Mitral Valve Disease in a Patient with Familial Hypercholesterolemia [56]

INTRODUCTION

We report a case of atherosclerosis in the mitral valve of a seven-year-old boy with familial hypercholesterolemia. This boy, born on August 7, 1949, had familial hypercholesterolemia type IIb and asthma. At birth, he had prominent cutaneous xanthomas along the extensor surfaces of his arms and legs, gluteal folds, and Achilles tendons. His serum lipid levels were as follows: cholesterol, 951 mg/dl; cholesterol esters, 666 mg/dl; fatty acids, 1032 mg/dl; and phospholipids, 600 mg/dl. On October 31, 1956, the boy was hospitalized for the evaluation of acute cyanosis and cardiac irregularity. Sudden apnea developed, and he died. An autopsy was performed. In 2009, we reexamined the heart to review the pathological features of the mitral valve. We also examined the mitral valve by light microscopy after Masson trichrome staining to reveal evidence of atherosclerosis and the presence of collagen. This study was approved by the institutional review board of the Mayo Foundation. On examination, left ventricular hypertrophy was present and was concentric. The mitral valve contained atherosclerotic lesions, primarily along the atrial aspect of the mitral valve leaflet. Microscopical examination showed plaques rich in lipid-laden foam cells (arrow), with focal areas of collagen and scant basophilic ground substance (Fig. 1a). The appearance was similar to that of vascular atherosclerosis (Fig. 1b). Atherosclerotic plaques were also present throughout the atrial surface of the mitral valve leaflet. In the United States and Europe, myxomatous mitral valve disease is the most common indication for mitral valve repair or replacement. The current study of a case from 1956 (before the widespread use of aggressive lipid-lowering strategies) demonstrates the relation between mitral valve disease and vascular atherosclerosis⁽¹⁾. It confirms the hypothesis that the mitral valve has an active cellular biology with the appearance of a lipid-rich plaque along the atrial surface of the valve leaflet.

Figure 1.