PATHOLOGY OF AORTIC-VALVE STENOSIS AND PURE AORTIC REGURGITATION - A CLINICAL MORPHOLOGIC ASSESSMENT .1.

This two-part article examines the histologic and morphologic basis fo r stenotic and purely regurgitant aortic valves. Part I discusses sten otic aortic valves and Part II will discuss causes of purely regurgita nt aortic valves. In over 95% of stenotic aortic valves, the etiology is one of three types: congenital (primarily bicuspid), degenerative. or rheumatic. Other rare causes of stenotic aortic valves include acti ve infective endocarditis, homozygous type II hyperlipoproteinemia, an d systemic lupus erythematosis. The causes of pure aortic regurgitatio n are multiple but can be separated into diseases affecting the valve (normal aorta) (infective endocarditis, congenital bicuspid, rheumatic , floppy), diseases affecting the walls of aorta (normal valve) (syphi lis, Marfan's, dissection), disease affecting both aorta and valve (ab normal aorta, abnormal valve) (ankylosing spondylitis), and diseases a ffecting neither aorta nor valve (normal aorta, normal valve) (ventric ular septal defect, systemic hypertension). Diseases affecting the aor tic valve alone are the most common subgroup of conditions producing p ure aortic valve regurgitation.