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Patient Evidence Summary
Doctor, I have atrial fibrillation and a bioprosthetic mitral valve, can I use Xarelto® to protect me from stroke?
People with a bioprosthetic mitral heart valve who also have atrial fibrillation can safely take Xarelto® to reduce the risk of stroke and other blood clots. Note: These results do not apply to people with a bioprosthetic aortic valve or anyone with a mechanical heart valve.
Study highlights
People with atrial fibrillation and a bioprosthetic mitral valve who took Xarelto® did not have more strokes, other blood clots, major bleeding, hospital admissions for heart failure or death compared to people who took warfarin.
Understanding the problem
In some cases, a heart valve may stop working properly (e.g. becomes too leaky or too narrow) and a replacement valve is needed. The replacement heart valve can be made from animal tissues (e.g. cow or pig) or from metal (mechanical heart valve). Valves that are made from animal tissues are called bioprosthetic valves.
Atrial fibrillation is an abnormal heart rhythm that can occur in people with underlying heart disease, including people with heart valve problems.
Some people with replacement heart valves and atrial fibrillation require anticoagulants to reduce the risk of clotting of the heart valve and stroke. Most commonly, people with both atrial fibrillation and a replacement heart valve are given warfarin. People who take warfarin need to have regular blood tests, called an INR, to ensure their medication dose is correct. Warfarin may interact with food and other medications.
Xarelto® does not require blood testing and interacts with few medications. From other studies, we know that Xarelto® is as safe and effective as warfarin for preventing stroke in people with atrial fibrillation. The researchers performing this study wanted to know if Xarelto® is as safe and effective as warfarin at preventing strokes and other blood clots in people with both atrial fibrillation and a bioprosthetic mitral heart valve.
Who? The study included 1,005 adults (mean age 59 years; 60% women; 56% white; 13% with prior history of stroke) with a bioprosthetic mitral valve and either atrial fibrillation or atrial flutter.
People were excluded if their doctor thought it was unsafe for them to be on anticoagulation or if they had medical illnesses that would prevent them from taking Xarelto®
What? The study compared Xarelto® with warfarin for 12 months.
Xarelto® | vs | Warfarin |
|---|---|---|
Xarelto® 20 mg once daily OR 15 mg once daily for people with reduced kidney function | Warfarin at doses aimed to maintain an INR between 2.0 and 3.0. INRs were measured at least once every 4 weeks. |
Xarelto® vs warfarin in people with a bioprosthetic mitral valve and atrial fibrillation or atrial flutter
Outcomes at 12 month | Result | |||
|---|---|---|---|---|
Major clinical events (Composite outcome) Includes: death, blood clots (stroke, transient ischemic attack (TIA), valve thrombosis, other systemic embolism), major bleeding, or hospitalization for heart failure | No effect No difference in the number of unwanted clinical events between people who took Xarelto® and people who took warfarin | |||
A composite outcome combines all of the different ways a treatment can affect people into one number to show the overall impact of the treatment. A school grade is an example of a composite outcome. The teacher combines many different activities that a student does over a school term into a single mark. One potential drawback of a composite outcome in medicine is that all treatment outcomes are considered equal, even when they aren't. For example, in this study being admitted to hospital is statisically considered as important as death. That is why it is also helpful to look at the individual outcomes (as shown in the Table below). However, it is important to understand that the number of events for each individual outcome is small so future larger studies might find a different result if they only focused on that single outcome. | ||||
| Outcomes at 12 months | Rate of events with Xarelto® | Rate of events with warfarin | Results | |
| Death | 4 out of 100 people | 4 out of 100 people | No effect* | |
| Stroke (any type) | 1 out of 100 people | 2 out of 100 people | About 1 less person out of 100 had a stroke on Xarelto® compared with those taking warfarin. | |
| Major bleeding | 1 out of 100 people | 3 out of 100 people | No effect* | |
| Blood clot forming on the new heart valve | 1 out of 100 people | 1 out of 100 people | No effect* | |
| Hospitalization for heart failure | 4 out of 100 people | 4 out of 100 people | No effect* | |
*Although the rates for the 2 groups look different, the differences were not statistically significant—this means that the difference could simply be due to chance rather than due to the different treatments.
This Evidence Summary is based on the following article:
Guimaraes HP, Lopes RD, de Barros E Silva PGM, et al. Rivaroxaban in Patients with Atrial Fibrillation and a Bioprosthetic Mitral Valve. N Engl J Med. 2020 Nov 14. doi: 10.1056/NEJMoa2029603. PubMed
Nicholas Howell is an MD/PhD Student in his final year at the University of Toronto. His PhD research examined relationships between environmental factors, such as neighbourhood walkability and air pollution, and cardiovascular health. His clinical interests lie within internal medicine, and he hopes to further explore topics surrounding thromboembolism and cardiovascular disease during his residency training.
Zachary Liederman, MD
Zach recently graduated from the University of Toronto Hematology Residency Program and is currently pursuing additional training as both a CanVECTOR fellow and as the Alexandra Yeo Fellow in Thrombosis and Hemostasis at the University of Toronto. He is in the process of completing a Master’s degree in medical education and looks forward to contributing to existing and new teaching projects centered around thromboembolism.
Published: Monday, April 19, 2021
Last Updated: Thursday, May 27, 2021
Please note that the information contained herein is not to be interpreted as an alternative to medical advice from a professional healthcare provider. If you have any questions about any medical matter, you should consult your professional healthcare providers, and should never delay seeking medical advice, disregard medical advice or discontinue medication based on information provided here.
, McMaster University