Functional mitral stenosis in patients with massive mitral annular calcification

Area of Science:

• Cardiology
• Cardiac Surgery
• Valvular Heart Disease

Background:

• Mitral annular calcification (MAC) is often associated with mitral insufficiency, particularly in elderly females.
• Previous descriptions focused on MAC causing mitral insufficiency, but its role in diastolic obstruction without leaflet stenosis was less clear.

Purpose of the Study:

• To investigate mitral diastolic obstruction in patients with mitral annular calcification without mitral leaflet stenosis.
• To determine the clinical and pathological features of this condition.

Main Methods:

• Retrospective study of six patients (3 male, 3 female, aged 43-77) with MAC and mitral diastolic obstruction.
• Analysis of catheterization data for diastolic gradients, surgical findings, and pathological examination.
• Review of clinical outcomes including valve replacement and left ventricular function.

Main Results:

• All six patients exhibited significant holodiastolic mitral gradients (mean 16 mm Hg) due to MAC.
• No evidence of mitral leaflet retraction, thickening, or commissural fusion was found.
• Three patients had severe mitral insufficiency, with causes including prolapsing leaflets and ruptured chordae tendineae.
• Left ventricular dilation was observed in three patients, associated with mitral regurgitation or mixed aortic valve disease.

Conclusions:

• Severe mitral annular calcification can independently cause significant mitral diastolic obstruction by impairing diastolic relaxation.
• This obstruction can coexist with or lead to mitral insufficiency and left ventricular dysfunction.
• Understanding MAC's impact on diastolic function is crucial for managing valvular heart disease.