Conference Coverage

Intracranial artery stenting shows promising 1-year results


 

REPORTING FROM ISC 2020

Limiting intracranial artery stenting to stroke patients who fit the tightly defined labeling the device has may have minimized periprocedural complications, as shown in the WEAVE trial results reported in 2019, but 1-year follow-up of most of the WEAVE patients also showed that intracranial stenting remains plagued by another issue, frequent restenosis.

Dr. Michael J. Alexander, professor of neurosurgery, Cedars-Sinai Medical Center, Los Angeles Mitchel L. Zoler/MDedge News

Dr. Michael J. Alexander

One-year after 129 patients received an intracranial stent that’s already on the U.S. market for treating severe atherosclerotic disease following an ischemic stroke, their incidence of death or repeat stroke was 9%, low enough to suggest benefit compared with historic control patients who were medically managed and had a 12% 1-year rate of death or stroke. This signal of incremental benefit from intracranial stenting may help spark renewed interest in an intervention that was largely forsaken in recent years because of safety concerns.

Assessing restenosis frequency

“Stenting seemed to confer some protection against severe or fatal strokes” in a study that provided “the largest 1-year follow-up of stenting” for intracranial atherosclerotic disease, the trigger for roughly 10% of all U.S. stroke cases, Michael J. Alexander, MD, said at the International Stroke Conference, sponsored by the American Heart Association.

What 1-year follow-up highlighted was the restenosis frequency, based on imaging follow-up for 107 of these 129 patients who had received a Wingspan nitinol, self-expanding stent. Seven patients developed symptomatic restenosis in the region of stent placement, and another 11 patients had asymptomatic restenosis that occluded at least 70% of the stented artery, a total 1-year restenosis rate of 18/107 (17%), reported Dr. Alexander, professor of neurosurgery and director of the Neurovascular Center at Cedars-Sinai Medical Center in Los Angeles. The mean time to detection of restenosis was 5 months, with a range of 1-11 months.

Intracranial stenting falls out of favor

The tested Wingspan stent first received Food and Drug Administration approval for intracranial artery placement in 2005, and then in August 2012 the agency tightened the labeled indication to a much smaller, more specifically defined group of patients: those 22-80 years old, with 70%-99% stenosis in a cerebral artery, with a history of at least two strokes, with stent placement timed more than 7 days following the most recent stroke, and refractory to medical therapy. This 2012 label change came in response to a concerning rate of periprocedural complications in patients who received intracrania artery stents as part of a study reported in 2011 that included many patients with clinical characteristics that fell outside the limits the agency later set in 2012. Results from the SAMMPRIS (Stenting vs. Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis) trial showed that among 451 randomized patients the 224 assigned to stenting had a 15% 30-day rate of death or stroke, compared with a 6% rate among control patients who did not receive a stent, a statistically significant difference that led to early stopping of the trial (New Engl J Med. 2011 Sep 15;365[11]:993-1003). At least half of the patients who received a stent in SAMMPRIS were 7 or fewer days out from their index event, a majority had either a single prior stroke or transient ischemic attack as their index event, and many had not been established as refractory to medical management.

Dr. Louise D. McCullough, professor of neurology, University of Texas Health Science Center at Houston Mitchel L. Zoler/MDedge News

Dr. Louise D. McCullough

The SAMMPRIS results and the subsequent relabeling of the Wingspan stent by the FDA had two consequences. First came a steep drop in the use of intracranial stenting. After SAMMPRIS, vascular neurologists “abandoned the stent; no one does intracranial stenting” today, commented Louise D. McCullough, MD, professor and chair of neurology at the University of Texas Health Science Center at Houston. The second consequence was an FDA mandate to run a new randomized study to reassess the periprocedural complications when clinicians placed the Wingspan intracranial stent in patients who fully matched the revised 2012 labeling.

That mandated study was the WEAVE (Post Market Surveillance Study of the Wingspan Stent System) trial, which enrolled 152 patients at 24 U.S. sites in a single-arm study, and found a 2.6% rate of death or stroke during the 30 days following intervention that beat the 4% benchmark rate prespecified in the trial’s design (Stroke. 2019 Apr;50[4]:889-94). The WEAVE findings provided even more evidence of the need for the tight labeling the device received in 2012. A safety communication from the FDA in April 2019 noted that an additional 46 patients received an intracranial artery stent during WEAVE despite falling outside the 2012 labeled indications, and this off-label group had a 24% incidence of periprocedural complications, compared with the 2.6% rate in the on-label group. The FDA’s statement reaffirmed the labeling restrictions and highlighted additional cautions and recommendations for using the device.

The WOVEN study

The 1-year follow-up of the WEAVE patients, an extension called the WOVEN (Wingspan One Year Vascular Imaging Events and Neurologic Outcomes) study, was investigator initiated with no commercial funding and included 129 of the original on-label patients (85%) at 15 of the original 24 participating centers.

In addition to the data collected in WOVEN on restenosis rates, follow-up tallied seven patients with a stroke in the vascular territory of the stent during the period that began 30 days after the procedure (when the WEAVE follow-up finished) and continued through 12 months, with no neurologic deaths. When combined with the 4 periprocedural events that occurred during WEAVE, the final WOVEN tally was 11 total events in 129 patients followed for 1 year (9%). Because WEAVE and WOVEN included no control patients, Dr. Alexander compared this 1-year incidence rate with the 12% rate among medically managed control patients in SAMMPRIS.

According to Dr. Alexander, the next step in the path to rehabilitating a clinical role for intracranial stenting is a new randomized study that compares stenting used exclusively to the 2012 labeling with medical management in high-risk patients, those with hemodynamic compromise.

Encouraging data, but is it compelling?

“There may be a benefit” from intracranial stenting, but “we need a larger trial to convince people” said Dr. McCullough. The WEAVE and new WOVEN findings provide a “signal that stenting may be better than medical therapy, but this was only in just over 100 patients. We’ll need a larger study,” she said in an interview. The findings also reinforced that restenosis remains a challenge for intracranial artery stenting.

“Intracranial atherosclerosis is very difficult to treat, and we need new strategies for these patients.” The WEAVE and WOVEN results “suggest that while the restenosis rate may be high, it may also be manageable.” Delaying stent placement to no sooner than 8 days after a stroke may be a key step for improving safety, but new approaches are also need to minimize the restenosis risk, Dr. McCullough noted.

WEAVE was sponsored by Stryker Neurovascular, the company that markets the Wingspan intracranial artery stent. WOVEN received no commercial funding. Dr. Alexander has been a consultant to Stryker Neurovascular. Dr. McCullough had no disclosures.

SOURCE: Alexander MJ et al. International Stroke Conference, Abstract LB4.

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