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 cm2 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 cm2 and aortic valve mean gradient ≥40 mm Hg, moderate AS when AVA ≥1 cm2, and indeterminate AS when AVA <1 cm2 and aortic valve mean gradient <40 mm Hg during stress) and the proposed combined transvalvular flow criteria (severe AS when AVA <1 cm2 at a flow rate ≥210 mL/s or projected AVA <1 cm2) 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.