Neoangiogenesis and Ossification in Senile Calcific Aortic Valve: A Histological and Immunohistochemical Study

Introduction: Aortic valve calcification is the most frequent pathological process necessitating surgical aortic valve replacement. It was until recently that the progressive calcification was considered as a degenerative disease with passive calcium deposition on the valve leaflets. Aim of the Work: This work was designed to elucidate some of the events occurring in senile calcific aortic stenosis. Materials and Methods: Calcific aortic valve leaflets were obtained from patients presenting with isolated severe senile calcific aortic stenosis admitted for aortic valve replacement. Paraffin sections of calcific aortic valves were examined histologically and immunohistichemically for CD 31 to detect neoangiogenesis and osteopontin (osteoblast marker). Results: Examination of calcific aortic valves revealed cells having features of osteocytes and positive for osteopontin. Multiple blood vessels were also detected compared to total absence in the normal aortic valves. Inflammatory cellular infiltration and cells having features of chondrocytes were recognizable. CD 31 immunopositivity was detected within the endothelium of the new vessels. Conclusions: There are three major events or phases going on within the senile calcific aortic valves. These are inflammatory cellular infiltration, neovessel formation and endochondral ossification rather than passive deposition of calcium. Hence, treatment should be directed according to the phase.