Transcatheter Aortic Valve Implantation in Very Low-Gradient Aortic Stenosis

Background: Transcatheter aortic valve implantation (TAVI) is beneficial in low-flow, low-gradient aortic stenosis (LGAS) (mean pressure gradient [MPG] ​<40 mmHg). The benefit and outcomes of TAVI in very low-gradient aortic stenosis (VLGAS) patients (MPG <25 mmHg) are under-reported. Methods: This retrospective cohort study analyzed 1173 patients with severe native valve aortic stenosis who underwent TAVI at a tertiary-care center between July 2012 and December 2021. Patients were divided into VLGAS (≤25 mmHg), LGAS (25 mmHg to 40 mmHg), and high-gradient aortic stenosis (≥40 mmHg) using MPG from transthoracic echocardiography. VLGAS and LGAS were subdivided into classical low-flow, paradoxical low-flow, and normal flow subgroups. The primary outcomes were symptom improvement (measured by New York Heart Association class improvement), quality-of-life improvement (measured by Kansas City Cardiomyopathy Questionnaire Summary Score increase), rehospitalization, and mortality. Outcomes were measured at 30 days and 1 year postimplant. Results: Most patients with VLGAS had symptom and quality-of-life improvement after TAVI. Fewer patients with VLGAS had symptom improvement at 1 ​year (p ​< ​0.01). One-year rehospitalization was the highest in VLGAS patients (p ​< ​0.01). All other primary outcomes were similar between groups. In subset analyses, 1-year symptom improvement only differed between normal flow subgroups, while rehospitalization and mortality only differed between low-flow subgroups. Conclusions: Trascatheter aortic valve implantation improves symptoms and quality of life in LGAS, including those with VLGAS. A lower degree of symptom improvement was observed in VLGAS at 1 ​year, primarily driven by those with normal flow states. Differences in mortality and rehospitalization were observed only in classical low-flow states.