Abstract 4364600: Non-Severe Aortic Stenosis with Reduced LVEF: Role of Dobutamine Stress Echo

Abstract

Background: Patients with low gradient non-severe aortic stenosis (AS) at rest, in the context of reduced left ventricular ejection fraction (LVEF) (less than 50%), occasionally undergo dobutamine stress echocardiogram (DSE). However, limited data is available in the literature regarding the utility of DSE in this context. Methods: We conducted a retrospective study on patients with non-severe AS and LVEF less than 50% at rest who underwent DSE after Institutional Review Board approval. Retrospective data was extracted including rest and DSE parameters using an internal database. Only patients greater than 18 years old, who had an LVEF less than 50%, mean gradient (MG) less than 40 mmHg, and valve area greater than or equal to 1 cm 2 at rest were included in the study. Univariate and multivariate regression methods were used to identify which resting variables were associated with severe AS (MG greater than 40 mm Hg and valve area less than 1 cm 2 ) with DSE. Results: A total of 124 patients were included in the study. The mean age of patients was 78 years (±9) and 84% were male. The mean resting LVEF was 34% (±8%) while it was 40% (±12%) with DSE, mean stroke volume index at rest was 39 mL/m2 (±9) while it was 45 mL/m2 (±10) with DSE, MG at rest was 20 mmHg (±7) while it was 31 mmHg (±10) with DSE, and mean aortic valve area at rest was 1.27 cm 2 (±0.27) while it was 1.24 cm 2 (±0.29) with DSE. Of the 124 patients with non-severe AS at rest, 13 (10.5%) patients had severe AS with DSE. MG at rest was associated with severe AS (OR 1.3; 95% Cl: 1.1 - 1.5; p < 0.001) in a multivariate logistic regression model after adjusting for age, sex, LVEF at rest, SV index at rest. Resting aortic valve mean gradient also showed the highest AUC in relation to likelihood of having severe AS (0.87) (figure 1). Conclusion: Our study indicated that DSE remains useful in identifying severe AS in certain patients (up to 10%) who exhibit non-severe AS at rest in the setting of reduced LVEF. Additionally, MG at rest is the most reliable parameter to determine those who may benefit from undergoing DSE. This is one of the first studies to our knowledge in the literature suggesting that DSE may still be useful in identifying severe AS patients despite non-severe AS (i.e., valve area greater than or equal to 1 cm 2 ) at rest with reduced LVEF. Further research is warranted to validate our findings.