Disturbances of the Thoracic Aorta Biomechanics in Degenerative Aortic Valve Stenosis.

Aim    To analyze the biomechanics of the thoracic aorta (TA) in degenerative calcific aortic stenosis (AS) using segmental ultrasound assessment of the aortic wall deformation.Material and methods        A total of 109 patients with severe AS and 11 healthy volunteers were evaluated. 2D speckle-tracking transesophageal echocardiography was performed in all patients. We calculated the global peak systolic circumferential strain (GCS, %), GCS normalized to pulse arterial pressure (GCS/PAP), and β2 stiffness index (SI) of the aortic wall at 4 levels of the TA: sinuses of Valsalva (SV), sinotubular junction (STJ), mid-ascending aorta (AA), and descending aorta (DA).Results In patients with aortic stenosis, GCS and GCS/PAP in all TA segments were statistically significantly lower than in healthy volunteers (SV: 3.1 [1.3; 4.4] and 3.8 [1.5; 5.9]; 12.2 [9.9; 13.4] and 20.2 [17; 28.6], p<0.001; at STJ level: 4.5 [2.4; 6.5] and 5.7 [3.3; 8.7]; 8.4 [5.6; 10] and 14.7 [10.9; 18.6], p<0.001; at AA level: 3.1 [0.8; 4.7] and 3.9 [1.4; 6.4]; 8.6 [7.6; 11.7] and 18.0 [12.1; 20.2], p<0.001; DA: 3.9 [3.1; 6] and 5.6 [3.6; 8.4]; 10.4 [7; 11.2] and 17.2 [14.1; 21.5], p<0.001, respectively). Furthermore, the SI in AS patients was statistically significantly increased to 19.1 [12.9; 26.5] and 4.8 [3.6; 5.3], p<0.001 in SV; 13.4 [10.1; 19.9] and 6.7 [5.6; 8.3], p<0.001 at STJ level; 17.8 [13.4; 26.9] and 5.6 [4.6; 8.1], p<0.001 at AA; 17.2 [11.1; 25.3] and 5.6 [4.6; 7.4], p<0.001 at DA, respectively. 69 (63.3%) AS patients had multidirectional GCS of the aortic wall in the aortic root and the TA ascending and descending sections. Patients with AS showed a uniform decrease in GCS and GCS/PAD and an increase in the SI and diameters in all TA segments from the aortic annulus to the descending section. In all AA segments, GCS, GCS/PAD and SI did not differ between AS patients with bicuspid aortic valve (AV) (n=47) and tricuspid AV (n=62) (p>0.05). An inverse correlation was found between the mean transaortic pressure gradient and GCS and GCS/PAD in the SV (r=-0.33; p<0.01, and r=-0.26; p<0.01, respectively) and in the AA (r=-0.23; p<0.05 and r=-0.21; p<0.05, respectively).Conclusion    Severe AS is associated with non-adaptive remodeling of the TA, reduced and multidirectional deformation along the circumference of the aortic wall in the aortic root, and the TA ascending and descending segments, which is closely related to disorders of transaortic hemodynamics.