Causes of mitral valve stenosis include rheumatic fever, congenital mitral stenosis, myxoma, prosthetic valves & valve calcification.
- Low cardiac output
- Valve: ventricular filling is impaired when the mitral orifice is reduced to 2cm2 and transvalvular pressure gradient develops on exercise. At 1cm2 a gradient of 20mmHg develops at rest to maintain normal cardiac output. Calcification may develop in the long run.
- Left atrium pressure rises, dilatation, thrombosis, fibrillation.
- Increased pulmonary venous pressure: dyspnea on exertion, hemoptysis and lung fibrosis. If pressure develops rapidly above 25mmHg this may lead to ulmonary edema. If gradual this leads to adaptation due to thickening of the walls in the pulmonary vessels.
- Increased pulmonary capillary wedge pressure.
- Pulmonary arteriolar constriction leading to disappearance of the murmur.
- Elevated pulmonary artery pressure.
- Pulmonary atherosclerosis
- Pulmonary regurgitation
- Tricuspid regurge
- Right sided failure.
- Peripheral thrombosis with pulmonary? embolism.
Treatment of grade 1 mitral stenosis
(mild MS by echo + exertional dyspnea < G2)
- Diuretics for congestive symptoms
- Prophylaxis against rheumatic fever and infective endocarditis.
- Anticoagulants if atrial fibrillation.
- Consider digoxin if atrial fibrillation and tachycardia.