Stenting Suitable for Extracranial Vertebral Disease

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Extracranial vertebral artery stenosis can be safely and effectively treated with stenting or angioplasty alone, according to a systematic review of the literature published online June 23, 2011, ahead of print in Stroke.

According to the study authors, there is currently no consensus on the optimal strategy for treating patients with this condition. Options include medical management and open surgery as well as endovascular treatments, which are becoming increasingly popular in recent years. “Unfortunately, there are limited natural history data for patients who present with [extracranial vertebral artery stenosis],” they note, in part because vertebral disease has been considered relatively benign since the contralateral artery can often compensate for reduced circulation.

Stroke, TIA Rare During Follow-up

To address this knowledge gap, researchers led by Rishi Gupta, MD, of the Emory University School of Medicine (Atlanta, GA), identified 27 articles from the medical literature that focused on patients with extracranial vertebral artery stenosis, 92% of whom had experienced stroke or transient ischemic attack (TIA) as their index event. Twenty-two of the studies were single-center and retrospective; of the remainder, only 1 was a multicenter, prospective, randomized trial.

Out of a total of 993 patients treated, the vast majority (98.7%) underwent primary stenting and the remaining 1.3% received primary angioplasty. Technical success was very high, with 99.3% of stenting cases achieving less than 20% residual stenosis. Among stented patients, 31% received DES.

Within 30 days of treatment, 11 patients (1.1%) had a stroke and 8 (0.8%) had a TIA. A small number of deaths were reported, but none were directly related to posterior ischemia after stenting. Over an average follow-up of 21 months, 1.3% of stented patients had a vertebrobasilar infarction and 6.5% had recurrent vertebrobasilar TIA symptoms.

Half of the total cohort (n = 498) underwent follow-up angiography. Most tests were driven by recurrent symptoms rather than protocol mandated. An additional 152 patients underwent Doppler ultrasound, but magnetic resonance imaging (MRI) and computed tomographic angiography (CTA) were rarely employed.

In studies that stratified restenosis by stent type, DES were far less likely to produce recurrent restenosis (11.2%) than were BMS (30%) over a mean follow-up of 24 months.

Reimbursement an Obstacle

In a telephone interview, L. Nelson Hopkins, MD, of University at Buffalo Neurosurgery (Buffalo, NY), told TCTMD that the lack of buzz about extracranial vertebral artery stenosis is largely due to the impression that the disease is fairly benign.

“People have 2 vertebral arteries, and I think for whatever reason the neurology community and more importantly the reimbursement community figures, ‘Well, if I’ve got 2 vertebrals and 1 of them is stenosed, it doesn’t make that much difference,’” he said.

The procedure is not covered by the Centers for Medicare and Medicaid Services, “so unless you can talk an insurance company into covering it, it’s not reimbursed,” Dr. Hopkins reported. “And yet, it’s well known from years and years of literature, particularly pathology literature, that extracranial vertebral artery disease is a cause of embolic strokes in the posterior circulation. When somebody is symptomatic, particularly if they have failed medical therapy, we treat them aggressively.”

Dr. Hopkins agreed that stenting with DES can reduce the risk of restenosis. And when restenosis does occur, the lesion is likely to be made up of fibrous growth or hyperplasia, Dr. Hopkins noted, and therefore unlikely to embolize and cause symptoms.

“It’s a disease that clearly deserves treatment,” he stressed. But despite being relatively common, extracranial vertebral artery disease still represents a fairly small market. Furthermore, without reimbursement, a large study is unlikely to be initiated, Dr. Hopkins said, adding, “It’s a little bit of an orphan disease.”

Lack of Detection

Another issue raised by Dr. Gupta is that the condition often goes undetected. Doppler imaging, typically the test of choice for carotid disease, can be challenging in the vertebral arteries, he said in a telephone interview with TCTMD.

Extracranial artery stenosis is “picked up incidentally a lot of the time,” often in patients being evaluated for carotid disease, Dr. Hopkins noted. “And [in this scenario] they’re usually considered asymptomatic, so there’s not an incentive to treat them.”

The overall lack of awareness is “probably why there’s been a little bit of a lag in acquiring data,” Dr. Gupta said, adding that the researchers hope the current paper spurs interest. They are currently trying to obtain funding for a randomized controlled trial.

In the meantime, Dr. Gupta advised clinicians that “if somebody has a stroke in the posterior circulation, it’s worthwhile to image these arteries,” possibly with CTA or MRI.

“And if this condition is found, ensure patients are on maximal medical therapy. But if the vessel configuration looks high risk, where maybe 1 is 90% blocked and the other is 100% blocked, stenting can be considered on a case-by-case basis,” he said.

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Source:
Stayman AN, Nogueira RG, Gupta R. A systematic review of stenting and angioplasty of symptomatic extracranial vertebral artery stenosis. Stroke. 2011;Epub ahead of print.

 

 

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