Prognostic Impact of Low-Flow Severe Aortic Stenosis in Small-Body Patients Undergoing TAVR: The OCEAN-TAVI Registry

Abstract

Objectives: This study aimed to analyze the prognostic impact of low-flow (LF) severe aortic stenosis in small-body patients undergoing transcatheter aortic valve replacement (TAVR).

Background: Western literature demonstrates a poor prognosis with paradoxical LF and low-flow low-gradient (LF-LG) severe aortic stenosis (AS), as defined by stroke volume index (SVi) <35 ml/m² and mean pressure gradient <40 mm Hg with preserved left ventricular ejection fraction (LVEF). However, this poor prognosis is contested in Japan owing to the smaller body size of Japanese patients relative to that of Western patients. Additionally, there are no reports of the prognostic implication of paradoxical LF or LF-LG severe AS in small-body patients undergoing TAVR.

Methods: This was a retrospective analysis of 723 consecutive Japanese patients (median age 85 years; 32.6% male; median body surface area 1.4 m²) who underwent TAVR for severe AS at 9 sites in Japan. The primary and secondary endpoints were cumulative all-cause and cardiovascular mortality after TAVR, respectively.

Results: Ninety-seven (13.4%) patients had paradoxical LF severe AS whereas 38 (5.3%) had paradoxical LF-LG with severe AS. PLF was associated with a significant increase in all-cause (hazard ratio [HR]: 3.00; 95% confidence interval [CI]: 1.34 to 6.72; p < 0.001) and cardiovascular mortality (HR: 5.58; 95% CI: 1.19 to 26.2; p < 0.01), as compared with patients' normal flow and preserved LVEF. PLF-LG was associated with a significant increase in all-cause mortality (HR: 3.76; 95% CI: 1.09 to 13.73; p < 0.01), as compared with normal flow high gradient with preserved LVEF. SVi was an independent predictor of cardiovascular mortality on multivariate analysis after adjustments for age, sex, clinically relevant variables, and other echocardiographic parameters (HR: 1.96; 95% CI: 1.19 to 3.23; p < 0.01).

Conclusions: Among Japanese small-body patients with severe AS, both paradoxical LF and LF-LG severe AS were associated with poor outcomes following TAVR. SVi was an independent predictor of cardiovascular mortality after TAVR. (Optimised Transcatheter Valvular Intervention registry [OCEAN-TAVI]; UMIN000020423).

Keywords: paradoxical low-flow low-gradient severe aortic stenosis; paradoxical low-flow severe aortic stenosis; small body; stroke volume index; transcatheter aortic valve replacement.