Surgical as Opposed to Transcatheter Aortic Valve Replacement Improves Basal Interventricular Septal Hypertrophy

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Background: Basal interventricular septum (IVS) hypertrophy (BSH) with reduced basal IVS contraction and IVS-aorta angle is frequently associated with aortic stenosis (AS). BSH shape suggests compression by the longitudinally elongated ascending aorta, causing basal IVS thickening and contractile dysfunction, further suggesting the possibility of aortic wall shortening to improve the BSH. Surgical aortic valve replacement (SAVR), as opposed to transcatheter AVR (TAVR), includes aortic wall shortening by incision and stitching on the wall and may potentially improve BSH. We hypothesized that BSH configuration and its contraction improves after SAVR in patients with AS.

Methods and Results: In 32 patients with SAVR and 36 with TAVR for AS, regional wall thickness and systolic contraction (longitudinal strain) of 18 left ventricular (LV) segments, and IVS-aorta angle were measured on echocardiography. After SAVR, basal IVS/average LV wall thickness ratio, basal IVS strain, and IVS-aorta angle significantly improved (1.11±0.24 to 1.06±0.17; −6.2±5.7 to −9.1±5.2%; 115±22 to 123±14°, P<0.001, respectively). Contractile improvement in basal IVS was correlated with pre-SAVR BSH (basal IVS/average LV wall thickness ratio or IVS-aorta angle: r=0.47 and 0.49, P<0.01, respectively). In contrast, BSH indices did not improve after TAVR.

Conclusions: In patients with AS, SAVR as opposed to TAVR improves associated BSH and its functional impairment.