- Last Updated: December 5, 2016
Stroke, defined as the rapid loss of brain function resulting from a disrupted blood supply to the brain, can result in permanent neurologic damage or death. Strokes can be classified as either Hemorrhagic or Ischemic. Ischemic strokes, which are caused by blockages of blood vessels, (e.g. by blood clots), account for almost 90% of strokes. Hemorrhagic strokes, which are caused by ruptured blood vessels and hemorrhage, account for about 10%.
Symptoms range from the inability to move limbs on one side of the body to impaired speech and vision. Important risk factors include age, high blood pressure and cholesterol, and diabetes.
According to estimates by the Centers for Disease Control and Prevention, almost 800,000 Americans experience a stroke each year. Stroke is also the 4th leading cause of death among Americans. In 2010, total costs related to stroke were almost $40 billion.
Treatment for stroke can vary depending on whether the stroke is Ischemic or Hemorrhagic.
Treatment for Ischemic stroke focuses on restoring blood flow to the brain by dissolving existing blood clots. This can be done with medications administered intravenously within approximately 4-5 hours of the onset of the stroke. Microcatheters can also be used to administer medications directly to the blocked artery or to mechanically break apart the clot.
Treatment for Hemorrhagic stroke focuses on both controlling bleeding and reducing pressure in the brain. Different medications can be given to counteract the effects of blood thinners or lower intracranial pressure and prevent vasospasm and seizure. Most intracerebral hemorrhages are caused by high blood pressure. Treatment involves controlling the blood pressure and in some cases invasive surgery to remove the blood clot from the brain. Intracerebral hemorrhage from other causes such as ruptured aneurysms and arteriovenous malformations involves treatment of the offending pathology and may involve surgical clipping of the aneurysm or surgical removal of the arteriovenous malformation. Endovascular coiling is another method by which aneurysms and arteriovenous malformations can be treated through a minimally invasive approach.
Focused Ultrasound Treatment
Preclinical research is exploring the ability of focused ultrasound to dissolve blood clots by directing ultrasound energy to cause vibrations that can either break the clot apart directly or make it more susceptible to the effects of thrombolytic agents. Researchers have shown the feasibility of treating both ischemic and hemorrhagic stroke as well as inducing reperfusion of occluded blood vessels in other organs of the body. More work is needed to optimize the parameters of focused ultrasound before research can reach the clinic.
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