Current designs of bileaflet mechanical heart valves put patients at an increased risk of thromboembolism. In particular, regurgitant flow through the b-datum line is associated with nonphysiologic flow characteristics such as elevated shear stresses, regions of recirculation, and increased mixing, all of which may promote thrombus formation. We have previously shown that passive flow control in the form of vortex generators mounted on the downstream leaflet surfaces can effectively diminish turbulent stresses. The objective of the current work is thus to determine the effect of vortex generators on the thromboembolic potential of the b-datum line leakage jet and to correlate that effect with the vortex generator-induced changes to the flow structure. Flow experiments were performed using a steady model of the transient b-datum line jet. These experiments encompassed flow visualization to gain an overall picture of the flow system, particle image velocimetry to quantify the flow field in detail, and in vitro experiments with human blood to quantify thrombus formation in response to the applied passive flow control. Thrombus formation was quantified over time by an assay for thrombin-antithrombin III (TAT III). In comparing results with and without vortex generators, significantly lower mean TAT III levels were observed at one time point for the case with vortex generators. Also, the TAT III growth rate of the case with vortex generators was significantly lower. While no differences in jet spreading were found with and without vortex generators, lower peak turbulent stresses were observed for the case with vortex generators. The results thus demonstrate the potential of applying passive flow control to cardiovascular hardware in order to mitigate the hemodynamic factors leading to thrombus formation.

1.
Thai
,
H.
, and
Gore
,
J.
, 2000,
Prosthetic Heart Valves
(
Valvular Heart Disease
),
J.
Alpert
,
J.
Dalen
and
S.
Rahimtoola
,
Lippincott Williams & Wilkins
,
Philadelphia, PA
.
2.
Baudet
,
E. M.
,
Oca
,
C. C.
,
Roques
,
X. F.
,
Laborde
,
M. N.
,
Hafez
,
A. S.
,
Collot
,
M. A.
, and
Ghidoni
,
I. M.
, 1985, “
A 5 1/2 Year Experience With the St. Jude Medical Cardiac Valve Prosthesis. Early and Late Results of 737 Valve Replacements in 671 Patients
,”
J. Thorac. Cardiovasc. Surg.
0022-5223,
90
(
1
), pp.
137
144
.
3.
Masters
,
R. G.
,
Pipe
,
A. L.
,
Walley
,
V.
, and
Keon
,
W.
, 1995, “
Comparative Results With the St. Jude Medical and Medtronic Hall Mechanical Valves
,”
J. Thorac. Cardiovasc. Surg.
0022-5223,
110
(
3
), pp.
663
671
.
4.
Chang
,
B.
,
Lim
,
S.
,
Kim
,
D. K.
,
Seo
,
J. Y.
,
Cho
,
S. Y.
,
Shim
,
W. H.
,
Chung
,
N.
,
Kim
,
S. S.
, and
Cho
,
B. K.
, 2001, “
Long-Term Results With St. Jude Medical and CarboMedics Prosthetic Heart Valves
,”
J. Heart Valve Dis.
0966-8519,
10
(
2
), pp.
185
194
.
5.
Ibrahim
,
M.
,
O’Kane
,
H.
,
Cleland
,
J.
,
Gladstone
,
D.
,
Sarsam
,
M.
, and
Patterson
,
C.
, 1994, “
The St. Jude Medical Prosthesis: A Thirteen-Year Experience
,”
J. Thorac. Cardiovasc. Surg.
0022-5223,
108
(
2
), pp.
221
230
.
6.
Sutera
,
S. P.
, 1977, “
Flow-Induced Trauma to Blood Cells
,”
Circ. Res.
0009-7330,
41
(
1
), pp.
2
8
.
7.
Hellums
,
J.
, 1994, “
1993 Whitaker Lecture: Biorheology in Thrombosis Research
,”
J. Biomed. Eng.
0141-5425,
22
(
5
), pp.
445
455
.
8.
Leverett
,
L. B.
,
Hellums
,
J. D.
,
Alfrey
,
C.
, and
Lynch
,
E.
, 1972, “
Red Blood Cell Damage by Shear Stress
,”
Biophys. J.
0006-3495,
12
(
3
), pp.
257
273
.
9.
Lu
,
P.
,
Lai
,
H.
, and
Liu
,
J. S.
, 2001, “
A Reevaluation and Discussion on the Threshold Limit for Hemolysis in a Turbulent Shear Flow
,”
J. Biomech.
0021-9290,
34
(
10
), pp.
1361
1364
.
10.
Ramstack
,
J.
,
Zuckerman
,
L.
, and
Mockros
,
L.
, 1979, “
Shear-Induced Activation of Platelets
,”
J. Biomech.
0021-9290,
12
(
2
), pp.
113
25
.
11.
Bluestein
,
D.
,
Niu
,
L.
,
Schoephoerster
,
R.
, and
Dewanjee
,
M.
, 1997, “
Fluid Mechanics of Arterial Stenosis: Relationship to the Development of Mural Thrombus
,”
Ann. Biomed. Eng.
0090-6964,
25
(
2
), pp.
344
356
.
12.
Colantuoni
,
G.
,
Hellums
,
J. D.
,
Moake
,
J.
, and
Alfrey
,
C.
, 1977, “
The Response of Human Platelets to Shear Stress at Short Exposure Times
,”
Trans. Am. Soc. Artif. Intern. Organs
0066-0078,
23
, pp.
626
31
.
13.
Yoganathan
,
A.
, 1995,
Cardiac Valve Prostheses
(
The Biomedical Engineering Handbook
),
J.
Bronzino
, ed.,
CRC
,
Boca Raton, FL
, pp.
1847
1870
.
14.
Dasi
,
L.
,
Ge
,
L.
,
Simon
,
H.
,
Sotiropoulos
,
F.
, and
Yoganathan
,
A.
, 2007, “
Vorticity Dynamics of a Bileaflet Mechanical Heart Valve in an Axisymmetric Aorta
,”
Phys. Fluids
1070-6631,
19
(
6
), pp.
067105
067117
.
15.
Simon
,
H.
, 2004,
Influence of the Implant Location on the Hinge and Leakage Flow Fields Through Bileaflet Mechanical Heart Valves
(
Chemical Engineering
),
Georgia Institute of Technology
,
Atlanta, GA
.
16.
Krishnan
,
S.
,
Udaykumar
,
H. S.
,
Marshall
,
J.
, and
Chandran
,
K. B.
, 2006, “
Two-Dimensional Dynamic Simulation of Platelet Activation During Mechanical Heart Valve Closure
,”
Ann. Biomed. Eng.
0090-6964,
34
(
10
), pp.
1519
1534
.
17.
Fallon
,
A.
,
Shah
,
N.
,
Marzec
,
U.
, and
Warnock
,
J.
, 2006, “
Flow and Thrombosis at Orifices Simulating Mechanical Heart Valve Leakage Regions
,”
ASME J. Biomech. Eng.
0148-0731,
128
(
1
), pp.
30
39
.
18.
Hathcock
,
J. J.
, 2006, “
Flow Effects on Coagulation and Thrombosis
,”
Arterioscler. Thromb. Vasc. Biol.
,
26
(
8
), pp.
1729
1737
.
19.
Bluestein
,
D.
,
Rambod
,
E.
, and
Gharib
,
M.
, 2000, “
Vortex Shedding as a Mechanism for Free Emboli Formation in Mechanical Heart Valves
,”
ASME J. Biomech. Eng.
0148-0731,
122
(
2
), pp.
125
134
.
20.
Fallon
,
A.
,
Dasi
,
L.
,
Marzec
,
U.
,
Hanson
,
S.
, and
Yoganathan
,
A.
, 2008, “
Procoagulant Properties of Flow Fields in Stenotic and Expansive Orifices
,”
Ann. Biomed. Eng.
0090-6964,
36
(
1
), pp.
1
13
.
21.
Dasi
,
L.
,
Murphy
,
D. W.
,
Glezer
,
A.
, and
Yoganathan
,
A.
, 2008, “
Passive Flow Control of Bileaflet Mechanical Heart Valve Leakage Flow
,”
J. Biomech.
0021-9290,
41
(
6
), pp.
1166
1173
.
22.
Gad-el-Hak
,
M.
, 2000,
Flow Control: Passive, Active, and Reactive Flow Management
,
Cambridge University Press
,
New York
.
23.
Fish
,
F. E.
, and
Lauder
,
G. V.
, 2006, “
Passive and Active Flow Control by Swimming Fishes and Mammals
,”
Annu. Rev. Fluid Mech.
0066-4189,
38
(
1
), pp.
193
224
.
24.
Pearcey
,
H.
, 1961,
Shock-Induced Separation and its Prevention by Design and Boundary Layer Cotnrol
(
Boundary Layer and Flow Control
),
G.
Lachmann
, ed.,
Pergamon
,
New York
, p.
2
.
25.
Fallon
,
A.
, (2006).
The Development of a Novel in vitro Flow System to Evaluate Platelet Activation and Procoagulant Potential Induced by Bileaflet Mechanical Heart Valve Leakage Jets
(
Chemical Engineering
),
Georgia Institute of Technology
,
Atlanta, GA
.
26.
Fallon
,
A.
,
Marzec
,
U.
,
Hanson
,
S.
, and
Yoganathan
,
A.
, 2007, “
Thrombin Formation In Vitro in Response to Shear-Induced Activation of Platelets
,”
Thromb. Res.
0049-3848,
121
(
3
), pp.
397
406
.
27.
Pelzer
,
H.
, and
Schwarz
,
A.
, and
Heimberger
,
N.
, 1988, “
Determination of Human Thrombin-Antithrombin III Complex in Plasma With an Enzyme-Linked Immunosorbent Assay
,”
Thromb. Haemost.
,
59
(
1
), pp.
101
116
.
28.
Lawson
,
N. J.
, and
Davidson
,
M. R.
, 1999, “
Crossflow Characteristics of an Oscillating Jet in a Thin Slab Casting Mould
,”
ASME J. Fluids Eng.
0098-2202,
121
(
3
), pp.
588
595
.
29.
Lawson
,
N. J.
, and
Davidson
,
M. R.
, 2001, “
Self-Sustained Oscillation of a Submerged Jet in a Thin Rectangular Cavity
,”
J. Fluids Struct.
0889-9746,
15
(
1
), pp.
59
81
.
30.
Lawson
,
N. J.
, and
Davidson
,
M. R.
, 2002, “
Oscillatory Flow in a Physical Model of a Thin Slab Casting Mould With a Bifurcated Submerged Entry Nozzle
,”
ASME J. Fluids Eng.
0098-2202,
124
(
2
), pp.
535
543
.
31.
Mi
,
J.
,
Nathan
,
G. J.
, and
Luxton
,
R.
, 2001, “
Mixing Characteristics of a Flapping Jet From a Self-Exciting Nozzle
,”
Flow Turbul. Combust.
,
67
(
1
), pp.
1
23
.
32.
Bradbury
,
L.
, and
Khadem
,
A.
, 1975, “
The Distortion of a Jet by Tabs
,”
J. Fluid Mech.
0022-1120,
70
, pp.
801
813
.
33.
Zaman
,
K. B. M. Q.
,
Reeder
,
M. F.
, and
Samimy
,
M.
, 1994, “
Control of an Axisymmetric Jet Using Vortex Generators
,”
Phys. Fluids
1070-6631,
6
(
2
), pp.
778
793
.
34.
Hui
,
H.
,
Kobayashi
,
T.
,
et al.
, 1999, “
Changes to the Vortical and Turbulent Structure of Jet Flows Due to Mechanical Tabs
,”
Proc. Inst. Mech. Eng., Part C: J. Mech. Eng. Sci.
0954-4062,
213
(
4
), pp.
321
329
.
35.
Yu
,
S.
,
Hou
,
Y.
, and
Low
,
S. C.
, 1998, “
The Flow Characteristics of a Confined Square Jet With Mixing Tabs
,”
Proc. Inst. Mech. Eng. Part G J. Aerosp. Eng.
,
212
(
2
), pp.
63
76
.
36.
Dumont
,
K.
,
Vierendeels
,
J.
,
et al.
, 2007, “
Comparison of the Hemodynamic and Thrombogenic Performance of Two Bileaflet Mechanical Heart Valves Using a CFD/FSI Model
,”
ASME J. Biomech. Eng.
0148-0731,
129
(
4
), pp.
558
565
.
37.
Manning
,
K.
,
Herbertson
,
L.
,
Fontaine
,
A.
, and
Deutsch
,
S.
, 2008, “
A Detailed Fluid Mechanics Study of Tilting Disk Mechanical Heart Valve Closure and the Implications to Blood Damage
,”
ASME J. Biomech. Eng.
0148-0731,
130
(
4
), pp.
041001
.
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