Clinical Decisions

Surgery and Blood Thinners

Blood thinners are medicines that thin your blood. This means that if you are taking a blood thinner, you have a higher risk of bleeding. But many patients need to take blood thinners. So, surgery and blood thinners are a challenge. Obviously, this is because of the added bleeding risk. This means that most people will need to stop taking the blood thinner to allow for a safer surgical procedure. Practically, two questions come up:

  1. When should I stop my blood thinner before surgery?
  2. When can I re-start my blood thinner after surgery?

This article will summarize the approach to surgery and blood thinners. If you want to read more, you might want to check out these 2022 guidelines.

Risk of Stopping a Blood Thinner

When we use the term “blood thinner” we mean medications such as Coumadin, and newer blood thinners such as rivaroxaban (Xarelto) and apixaban (Eliquis).

In general, people take these medications for two main reasons: to prevent stroke if they suffer from atrial fibrillation or to prevent and treat blood clots in their veins.

The risk of stopping a blood thinner depends on several factors:

  • Why are you taking a blood thinner in the first place? For instance, stopping a blood thinner can be risky with certain types of mechanical heart valves. But there is probably less risk if you are taking a low dose blood thinner because of a blood clot you had years ago.
  • Are you healthy or do you have many medical conditions? For example, stroke risk is higher if your heart is not healthy or if you have hypertension. There are calculators that can help you assess risk.

When to Stop a Blood Thinner Before Surgery

Deciding when to stop a blood thinner before surgery can be easy. There are only a few factors to consider:

  1. What is the risk of bleeding from this particular surgery? If the surgery is higher risk, like brain surgery, you will stop the blood thinner sooner.
  2. What is the risk of a blood clot off the blood thinner? Basically, the higher the risk, the less time you will want to be off a blood thinner.
  3. Are you taking Coumadin or are you taking a DOAC? Usually, you will need to stop Coumadin 5 days before surgery. But with DOAC you can stop only 2-3 days before surgery.

What if My Clotting Risk is Very High?

Sometimes the risk of being off a blood thinner is very high. Even if only for a few days. In these cases you need to consider something called “bridging”. Bridging means taking a short-acting blood thinner right up to the time of surgery. In general, bridging is not a good idea. There is more risk of bleeding in people who bridge than in those who do not. But in uncommon instances, that is still the safest decision for a particular person.

When to Re-Start Blood Thinners After Surgery?

Once surgery is done, the goal is to get back on the blood thinner as soon as possible. The logic is simple. Blood clots after surgery are common. Getting back on the blood thinner should prevent these from happening.

But this is not always easy to do. Sometimes, there is still a risk for bleeding for a few days after surgery. Brain surgery is the most complicated. There may still be a risk of a brain bleed two weeks after brain surgery.

For this reason, we think about the following factors when we decide when to start a blood thinner after surgery:

  1. What kind of surgery was this? For instance, was this a simple skin biopsy or was this a complicated spinal surgery
  2. How did the surgery go? Was there much bleeding or was the surgeon able to control all the bleeds?
  3. What is the risk of not taking the blood thinner for a few days? An example of a high-risk situation is a fresh blood clot in the leg. But other situations are not as risky. For instance if there is atrial fibrillation in an otherwise healthy person

The most important person to talk to about when to start a blood thinner after surgery is the surgeon. They usually know how the surgery went and they will be able to assess the risk of starting a blood thinner too soon. If you have a clotting expert who follows you, make sure they make a plan together with the surgeon before the surgery. That way everyone knows what to expect.

Dr. Ido Weinberg

Dr. Ido Weinberg is a Vascular Medicine specialist at Massachusetts General Hospital. He is President-Elect of the Society for Vascular Medicine. Dr. Weinberg treats hundreds of patients with blood clots every year. He publishes extensively on blood clots and he speaks frequently about blood clots in international conferences.

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