Key result
CT-derived echocardiography correction reclassifies ~39% of severe AS to moderate, linked to better survival.
Why the study?
To evaluate severity reclassification rates and 5-year survival in patients with severe AS and preserved LVEF using a CT-derived correction factor for echocardiographic AVA and SVi measurements.
Does the application of a CT-derived correction factor to echocardiographic measurements improve severity grading and prediction of 5-year survival in patients with severe AS and preserved LVEF?
Cohort (n=1,450)
Does the application of a CT-derived correction factor to echocardiographic measurements improve severity grading and prediction of 5-year survival in patients with severe AS and preserved LVEF?
Applying a CT-derived correction factor of 1.13 to echocardiographic LVOT diameter measurements significantly improves the accuracy of AS severity grading and prognostic stratification.
Answers are grounded in this paper and cite their sources.
May refine AS grading and risk stratification in observational cohorts; leaves open prospective validation before practice change.
AimsTo assess rates of reclassification of severity and associated 5-year survival in patients with severe aortic stenosis (AS) and preserved left ventricular ejection fraction (LVEF) after application of a CT-derived correction factor (CF) to refine the measurement of aortic valve area (AVA) and stroke volume index (SVi) using Doppler echocardiography.Methods and resultsWe enrolled 1450 patients with severe AS and preserved LVEF from a French registry. Multiplication of echocardiographic LV outflow tract diameter by a CT-derived CF of 1.13 to calculate the AVA and SVi using the continuity equation resulted in reclassification of 39% of patients from severe to moderate AS (AVA > 1 cm2) and 77% from low flow (LF, SVi < 35 ml/m2) to normal flow (NF, SVi ≥ 35 ml/m2). After application of the CF, 5-year survival with conservative management was 50 ± 4% for severe AS compared to 62 ± 4% for moderate AS (p < 0.001). A strategy of medical management followed by intervention for severe AS was associated with higher risk of mortality over 5-year follow-up after adjustment for covariates and application of the CF (HR 1.35 [1.10–1.55], p = 0.015). Five-year survival was also poorer in patients remaining in the LF group after application of the CF, even after valve intervention (72%, 66% and 47% for NF to NF, LF to NF and LF to LF, respectively). After adjustment for covariates (including intervention), risk of mortality was higher in LF to LF patients compared to NF to NF (HR 1.78 [1.25–2.56]), but similar for NF to NF and LF to NF (HR 1.20 [0.90–1.60]).ConclusionRefined accuracy of echocardiographic LV outflow tract diameter measurement using a CF of 1.13 before derivation of AVA and SVi in patients with severe AS and preserved LVEF allows improved grading of severity, and prediction of prognosis. We recommend implementation of the CF during routine echocardiography when using the continuity equation for Doppler haemodynamic measurements.
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Kardos et al. (2022) conducted a cohort in Severe aortic stenosis with preserved LVEF (n=1,450). CT-derived correction factor of 1.13 vs. Standard measurement (no correction factor) was evaluated on 5-year survival with conservative management (severe vs moderate AS after reclassification) (p=<0.001). Applying a CT-derived correction factor of 1.13 to echocardiography reclassified 39% of severe AS patients to moderate AS, who had significantly better 5-year survival (62% vs 50%, P<0.001).
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