Anybody who has ever known a stroke victim can probably attest to how heartbreaking and life-changing the event can be.

The challenge in stroke treatment is that within minutes of an occlusion of a cerebral artery, brain cells begin to die, creating a non-salvageable region called the infarct core. Most strokes also involve a region of brain tissue – called the penumbra – that is lacking sufficient oxygen for long-term survival, but can be saved if blood flow is restored or augmented.

Unfortunately, the only FDA-approved drug to treat the most common type of stroke – Genentech’s (South San Francisco, California) tissue plasminogen activator (tPA) – must be given within three hours, and only about 3% to 4% of ischemic stroke patients show up to the emergency room in time — or are not diagnosed quickly enough — to receive the clot-busting drug.

With this in mind, several companies are working to widen the time window for ischemic stroke patients. One such company, Penumbra (San Leandro, California), recently received FDA clearance of its Penumbra system.

The Penumbra system is a package of tools used by neuro interventional specialists to remove occlusions from the large vessels of the brain that are causing an acute ischemic stroke. It works on the proximal surface of the occlusion, optimizing safety and eliminating the need for navigation beyond the occlusion, according to the company. The system is comprised of an aspiration platform containing multiple devices that are size-matched to the specific neurovascular anatomy allowing clots to be gently aspirated out of intracranial vessels.

The Penumbra system is indicated for use in the revascularization of patients with acute ischemic stroke secondary to intracranial large vessel occlusive disease within eight hours of symptom onset. Penumbra said it would begin commercialization of the device in the U.S. immediately.

When tPA is used for treating ischemic stroke patients, and the drug is used beyond three hours, the patient has a higher likelihood of hemorrhaging than if it used within the three-hour window, Arani Bose, MD, chairman and founder of Penumbra, told Medical Device Daily.

“In our application there is no tPA, it is a drug-free environment,” Bose said. “By not using drugs you buy yourself the additional time window.”

The company said the American Stroke Association (ASA; Dallas) has accepted clinical results from the pivotal trial of the Penumbra system for presentation at the 2008 ASA International Stroke Conference in New Orleans. The abstract was accepted under the Late “Breaking Science” category and will be presented by Cameron McDougall, MD, chief of endovascular neurosurgery at Barrow Neurological Institute (Phoenix), on Feb. 22 in Plenary Session III. Based on the ASA’s requirements, the clinical data is embargoed from public disclosure prior to presentation at the conference, Penumbra noted.

“We were very impressed with the performance and efficacy of the Penumbra system during the clinical trial, and are excited to now have access to this important tool to treat acute ischemic stroke patients in our daily practice. This system of tools is an important advance that may transform the acute treatment of this devastating disease,” said Michael Madison, MD, director of interventional neuroradiology at St. Paul Radiology (St. Paul, Minnesota).

In the pivotal trial, in addition to the multiple aspiration devices, the system included a clot-grabbing device intended for use if the aspiration devices were not successful. Based on the results of the trial with the aspiration devices, and due to the small number of cases in which the clot-grabbing device was necessary, Penumbra, in consultation with the FDA, decided to exclude the clot-grabbing device from its final submission.

The Penumbra System is CE-marked and has been commercially available in Europe since June.

“Acute ischemic stroke is a major public health issue and its treatment often requires a variety of therapeutic approaches. We welcome the addition of the Penumbra System to the therapeutic options available to the neuro interventionalist, and look forward to seeing it in clinical practice,” said Mary (Lee) Jensen, MD, a professor of radiology and neurosurgery at the University of Virginia Health System (Charlottesville) and president of the Society of NeuroInterventional Surgery (Fairfax, Virginia).

“Physicians treating patients with acute ischemic stroke often have limited treatment options to offer, particularly for patients presenting beyond the three-hour time window for intravenous thrombolysis. The availability of a new endovascular device system that may allow safe revascularization of occluded vessels and restoration of brain blood flow in acute ischemic stroke for up to eight hours after symptom onset is a promising development. We look forward to additional data addressing the effect of revascularization on clinical outcome,” said Pierre Fayad, MD, the Reynolds Centennial Professor and chairman of the Department of Neurological Sciences at the University of Nebraska Medical Center (Omaha) and chair-elect of the Stroke and Vascular Neurology section of the American Academy of Neurology (St. Paul).

CoAxia (Maple Grove, Minnesota) also is trying to give ischemic stroke patients more time to get treatment with its NeuroFlo Perfusion Augmentation Therapy. In June the company reported enrolling the first two patients in its Flo 24 safety and feasibility study of NeuroFlo in ischemic stroke patients who show up for treatment as late as 24 hours after symptoms begin. CoAxia said it believes NeuroFlo is the first intervention evaluated which attempts to improve blood flow to the brain this late after a stroke (Medical Device Daily, June 4, 2007).

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