method is still no substitute for a randomized trial, however, and the registry lacked key variables such as details of each patient’s neurologic symptoms and existing medical therapy.

“Any apparently favorable results with TCAR using the instrumental variable methodology are, at best, hypothesis generating, and readers should not interpret them as encouragement for ongoing use of TCAR in routine clinical practice,” Abbott warned.

Ultimately, she asked of operators: “Why use a new, alternative procedure, such as TCAR, with its necessary learning curves, when it is not proven to be as safe as or safer than CEA, and TCAR has no proven superior stroke risk reduction benefit compared with current noninvasive medical intervention alone?”