Mitral Fibrous Ring Causing Mitral Stenosis

 Mitral Fibrous Ring Causing Mitral Stenosis

Mitral annular calcification (MAC) or mitral fibrous ring can cause mitral stenosis, particularly in elderly patients. The calcification or fibrosis of the mitral annulus can extend to the leaflets, causing restricted mobility and stenosis.

Causes

- Degenerative changes

- Aging

- Hypertension

- Atherosclerosis

- Chronic kidney disease

Echo Findings

- Mitral annular calcification or fibrosis on 2D echo

- Restricted mobility of the mitral leaflets

- Reduced mitral valve area

- Increased transmitral gradient

- Doppler echo can estimate the mitral valve area and gradient

Severity Assessment

- Mild MAC: small, localized calcification

- Moderate MAC: larger calcification with restricted leaflet mobility

- Severe MAC: extensive calcification with significant leaflet immobility and stenosis

Clinical Implications

- Mitral stenosis can lead to symptoms like dyspnea, fatigue, and palpitations

- Severe MAC can increase the risk of cardiovascular events and mortality

- Echo findings can guide management decisions, including the need for intervention or surgery.

In clinical practice, echocardiography plays a crucial role in diagnosing and assessing the severity of mitral stenosis caused by mitral annular calcification or fibrosis.

Mitral Fibrous Ring vs Bioprosthesis on Echo

Mitral fibrous ring and bioprosthetic valves can be distinguished on echocardiography based on their appearance and functional characteristics.

Mitral Fibrous Ring

- Appears as a thickened, calcified, or fibrotic structure at the mitral annulus

- Restricted mobility of the mitral leaflets

- Reduced mitral valve area

- Increased transmitral gradient

- May have associated mitral regurgitation

Bioprosthetic Valve

- Appears as a distinct, circular or oval structure at the mitral position

- Leaflets are typically thin and mobile

- May have a characteristic "stent" or "frame" appearance

- Normal bioprosthetic valves have a mean gradient < 5 mmHg and a valve area > 1.5 cm2

- May have associated mitral regurgitation, stenosis, or other complications

Key Differences

- Location: Mitral fibrous ring is located at the native mitral annulus, while a bioprosthetic valve is located at the mitral position, replacing the native valve.

- Appearance: Mitral fibrous ring appears as a thickened, calcified, or fibrotic structure, while a bioprosthetic valve has a distinct, circular or oval appearance.

- Mobility: Mitral fibrous ring has restricted mobility, while a bioprosthetic valve has mobile leaflets.

Echo Findings

- 2D echo: Assess the location, size, and mobility of the mitral fibrous ring or bioprosthetic valve.

- Doppler echo: Evaluate the transmitral gradient, valve area, and regurgitation.

- 3D echo: Provide additional information on the valve anatomy and function.

Clinical Implications

- Accurate diagnosis is crucial for guiding management decisions, including the need for intervention or surgery.

- Echo findings can help identify complications, such as mitral regurgitation or stenosis, and monitor the effectiveness of treatment.