title: Left Ventricular Assist Device Thrombosis Is Associated With an Increase in the Systolic-to-Diastolic Velocity Ratio Measured at the Inflow and Outflow Cannulae.
abstract: OBJECTIVE
  To determine whether the ratio of peak systolic-to-nadir diastolic velocity (S/D ratio) measured using Doppler at the left ventricular assist device (LVAD) inflow and outflow cannulae is associated with pump thrombosis and to determine whether there is an absolute decrease in the diastolic cannula velocities in LVAD thrombosis.
  
  
  METHODS
  Retrospective chart review.
  
  
  METHODS
  University hospital.
  
  
  METHODS
  Patients who underwent LVAD exchange.
  
  
  METHODS
  None.
  
  
  RESULTS
  Transesophageal echocardiograms were reviewed from all patients with the HeartMate II device (Thoratec Corporation, Pleasanton, CA) over a 6-year period and who underwent LVAD exchange for pump thrombosis. The following 3 time points were evaluated: (1) initial LVAD placement (prethrombosis), (2) thrombosis, and (3) exchanged LVAD placement (postthrombosis). Systolic and diastolic flow velocities were examined using pulse-wave spectral Doppler at the inflow and outflow cannulae, and the S/D ratio for each was determined. Statistical analysis was performed with SAS, version 9.4 (SAS Institute, Cary, NC), using 2-tailed tests and alpha = 0.05. Thirteen patients were included in the study. Significant differences were observed in S/D ratios among the 3 phases at both the inflow (p = 0.0234) and outflow (p = 0.0047) cannulae. Pairwise tests of the inflow cannulae showed that the mean S/D ratio at the time of thrombosis (mean ± standard deviation [SD], 4.29 ± 1.74) was significantly greater than the prethrombosis ratio (2.49 ± 0.65; p = 0.0069). Among outflow measurements, the mean S/D ratio at thrombosis (3.94 ± 1.34) was significantly higher than both the prethrombosis (2.63 ± 0.56; p = 0.0025) and postthrombosis (2.74 ± 0.83) (p = 0.0093) ratios. Decreases in diastolic velocities were not statistically significant at the inflow cannula. At the outflow cannula, there was a significant difference in diastolic velocity among the phases (p = 0.0233). Specifically, the postthrombosis diastolic measurements (41.50 ± 9.94) were significantly higher than both the prethrombosis (26.85 ± 10.13; p = 0.0140) and thrombosis (26.7 ± 15.35; p = 0.0151) values.
  
  
  CONCLUSIONS
  An increased S/D ratio measured with Doppler at the LVAD inflow and outflow cannulas may be associated with pump thrombosis. Decreased diastolic cannula velocities were not observed in LVAD thrombosis.
authors.affiliation: Department of Anesthesia, Tufts Medical Center, Boston, MA.
authors.forename: Ankit
authors.initials: A
authors.lastname: Jain
authors.affiliation: Department of Anesthesia, Tufts Medical Center, Boston, MA.
authors.forename: Ben
authors.initials: B
authors.lastname: Rohrer
authors.affiliation: Department of Anesthesia, Tufts Medical Center, Boston, MA.
authors.forename: Brian
authors.initials: B
authors.lastname: Gebhardt
authors.affiliation: Tufts Clinical and Translational Science Institute, Tufts University, Boston, MA; Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, Boston, MA.
authors.forename: Janis L
authors.initials: JL
authors.lastname: Breeze
authors.affiliation: Department of Anesthesia, Yale University School of Medicine, New Haven, CT.
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Quick
authors.affiliation: Department of Cardiothoracic Surgery, Tufts Medical Center, Boston, MA.
authors.forename: Gregory
authors.initials: G
authors.lastname: Couper
authors.affiliation: Department of Cardiology, Tufts Medical Center, Boston, MA.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Kiernan
authors.affiliation: Department of Cardiology, Tufts Medical Center, Boston, MA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Lawrence
authors.affiliation: Department of Anesthesia, Tufts Medical Center, Boston, MA. Electronic address: FCobey@tuftsmedicalcenter.org.
authors.forename: Frederick C
authors.initials: FC
authors.lastname: Cobey
mesh_terms: D000368:Aged; D000072601:Cannula; D017548:Echocardiography, Transesophageal / Q000639:trends; D005260:Female; D006353:Heart-Assist Devices / Q000009:adverse effects* / Q000639:trends; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013927:Thrombosis / Q000000981:diagnostic imaging* / Q000209:etiology* / Q000503:physiopathology
keywords: Doppler; echocardiography; left ventricular assist device; thrombosis