title: Association of HeartMate II left ventricular assist device flow estimate with thermodilution cardiac output.
abstract: Cardiac output (CO) assessment is important in treating patients with heart failure. Durable left ventricular assist devices (LVADs) provide essentially all CO. In currently used LVADs, estimated device flow is generated by a computerized algorithm. However, LVAD flow estimate may be inaccurate in tracking true CO. We correlated LVAD (HeartMate II) flow with thermodilution CO during postoperative care (day 2-10 after implant) in 81 patients (5,616 paired measurements). Left ventricular assist device flow and CO correlated with a low correlation coefficient (r = 0.42). Left ventricular assist device readings were lower than CO measurements by approximately 0.36 L/min, trending for larger difference with higher values. Left ventricular assist device flow measurements showed less temporal variability compared with CO. Grouping for simultaneous measured blood pressure (BP < 60, 60-70, 70-80, 80-90, and ≥90), the correlation of CO with LVAD flow differed (R = 0.42, 0.67, 0.48, 0.32, 0.32, respectively). Indicating better correlation when mean blood pressure is 60 to 70 mm Hg. Left ventricular assist device flow generally trends with measured CO, but large variability exists, hence flow measures should not be assumed to equal with CO. Clinicians should take into account variables such as high CO, BP, and opening of the aortic valve when interpreting LVAD flow readout. Direct flow sensors incorporated in the LVAD system may allow for better estimation.
authors: From the *Division of Cardiovascular Diseases, †Department of Health Sciences Research, ‡Department of Anesthesiology, and §Division of Cardiothoracic Surgery, Mayo Clinic, Rochester, Minnesota; and ¶Division of Cardiac Surgery University Hospitals Case Medical Center, Cleveland, Ohio.
authors: Tal
authors: T
authors: Hasin
authors: Marianne
authors: M
authors: Huebner
authors: Zhuo
authors: Z
authors: Li
authors: Daniel
authors: D
authors: Brown
authors: John M
authors: JM
authors: Stulak
authors: Barry A
authors: BA
authors: Boilson
authors: Lyle
authors: L
authors: Joyce
authors: Naveen L
authors: NL
authors: Pereira
authors: Sudhir S
authors: SS
authors: Kushwaha
authors: Soon J
authors: SJ
authors: Park
mesh_terms: D002302:Cardiac Output / Q000502:physiology*; D005260:Female; D006333:Heart Failure / Q000601:surgery; D006353:Heart-Assist Devices; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013815:Thermodilution