How are blood thinners used to prevent strokes?

How do these clotting systems play into “blood thinners?” Blood thinners can be split into two categories:

1. Anticoagulants that work on the coagulation cascade, or

2. Antiplatelet that decrease the “stickiness” of platelets

What are examples of antiplatelet medications? The most commonly known antiplatelet medication is aspirin. This binds with an enzyme on the platelet cell fragments called COX-1, which irreversibly causes the platelet to be less “sticky.” Other newer antiplatelet medications work on platelet aggregation by inhibiting the ADP receptor and then the glycoprotein GPIIb/IIIa complex, which keeps the platelets from sticking together, and keeps fibrinogen from binding. Examples of medications that work on this pathway include clopidogrel (Plavix) and eptifidbatide (Integrilin). Clopidogrel can be metabolized at different rates depending on different medications or genetics, so your Neurologist may consider testing to see how you respond to this medication if using it. Another option for blocking platelets includes medications that inhibitor PDE3 activity, such as cilostazol (Pletal). In general, antiplatelets tend to have a weaker blood thinning effect than anticoagulants. If a bleeding event occurs, most of the time the treatment is simply holding pressure and waiting. If the bleeding is life threatening, occasionally medications can be given, or a platelet transfusion can be considered.

How does a Neurologist choose to use an anticoagulant or an antiplatelet to prevent stroke? After a person has experienced a stroke and is recovering, the most important thing for the Neurologist to do is to investigate the cause of the stroke, as this greatly changes the measures taken to prevent another stroke from happening. The NeuroX Neurologist can take a detailed history and review diagnostic tests to customize your therapy to best prevent another stroke. Anticoagulant medications are most commonly used when a stroke is caused by a blood clot coming from the heart in an abnormal heart rhythm called atrial fibrillation, also referred to as afib. In afib, the top part of the heart quivers and does not empty well, leading to the formation of blood clots. Anticoagulants keep blood clots from forming and therefore prevent stroke. The Neurologist will take many factors into account – including age, diet, kidney function, weight, and patient preference – to customize the therapy and choose the best medication. Other examples when anticoagulants may be considered include genetic conditions that cause a hypercoagulable state where the person is more likely to form blood clots, dissection or tearing of blood vessels in the head or neck, certain autoimmune conditions, or other uncommon causes. In general, antiplatelet medications are used when someone has stenosis – the narrowing of small or large blood vessels in the head or neck due to high cholesterol, high blood pressure, diabetes, smoking, or other causes. This is called atherosclerosis, which some people think of as “hardening of the arteries.” Your Neurologist will be aware that certain areas of the brain are more susceptible to these effects. While we mentioned that anticoagulants are often considered “stronger blood thinners,” they actually do not work as well as antiplatelets in these types of strokes. In some circumstances involving these types of strokes, a Neurologist will consider putting a person on two antiplatelet medications for a short period of time to reduce the risk of stroke. This is based on a high quality clinical trial in this patient population, in which several NeuroX Neurologists were clinical investigators. Another example of when two antiplatelet medications may be considered is if the person has a stent in the artery, or there is a severe narrowing of one of the large blood vessels in the brain. Blood thinners are a cornerstone of preventing stroke, but it is important that a true expert help customize your therapy to best help prevent another stroke. This is a complex medical decision, and a NeuroX consultant is prepared and knowledgeable to tailor the treatment. Author: Brad Haveman-Gould, MHS, PA-CNeurology Physician Assistant

Further resources:

1. https://www.mayoclinic.org/diseases-conditions/stroke/symptoms-causes/syc-20350113

2. https://www.stroke.org/-/media/stroke-files/lets-talk-about-stroke/prevention/anticoagulants-and-antiplatelet-agents-ucm_310825.pdf?la=en

3. https://www.stroke.org/en/life-after-stroke/preventing-another-stroke/stroke-prevention-checklist

4. https://www.heart.org/en/health-topics/heart-attack/treatment-of-a-heart-attack/understanding-your-options-when-taking-aspirin-and-other-antiplatelet-drugs