Assessment of the prognostic significance of low gradient severe aortic stenosis and preserved left ventricular function requires the integration of the consistency of stroke volume calculation and clinical data

Background: This study was to evaluate the prognostic significance of low gradient severe aortic stenosis (LG SAS) and preserved left ventricular ejection fraction (LVEF) with the integration of echocardiographic and clinical data. Methods: The study included 172 patients with LG SAS (AVAi ≤ 0.6 cm²/m², mean aortic pressure gradient < 40 mm Hg) and LVEF (≥ 50%). LV outflow tract diameters were measured at both the aortic valve annulus and 5 mm below the annulus for the measurement consistency. Patients were divided into the low flow LG SAS (LF/LG SAS: SVi < 35mL/m² and AVAi ≤ 0.6 cm²/m²) and normal-flow LG SAS groups (NF/LG SAS: SVi ≥ 35mL/m² and AVAi ≤ 0.6 cm²/m²). Echocardiographic findings and clinical data were systematically analyzed with mean follow-up of 3.0 ± 1.6 years. Results: LF/LG SAS had significantly smaller AVAi, lower SVi, a higher prevalence of atrial fibrillation (28% vs 12% P =.01) and diabetes (47% vs 27% P =.007) and lower 3-year cumulative survival than NF/LG SAS. Multivariable analysis showed that dyspnea, renal dysfunction (CI 1.42-3.99, P <.01), left atrial diameter, and SVi were independently associated with an increased risk for all-cause mortality. Aortic valve intervention (AVI) improved survival in LF/LG SAS (68% vs 48%, P <.05) in comparison with medical management (HR: 4.20, CI: 1.12-15.76, P =.03), but only modestly in NF/LG SAS (75% vs 65% P >.05). Conclusion: Outcome of LG SAS was independently associated with clinical characteristics. AVI likely improved outcome of LF/LG SAS who had high-risk clinical characteristics and unfavorable echocardiographic findings.