Stenting, Surgery Equally Durable in Symptomatic Carotid Stenosis

Patrice Wendling

February 15, 2019

HONOLULU — Carotid stenting and surgery provide similar long-term protection from stroke for symptomatic patients with severe carotid stenosis followed for up to a decade in a pooled patient-level analysis of four major randomized trials.

The primary outcome of ipsilateral stroke 120 days after randomization out to 10 years occurred in 3.0% of patients with carotid endarterectomy and 2.9% of patients with stenting at 5 years. This translates into near identical annual event rates per person-year of 0.60% and 0.64%, respectively (hazard ratio [HR], 1.06; 95% CI, 0.73 - 1.54).

"Really this is what kind of surprised us with all of these studies, is that once the patients underwent their successful endarterectomy or stent, there was an exceptionally low rate of subsequent ipsilateral stroke," study author Thomas Brott, MD, professor of neurology and director for research, Mayo Clinic, Jacksonville, Florida, said here at the International Stroke Conference (ISC) 2019.

When peri- and postprocedural risks were combined, however, "here we have a different story," he added.

The risk for any stroke or death within 120 days and ipsilateral stroke after 120 days to 10 years was 8.3% with surgery and 11.4% with stenting at 5 years. This risk difference carried forward at 1, 3, 6, and 9 years with formal analysis, resulting in a 45% advantage for carotid surgery over stenting (HR, 1.45; 95% CI, 1.20 - 1.75).

"All the action is occurring in the first couple of days after the performance of these procedures, showing a safety advantage of carotid surgery over carotid stenting but an equivalent durability," Brott said.

That said, he observed that the last patient stented in these trials was stented back in 2008. "If stenting has become safer over the intervening decade, stenting and surgery could be comparable, or nearly so, for the combined outcomes of periprocedural stroke and death plus postprocedural ipsilateral stroke," Brott said.

Not So Fast

"Brott and colleagues express the hope that improvements in CAS will reduce periprocedural risks, but passing catheters through stiff, tortuous, and craggy arteries that have a high plaque burden is hazardous and probably explains the higher risk of stenting in older patients (>70 years)," J. David Spence, MD, Robarts Research Institute, Western University, London, Ontario, Canada, said in an editorial, accompanying the online publication of the study in Lancet Neurology.

Improvements in carotid artery stenting (CAS) that use catheters inserted from a femoral or brachial artery are unlikely to further reduce the risk for periprocedural events, he noted. Stenting using flow reversal to prevent showers of microemboli that are common during stenting and associated with small infarctions is an approach more likely to achieve results similar to carotid endarterectomy (CEA), but further research is needed.

"The key message that clinicians should take from Brott and colleagues' report is that CEA is superior to CAS, so CAS should be reserved for selected patients," Spence said.

Factors that might favor stenting could include younger age, specific anatomic features such as stenosis that is in the very distal internal carotid, lack of arterial tortuosity leading to the stenosis, absence of or only minimal plaque calcification, and presence of local tissue scarring after previous surgery or radiation, he said. Patients receiving anticoagulation for indications such as atrial fibrillation might also be more suitable for stenting.

Still, "patients are likely to prefer a less-invasive procedure, so they should be informed that outcomes with CEA are generally better than with CAS," Spence concluded.

Weighing the Balance

The concept behind the study was to compare surgery and stenting with regard to clinical durability, which is important as the average life expectancy for patients at age 70 is now about 15 years for both sexes, Brott explained.

The preplanned analysis comprised 4754 patients from the previously reported EVA-3S, SPACE, ICSS, and CREST trials. Patients were followed for a maximum of 12.4 years, with a median follow-up ranging from 2.0 to 6.9 years across the trials. The patients' mean age was 70 years and 70% were men.

Subgroup analyses showed that the postprocedural durability of the two procedures was comparable out to 10 years regardless of the subgroup, he said.

Also of interest, the annual rates of nonipsilateral strokes (including posterior circulation strokes) per person-year trended slightly higher in the postprocedural period, at 0.78 for stenting and 0.85 for surgery, compared with the 0.6% rate observed for ipsilateral strokes.

"Because stroke outside the territory of the treated carotid is not lower, the low rates of ipsilateral stroke may in part be from the endarterectomy and from the stent and not just from advances in medical management and the decline in cigarette smoking," Brott said.

To punctuate the point, he highlighted the dramatic fall in the annual postprocedural risk for any stroke from 4.5% in the NASCET trial in 1999 to 1.4% for endarterectomy and 1.5% for stenting in this pooled analysis and 0.6% in a general population in the REGARDS trial.

Asked during discussion of the results how he would decide between the two procedures today, Brott replied that it's hard to know because of the potential improvements in safety.

"Carotid surgery between 1980 and 1990 improved quite a bit with regard to safety, but clearly older patients have a higher risk with carotid stenting," he said. "So first of all, how old is the patient? How much arterial tortuosity is there? How much calcification is there in the arterial tree? If those factors are favorable, then I think stenting and endarterectomy today are likely comparable."

Brott, his coauthors, and Spence report no relevant conflicts of interest.

Lancet Neurol. 2019; Published online February 6, 2019. Abstract, Editorial

International Stroke Conference (ISC) 2019. Presented February 6, 2019.

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