Invasive Hemodynamic Characteristics of Low Gradient Severe Aortic Stenosis Despite Preserved Ejection Fraction

Objectives The study sought to compare echocardiographic with invasive hemodynamic data in patients with “paradoxic” aortic stenosis and in patients with conventionally defined severe aortic stenosis. Background Controversy exists whether low gradient severe aortic stenosis despite preserved ejection fraction (“paradoxic” aortic stenosis; aortic valve area 40 mm Hg, ejection fraction ≥50%) were also analyzed. Results In patients with “paradoxic” aortic stenosis, orifice area by echo (0.80 ± 0.15 cm2 ) and catheterization showed modest agreement, whether stroke volume was measured by oxymetry (0.69 ± 0.16 cm2 , bias 0.14 ± 0.17 cm2 ), or by thermodilution (0.85 ± 0.19 cm2 , bias −0.03 ± 0.19 cm2 ). Mean systolic gradients were very similar (32 ± 7 mm Hg vs. 31 ± 6 mm Hg; bias −0.08 ± 7.8 mm Hg). In comparison, in patients with conventionally defined severe aortic stenosis, orifice area by echo was 0.72 ± 0.17 cm2 and by catheterization 0.51 ± 0.15 cm2 (oxymetry) and 0.68 ± 0.21 cm2 (thermodilution), respectively, and mean systolic gradient 51 ± 10 mm Hg and 55 ± 8 mm Hg, respectively. Ejection fractions did not differ significantly in both groups. Ascending aortic diameter was significantly smaller in the “paradoxic” aortic stenosis group than in patients with conventionally defined severe aortic stenosis (28 ± 5 mm vs. 31 ± 5 mm), and energy loss index was significantly larger (0.51 ± 0.12 cm2 /m2 vs. 0.42 ± 0.09 cm2 /m2 , respectively). Heart rate and mean blood pressure during echo and catheterization were not significantly different. Conclusions Occurrence of low gradient severe aortic stenosis despite preserved ejection fraction was confirmed by invasive hemodynamics and was not the result of a systematic bias in the echo calculation of aortic orifice area.