title: Moderate Aortic Valvular Insufficiency Invalidates Vortex Formation Time as an Index of Left Ventricular Filling Efficiency in Patients With Severe Degenerative Calcific Aortic Stenosis Undergoing Aortic Valve Replacement.
abstract: OBJECTIVE
  Transmitral blood flow produces a vortex ring (quantified using vortex formation time [VFT]) that enhances the efficiency of left ventricular (LV) filling. VFT is attenuated in LV hypertrophy resulting from aortic valve stenosis (AS) versus normal LV geometry. Many patients with AS also have aortic insufficiency (AI). The authors tested the hypothesis that moderate AI falsely elevates VFT by partially inhibiting mitral leaflet opening in patients with AS.
  
  
  METHODS
  Observational study.
  
  
  METHODS
  Veterans Affairs medical center.
  
  
  METHODS
  Patients with AS in the presence or absence of moderate AI (n = 8 per group) undergoing aortic valve replacement (AVR) were studied after institutional review board approval.
  
  
  METHODS
  None.
  
  
  RESULTS
  Under general anesthesia, peak early LV filling (E) and atrial systole (A) blood flow velocities and their corresponding velocity-time integrals were obtained using pulse-wave Doppler transesophageal echocardiography (TEE) to determine E/A and atrial filling fraction (beta). Mitral valve diameter (D) was calculated as the average of major and minor axis lengths obtained in the midesophageal bicommissural (transcommissural anterior-lateral-posterior medial) and LV long-axis (anterior-posterior) TEE imaging planes, respectively. VFT was calculated as 4·(1-beta)·SV/πD(3), where SV = stroke volume measured using thermodilution. Hemodynamics, diastolic function, and VFT were determined during steady-state conditions before cardiopulmonary bypass. The severity of AS (mean and peak pressure gradients, peak transvalvular jet velocity, aortic valve area) and diastolic function (E/A, beta) were similar between groups. Moderate centrally directed AI was present in 8 patients with AS (ratio of regurgitant jet width to LV outflow tract diameter of 36±6%). Pulse pressure and mean pulmonary artery pressure were elevated in patients with versus without AI, but no other differences in hemodynamics were observed. Mitral valve minor and major axis lengths, diameter, and area were reduced in the presence versus the absence of AI. VFT was increased significantly (5.7±1.7 v 3.2±0.6; p = 0.00108) in patients with AS and AI compared with AS alone.
  
  
  CONCLUSIONS
  Moderate AI falsely elevates VFT in patients with severe AS undergoing AVR by partially inhibiting mitral valve opening. VFT may be an unreliable index of LV filling efficiency with competitive diastolic flow into the LV.
authors.affiliation: Anesthesia Service, Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, WI. Electronic address: pspagel@mcw.edu.
authors.forename: Paul S
authors.initials: PS
authors.lastname: Pagel
authors.affiliation: Anesthesia Service, Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, WI.
authors.forename: Brent T
authors.initials: BT
authors.lastname: Boettcher
authors.affiliation: Anesthesia Service, Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, WI.
authors.forename: Derek J
authors.initials: DJ
authors.lastname: De Vry
authors.affiliation: Anesthesia Service, Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, WI.
authors.forename: Julie K
authors.initials: JK
authors.lastname: Freed
authors.affiliation: Anesthesia Service, Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, WI.
authors.forename: Zafar
authors.initials: Z
authors.lastname: Iqbal
mesh_terms: D000368:Aged; D001021:Aortic Valve / Q000473:pathology* / Q000503:physiopathology; D001022:Aortic Valve Insufficiency / Q000503:physiopathology*; D001024:Aortic Valve Stenosis / Q000150:complications* / Q000503:physiopathology*; D002114:Calcinosis / Q000150:complications* / Q000503:physiopathology*; D005260:Female; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000150:complications* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013997:Time Factors
keywords: aortic insufficiency; aortic stenosis; diastolic function; early left ventricular filling; fluid mechanics; intraventricular blood flow; transmitral blood flow efficiency; vortex formation time