PMID- 29715362
OWN - NLM
STAT- MEDLINE
DCOM- 20190930
LR  - 20190930
IS  - 1528-8951 (Electronic)
IS  - 0148-0731 (Linking)
VI  - 140
IP  - 7
DP  - 2018 Jul 1
TI  - Characterizing the HeartMate II Left Ventricular Assist Device Outflow Using 
      Particle Image Velocimetry.
LID - 10.1115/1.4039822 [doi]
AB  - Ventricular assist devices (VADs) are implanted in patients with a diseased 
      ventricle to maintain peripheral perfusion as a bridge-to-transplant or as 
      destination therapy. However, some patients with continuous flow VADs (e.g., 
      HeartMate II (HMII)) have experienced gastrointestinal (GI) bleeding, in part 
      caused by the proteolytic cleavage or mechanical destruction of von Willebrand 
      factor (vWF), a clotting glycoprotein. in vitro studies were performed to measure 
      the flow located within the HMII outlet cannula under both steady and 
      physiological conditions using particle image velocimetry (PIV). Under steady 
      flow, a mock flow loop was used with the HMII producing a flow rate of 3.2 L/min. 
      The physiological experiment included a pulsatile pump operated at 105 BPM with a 
      ventricle filling volume of 50 mL and in conjunction with the HMII producing a 
      total flow rate of 5.0 L/min. Velocity fields, Reynolds normal stresses (RNSs), 
      and Reynolds shear stresses (RSSs) were analyzed to quantify the outlet flow's 
      potential contribution to vWF degradation. Under both flow conditions, the HMII 
      generated principal Reynolds stresses that are, at times, orders of magnitude 
      higher than those needed to unfurl vWF, potentially impacting its physiological 
      function. Under steady flow, principal RNSs were calculated to be approximately 
      500 Pa in the outlet cannula. Elevated Reynolds stresses were observed throughout 
      every phase of the cardiac cycle under physiological flow with principal RNSs 
      approaching 1500 Pa during peak systole. Prolonged exposure to these conditions 
      may lead to acquired von Willebrand syndrome (AvWS), which is accompanied by 
      uncontrollable bleeding episodes.
FAU - Rowlands, Grant W
AU  - Rowlands GW
AD  - Department of Biomedical Engineering, The Pennsylvania State University, 205 
      Hallowell Building, University Park, PA 16802.
FAU - Good, Bryan C
AU  - Good BC
AD  - Department of Biomedical Engineering, The Pennsylvania State University, 205 
      Hallowell Building, University Park, PA 16802.
FAU - Deutsch, Steven
AU  - Deutsch S
AD  - Department of Biomedical Engineering, The Pennsylvania State University, 205 
      Hallowell Building, University Park, PA 16802.
FAU - Manning, Keefe B
AU  - Manning KB
AD  - Professor Department of Biomedical Engineering, The Pennsylvania State 
      University, 205 Hallowell Building, University Park, PA 16802.
AD  - Department of Surgery, Penn State Hershey Medical Center, Hershey, PA 17033 
      e-mail: .
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - J Biomech Eng
JT  - Journal of biomechanical engineering
JID - 7909584
SB  - IM
MH  - *Heart-Assist Devices
MH  - *Mechanical Phenomena
MH  - *Optical Phenomena
MH  - *Rheology
MH  - Systole
EDAT- 2018/05/02 06:00
MHDA- 2019/10/01 06:00
CRDT- 2018/05/02 06:00
PHST- 2017/07/25 00:00 [received]
PHST- 2018/05/02 06:00 [entrez]
PHST- 2018/05/02 06:00 [pubmed]
PHST- 2019/10/01 06:00 [medline]
AID - 2677750 [pii]
AID - 10.1115/1.4039822 [doi]
PST - ppublish
SO  - J Biomech Eng. 2018 Jul 1;140(7). doi: 10.1115/1.4039822.