Baylor Heart and Vascular Institute, Baylor University Medical Center, Dallas, Texas; Department of Internal Medicine (Division of Cardiology), Baylor University Medical Center, Dallas, Texas; Department of Pathology, Baylor University Medical Center, Dallas, Texas.
Baylor Heart and Vascular Institute, Baylor University Medical Center, Dallas, Texas.
J Am Coll Cardiol. 2014 Apr 29;63(16):1667-74. doi: 10.1016/j.jacc.2013.11.017. Epub 2013 Dec 11.
The aim of the study is to describe gross and histological features of operatively excised portions of mitral valves in patients with mitral valve prolapse (MVP).
Although numerous articles on MVP (myxomatous or myxoid degeneration, billowing or floppy mitral valve) have appeared, 2 virtually constant histological features have been underemphasized or overlooked: 1) the presence of superimposed fibrous tissue on both surfaces of the leaflets and surrounding many chordae tendineae; and 2) the absence of many chordae tendineae on the ventricular surfaces of the leaflets as the result of their being hidden (i.e., covered up) by the superimposed fibrous tissue.
We examined operatively excised portions of prolapsed posterior mitral leaflets in 37 patients having operative repair.
Histological study of elastic-tissue stained sections disclosed that the leaflet thickening was primarily due to the superimposed fibrous tissue. All leaflets had variable increases in the spongiosa element within the leaflet itself with some disruption and/or loss of the fibrosa element and occasionally complete separation of it from the spongiosa element. Both the leaflet and chordae were separated from the superimposed fibrous tissue by their black-staining elastic membranes.
These findings demonstrate that the posterior leaflet thickening in MVP is mainly due to the superimposed fibrous tissue rather than to an increased volume of the spongiosa element of the leaflet itself. The superimposed fibrous tissue on both leaflet and chordae is likely the result of subsequent abnormal contact of the leaflets and chordae with one another. Chordal rupture (i.e., missing chordae) occurred in all 37 patients, but finding individual ruptured chords was rare.
本研究旨在描述二尖瓣脱垂（MVP）患者二尖瓣切开术中切除部分的大体和组织学特征。
尽管已有许多关于 MVP（黏液样或黏液样变性、膨出或松软二尖瓣）的文章发表，但有 2 个几乎不变的组织学特征被低估或忽视：1）瓣叶两面和周围许多腱索上都有叠加的纤维组织；2）瓣叶心室面的许多腱索缺失，因为它们被叠加的纤维组织所隐藏（即被覆盖）。
我们检查了 37 例行手术修复的 MVP 患者的脱垂后二尖瓣叶术中切除部分。
对弹性组织染色切片进行组织学研究显示，瓣叶增厚主要是由于叠加的纤维组织。所有瓣叶在瓣叶本身的海绵体元素中都有不同程度的增加，部分纤维层元素受到破坏和/或丧失，偶尔会完全与其分离。瓣叶和腱索都被其黑色染色的弹性膜与叠加的纤维组织分离。
这些发现表明，MVP 中后瓣叶增厚主要是由于叠加的纤维组织，而不是瓣叶本身海绵体元素体积的增加。瓣叶和腱索上的叠加纤维组织可能是瓣叶和腱索之间异常接触的结果。所有 37 例患者均发生腱索断裂（即缺失腱索），但很少发现单个断裂的腱索。
