Circumferential vascular strain rate to estimate vascular load in aortic stenosis: a speckle tracking echocardiography study

Evaluation of vascular mechanics through two-dimensional speckle-tracking (2D-ST) echocardiography is a feasible and accurate approach for assessing vascular stiffening. Degenerative aortic stenosis (AS) is currently considered a systemic vascular disease where rigidity of arterial walls increases. To assess the circumferential ascending aorta strain rate (CAASR) in thoracic aortas of patients with AS, applying 2D-ST technology. 45 patients with indexed aortic valve areas (iAVA) ≤0.85 cm(2)/m(2) were studied. Global CAASR served to assess vascular deformation. Clinical, echocardiographic, and non-invasive hemodynamic data were collected. A follow up (955 days) was also performed. Average age of the cohort was 76. ± 10.3 years, with gender balance. Mean iAVA was 0.43 ± 0.15 cm(2)/m(2). Waveforms adequate for determining CAASR were found in 246 (91 %) of the 270 aortic segments evaluated, for a mean global CAASR of 0.74 ± 0.26 s(-1). Both intra- and inter-observer variability of global CAASR were deemed appropriate. CAASR correlated significantly with age (r = -0.49, p < 0.01), the stiffness index (r = -0.59, p < 0.01), systemic arterial compliance and total vascular resistance. There was a significant positive correlation between CAASR, body surface area (BSA), iAVA, and a negative relationship with valvulo-arterial impedance and E/e' ratio (r = -0.37, p = 0.01). The stiffness index was (β = -0.41, p < 0.01) independently associated with CAASR, in a model adjusted for age, BSA, iAVA and E/e'. Patients with a baseline CAASR ≤0.66 s(-1) had a worse long-term outcome (survival 52.4 vs. 83.3 %, Log Rank p = 0.04). CAASR is a promising echocardiographic tool for studying the vascular loading component of patients with AS.