Evaluation of progression in nonrheumatic aortic valvular stenosis by scanning acoustic microscopy

To investigate distributions of hardness and thickness in nonrheumatic aort ic stenosis (AS), scanning acoustic microscopy was used. The acoustic propa gation speed (APS: m/s) and thickness at three sites (tip, middle and base) of aortic valve were measured in 18 cusps from 7 surgical patients with AS (late lesion), 27 showing mild lesions from 9 autopsy cases (early lesion) and 18 healthy from 6 autopsy cases (healthy), These were measured in each laver of cusps: fibrosa CF), spongiosa (S) or ventricularis (V), In early lesions, an increase in APS preceded the thickening and distributed in the tip (1666 +/- 107), the three layers of the middle (F: 1782 +/- 121; S: 159 0 +/- 38; V: 1636 +/- 59) and the fibrosa of the base (1736 +/- 203), In la te lesions, APS of the tip and three layers of the base were markedly incre ased. Progressive nonrheumatic AS is characterized by increased hardness th at precedes the thickening, and its distribution mag be related to mechanic al stress. (C) 2000 World Federation for Ultrasound in Medicine & Biology.