Cerebral interventional radiology: New options for stroke victims

Every 40 seconds, someone has a stroke; every 4 minutes, someone dies from stroke. Strokes are the fourth leading cause of death in the United States. The two different types of stroke are ischemic (approximately 85% of strokes) and hemorrhagic (15%).

The saying “Time is brain” reflects the need for urgent stroke treatment. It also underlies the increase in the number of primary stroke centers and certified stroke centers in the United States and Europe. The Brain Attack Coalition’s guidelines for the basic components of primary stroke centers were published in 2000, 4 years after the Food and Drug Administration approved thrombolytic tissue plasminogen activator (tPA) for the treatment of acute ischemic stroke. These guidelines provided a roadmap for hospitals to develop a stroke system of care using the best evidence.

In December 2003, the Joint Commission launched a disease-specific care certification in collaboration with the American Heart Association/American Stroke Association (AHA/ASA) in an effort to foster better outcomes for stroke. As of October 1, 2009, more than 600 certified primary stroke centers existed in the United States. Certified primary stroke centers meet the following requirements:

  • use standardized methods of delivering care based on the Brain Attack Coalition recommendations
  • support patients’ self-management activities
  • provide treatments and interventions tailored to meeting patients’ individual needs
  • promote the flow of patient information across care settings while being sensitive to regulations of the Health Insurance Portability and Accountability Act
  • analyze standardized performance measure data to promote continual process-improvement, using such tools such as AHA/ASA’s Get With the Guidelines Patient Management Tool
  • demonstrate application of and compliance with clinical practice guidelines outlined by AHA/ASA.

In 2005, a new guideline for the development of comprehensive stroke centers was published regarding the use of endovascular and neurosurgical interventions for some patients with acute stroke. Although no certification delineates primary versus comprehensive certified stroke centers, the Joint Commission is investigating the need for a separate designation.

Key interventions

Because some stroke symptoms can be reversed with prompt diagnosis and treatment, healthcare providers should use standardized protocols to improve outcomes. The Brain Attack Coalition recommends the following key interventional components be integrated into hospital-based programs to improve patient outcomes:

  • treatment by healthcare personnel with expertise in neurosurgery and endovascular techniques
  • advanced neuroimaging techniques, such as magnetic resonance imaging, computed tomography, and angiography
  • surgical and endovascular techniques, including intracranial aneurysm clipping and coiling, carotid endarterectomy, and intra-arterial thrombolytic therapy
  • specific infrastructure and program elements, such as intensive care and participation in a stroke registry (for instance, the Paul Coverdell National Acute Stroke Registry).

Small window of treatment

Treatment options for ischemic stroke patients depend on the time elapsed since symptom onset. Alteplase (Activase), a recombinant tPA, has been widely used to optimize brain perfusion in stroke patients. This I.V. thrombolytic (“clot buster”) reduces or eliminates stroke symptoms in the acute setting in 30% of patients who are eligible to receive it.


The optimal window for tPA delivery in patients who meet tPA criteria is 3 hours from symptom onset. During this window, the penumbra of brain tissue beyond the clot (the site of secondary injury caused by the primary stroke) may still be viable. I.V. tPA has a 30% recanalization rate when given within 3 hours of symptom onset in the short term, and has been shown to improve overall recovery rates at 1 year post-stroke.

Unfortunately, only 2% to 3% of ischemic stroke victims meet I.V. tPA criteria. Patients can’t receive tPA if they:

  • have had recent surgery
  • received recent blood thinner therapy increasing prothrombin time
  • have suffered a hemorrhagic stroke
  • have nonthrombotic emboli
  • are younger than age 18
  • have rapidly improving symptoms.

Because of the small number of patients presenting to emergency departments within the treatment window who meet I.V. tPA eligibility requirements, additional treatment options have been developed. These include endovascular stenting, balloon angioplasty, intra-arterial thrombolytics, and clot or plaque retrieval.

Interventional radiology treatments for stroke

Cerebrovascular interventional radiology treatments expand the treatment options for acute ischemic stroke victims. Recent innovations include the MERCI Retriever®, Penumbra System®, and intra-arterial tPA. Each offers a longer treatment window and can be used in some patients ineligible for I.V. tPA.

Approved in 2004, the Mechanical Embolus Removal in Cerebral Ischemia (MERCI) Retriever is the first mechanical device for use in endovascular procedures in stroke patients. With a treatment window of up to 8 hours from symptom onset, the MERCI Retriever is most successful when used in larger cerebral vessels, such as the vertebral arteries, basilar artery, internal carotid arteries, and middle cerebral artery. The corkscrew-shaped device is threaded directly into the clot. The interventional radiologist or neurosurgical interventionist threads the microcatheter into the femoral artery, advances the device to the site of the clot, deploys the retriever into the clot to capture it, inflates a balloon to occlude blood flow, and pulls the clot through the catheter.

Another innovation, approved in 2008, is a thrombo-aspiration device called the Penumbra System. Offering an 8-hour window from onset of acute ischemic stroke symptoms, it has been 82% successful in recanalization. Introduced through percutaneous angiography, the system is threaded into the cerebral circulation to the area of the clot; the interventional radiologist deploys a separator to break up the clot and the Penumbra device then sucks the clot out.

Another new treatment is intra-arterial tPA administration, often used in conjunction with the MERCI Retriever or the Penumbra System. When delivered intra-arterially directly to the site of the clot, tPA has the same clot-busting potential as when given I.V., but with a longer treatment window—6 hours from symptom onset.

Nursing care

Interventional stroke therapies come with certain risks and require specific nursing care. The bedside nurse plays an integral role in assuring patient safety and improving outcomes. (See the box below.)

Cerebrovascular Interventional Radiology

Key interventions for patients who’ve undergone an interventional stroke procedure include frequent observation, thorough assessment of neurologic status, and close insertion-site monitoring for bleeding and hematoma. The patient may be admitted to a neurosurgical intensive-care unit for the first 24 hours for monitoring and neurologic exams. These exams can detect signs of intracranial bleeding and hemorrhagic stroke, and may involve use of the Glasgow Coma Scale, Four Score coma scale, or the National Institutes of Health Stroke Scale. Monitor the patient closely at all times to ensure the best outcomes.

Heparin is given during interventional procedures, putting patients at increased risk for bleeding; be sure to monitor for signs and symptoms of bleeding. Also be aware that patients may have mild to moderate pain; assess for pain according to your facility’s protocol.

During discharge education, teach the patient and family about the medication regimen, required dietary and other lifestyle modifications, and counseling regarding smoking cessation and other habits that may increase the risk of stroke or stroke recurrence.

Tina Cronin is a clinical nurse specialist, the director of neurosciences, and stroke program coordinator at Piedmont Medical Center in Rock Hill, South Carolina.

References

Adams HP Jr, del Zoppo G, Alberts MJ, et al. Guidelines for the early management of adults with ischemic stroke: a guideline from the American Heart Association/American Stroke Association Stroke Council, Clinical Cardiology Council, Cardiovascular Radiology and Intervention Council, and the Atherosclerotic Peripheral Vascular Disease and Quality of Care Outcomes in Research Interdisciplinary Working Groups. Stroke. 2007;38(5):1655-1711.

Alberts MJ, Hademenos G, Latchaw R, et al. Recommendations for the establishment of primary stroke centers. Brain Attack Coalition. JAMA. 2000;283(23):3102-3109.

Alberts MJ, Latchaw RE, Selman WR, et al. Recommendations for comprehensive stroke centers: a consensus statement from the Brain Attack Coalition. Stroke. 2005;36(7):1597-1616.

Barker E. Neuroscience Nursing: A Spectrum of Care. 3rd ed. St. Louis, MO: Mosby; 2007.

Barker E. A new weapon to combat stroke. RN. 2006;69(3):26-29.

Brain Attack Coalition. www.stroke-site.org. Accessed February 1, 2011.

Centers for Disease Control and Prevention. Stroke drops to the fourth leading cause of death in 2008. December 9, 2010. www.cdc.gov/media/pressrel/2010/r101209.html. Accessed February 1, 2001.

Joint Commission. The Joint Commission Primary Stroke Center Certification. www.jointcommission.org/certification/primary_stroke_centers.aspx. Accessed February 1, 2011.

Laino C. Novel aspirating device reportedly improves re-perfusion in stroke patients. Neurology Today. 2008;8(8):18-19.

MERCI Retrieval System. Concentric Medical. www.concentric-medical.com/merci-retrieval-system. Accessed February 1, 2011.

National Institute of Neurological Disorders and Stroke rt-PA Stroke Study Group. Tissue plasminogen activator for acute ischemic stroke. N Engl J Med. 1995;333(24):1581-1587. www.nejm.org/doi/full/10.1056/NEJM199512143332401. Accessed February 1, 2011.

Penumbra System. Penumbra, Inc. www.penumbrainc.com/products/penumbra-system/. Accessed February 1, 2011.

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