NEW ORLEANS — A novel clot removal device appears safe and effective for revascularizing patients with acute ischemic stroke secondary to large vessel occlusion, according to results of a multicenter study of 125 acute stroke patients.
Of those patients in a prospective, single-arm trial designed to assess the safety and efficacy of the Penumbra System (Penumbra Inc.), 82% were successfully revascularized. Successful revascularization—the primary end point in the study—was defined as a change from a Thrombosis in Myocardial Infarction (TIMI) risk score of 0 or 1 to a score of 2 or 3 following treatment with the device, Dr. Cameron McDougall reported at International Stroke Conference 2008.
The Penumbra System comprises multiple device options, including a reperfusion catheter for aspirating clots, a separator designed to allow the reperfusion catheter to aspirate continually, and a thrombus removal ring designed to grasp and capture calcified clots that are not aspirated. The operator selects the appropriate device platform based on the nature of the thrombotic occlusion and the angio-architecture of the target vessel.
In the current trial (the Penumbra Stroke Trial), TIMI 2 or 3 revascularization scores were achieved in 81% of patients using only the aspiration device platform; only one patient required use of the extraction (clot grasping) device, for a revascularization rate of 82% when both were used, Dr. McDougall of Barrow Neurological Institute, Phoenix, reported.
A favorable outcome, defined as either a 4-point improvement on the National Institutes of Health Stroke Scale (NIHSS) at discharge, a 10-point improvement on the NIHSS (or a score of 0–1) at discharge, or a 90-day modified Rankin Scale score of 2 or less, occurred in 58%, 27%, and 25% of patients, respectively. Better outcomes occurred in those with a baseline NIHSS score of 20 or less, compared with those with higher scores (see graphic). All-cause mortality was 26% at 30 days, and 33% at 90 days.
The trend for improved outcome with revascularization was consistent across all neurologic functional measures, noted Dr. McDougall, who had no financial or other relationships to disclose.
The device also proved safe, he said at the conference, which was sponsored by the American Stroke Association.
Four procedural serious adverse events were reported in four patients, but none were attributed to the device, and no device malfunctions or breakage occurred. A total of 35 patients (28%) had intracranial hemorrhage at 24 hours, including 14 (11%) who were symptomatic.
Patients in the trial had a mean age of 63 years, baseline NIHSS scores of at least 8, and presented within 8 hours of symptom onset. Those who presented within 3 hours of symptom onset had to be ineligible for, or refractory to recombinant tissue-type plasminogen activator (rTPA) therapy to be enrolled.
The target vessel was the internal carotid artery in 18% of patients, the middle cerebral artery in 70%, the vertebrobasilar artery in 9%, and another vessel in 3%.
The median time to arterial puncture from the time of symptom onset was 4 hours, and the median time to revascularization was 45 minutes.
Serious adverse events that occurred in study participants included two perforations, and two intracerebral hemorrhages, including one that was a result of perforation, for a serious adverse event rate of 3%.
Compared with historic controls from a trial of the Mechanical Embolus Removal in Cerebral Ischemia (MERCI) clot retrieval device—as established prior to the Penumbra Stroke trial—the outcomes with the Penumbra System were superior (82% vs. 48% recanalization rates).
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