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What is anticoagulation and antiplatelet therapy?

Commonly known as “blood thinners,” these are medications that prevent blood clots from forming and also keep existing blood clots from getting larger. Clots in your arteries, veins, and heart can cause heart attacks, strokes, and blockages.

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There are two main types of blood thinners:

  • Anticoagulants slow down your body’s process of making clots.  Common anticoagulant medications  are warfarin (Coumadin), enoxaparin (Lovenox), heparin, rivaroxaban (Xarelto), apixaban (Eliquis), dabigatran (Pradaxa)

  • Antiplatelets prevent blood cells called platelets from clumping together to form a clot.  Common antiplatelets medications are aspirin, clopidogrel (Plavix), prasugrel (Effient) and ticagrelor (Brilinta).

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​When you take a blood thinner, follow directions carefully. Blood thinners may interact with certain foods, medicines, vitamins, and alcohol. Make sure that your healthcare provider knows all of the medicines and supplements you are using. You may need regular blood tests to check how well your blood is clotting. It is important to make sure that you’re taking enough medicine to prevent clots, but not so much that it causes bleeding.

Why am I taking a blood thinner?

 You may take a blood thinner if you have

  • Certain heart or blood vessel diseases such as coronary artery disease or peripheral vascular disease

  • An abnormal heart rhythm called atrial fibrillation

  • (Or have) had a blood clot

  • A heart valve replacement

  • A risk of blood clots after surgery

  • Congenital heart defects

What do I need to do if I am having a procedure?

When planning an interventional radiology (IR) procedure your coagulation status must be assessed and optimized to best balance the risk of bleeding and thrombosis (clot formation). The following must be considered;

  • bleeding risks associated with the procedure

  • medications you are taking that alter coagulation or platelet function

  • Your underlying thromboembolic risk

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When deciding how to best manage periprocedural blood thinning medications it is important to first consult:

  • the interventional radiologist who will be performing the procedure

  • departmental or health service guidelines

  • cardiologist – if you have had a previous heart procedure or surgery (stent, bypass), mechanical cardiac valves or have high-risk atrial fibrillation

  • hematologist – advice with specific blood disordered (thrombophilias, coagulopathies) or regarding the reversal of anticoagulants

Procedural bleeding risk assessment:

The risk and consequences of bleeding associated with a procedure can be grouped into three levels of risk:

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Low Risk

  • PICC placement

  • Drainage catheter exchange

  • Central line removal

  • IVC filter placement

  • Thoracocentesis or Paracentesis

  • Superficial aspiration or biopsy

  • Joint injection or aspiration

  • Thyroid biopsy

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Moderate Risk

  • Facet joint block

  • Lumbar puncture

  • Lung biopsy

  • Radiofrequency ablation

  • Epidural injection

  • Gastrostomy tube insertion

  • Liver biopsy

  • Uterine fibroid embolization

  • Prostate artery embolization

  • Chemoembolization

  • Angiography

  • Venous interventions

  • Intra-abdominal, thoracic wall or retroperitoneal abscess drainage

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High Risk

  • TIPS procedure

  • Biliary interventions involving a new tract (cholangiogram)

  • Complex radiofrequency ablation

  • Renal biopsy

  • Nephrostomy placement

​Procedural screening:

Coagulation screening may be useful in selective cases in recognizing and correcting underlying abnormalities. When to perform preprocedural coagulation screening:

  • possible underlying coagulopathies (previously unexplained hemorrhage, renal disease, liver disease, hematological disease)

  • to ensure adequate reversal once anticoagulants are stopped (only available for some anticoagulants)

  • High Risk – need to check INR, aPTT, CBC

  • Moderate Risk – CBC, INR routinely recommended

  • Low Risk – no testing is routinely recommended though labs may be checked

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Aims for coagulation parameters:

  • Low Risk: INR <2.0, consider transfuse platelets if <50,000/μL

  • Moderate Risk: INR <1.5, APTT <1.5 x control, transfuse platelets if <50,000/μL

  • High Risk: INR <1.5, APTT <1.5 x control, transfuse platelets if <50,000/μL

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*These are general screening guidelines, which may be modified on a case by case basis.

What does “bridging” of anticoagulation mean? 

The intent of bridging is to minimize the time the patient is not anticoagulated, thereby minimizing the risk for clot formation. However, this needs to be balanced with the importance of mitigating the risk of perioperative bleeding. 

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If you are taking a blood thinner called warfarin (Coumadin),  it typically needs to be stopped for a procedure so there won’t be an increased risk of bleeding. Usually we stop the Coumadin 5 days before the procedure. Although you can start the Coumadin the day after your procedure, it will take about 4-5 days to get to a therapeutic level where it starts to be effective in preventing clots. During this time you may need additional protection from blood clots.

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A different medication that works faster (and wears off faster) is started to protect you during the time it takes the Coumadin to reach therapeutic level. This is called bridging!  The new medication will “bridge” the period of time when Coumadin’s effect has been decreased.  This is most commonly done with the medication enoxaparin (Lovenox).

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​If you have a mechanical mitral valve or atrial fibrillation with a history of stroke, you will need bridging.   Still, even with bridging there is always a risk of stroke when having to stop any anticoagulation therapy for any duration of time.  Be sure to consult with your interventional radiologist and your prescribing health care provider (cardiologist, hematologist, primary care physician) whether you need bridging not. 

How is bridging done?

If you require bridging for your procedure, your Coumadin needs to be stopped for 5 days prior to your procedure.  After stopping Coumadin, you will need to start Lovenox on Day #3 and continue taking up until the day of the procedure.  On the day of your procedure, do NOT take any blood thinners.  The day after your procedure you are to resume both your Coumadin and Lovenox everyday for the next 4 days.  On the 5th day you will STOP Lovenox and take Coumadin only.  You may be instructed to recheck your INR in case your Coumadin may need dose adjustments.  Refer to the attached calendar for a visual example.

Coumadin bridging:

(*This is an example.  You dates may vary)

Sunday

Monday

Tuesday

Wednesday

Thursday

Friday

Saturday

 

1

2

3

4

5

6

7

8

9

Last dose of

Coumadin

10

NO blood thinners

11

NO blood thinners

12

Lovenox

13

Lovenox

14

Lovenox

15

Lovenox

16

PROCEDURE

(NO blood thinners)

17

RESTART Coumadin

+

 Lovenox

18

Coumadin

+

 Lovenox

19

Coumadin

+

 Lovenox

20

Coumadin

+

Lovenox

21

Coumadin Only

(may need to check INR)

22

Coumadin

23

Coumadin

24

Coumadin

25

Coumadin

…continue taking daily as prescribed…

26

*You may need to follow-up with your prescribing physician regarding INR/dose adjustments as needed

What if I am taking a different anticoagulant than Coumadin?

 If you are taking:

  • Rivaroxaban (Xarelto)– taken once a day, you will need to stop taking Xarelto for 2 days (2 doses) before your procedure if you have normal kidney function.  If you have decreased kidney function then you should stop taking for 3 days (3 doses) prior to your procedure.  You can restart the day after your procedure.

 Stopping Xarelto: 

(*This is an example. Your actual dates may vary)

Sunday

Monday

Tuesday

Wednesday

Thursday

Friday

Saturday

 

1

2

3

4

5

6

7

Xarelto

8

Xarelto

9

Xarelto

10

Xarelto

11

Xarelto

12

Xarelto

13

Xarelto

*Stop taking only if you have decreased kidney function

14

NO Xarelto

15

NO Xarelto

16

PROCEDURE

(NO Xarelto)

17

RESTART Xarelto

18

Xarelto

19

Xarelto

20

…Continue Xarelto daily as prescribed…

21

22

23

24

25

26

  •  Apixaban (Eliquis)– taken twice a day, you will need to stop taking for 2 days (4 doses) before your procedure if you have normal kidney function.  If you have decreased kidney function then you should stop taking for 3 days (6 doses) prior to your procedure.  You can restart the medication the day after your procedure.

Stopping Eliquis: 

(*This is an example. Your actual dates may vary)

Sunday

Monday

Tuesday

Wednesday

Thursday

Friday

Saturday

 

1

2

3

4

5

6

7

Eliquis (AM)

Eliquis (PM)

8

Eliquis (AM)

Eliquis (PM)

9

Eliquis (AM)

Eliquis (PM)

10

Eliquis (AM)

Eliquis (PM)

11

Eliquis (AM)

Eliquis (PM)

12

Eliquis (AM)

Eliquis (PM)

13

Eliquis (AM)

Eliquis (PM)

*Stop taking today only if you have decreased kidney function

14

NO Eliquis

15

NO Eliquis

16

PROCEDURE

(NO Eliquis)

17

RESTART Eliquis (AM)

Eliquis (PM)

18

Eliquis (AM)

Eliquis (PM)

19

Eliquis (AM)

Eliquis (PM)

20

…Continue taking Eliquis daily as prescribed…

21

22

23

24

25

26

What if I am taking antiplatelet therapy?

When platelets come together (aggregate) they can cause arterial ischemic events including coronary artery disease, cerebrovascular accidents (strokes) and peripheral arterial disease. As such, antiplatelet therapy plays a very important role in preventing recurrent events in the individuals who are affected by one of these conditions.

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You may be on one or two of the following antiplatelet medications: aspirin, clopidogrel (Plavix), prasugrel (Effient) and ticagrelor (Brilinta).  Depending on the reason for which you are taking antiplatelet therapy, you may need to stop one or both of your medications prior to your procedure to reduce the risk of bleeding.  

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Stopping antiplatelet therapy can increase your risk for stroke or cardiovascular events.  You should consult with your prescribing physician to discuss if it is appropriate for you to stop your medication(s) prior to any invasive procedure. 

If taking:

Low Risk

Moderate Risk

High Risk

Aspirin

Do not need to stop

Do not need to stop if low dose (81mg)

Stop taking for 5 full days before procedure if high dose (325mg)

Stop taking for 5 full days before procedure

Plavix, Effient, Brilinta

Stop taking for 5 full days before your procedure

Stop taking for 7 full days before your procedure

Stop taking for 7 full days before your procedure

You may resume your antiplatelet medication the day after your procedure.

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