Dr. Risley explained that the majority of strokes (87%) are ischemic strokes, or caused by a clot or restriction of blood flow causing loss of oxygen to brain tissue. These clots most frequently come from cholesterol plaques that build up in the carotid arteries (the large vessels in your neck). Over time these plaques become bumpy and small pieces break off and travel to vessels within the brain. Medications such as aspirin and plavix (clopidogrel) help to prevent sticky cells called platelets from clumping up around these plaques and restricting blood flow.
For some who have heart conditions such as atrial fibrillation (AFib) clots can form in the heart by a pooling of blood in the upper chambers when they fibrillate, or twitch, rather than pump effectively. This also happens with congestive heart failure (CHF) when the heart muscle is weakened and unable to pump thoroughly. Dr. Risley compared this to paint thickening, or congealing, in the roller tray after time. These conditions are treated with anticoagulants, or “blood thinners”, such as warfarin, pradaxa or xarelto. These medications prevent the thickening and clotting of the blood in order to prevent heart attack and stroke. Some individuals have both carotid artery disease and heart conditions such as AFib and CHF and may need to take both aspirin and an anticoagulant.
Anticoagulants decrease risk of a secondary stroke by 67%. Those that have a history of ischemic stroke should be on anticoagulation to prevent a recurrent stroke, although some people may have other medical conditions that make these medications too dangerous.
Tissue Plasminogen Activator (tPA) was a prime topic of discussion. TPA is a clot busting drug that can be given within a three hour window after the first signs of stroke begin. The brain is very sensitive to injury and as soon as these cells start to lose blood flow, symptoms begin to occur. Over a million brain cells die each minute of a stroke. Death of brain cells cannot be reversed, however the area of injury surrounding the dead cells can often be saved with tPA and/or surgical clot removal. Certain conditions can prevent an individual from receiving tPA. A history of bleeding on the brain, and recent history of heart attack or surgery are a few such conditions. Use of newer anticoagulants such as pradaxa or xarelto prevent treatment with tPA as the bleeding times can’t be monitored or reversed with these types of medications. Treatment with tPA in these cases would have too high a risk of uncontrolled bleeding. Warfarin, however, can be monitored by an INR. If the INR is low enough, the decision may be made to treat with tPA to stop the progression of brain cell death associated with stroke.
For those patients that are not eligible for tPA, surgical removal of the clot may be possible in some cases by threading a catheter from the large artery in the groin up to the artery within the brain where the clot is located. For a general idea of the Penumbra device used click here. For the general idea of the Solitaire device used click here. The time frame for this procedure is longer than that of tPA, previously up to 6-8 hours after first sign of stroke. More recently however, certain cases have had successful outcomes when performed past this time period.
Stroke can also be caused by a bleeding of blood vessels, primarily caused by high blood pressure. These hemorrhagic strokes often occur deeper within the brain and account for the other 13% of strokes. Treatment for these strokes is limited, and consist mainly of controlling blood pressure and allowing the body itself to stop the bleeding on its own. For patients on the anticoagulant warfarin, correcting increased bleeding times is important as well. In severe cases, where bleeding causes a large mass of pooled blood on the brain, a surgeon can remove the blood to reduce pressure and restore brain function.
Another important topic of discussion was the recovery period. Stroke recovery takes on average 9-12 months. Although recovery can extend past the one year mark in some cases, the return of function is mostly limited to this period. Although the original area of brain that was damaged by the stroke will never heal, different areas of the brain can take over, building new connections to accomplish the same task. Although these new connections are not as effective as the original ones, with consistent therapy some degree of function can be returned.
If you missed Monday’s meeting, we encourage you to keep an eye on our Facebook page as Dr. Risley has offered to return later this spring or summer for another question and answer session. The expertise she shared was truly invaluable to the group. We hope this summary is beneficial to you in your recovery.