INCREASED MYOCARDIAL ECHO DENSITY IN LEFT-VENTRICULAR PRESSURE AND VOLUME OVERLOAD IN HUMAN AORTIC VALVULAR DISEASE - AN ULTRASONIC TISSUE CHARACTERIZATION STUDY

Quantitatively assessed ultrasonic backscatter is an index of ultrason ic tissue characterization directly related to morphometrically evalua ted collagen content in human beings. Our objective was to assess myoc ardial reflectivity pattern in patients with severe left ventricular h ypertrophy caused by either aortic stenosis (AS) or aortic regurgitati on (AR). Ten patients with AS, 10 patients with AR, and 10 closely age - and gender-matched healthy controls were studied by two-dimensional Doppler echocardiography. By using an echocardiographic prototype, we performed a radiofrequency analysis to obtain quantitative operator-in dependent measurements of the integrated backscatter signal of the ven tricular septum and the posterior wall (integrated backscatter index: IBI, expressed in percentage). All patients with stenosis or aortic in sufficiency showed a normal regional and global resting systolic funct ion (fractional shortening: AS = 36.0 +/- 6.6 versus AR = 40.3 +/- 6.2 versus control = 40.2 +/- 8.7; p = not significant [NS]). Left ventri cular mass index (Devereux's formula) was markedly increased in patien ts with stenosis or aortic insufficiency (AS = 199.3 +/- 18 versus AR = 208.8 +/- 60 versus control = 97.3 +/- 11 g/m(2); p < 0.0001). Myoca rdial echo density was increased in patients with stenosis or aortic i nsufficiency in comparison with controls, both in the septum (IBI%: AR = 40.7 +/- 7.9 versus AS = 33.4 +/- 4.2 versus control = 23.0 +/- 6.2 ; p < 0.0001) and in the posterior wall (IBI%: AR = 27.1 +/- 4.3 versu s AS = 23.0 +/- 2.6 versus control = 15.0 +/- 4.2; p < 0.0001). No sig nificant correlations were found between septal and posterior wall IBI and their thickness. Abnormally increased myocardial echo density-pos sibly related to disproportionate collagen deposition-can be detected in patients with pressure or volume overload caused by aortic valve di sease and without overt systolic dysfunction.