Anticoagulation Medication (Blood Thinners)

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If you receive a mechanical heart valve, your doctor will likely prescribe an anticoagulant medication (blood thinner) to prevent blood clots from forming on or around your new valve. The most common anticoagulation drug prescribed is warfarin (Coumadin®).

Anticoagulants Control Blood Clotting

Anticoagulation medication helps control how fast your blood clots, which helps prevent clots from forming inside your heart, arteries or veins. Anticoagulants can also prevent existing clots from getting larger or from breaking off and traveling to your major organs.

Blood Tests with Anticoagulants

Once you begin taking anticoagulation medications, you will need regular blood tests to determine if the medication is working. You will go to a laboratory about once a month for the clotting-time tests and your doctor will use the test results to determine whether to change your anticoagulant medication dosage. There are also home self-testing kits available. St. Jude Medical works with Alere to provide patient self-testing services to physicians and patients with mechanical heart valves. Visit to learn more.

Watching Your Diet, Other Medications and Vitamins

Certain prescription medication, over-the-counter medication, foods and alcohol may affect how warfarin works, so it is important to discuss all of your medications, vitamin supplements and your diet with your doctor. Some slight modifications may be necessary.

Before you have a medical or dental procedure, be sure to tell your doctor or dentist that you have an implanted device and are taking warfarin. You may need to make a short-term adjustment in your anticoagulant medication before the procedure.

Fact vs. Fiction About Anticoagulants

While some people have strong feelings about the risks of anticoagulants, warfarin is one of the most frequently prescribed drugs in the U.S., with more than 17.8 million prescriptions dispensed annually. New medications are also being introduced. A significant percentage of patients undergoing mitral valve surgery also have atrial fibrillation (AF), which requires patients to be on anticoagulation.2 Fortunately, St. Jude Medical® mechanical heart valves have been studied for over 25 years and consistently demonstrate low anticoagulant-related complications.3,4

Studies have shown that anticoagulation can be managed safely for patients of all ages and in fact, perform well in selected older patients with no increased risk of bleeding or thromboembolism.5

Anticoagulation-related complications can be further reduced through patient self-testing. A randomized study showed a reduced complication with international normalized ratio (INR) self-management when compared to conventional management in the clinic.6 INR is a blood test that measures the time it takes for blood to clot and compares it to an average.

St. Jude Medical is a strong supporter of patient self-testing and works with Philips Remote Cardiac Services and HemoSense to provide patient self-testing services to physicians and patients with mechanical heart valves. Visit  or to learn more.

Coumadin® is a registered trademark of Bristol-Myers Squibb Company

1Leading Prescriptions Dispensed-through all Channels. Chain Drug Review [serial online]. August 30, 1999; 21(14):RX74. Available from TableBase (Responsive database Services, Inc.), Beachwood, OH. Accessed May, 2001.

2Benussi S, Pappone C, Nascimbene S, et al. A simple way to treat chronic atrial fibrillation during mitral valve surgery: the epicardial radiofrequency approach. Eur J Cardiothorac Surg. 2000; 17:524-529.

3Emery RW, Krogh CC, Arom KV, Emery AM, et al. The St. Jude Medical cardiac valve prosthesis: a 25-year experience with a single valve replacement. Ann Thorac Surg 2005:79:776-83. 

4Ikonomidis JS, Kratz JM, Crumbley III JA, Stroud MR, et al. Twenty-year experience with the St. Jude Medical mechanical valve prosthesis. J Thorac Cardiovasc Surg 2003:126:2022-31.

5Masters RG, Semelhago LC, Pip AL, Keon WJ. Are older patients with mechanical heart valves at increased risk? Ann Thorac Surg. 1999;68:2169-2172.

6Koertke H, Koerfer R. International Normalized Ratio self-management after mechanical heart valve replacement: is an early start advantageous, Ann Thorac Surg. 2001;72:44-8.