Thrombotic calcific mitral stenosis. Morphology of the calcific mitral valve.

Abstract

We compared the morphology of the calcific stenotic mitral valve (CSMV) with noncalcific stenotic mitral valves (NCSMV) removed at surgery; control valves were obtained at autopsy. X-rays of the excised valves permitted localization and quantitation of calcification. A classification of CSMV applicable to noninvasive techniques based on this methodology is presented. Moderate to heavily CSMV had greater weight, volume, specific gravity, weight per area, with smaller orifice size when compared with NCSMV and controls. Leaflet mobility was obliterated in moderate to heavily CSMV, while most NCSMV had some degree of leaflet mobility. Surface morphology was strikingly different in CSMV with 1) surface ulceration , due to eruption of the underlying calcific focus through valvular endothelium, 2) thrombosis in the areas of ulceration ( associated with symptomatic arterial embolization in four patients), 3) whisker formation , filamentous stalks along the line of valve closure. Calcification in the CSMV is viewed as an active, progressive process resulting in altered physical characteristics of the valve, progressive leaflet immobility and orifice narrowing, and eruptive surface changes with thrombus formation and arterial embolization arising from the CSMV itself. Clinical implications and a rationale for more precise classification of mitral stenosis on the basis of valvular calcification are presented.