A new echocardiographic evaluation of ascending aorta elasticity in patients with bicuspid aortic valve

Background: Bicuspid aortic valve (BAV) is one of the most common congenital heart diseases, frequently associated with diffused alterations of aortic wall. The aim of this study is to detect whether increased aortic stiffness, very often found in these patients, and traditionally evaluated through echocardiography, has a correlation with aortic strain, evaluated by speckle tracking imaging (STI) technique. Methods: We enrolled 43 patients (mean age 36,5±16,2 years) with BAV and 13 normal subjects (mean age 30,9±10,6 years), with comparable age and body surface area (BSA). We obtained all the measurements of aortic diameters (annulus, sinus of Valsalva (SV), sinu-tubular junction (STJ) and ascending aorta) by a parasternal long-axis view and indexed them for BSA. Aortic stiffness was calculated using the formula [ln(SBP/DBP)/[(AoS − AoD)/AoD], according to what already shown in literature, where AoS and AoD were systolic and diastolic diameters respectively, and SBP and DBP, systolic and diastolic blood pressure, respectively. Longitudinal strain (LS) of ascending aorta has been estimated as the average between anterior and posterior aortic walls strain values; these measurements were obtained off-line by a software for STI analysis (Echopac, GE Horten, Norway). The same software allows the calculation of ascending aorta circumferential strain (CS), obtained by the parasternal short-axis view at the level of aortic root, just above the valve leaflets. Results: Ascending aorta was larger in BAV patients than in controls (17±7,7 mm/m2 vs. 10,5±6,2 mm/m2; p=0,001). Aortic stiffness was increased in BAV patients compared to controls (8,63±7,39 vs 3,77±1,75; p=0,003), whereas LS by STI was significantly reduced (22,9±7,7 vs 48,8±13; p=0,001). In overall population, aortic stiffness was inversely related with left ventricle ejection fraction (r=−0,40, p=0.007) and aortic LS, estimated by STI (r=−0,46; p=0,014), whereas it was directly related with age (r=0,55, p<0.001) and aortic diameters (r=0,36, p=0,01; r=0,50, p=0,001; r=0,42, p=0,005 for SV, STJ and ascending aorta, respectively). An inverse relation has been found also between CS, estimated by STI, and aortic diameters (r=−0,35, p=0,019; r=−0,41, p=0,004; r=0,38, p=0,009, for SV, STJ and ascending aorta, respectively). Conclusions: BAV is often associated with aortic elasticity impairment. Aortic LS and CS by STI well correlate with aortic dimensions and stiffness. STI allows a new evaluation of aorthopathy that could be applyed in different BAV types which probably cause a different aortic walls strain.