Prevalence and Significance of ATTR Aortic Valve Amyloidosis in Degenerative Aortic Stenosis

Cardiac amyloidosis is a restrictive cardiomyopathy with a potentially severe prognosis that can be life-threatening. It is linked in the vast majority of cases to a light chain deposition of immunoglobulin or transthyretin. Although myocardial involvement is predominant, other locations are possible: the atrioventricular conduction system, coronary arteries and valve leaflets. In systematic histological analyzes, deposits of amyloidosis infiltrating the aortic valve have been reported with a frequency of up to 74% for degenerative RA. The nature of these deposits has never been established because the immunostaining carried out all remained negative, probably due to decalcification prior to cutting. Currently, these deposits are considered to be local degenerative phenomena without clinical repercussions. However, the use of bone scintigraphy has shown a high prevalence, between 14 and 16%, of ATTR cardiac amyloidosis in patients with severe RA. The diagnosis of ATTR amyloidosis has been proven histologically in a few patients. Sequencing of the TTR gene has shown that they are mainly wild forms. In fact, the prevalence of transthyretin mutations in our local cohort is 20%. The objective of this study is to determine by proteomic analysis based on mass spectrometry, the prevalence of ATTR aortic valve amyloidosis in patients undergoing surgical valve replacement for degenerative aortic stenosis.