Ischemic types of stokes are caused by a thrombus or embolus. A blood clot in an area outside of the brain, such as the heart or neck, dislodges from its site of origin and circulates through the bloodstream toward the brain, where it blocks off a blood vessel. This condition is also referred to as a cerebral embolism. The resulting oxygen deprivation to the brain causes an ischemic stroke. Immediate medical treatment prevents further damage to nerve cells in the brain.
Medication
Thrombolytic drugs, also called "clot busters" dissolve an existing clot when administered by intravenous injection. The Food and Drug Administration (FDA) approved a thrombolytic called tPA, or tissue plasminogen activator, for acute treatment of strokes. According to the Mayo Clinic, from the time of onset for an ischemic stroke, there is only a three-hour window that tPA can be given to increase chances of full recovery. Beyond the three hours, the dangerous bleeding risks associated with thrombolytics outweigh the benefits. Other medications that may be used in treatment include anticoagulant and antiplatelet drugs. These help prevent the existing clot from getting larger and prevent formation of new clots. Unfortunately, the American Stroke Association says only 3 to 5 percent of stroke patients arrive to the hospital on time to be considered for this treatment.
Clot Retrieval
According to the National Stroke Association (NSA), two types of acute treatments are available that extend beyond the three-hour time limit for intravenous tPA therapy. The Penumbra system, which can be used within eight hours of a stroke onset, works by restoring blood flow in the brain by suctioning out the blood clot. The NSA states the MERCI retrieval system can treat individuals ineligible for thrombolytic therapy, those who missed the three-hour window and those who failed to respond to intravenous tPA. The MERCI retrieval system is a tiny device that wraps around the blood clot and removes it from the body.
Surgery
Following a stroke, surgical procedures aim to re-establish blood flow and oxygenation in the brain to prevent further damage. Revascularization techniques consist of bypassing the blocked area with grafting a vessel to a cerebral artery, according to the Mayo Clinic. A procedure called angioplasty involves insertion of a balloon-tipped catheter into the area of obstruction. As the balloon inflates, it exerts pressure on the plaque compressing it to the vessel walls thus restoring blood flow. A tiny mesh-like tube called stent is placed within the vessel to prop open the newly compressed area and prevent a recurrence.
