title: Accurate Quantification Methods for Aortic Insufficiency Severity in Patients With LVAD: Role of Diastolic Flow Acceleration and Systolic-to-Diastolic Peak Velocity Ratio of Outflow Cannula.
abstract: The aim of this study was to develop a technique to measure regurgitant flow throughout the entire cardiac cycle that would more accurately measure aortic insufficiency (AI) severity in patients with continuous-flow left ventricular assist devices (CF-LVADs).
  
  
  
  AI is a common problem after CF-LVAD implantation. Current echocardiographic evaluation of AI does not take into account the unique flow properties present in patients with CF-LVADs.
  
  
  
  In this prospective study, patients with LVADs who had varying degrees of AI (N = 20) underwent simultaneous right-sided heart catheterization (RHC) and transthoracic echocardiography (TTE). Regurgitant fraction (RF) across the aortic valve was calculated by subtracting the cardiac output obtained using the Fick method from the total systemic flow measured using the sum of the product of the velocity time integral and the cross-sectional area of the LVAD outflow cannula and aortic valve, respectively. The RFs were then compared with the following: 1) traditional TTE grading parameters; and 2) new TTE parameters unique to LVAD physiology, namely the diastolic flow acceleration and the systolic-to-diastolic peak velocity (S/D) ratio of the LVAD outflow cannula.
  
  
  
  Patients without evidence of AI had an RF approaching zero (2.4 ± 4.6%). Patients with trace and mild AI had an RF of 31.0 ± 5.4%, whereas patients with moderate or severe AI had an RF of 45.8 ± 3.6%. RF correlated better with pulmonary capillary wedge pressure (PCWP) than with vena contracta (correlation coefficient [R] = 0.73 vs. 0.56). The new TTE parameters (S/D ratio and diastolic acceleration) highly correlated with RF (R = 0.91 and 0.94, respectively) and more strongly correlated with PCWP than did vena contracta (R = 0.82 and 0.65 vs. 0.56).
  
  
  
  RF measured by simultaneous RHC and TTE better correlates with clinical filling pressures than do traditional TTE parameters and may identify significant AI that could be underestimated using conventional measures. Novel TTE parameters, unique to CF-LVAD physiology, better correlate with RF and filling pressures than do our current TTE measurements.
authors.affiliation: Department of Medicine, University of Chicago Medical Center, Chicago, Illinois.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Grinstein
authors.affiliation: Department of Medicine, University of Chicago Medical Center, Chicago, Illinois.
authors.forename: Eric
authors.initials: E
authors.lastname: Kruse
authors.affiliation: Department of Medicine, University of Chicago Medical Center, Chicago, Illinois.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Sayer
authors.affiliation: Department of Medicine, University of Chicago Medical Center, Chicago, Illinois.
authors.forename: Savitri
authors.initials: S
authors.lastname: Fedson
authors.affiliation: Department of Medicine, University of Chicago Medical Center, Chicago, Illinois.
authors.forename: Gene H
authors.initials: GH
authors.lastname: Kim
authors.affiliation: Division of Cardiology, Montefiore Medical Center, New York, New York.
authors.forename: Ulrich P
authors.initials: UP
authors.lastname: Jorde
authors.affiliation: Department of Medicine, University of Chicago Medical Center, Chicago, Illinois; Department of Surgery, University of Chicago Medical Center, Chicago, Illinois.
authors.forename: Colleen
authors.initials: C
authors.lastname: Juricek
authors.affiliation: Department of Medicine, University of Chicago Medical Center, Chicago, Illinois; Department of Surgery, University of Chicago Medical Center, Chicago, Illinois.
authors.forename: Takeyoshi
authors.initials: T
authors.lastname: Ota
authors.affiliation: Department of Medicine, University of Chicago Medical Center, Chicago, Illinois; Department of Surgery, University of Chicago Medical Center, Chicago, Illinois.
authors.forename: Valluvan
authors.initials: V
authors.lastname: Jeevanandam
authors.affiliation: Department of Medicine, University of Chicago Medical Center, Chicago, Illinois.
authors.forename: Roberto M
authors.initials: RM
authors.lastname: Lang
authors.affiliation: Department of Medicine, University of Chicago Medical Center, Chicago, Illinois. Electronic address: nuriel@medicine.bsd.uchicago.edu.
authors.forename: Nir
authors.initials: N
authors.lastname: Uriel
mesh_terms: D000368:Aged; D001021:Aortic Valve / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001022:Aortic Valve Insufficiency / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D001783:Blood Flow Velocity; D006328:Cardiac Catheterization; D002302:Cardiac Output; D015150:Echocardiography, Doppler; D005260:Female; D006353:Heart-Assist Devices / Q000009:adverse effects; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D011474:Prosthesis Design; D011669:Pulmonary Wedge Pressure; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D016277:Ventricular Function, Left
keywords: LVAD; aortic insufficiency; heart failure