Quantitative analysis of human heart valves: Does anorexigen exposure produce a distinctive morphological lesion?

Abstract

The need for more detail regarding the clinical and morphological features of human heart valves has become evident due to recent controversy regarding anorexigen-associated valvular dysfunction. In the present study, we used quantitative digital image analysis of geometric and compositional features to compare the histopathology of cardiac valves excised from patients treated with anorexigens as compared to normal, floppy, rheumatic and carcinoid valves. Anorexigen-exposed valves had the greatest number of onlays/valve ( P<.0001), while rheumatic valves showed the greatest average onlay size and thickness of the comparison groups studied ( P=.01). The valve onlays from anorexigen-exposed, carcinoid and floppy valves contained a greater percentage of glycosaminoglycans (GAGs) as compared to normal and rheumatic valves ( P=.01). The anorexigen-exposed valve propers contained more GAGs than any other comparison group ( P=.02). Vessels were prominent in both onlay and valve proper regions of carcinoid valves, in the anorexigen-exposed valve onlays and in rheumatic valve propers. Thus, the number of onlays, their size, the degree of GAG deposition, and the presence and location of vessels and leukocytes were important features distinguishing anorexigen-exposed valves from normal valves. Discriminant analyses, based on geometry, color composition or color composition, and vessel and leukocyte counts combined, were able to separate the valves into distinguishable groups. Our findings demonstrate that specific microscopic features can be used to separate anorexigen-associated heart valve lesions from normal valves and valve lesions associated with other pathologies, and suggest that a distinctive pathological process may exist in many anorexigen-exposed valves.