title: Low gradient severe aortic stenosis with preserved ejection fraction: reclassification of severity by fusion of Doppler and computed tomographic data.
abstract: OBJECTIVE
  Low gradient severe aortic stenosis (AS) with preserved left ventricular ejection fraction (LVEF) may be attributed to aortic valve area index (AVAi) underestimation due to the assumption of a circular shape of the left ventricular outflow tract (LVOT) with 2-dimensional echocardiography. The current study evaluated whether fusing Doppler and multidetector computed tomography (MDCT) data to calculate AVAi results in significant reclassification of inconsistently graded severe AS.
  
  
  RESULTS
  In total, 191 patients with AVAi < 0.6 cm2/m2and LVEF ≥ 50% (mean age 80 ± 7 years, 48% male) were included in the current analysis. Patients were classified according to flow (stroke volume index <35 or ≥35 mL/m2) and gradient (mean transaortic pressure gradient ≤40 or >40 mmHg) into four groups: normal flow-high gradient (n = 72), low flow-high gradient (n = 31), normal flow-low gradient (n = 46), and low flow-low gradient (n = 42). Left ventricular outflow tract area was measured by planimetry on MDCT and combined with Doppler haemodynamics on continuity equation to obtain the fusion AVAi. The group of patients with normal flow-low gradient had significantly larger AVAi and LVOT area index compared with the other groups. Although MDCT-derived LVOT area index was comparable among the four groups, the fusion AVAi was significantly larger in the normal flow-low gradient group. By using the fusion AVAi, 52% (n = 24) of patients with normal flow-low gradient and 12% (n = 5) of patients with low flow-low gradient would have been reclassified into moderate AS due to AVAi ≥ 0.6 cm2/m2.
  
  
  CONCLUSIONS
  The fusion AVAi reclassifies 52% of normal flow-low gradient and 12% of low flow-low gradient severe AS into true moderate AS, by providing true cross-sectional LVOT area.
authors.affiliation: Department of Cardiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, PO Box 9600, 2300 RC Leiden, The Netherlands Department of Cardiology, AHEPA University Hospital, Thessaloniki, Greece.
authors.forename: Vasileios
authors.initials: V
authors.lastname: Kamperidis
authors.affiliation: Department of Cardiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, PO Box 9600, 2300 RC Leiden, The Netherlands.
authors.forename: Philippe J
authors.initials: PJ
authors.lastname: van Rosendael
authors.affiliation: Department of Cardiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, PO Box 9600, 2300 RC Leiden, The Netherlands.
authors.forename: Spyridon
authors.initials: S
authors.lastname: Katsanos
authors.affiliation: Department of Cardiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, PO Box 9600, 2300 RC Leiden, The Netherlands.
authors.forename: Frank
authors.initials: F
authors.lastname: van der Kley
authors.affiliation: Department of Cardiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, PO Box 9600, 2300 RC Leiden, The Netherlands.
authors.forename: Madelien
authors.initials: M
authors.lastname: Regeer
authors.affiliation: Department of Cardiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, PO Box 9600, 2300 RC Leiden, The Netherlands.
authors.forename: Ibtihal
authors.initials: I
authors.lastname: Al Amri
authors.affiliation: Department of Cardiology, AHEPA University Hospital, Thessaloniki, Greece.
authors.forename: Georgios
authors.initials: G
authors.lastname: Sianos
authors.affiliation: Department of Cardiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, PO Box 9600, 2300 RC Leiden, The Netherlands.
authors.forename: Nina Ajmone
authors.initials: NA
authors.lastname: Marsan
authors.affiliation: Department of Cardiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, PO Box 9600, 2300 RC Leiden, The Netherlands.
authors.forename: Victoria
authors.initials: V
authors.lastname: Delgado
authors.affiliation: Department of Cardiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, PO Box 9600, 2300 RC Leiden, The Netherlands j.j.bax@lumc.nl.
authors.forename: Jeroen J
authors.initials: JJ
authors.lastname: Bax
keywords: Echocardiography; Low flow–low gradient; Multidetector computed tomography; Normal flow–low gradient; Severe aortic stenosis