Mitral Valve Disease
Your heart has four chambers: two atria and two ventricles. Between each chamber is a valve that opens to allow blood to pass from the top chambers (the atria) to the bottom chambers (the ventricles). When the ventricles contract to pump out the blood, the valves close to ensure that the blood doesn't leak back the way it came.
The mitral valve separates the left atrium from the left ventricle. Unlike the three other valves in the heart which have three flaps or cusps, the mitral valve only has two. When the pressure in the left ventricle drops at the end of the heartbeat, the mitral valve opens and oxygen rich blood from the left atrium flows into the left ventricle. When the left ventricle pumps the blood to the body the mitral valve closes so that the majority of the blood moves forward. If the mitral valve doesn't function correctly, blood in the atrium may have trouble getting into the ventricle (mitral stenosis) or blood in the left ventricle may flow backwards into the left atrium (mitral insufficiency).
Mitral Stenosis
Mitral stenosis occurs when the opening of the valve becomes significantly narrowed and thus impedes the flow of blood. This is almost always associated with rheumatic fever secondary to streptococcal infection earlier in life. This leads to thickening and stiffening of the leaflets which can then no longer move normally. Often the leaflets will become partially fused together, dramatically narrowing the opening of the valve. With restriction of inflow of blood the heart must work much harder to supply the body with nourishment and oxygen. Eventually this leads to cardiac failure.
Mitral Insufficiency
The mitral valve can become insufficient because of intrinsic disease of the valve itself or secondarily because of disease states causing a dilated left ventricle.
A diseased mitral valve causes primary mitral regurgitation. Diseases that affect the mitral valve include myxomatous degeneration, rheumatic heart disease, infective endocarditis, collagen vascular diseases (ie: SLE, Marfan's syndrome), trauma from balloon valvulotomy of the mitral valve, and reactions to certain forms of medication (e.g. fenfluramine).
A dilated left ventricle causes secondary mitral regurgitation. When left ventricular dilatation occurs, the mitral valve becomes stretched open. The cusps become displaced and unable to close sufficiently. Causes of a dilated left ventricle include ischemic cardiomyopathy because of coronary artery disease, toxic cardiomyopathy secondary to drugs or poisons, dilated cardiomyopathy usually related to aortic valvular disease, infectious cardiomyopathy usually as a result of a viral infection, and idiopathic cardiomyopathy of unknown cause.
The heart must work much harder to "repump" the leaked blood in order to have adequate forward flow. Eventually it wears out and cardiac failure ensues.
Surgical Treatment
Mitral valve stenosis or regurgitation can be treated surgically by repairing or replacing the valve. In most cases of repair abnormal leaflet tissue is removed and the leaflets are resuspended. A synthetic ring is sewn in place around the valve to return the opening to normal size and shape. When repair is not possible, the valve is replaced. Valve replacements are performed using either mechanical valves made from inert materials or with biological valves derived from animals (pig, cow, or horse) or human valves harvested from organ donors.
Our surgeons specialize in cardiac valve repair and replacement at MountainStar Cardiovascular Surgery. Whether you live in Salt Lake City, Ogden, or Utah Valley, or anywhere in the country, contact MountainStar Cardiovascular Surgery or call us at 801-743-4750 today.