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How Medical Negligence Can Lead to Stroke in Patients With Atrial Fibrilation

June 21, 2024  ·  By HM&M

Atrial fibrillation (AFib) is a common heart condition affecting millions annually. However, if it’s not properly managed, it can lead to blood clots and severe strokes.

Coumadin, an anticoagulant medication, has been crucial for stroke prevention in AFib patients for decades, but it requires careful monitoring to maintain therapeutic INR levels. Have you suffered a stroke after being prescribed Coumadin? Read on to learn your rights.

>>> Related Read: Chicago Jury Awards Record Verdict to 72-Year-Old Man Who Suffered Stroke Due to Medical Malpractice

What is Atrial Fibrillation?

Atrial fibrillation (AFib) is one of the most common types of heart conditions, affecting millions of people per year. During atrial fibrillation, the atria of the heart are not pumping regularly. Atrial fibrillation causes blood to pool and stagnate in the atria. Because the blood pools and stagnates, clots form.

Clots that form in the atria of the heart can grow to be very large, break off and travel to the brain, resulting in severe stroke. Accordingly, AFib patients must be on anticoagulant medication to prevent clots when the blood pools, thereby protecting the patient from stroke.

What is Coumadin?

Coumadin is an anticoagulant medication that healthcare providers have prescribed to prevent strokes in patients with atrial fibrillation since the 1950’s. Coumadin not only prevents strokes, but also reduces the severity of the stroke if one occurs.

Everybody metabolizes Coumadin in the body differently. Therefore, each patient’s proper dosage of Coumadin is individualized. However, Coumadin is only effective if the patient’s INR levels are “therapeutic”–or in a safe range between 2.0 and 3.0.

Protime/INR is the blood test used to determine if a person’s blood is properly thinned with Coumadin to prevent stroke. Protime is the test, and INR is the result.

The therapeutic INR level for people with atrial fibrillation is 2.0 – 3.0. The therapeutic INR level of 2.0 – 3.0 for patients on Coumadin with atrial fibrillation is, and has been, the universally accepted and proven standard for effective stroke prevention for decades.

Patients cannot manage Coumadin therapy—or the laboratory testing required to make sure the drug is working, and that the INR level is therapeutic—on their own. Trained medical professionals, including cardiologists, internists, nephrologists, family practitioners, nurse practitioners and physician assistants, must closely monitor the patient’s INR levels and adjust the Coumadin dose. If the medical providers fail to closely monitor INR levels and adjust the blood-thinning medication, leading to a stroke, the providers are medically negligent.

How is Coumadin Related to Stroke?

If a patient’s INR is below 2.0 (also known as “subtherapeutic”), a healthcare provider must increase the patient’s Coumadin dosage until the patient is therapeutic between 2.0 – 3.0. The standard of care is to “check and adjust” – check the INR level and adjust the Coumadin dosage until the patient achieves therapeutic levels.

When a patient begins Coumadin, daily INR testing is required until the proper Coumadin dosage is established. The proper Coumadin dosage is established when the patient has three consecutive therapeutic INR levels between 2.0 – 3.0.

When a person with atrial fibrillation is subtherapeutic on Coumadin, a clot can form in the heart. Each day the person remains subtherapeutic, the clot grows. Eventually, when the clot grows large enough, a piece of the clot, or embolus, can break off. The embolus is pumped by the heart directly into the right Middle Cerebral Artery, travels to the brain, and causes a cardioembolic stroke.

Conversely, when a patient on Coumadin has an INR above 3.0 (supratherapeutic), there is an increased risk of internal bleeding.

Accordingly, it is imperative that a competent healthcare provider closely monitor and manage patients’ Coumadin therapy to ensure INR levels remain between 2.0 – 3.0. Failure to closely monitor and manage patients on Coumadin is negligent and can result in catastrophic health consequences.


The only way to know whether a Coumadin patient suffered a stroke because of medical negligence is to speak with a qualified, specialized medical malpractice attorney.

The team at Hurley McKenna & Mertz has years of experience fighting for stroke victims and their families.  We recently obtained a record setting 2024 jury verdict against OSF HealthCare System on behalf of a 72-year-old man with AFib who suffered a catastrophic stroke because Cardiologists and Advanced Practice Nurses failed to monitor the patient’s INR levels or increase his dose of Coumadin to prevent cardioembolic stroke.

Our team at Hurley McKenna & Mertz can gather the facts about your case and help you determine whether a stroke occurred because of medical negligence.

To speak with an attorney, contact us for a free consultation today.

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