21 of 126
oIn Chronic MR: LV and LA enlargement, calcification of mitral annulus may be seen if it is the cause of MR
oTypically shows LA enlargement and signs of LV hypertrophy.
Echocardiography: oCan often identify structural cause of MR. oCan grade its severity by color Doppler analysis. oLV size and function (stroke volume often increased due to Frank-Sterling compensation for the inc. volume)
Useful for identifying a coronary ischemic cause and for grading the severity of the MR.
The characteristic hemodynamic abnormality is a large “v” wave on the pulmonary capillary wedge pressure tracing (this reflects the LA pressure).
Aims of treatment are to augment forward CO, reduce regurgitation into the LA, and relieve pulmonary
congestion. Acute MR needs treatment IMMEDIATELY; Chronic MR is a wait and see deal.
oMR w/ heart failure: I.V. diuretics to relieve pulmonary edema, vasodilators to reduce resistance to forward CO oIn Chronic MR, give oral arteriolar vasodilators to improve forward CO
oMitral valve surgery: can have valve replacement or repair…either should be performed before heart failure comes about, but must delay surgery as long as possible due to operative mortality (8-10% for replacement; 2- 4% for repair)
Valve replacement: drawbacks of prosthetic valves – timing for chronic MR replacement is difficult to
determine as life with replacement is not always clearly better than the natural history of the disease. 10-year survival rate is 50%. Better for older patients with extensive pathology.
Valve repair: eliminates many problems due to artificial valves; involves surgical reconstruction of parts of
valve responsible for the regurgitation. Postoperative survival rate seems to be better than natural history of MR…allows for earlier surgical intervention. 10-year survival rate is 80%. Better for young patients with myxomatous involvement of the mitral valve.