Low-Flow Severe Aortic Stenosis in Small Patients Undergoing TAVR

Study Questions:

What is the prognosis of patients with smaller body size with low-flow (LF) and LF low-gradient (LF-LG) severe aortic stenosis (AS) treated with transcatheter aortic valve replacement (TAVR)?


This study retrospectively evaluated 723 consecutive patients with severe AS treated with TAVR at nine sites in Japan (median body surface area of 1.4 m2), and evaluated mortality in patients stratified by normal versus abnormal ejection fraction (EF), the presence of low-gradient (<40 mm Hg) vs. high-gradient, and low-flow (<35 ml/m2) vs. normal-flow severe AS.


Among 598 patients with normal left ventricular EF, 97 had LF severe AS (16.2%), and 38 of these had LF-LG severe AS (6.3% of total). Compared to normal-flow and normal EF severe AS patients as a baseline, those with LF severe AS had increased total mortality (hazard ratio [HR], 3.0; 95% confidence interval [CI], 1.3-6.7; p < 0.001) and cardiovascular mortality (HR, 5.6; 95% CI, 1.2-26.2; p < 0.01). In comparison to individuals with normal-flow high-gradient severe AS as a baseline, those with LF-LG severe AS (HR, 3.8; 95% CI, 1.1-13.7; p < 0.01) and LF-high-gradient severe AS (HR, 3.1; 95% CI, 1.04-9.4; p < 0.01) had increased total mortality. The optimal receiver-operating curve cutoffs of stroke volume index (SVI) for predicting total and cardiovascular mortality were 35.3 ml/m2 for each. SVI was independently associated with cardiovascular mortality (HR, 2.0; 95% CI, 1.2-3.2; p < 0.01).


Among patients in Japan with a small median body size, LF and LF-LG severe AS are associated with increased mortality after TAVR. The optimal cutoff for SVI in this population was not different from current guidelines, and SVI is independently associated with cardiovascular mortality.


LF-LG severe AS in patients with normal systolic function is associated with increased mortality and is associated with worse outcomes following TAVR. Prior literature has predominantly evaluated larger patients from Western populations, and it has been unclear if these findings are applicable to smaller Japanese patients. This study examines outcomes following TAVR in Japanese patients (median body surface area 1.4 m2) and observes that those with LF severe AS and LF-LG severe AS experience increased mortality. The current threshold to define LF (<35 ml/m2) appears to be an optimal cutpoint in this population as well, and SVI is an independent predictor of cardiovascular (but not overall) mortality. These findings refine our understanding of the prognostic implications of LF and LF-LG severe AS and treatment with TAVR in more diverse populations.

Clinical Topics: Cardiac Surgery, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Valvular Heart Disease, Aortic Surgery, Cardiac Surgery and Heart Failure, Cardiac Surgery and VHD, Interventions and Imaging, Interventions and Structural Heart Disease

Keywords: Aortic Valve Stenosis, Body Size, Body Surface Area, Cardiac Surgical Procedures, Diagnostic Imaging, Heart Valve Diseases, Heart Valve Prosthesis, Mortality, Stroke Volume, Systole, Transcatheter Aortic Valve Replacement

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