title: Integration of 3D imaging data in the assessment of aortic stenosis: impact on classification of disease severity.
abstract: BACKGROUND
  In patients with aortic stenosis (AS), precise assessment of severity is critical for treatment decisions. Estimation of aortic valve area (AVA) with transthoracic echocardiographic (TTE)-continuity equation (CE) assumes a circular left ventricular outflow tract (LVOT). We evaluated incremental utility of 3D multidetector computed tomography (MDCT) over TTE assessment of AS severity.
  
  
  RESULTS
  We included 51 patients (age, 81±8 years; 61% men; mean gradient, 42 ± 12 mm Hg) with calcific AS who underwent evaluation for treatment options. TTE parameters included systolic LVOT diameter (D) and continuous and pulsed wave (CW and PW) velocity-time integrals (VTI) through the LVOT and mean transaortic gradient. MDCT parameters included systolic LVOT area, ratio of maximal to minimal LVOT diameter (eccentricity index), and aortic planimetry (AVA(p)). TTE-CE AVA [(D(2)×0.786×VTIpw)/VTIcw] and dimensionless index (DI) [VTIpw/VTIcw] were calculated. Corrected AVA was calculated by substituting MDCT LVOT area into CE. The majority (96%) of patients had eccentric LVOT. LVOT area, measured on MDCT, was higher than on TTE (3.84 ± 0.8 cm(2) versus 3.03 ± 0.5 cm(2), P<0.01). TTE-AVA was smaller than AVA(p) and corrected AVA (0.67 ± 0.1cm(2), 0.82 ± 0.3 cm(2), and 0.86 ± 0.3 cm(2), P<0.01). Using TTE measurements alone, 73% of patients had congruence for severe AS (DI ≤0.25 and CE AVA <0.8 cm(2)), which increased to 92% using corrected CE.
  
  
  CONCLUSIONS
  In patients with suspected severe AS, incorporation of MDCT-LVOT area into CE improves congruence for AS severity.
authors: Heart and Vascular Institute and Imaging Institute, the Cleveland Clinic, Cleveland, OH 44195, USA.
authors: Bridget
authors: B
authors: O'Brien
authors: Paul
authors: P
authors: Schoenhagen
authors: Samir R
authors: SR
authors: Kapadia
authors: Lars G
authors: LG
authors: Svensson
authors: Leonardo
authors: L
authors: Rodriguez
authors: Brian P
authors: BP
authors: Griffin
authors: E Murat
authors: EM
authors: Tuzcu
authors: Milind Y
authors: MY
authors: Desai
mesh_terms: D000369:Aged, 80 and over; D001024:Aortic Valve Stenosis / Q000145:classification* / Q000175:diagnosis; D003937:Diagnosis, Differential; D004452:Echocardiography / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed / Q000379:methods*