Abstract 15001: Fusion of Echocardiographic Hemodynamic Data and Computed Tomographic Anatomical Data of the Aortic Valve Determine Severity of Low-Gradient Aortic Stenosis with Preserved Ejection Fraction
Introduction: Severe aortic stenosis with preserved left ventricular ejection fraction is classified into 4 groups, according to flow and gradient, with still debatable underlying pathophysiology.
Hypothesis: The use of multi-detector computed tomography (MDCT) and Doppler echocardiography refines the differential characteristics and true severity of each aortic stenosis group.
Methods: Patients with severe aortic stenosis [aortic valve area index (AVAi) <0.6cm2/m2] and ejection fraction ≥50% (n=191, age 80±7 years, 48.2% male) with echocardiography and MDCT prior to transcatheter aortic valve replacement were included. Patients were classified into 4 groups based on stroke volume index (≤35 or >35 ml/m2) and mean pressure gradient (≤40 or >40mmHg): 1. Normal-flow, high-gradient, 2. Low-flow, high-gradient, 3. Normal-flow, low-gradient, 4. Low-flow, low-gradient. Aortic valve calcium was evaluated on MDCT. Fusion AVAi was estimated by continuity equation using Doppler hemodynamics and MDCT left ventricular outflow tract (LVOT) area.
Results: AVAi and LVOT area index were both significantly different among the 4 groups when evaluated by echocardiography. On MDCT, although LVOT area index was comparable among groups, fusion AVAi remained significantly different (Figure): normal-flow, low-gradient had the largest area (0.62±0.11cm2/m2), resulting in reclassification into moderate stenosis in 52% of these patients, while low-flow, low-gradient group had comparable fusion AVAi to normal-flow, high-gradient group. Aortic valve calcium load was largest among patients with high-gradient (median 3412AU for normal-flow and 3181AU for low-flow) and was comparable between patients with low-gradient (2143AU for normal-flow and 2310AU for low-flow).
Conclusion: MDCT refines the hemodynamic characterization of low gradient AS patients by providing more accurate AVAi estimation and calcium load.
Author Disclosures: V. Kamperidis: Research Grant; Significant; European Association of Cardiovascular Imaging research grant, European Society of Cardiology traing grant, Hellenic Society of Cardiology traing grant, Hellenic foundation of Cardiology research grant. P.J. van Rosendael: None. S. Katsanos: Research Grant; Significant; Hellenic Society of Cardiology training grant. F. van der Kley: None. M. Regeer: None. I. Al Amri: None. G. Sianos: None. N. Ajmone Marsan: None. J.J. Bax: None. V. Delgado: Speakers Bureau; Modest; Abbott Vascular speaking fees.
- © 2014 by American Heart Association, Inc.