Why do patients have to take anticoagulants when they receive and artificial valve in their heart?

Stop clotting. Certain types (often metallic) of heart valves are prone to forming blood clots. Such clots can shoot out to the lungs or the brain.
Avoid strokes. Mechanical valves cause some turbulence in the blood flow. This can cause clots to form and float up to the brain where they become lodged in the smaller vessels and block the blood flow to a portion of the brain resulting in a stroke. A blood thinner helps prevent this from occurring.
Blood clot. The layer of cells lining the heart and all blood vessels allows blood to pass without clotting. A break in the layer from injury recruits platelets and clotting factors to form clot and seal the injury. A mechanical valve will encourage clot by having areas of slow flow and places for clot to stick.

Related Questions

Pat. With prosthetic heart valve on warfarin and developed ich. When and whow we return anticoagulant?

The risk of. Hemorrhage complications in the above setting is 1% per year. If ich occur the anticiagulation have to be reverse and most probably the clot evacuated. When to restart is controversial depending on the prosthetic valve (mitral vs aortic), atrial fibrillation, enlarge atrial chamber and systolic ventricular dysfunction. Each case is different but up to 14 days may be safe. Neuro and cardiac follow.
Anticoagulation. This is a more complex issue than what can be covered here. An intracerebral hemorrhage while on warfarin is an emergency, and reversal of the anticoagulant is essential. Restarting anticoagulant for prosthetic valve protection can only be done when the neurosurgeon is confident that the bleeding in the brain has been adequately stopped and the risk for re-bleeding has been controlled.

Pat. With mitral prosthetic heart valve and develope sah. When we restart anticoagulant and we start by lmwh or warfarin?

No good answer. I'm presuming sah is "subarachnoid hemorrhage". The answer depends on if the mitral valve is bioprosthetic or mechanical (i presume mechanical in a 36 yo) and if the rhythm is sinus or atrial fib (common in this setting). There are no controlled trials to guide this. There is no right answer. Be guided by the cardiologist's experience that you know and trust. Good luck with this difficult situation.

When a patient has a heart attachk when do you know to use thrombolytic agents or anticoagulants?

Not used much any mo. Now a days unless in a very rural location without angioplasty capabilities, thrombolyics are rarely used. Pts are usually give oral antiplts and IV blood thinners and taken imediately to the cath lab. The earlier the better. Target door to balloon time of 90 min or less.