ISC 2009: Primary Stenting in Ischemic Stroke Promising; Pilot Extension Planned

Susan Jeffrey

February 26, 2009

February 26, 2009 (San Diego, California) — Pilot results using primary stenting in a series of 20 patients with acute ischemic stroke has shown that recanalization of the infarct vessel was achieved in all patients, with 45% of patients achieving a modified Rankin Scale (mRS) score of 0 or 1, indicating no or little disability.

Mortality was 25% in this series, high but comparable, the researchers say, to other stroke treatments.

Dr. J Mocco

"Are stents the answer for acute stroke? These data certainly do not yet prove it, but it sure looks promising," J Mocco, MD, from the University of Buffalo department of neurosurgery, in New York, told Medscape Neurology & Neurosurgery. "Based on this data, the [Food and Drug Administration] FDA has approved an additional 20-patient extension to continue this prospective data collection, which, hopefully, would possibly lead to a definitive trial."

Results of this pilot trial, called Stent-Assisted Recanalization for Acute Ischemic Stroke (SARIS), were presented at the American Stroke Association International Stroke Conference 2009. The study is funded by Boston Scientific.

Recanalization Key

Acute recanalization has been associated with improved outcomes in stroke patients, Dr. Mocco noted. Results from recent studies using mechanical revascularization techniques such as the MERCI retriever have shown an improvement in clinical outcomes, defined as achievement of mRS scores of 0 to 3, on the order of 40% to 50% among patients who are recanalized vs those who are not.

One option to achieve recanalization is primary stenting. In 2006, this group reported in Neurosurgery an open trial of stenting for acute stroke after failed thrombolytic and other mechanical therapies. Among 18 patients with an average National Institutes of Health Stroke Scale (NIHSS) score of 14 at baseline, TIMI 2 or 3 flow was restored in 14 patients. Six patients died in the series, but of 12 survivors, the average NIHSS score at discharge was 6.5 (Ecker RD et al. Neurosurgery 2006;58:458-463). This prior series was done using a coronary stent.

CT perfusion study showing increased mean transit time in right MCA distribution (Source: University of Buffalo Neurosurgery)

They subsequently reported a second retrospective series after self-expanding intracranial stents became available, as did another group, again suggesting apparent benefit. Based on this early experience, the FDA approved SARIS, a prospective pilot study of 20 patients using the Wingspan stent as the primary treatment to achieve revascularization. The aim was to assess the safety of this approach, as well as angiographic improvement of flow.

Patients were eligible if they presented within 8 hours of symptom onset, although Dr. Mocco noted that 2 patients were treated beyond this window. All had a focal occlusion less than 14 mm. Intravenous tissue plasminogen activator (tPA) was either contraindicated or was received at least 1 hour prior with no improvement; 2 patients fell into this latter category. Patients were excluded if computed tomography (CT) perfusion imaging showed that greater than one-third of the at-risk territory was not salvageable, with low cerebral blood flow or "black hole," he noted.

Of the 20 patients, 14 were female and 6 male, with a mean age of 63 years. The presenting NIHSS score was 14 + 4, with a median of 13. TIMI flow scores demonstrated occlusion of at least TIMI 0 or 1, with 85% having TIMI 0 flow.

High Recanalization Rates

After intervention, they were able to achieve recanalization in all patients, restoring 40% to TIMI 2 and 60% to TIMI 3, or full flow. "This is highly significant compared with presenting TIMI scores," Dr. Mocco noted.

In terms of clinical improvement, 65% of the patients improved by 4 or more NIHSS points during their hospitalization, whether this ended with discharge or death.

At 30 days, 60% of patients achieved an mRS score of 3 or less, he noted, and 45% a score of 0 or 1, indicating no or little disability.

Intracranial hemorrhage occurred in 3 patients. Two of these were symptomatic for a 10% symptomatic rate, "which is exactly — 9% to 10% — what was seen in the IMS trial and the IV tPA trial," he said.

However, mortality was "substantial" in this series, at 25%, although this number still compares with rates seen in the final Multi-MERCI trial (34%) and the NINDS IV tPA trial (21%), Dr. Mocco said. He reviewed the 5 deaths during his presentation:

  • A 24-year-old male improved modestly immediately postprocedure but in the intensive-care unit (ICU) was found to have a 6-cm vegetation in his heart on echocardiogram, decreasing cardiac output and causing multiple embolic events to his viscera and organs. "He eventually passed with multiple embolic events," Dr. Mocco noted.

  • An 81-year-old female, an 82-year-old female, and a 61-year-old male had no or modest improvement after the procedure, but all still had significant deficit after a few days, and the families withdrew care based on the patients' previously expressed wishes, he said.

  • Finally, a 24-year-old male who had had a stroke during elective surgery improved dramatically from an NIHSS score of 11 to 3. He had a baseline congenital cardiac anomaly that required anticoagulation, but treatment had been stopped during the elective nasopharyngeal surgery. A few hours after being anticoagulated for the primary stenting procedure, he had a massive hemorrhage from the previous surgical site, with significant aspiration and severe respiratory compromise leading to death.

Based on these results, the FDA has approved an extension of the study for an additional 20 patients, Dr. Mocco said. "We have FDA approval and are just waiting for approval from Boston Scientific to proceed," he told Medscape Neurology & Neurosurgery.

In this series, most patients received the Wingspan stent, he noted, but 2 were actually treated using the Enterprise stent (Codman) because they find it to be more navigable through tortuous vessel anatomy. Dr. Mocco also presented a second retrospective study here of cases using the Enterprise stent with good results.

Cautious Assessment

Cheryl Bushnell, MD, from Wake Forest University Health Sciences, in Winston-Salem, North Carolina, moderated a press conference here where these results were presented. She cautioned that the study is still small. "It certainly looks promising, but it needs to be assessed in a larger study with a control group or at least have historical controls from a similar population," she told Medscape Neurology & Neurosurgery.

"I think the major issue there is that it requires a highly skilled, properly trained interventionalist to put that stent in, and there have been a lot of problems with intracranial stents in the past," she added. In their own experience, restenosis is a frequent problem, although with other stents than the Wingspan, she noted. Stents can create a nidus for clot formation, so it will be critical that patients receive clopidogrel and aspirin after the procedure, at the proper dose, she added.

Mark Alberts MD, professor of neurology at Northwestern University Feinberg School of Medicine, in Chicago, Illinois, said that this represents, in his view, "the evolution of stroke care," after pharmacologic and mechanical intervention.

"The impressive thing about this trial is they were able to achieve in basically 100% of the cases some degree of perfusion, so they were successful in getting the artery open," he told Medscape Neurology & Neurosurgery. This is an "important victory," he said, because, depending on the study, mechanical devices do not work in a significant proportion of cases. "The fact that this worked in 100% is good, but we'll see if this can be reproduced by other people in other centers."

However, he expressed concern about the mortality rates, both in the original series from 2006 and now in this new series, of 25%. "Typically, the death rate from ischemic stroke is 5% to 10%," he noted.

The other key point is that this is "a highly specialized treatment that could really only be done in very specialized centers with a lot of infrastructure and expertise," Dr. Alberts said.

The study was funded by Boston Scientific. Dr. Mocco reports receiving funding from the Brain Aneurysm Foundation. He has also received honoraria from Cordis.

American Stroke Association International Stroke Conference 2009: Abstract 144. Presented February 19, 2009.


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