Changes in aortic distensibility following surgical aortic valve replacement: the role of valve morphology (is it different according to distinct aortic valve morphology?)

Abstract Background Degenerative aortic stenosis (AS) often coexists with arterial stiffness, together imposing a combined load on the left ventricle (LV). Aortic distensibility (AD) is a measure of local arterial stiffness and load. The impact of aortic stenosis treatment on AD remains under characterized, with limited and conflicting evidence from small studies and lack of data according to distinct aortic valve morphologies. Objective Assess changes in AD after aortic stenosis surgical treatment, and to determine whether these changes differ according to aortic valve morphology. Methods Single-centre, prospective study of 158 patients with severe symptomatic AS (mean age 71±8 years, 50% male; mean transaortic gradient 61±17mmHg, mean indexed aortic valve area 0.4±0.1cm2/m2 and mean LV ejection fraction 58±9%) referred for surgical aortic valve replacement (SAVR) between 2019 and 2022. Patients with previous cardiomyopathy, concomitant moderate or severe aortic regurgitation and severe valve dysfunction beyond AS were excluded. All participants underwent transthoracic echocardiography (TTE) and cardiac magnetic resonance (CMR) within 3 months before and after SAVR. Valve morphology was determined either from TTE or surgical reports. Average systolic and diastolic ascending aortic dimensions were measured at cine CMR images on the three-chamber and coronal LV outflow views, at the level of pulmonary artery bifurcation, as well as on the descending aorta at four-chamber view. Maximum and minimum aortic areas were inferred and AD calculated. Valvulo-arterial impedance (Zva) was derived from TTE as a measurement of combined valvular and arterial load. Relative valve load (RVL) was also calculated. Results 128 patients were included (complete pre- and post-SAVR imaging studies (73 years 69-77; 48% male), 15% with bicuspid aortic valve (BAV). All patients with high gradient, preserved LV function. AD increased after SAVR (1.4 0.7-2.2 × 10−3 vs 1.57 0.8-2.4 × 10−3 mmHg−1, before and after SAVR respectively, p=0.328. Subgroup analysis showed a similar trend in patients with tricuspid aortic valves (TAV) (1.3 0.7-2.2 ×10−3 vs 1.7 0.8-2.4 ×10−3 mmHg−1, p=0.203), while BAV patients exhibited a slight decrease (1.8 0.8-3.1 ×10−3 vs 1.6 1.1-2.5 ×10−3 mmHg−1, p=0.753), with higher baseline distensibility. SAVR led to a significance reduction in Zva (4.59 3.76-5.14 mmHg/mL/m² vs. 3.54 2.77-4.98 mmHg/mL/m², p=0.009), due to significant reduction in RVL (13.5 10.9-16.7 vs 3.29 2.26-4.76 ml/m2, p0,001), consistent across both BAV and TAV subgroups. Conclusion In patients with severe AS undergoing SAVR, AD showed a non-significant change, with divergent trends based on valve morphology. As expect, SAVR led to a significant reduction in Zva driven by a marked decrease in RVL. These findings suggest that while SAVR improves overall afterload, its impact on intrinsic aortic stiffness may be variable and influenced by valve morphology.Aortic Distensibility:BAV vs TAV Zva and RVL before and after SAVR