Comments on: I know someone that had a mitral valve replaced because of leakage. She is now taking Coumadin and was told?

By: Dr. C

Dr. C — Sat, 06 Dec 2008 23:54:05 +0000

Patients with mechanical mitral valves (vs. bioprosthetic) need life-long anticoagulation because they may have a high rate of red blood cell destruction due to valve-blood interactions. Aspirin alone is not enough. Patients with bioprosthetic valves (tissue valves) generally do not need warfarin (Coumadin).

Warfarin works by preventing the body from turning vitamin K into various clotting factors. Its effectiveness is measured by an INR. Vitamin K is found in green leafy vegetables. As a result, eating a diet high in vitamin K may make the warfarin less effective, requiring a higher dose.

However, contrary to most doctor’s beliefs, patients should NOT completely avoid eating vitamin K sources when on warfarin. It is true that patients with low vitamin K intake need lower Coumadin doses to achieve a therapeutic INR. However, they are more likely to have an unstable INR, spend less time in a therapeutic INR range, and at higher risk for complications due to a very high INR (bleeding) or very low INR (clotting, red blood cell destruction). Patients should continue to eat regular, small amounts and avoid large meals of these vegetables. A 1/2 cup of spinach is enough to alter your INR. In fact, there is even evidence that regular supplementation with vitamin K can improve INR stability.

You or your acquaintance should discuss her concerns with her physician.

By: The Doc

The Doc — Fri, 05 Dec 2008 16:17:14 +0000

Yeah, the reason she can’t have food that contains a lot of vitamin K is because the way warfarin causes anticoagulation (blood thinning) is by interfering with the body’s ability to use that vitamin, which is necessary to make several proteins which are necessary for proper clotting.
So if you eat lots of vitamin K, you’re actually taking the antidote to warfarin, we even use it in the hospital to reverse the effects if somebody comes in with a very high INR (indicating too much anticoagulation). It’s just the way the drug works, nothing can be done to change that, it’s really the only effective oral anticoagulant we have.

By: cardiophile

cardiophile — Tue, 02 Dec 2008 13:54:51 +0000

Vitamin K antagonises the effect of Coumadin. So foods containing Vitamin K will neutralise the effect of the drug, leading to clot formation in the replaced valve, which is a dangerous situation. Whatever vegetables she is planning to take should be in a regular fashion so that her doctor can adjust the dose of Coumadin accordingly. If she takes Vitamin K containing vegetables without the doctor’s knowledge, doctor will adjust the dose to a higher level, seeing the INR test result at a lower level. Then if she stops taking the vegetables, the INR will go high and she will have bleeding manifestations.
Baby aspirin is not enough to prevent clot formation in a mechanical valve, Coumadin is required.

By: Equisetum

Equisetum — Mon, 01 Dec 2008 14:18:25 +0000

Vitamin K is vital in helping blood to clot. Coumadin works by blocking this pathway. If one day she eats lots of leafy green vegetables, with all that vitamin K they contain, her blood will not be sufficiently anti-coagulated. Her INR results will be all over the place, and her dosage will have to be adjusted constantly.