Novel Transvalvular Flow Criteria Reduce Indeterminate Stress Echocardiography and Refine Risk Stratification in Low-Gradient Aortic Stenosis

Abstract

BACKGROUND: Guidelines advocate the use of dobutamine stress echocardiography (DSE) in low-gradient aortic stenosis (aortic valve area [AVA] <1 cm 2 with aortic valve mean gradient <40 mm Hg) with reduced left ventricular ejection fraction (<50%) for subsequent patient management. A significant proportion of patients have nondiagnostic DSE (indeterminate aortic stenosis [AS]). METHODS: We aimed to assess the impact of DSE on the management of patients with classical low-gradient aortic stenosis and the use of the newly proposed transvalvular flow–based criteria for AS classification. Accordingly, we retrospectively analyzed 287 patients with classical low-gradient aortic stenosis who underwent DSE. Both the conventional (severe AS when AVA <1 cm 2 and aortic valve mean gradient ≥40 mm Hg, moderate AS when AVA ≥1 cm 2 , and indeterminate AS when AVA <1 cm 2 and aortic valve mean gradient <40 mm Hg during stress) and the proposed combined transvalvular flow criteria (severe AS when AVA <1 cm 2 at a flow rate ≥210 mL/s or projected AVA <1 cm 2 ) were assessed. RESULTS: After DSE, 84 (29%) patients had severe AS, 81 (28%) had moderate AS, and 122 (43%) had indeterminate AS. Over the median follow-up of 12.0 (interquartile range, 5–33) months, more patients with severe AS (73%) underwent aortic valve intervention compared with those with moderate (40%) and indeterminate AS (44%; P <0.001). Use of the newly proposed criteria in the indeterminate AS group improved the proportion of diagnostic tests in the overall population from 57% to 91% and reduced the proportion of indeterminate AS to 9%. Aortic valve intervention was beneficial in patients with reclassified severe AS (HR, 0.50 [95% CI, 0.27–0.92]; P =0.03), whereas the benefit was uncertain in the remaining indeterminate AS group (HR, 0.77 [95% CI, 0.22–2.75]; P =0.69). After aortic valve intervention, patients with conventionally diagnosed severe AS had a better outcome compared with patients with reclassified severe AS (HR, 2.88 [95% CI, 1.34–6.21]; P =0.007). CONCLUSIONS: In this real-world study, the transvalvular flow–based criteria for severe AS markedly reduced the number of indeterminate DSE. Within the indeterminate AS group, patients with reclassified severe AS derived benefit from aortic valve intervention.

The authors' abstract, as published at the source. Circulation Cardiovascular Imaging, 2026 · DOI ↗