Assessment of Severity in Aortic Stenosis—Incremental Value of Endocardial Function Parameters Compared With Standard Indexes

Abstract 

Several studies have reported that patients (pts) with severe aortic stenosis and similar pressure gradients or even similar aortic valve areas may have quite different symptomatic status and clinical outcomes suggesting that other factors might have a significant impact on the pathophysiology of this disease. Our purpose was to assess the severity of subendocardial wall dysfunction in symptomatic and asymptomatic pts with aortic stenosis using tissue Doppler imaging (TDI), strain rate imaging (SRI) and cyclic variation of integrated backscatter (IB). We studied 68 pts with aortic valvar stenosis and 46 subjects with no signs of heart disease. SRI/IB indexes were calculated in the apical four chambers views at endocardial level. Early diastolic endocardial strain rate showed the best correlation with transvalvar pressure gradients and valve areas. Compared with controls, symptomatic pts showed a more marked decrease in endocardial strain, strain rate and cyclic variation of IB. Receiver operating characteristic (ROC) curves suggested that the thresholds offering an adequate compromise between sensitivity and specificity for the prediction of symptoms were ≥60 mm Hg for the pressure gradient, less than 0.60 cm²/m² for aortic valve area, less than 20% for strain, less than 2.0 s⁻¹ for strain rate and less than 3.0 dB for cyclic variation. The combination of pressure gradient, aortic valve area and SRI/IB parameters resulted in an improvement of the overall performance for predicting the symptomatic state. Thus, SRI/IB parameters have an incremental value in differentiating symptomatic and asymptomatic pts with aortic stenosis compared with conventional hemodynamic parameters. (E-mail: vitar@tiscali.it)

Key Words: Echocardiography, Tissue Doppler imaging, Strain rate imaging, Strain imaging, Integrated backscatter, Subendocardial dysfunction, Aortic stenosis