Prognostic Significance of Valvuloarterial Impedance and Left Ventricular Longitudinal Function in Asymptomatic Severe Aortic Stenosis Involving Three-Cuspid Valves

The purpose of the present study was to evaluate the role of left ventricular global afterload and various echocardiographic parameters of systolic function in a prospective cohort of 52 asymptomatic patients with severe aortic stenosis (indexed aortic valve area 0.4 ± 0.1 cm2/m2) and normal left ventricular ejection fraction (61 ± 5%). Using 2-dimensional speckle tracking echocardiography, myocardial strain, rotation, and twist were evaluated. The valvuloarterial impedance (Zva) was calculated as a measure of left ventricular global afterload. The predefined end points were the occurrence of symptoms (dyspnea, angina, syncope), aortic valve replacement, and death. At study entry, all patients had decreased longitudinal strain (LS) (−15 ± 4%) and increased circumferential strain (−22 ± 5%), twist (24 ± 7°), and Zva (5.8 ± 2 mm Hg/ml/m2). Increased Zva was closely associated with the circumferential strain increase (r = 0.59, p = 0.02) and LS decrease (r = −0.56, p = 0.016). In contrast, no relation was found between myocardial function and transaortic gradients. During follow-up (11 ± 7.5 months), on univariate Cox regression analysis, the predictors of events were the left ventricular ejection fraction (p = 0.02), mass index (p = 0.01), LS (p <0.0001), radial strain (p = 0.04), and Zva (p = 0.0002). On multivariate Cox regression analysis, only the global LS (p = 0.03) and Zva (p = 0.03) were independently associated with the combined end point. Using receiver operating characteristic curve analysis, a LS of ≤−18% (sensitivity 96%, specificity 73%) and a Zva of ≥4.7 mm Hg/ml/m2 (sensitivity 100%, specificity 91%) were identified as the best cutoff values to be associated with events. In conclusion, in asymptomatic patients with severe aortic stenosis, the degree of global afterload and its consequences on longitudinal function might play a role in clinical practice.