Abstract
We compare the velocity and shear obtained from particle image velocimetry (PIV) and computational fluid dynamics (CFD) in a pulsatile ventricular assist device (VAD) to further test our thrombus predictive methodology using microscopy data from an explanted VAD. To mimic physiologic conditions in vitro, a mock circulatory loop was used with a blood analog that matched blood's viscoelastic behavior at 40% hematocrit. Under normal physiologic pressures and for a heart rate of 75 bpm, PIV data is acquired and wall shear maps are produced. The resolution of the PIV shear rate calculations are tested using the CFD and found to be in the same range. A bovine study, using a 50 cc Penn State V-2 VAD, for 30 days at a constant beat rate of 75 beats per minute (bpm) provides the microscopic data whereby after the 30 days, the device is explanted and the sac surface analyzed using scanning electron microscopy (SEM) and, after immunofluorescent labeling for platelets and fibrin, confocal microscopy. Areas are examined based on PIV measurements and CFD, with special attention to low shear regions where platelet and fibrin deposition are most likely to occur. Data collected within the outlet port in a direction normal to the front wall of the VAD shows that some regions experience wall shear rates less than 500 s-1, which increases the likelihood of platelet and fibrin deposition. Despite only one animal study, correlations between PIV, CFD, and in vivo data show promise. Deposition probability is quantified by the thrombus susceptibility potential, a calculation to correlate low shear and time of shear with deposition.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 54-69 |
| Number of pages | 16 |
| Journal | Cardiovascular Engineering and Technology |
| Volume | 5 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 1 2014 |
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All Science Journal Classification (ASJC) codes
- Biomedical Engineering
- Cardiology and Cardiovascular Medicine
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The Use of Fluid Mechanics to Predict Regions of Microscopic Thrombus Formation in Pulsatile VADs. / Topper, Stephen R.; Navitsky, Michael A.; Medvitz, Richard B.; Paterson, Eric G.; Siedlecki, Christopher; Slattery, Margaret June; Deutsch, Steven; Rosenberg, Gerson; Manning, Keefe B.
In: Cardiovascular Engineering and Technology, Vol. 5, No. 1, 01.01.2014, p. 54-69.Research output: Contribution to journal › Article
TY - JOUR
T1 - The Use of Fluid Mechanics to Predict Regions of Microscopic Thrombus Formation in Pulsatile VADs
AU - Topper, Stephen R.
AU - Navitsky, Michael A.
AU - Medvitz, Richard B.
AU - Paterson, Eric G.
AU - Siedlecki, Christopher
AU - Slattery, Margaret June
AU - Deutsch, Steven
AU - Rosenberg, Gerson
AU - Manning, Keefe B.
PY - 2014/1/1
Y1 - 2014/1/1
N2 - We compare the velocity and shear obtained from particle image velocimetry (PIV) and computational fluid dynamics (CFD) in a pulsatile ventricular assist device (VAD) to further test our thrombus predictive methodology using microscopy data from an explanted VAD. To mimic physiologic conditions in vitro, a mock circulatory loop was used with a blood analog that matched blood's viscoelastic behavior at 40% hematocrit. Under normal physiologic pressures and for a heart rate of 75 bpm, PIV data is acquired and wall shear maps are produced. The resolution of the PIV shear rate calculations are tested using the CFD and found to be in the same range. A bovine study, using a 50 cc Penn State V-2 VAD, for 30 days at a constant beat rate of 75 beats per minute (bpm) provides the microscopic data whereby after the 30 days, the device is explanted and the sac surface analyzed using scanning electron microscopy (SEM) and, after immunofluorescent labeling for platelets and fibrin, confocal microscopy. Areas are examined based on PIV measurements and CFD, with special attention to low shear regions where platelet and fibrin deposition are most likely to occur. Data collected within the outlet port in a direction normal to the front wall of the VAD shows that some regions experience wall shear rates less than 500 s-1, which increases the likelihood of platelet and fibrin deposition. Despite only one animal study, correlations between PIV, CFD, and in vivo data show promise. Deposition probability is quantified by the thrombus susceptibility potential, a calculation to correlate low shear and time of shear with deposition.
AB - We compare the velocity and shear obtained from particle image velocimetry (PIV) and computational fluid dynamics (CFD) in a pulsatile ventricular assist device (VAD) to further test our thrombus predictive methodology using microscopy data from an explanted VAD. To mimic physiologic conditions in vitro, a mock circulatory loop was used with a blood analog that matched blood's viscoelastic behavior at 40% hematocrit. Under normal physiologic pressures and for a heart rate of 75 bpm, PIV data is acquired and wall shear maps are produced. The resolution of the PIV shear rate calculations are tested using the CFD and found to be in the same range. A bovine study, using a 50 cc Penn State V-2 VAD, for 30 days at a constant beat rate of 75 beats per minute (bpm) provides the microscopic data whereby after the 30 days, the device is explanted and the sac surface analyzed using scanning electron microscopy (SEM) and, after immunofluorescent labeling for platelets and fibrin, confocal microscopy. Areas are examined based on PIV measurements and CFD, with special attention to low shear regions where platelet and fibrin deposition are most likely to occur. Data collected within the outlet port in a direction normal to the front wall of the VAD shows that some regions experience wall shear rates less than 500 s-1, which increases the likelihood of platelet and fibrin deposition. Despite only one animal study, correlations between PIV, CFD, and in vivo data show promise. Deposition probability is quantified by the thrombus susceptibility potential, a calculation to correlate low shear and time of shear with deposition.
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U2 - 10.1007/s13239-014-0174-x
DO - 10.1007/s13239-014-0174-x
M3 - Article
AN - SCOPUS:84894662611
VL - 5
SP - 54
EP - 69
JO - Cardiovascular Engineering and Technology
JF - Cardiovascular Engineering and Technology
SN - 1869-408X
IS - 1
ER -