Blood Thinners: To Continue or Not

Blood thinners taken to prevent stroke should be discussed in detail before any surgery

/ Author:  / Reviewed by: Robert Carlson, M.D

(RxWiki News) Blood thinners are a mixed blessing for patients. On one hand, they can prevent strokes. But on the other, they can cause serious bleeding during surgery.

Surgeons sometimes have patients stop blood thinners before surgery to avoid dangerous bleeding.

The key question is: do the benefits of preventing clots and a possible stroke outweigh the risks of bleeding during surgery? It depends on the medication as well as the procedure, according to new guidelines from the American Academy of Neurology.

According to these guidelines, doctors must carefully evaluate the use of blood thinners before a patient on blood thinning medication undergoes any surgery.

"Tell your surgeon which medications you're taking before surgery."

The new guidelines were based on a study conducted by Melissa Armstrong, MD, assistant professor of neurology at the University of Maryland School of Medicine in Baltimore, along with collaborators from other US universities.

The study focused on blood thinner medications, or anticoagulants, such as aspirin and warfarin, and whether their continued use during surgery should be recommended.

Blood thinners are usually prescribed to patients who have had a stroke, a condition in which blood supply to the brain is blocked by a blood clot. The blood thinners help prevent formation of new blood clots, thus reducing the risk of future strokes.

Blood thinners are also given to people with atrial fibrillation, a type of abnormal rhythm of the heart, to avoid clots from forming, dislodging and then reaching the brain and blocking blood vessels.

The study listed certain procedures in which continuing blood thinners was not associated with increased risk of bleeding during surgery. These procedures included dental procedures, certain eye surgeries, endoscopies (looking inside the body with a small camera) and biopsies (taking a sample of tissue for testing).

The risk of bleeding may be higher if blood thinners are continued in other procedures, including some orthopedic surgeries. There was not enough evidence available to make recommendations for some procedures.

Overall, the original study stated that risks and benefits vary depending on what type of blood thinner is used and the type of surgical procedure.

The new guidelines, based on these results, state that the question of risk of bleeding versus benefit of preventing stroke needs to be considered at an individual level rather than creating rules for the general patient population.

It is recommended that patients taking blood thinners to prevent stroke should work closely with their doctors to determine if these medications should be discontinued before surgery to avoid the risk of bleeding or continued to sustain the stroke prevention benefits.  

According to the guidelines, neurologists should inform both patients taking blood thinners and their surgeons that discontinuing these medications is associated with increased stroke risk.

“There may be millions of Americans taking antithrombotic medications for stroke prevention. For every dental procedure, minor medical procedure, or surgery these people plan to have, it is important to balance stroke risk from stopping an antithrombotic agent with a procedure’s bleeding risk if the medication is continued,” said Dr. Armstrong.

“This guideline helps patients and physicians know what evidence tells us about these different risks. A person’s health history and preferred course of action are also important to discuss when making this decision,” she said.

The original study was published on May 28 in Neurology, the official journal of the American Academy of Neurology.

The study received funding from the American Academy of Neurology.

Michael Schneck, one of the co-authors reported having worked on trials sponsored by the NIH, Lundbeck Pharmaceuticals, Brigham & Women’s/Schering Plough, Gore Inc., NMT Medical and He is currently working on an investigator-initiated project to be funded by Baxter, Inc. He has also served on speakers’ bureaus for Boehringer-Ingelheim and Bristol-Myers Sanofi but is not associated with these companies in past 2 years.

None of the other authors reported any conflicts of interest or relevant financial relationships.

Reviewed by: 
Review Date: 
May 28, 2013
Last Updated:
August 8, 2013