Both structural and functional evaluations of the endothelium exist in order to diagnose cardiovascular disease (CVD) in its asymptomatic stages. Vascular reactivity, a functional evaluation of the endothelium in response to factors such as occlusion, cold, and stress, in addition to plasma markers, is the most widely accepted test and has been found to be a better predictor of the health of the endothelium than structural assessment tools such as coronary calcium scores or carotid intima-media thickness. Among the vascular reactivity assessment techniques available, digital thermal monitoring (DTM) is a noninvasive technique that measures the recovery of fingertip temperature after 2–5 min of brachial occlusion. On release of occlusion, the finger temperature responds to the amount of blood flow rate overshoot referred to as reactive hyperemia (RH), which has been shown to correlate with vascular health. Recent clinical trials have confirmed the potential importance of DTM as an early stage predictor of CVD. Numerical simulations of a finger were carried out to establish the relationship between DTM and RH. The model finger consisted of essential components including bone, tissue, major blood vessels (macrovasculature), skin, and microvasculature. The macrovasculature was represented by a pair of arteries and veins, while the microvasculature was represented by a porous medium. The time-dependent Navier–Stokes and energy equations were numerically solved to describe the temperature distribution in and around the finger. The blood flow waveform postocclusion, an input to the numerical model, was modeled as an instantaneous overshoot in flow rate (RH) followed by an exponential decay back to baseline flow rate. Simulation results were similar to clinically measured fingertip temperature profiles in terms of basic shape, temperature variations, and time delays at time scales associated with both heat conduction and blood perfusion. The DTM parameters currently in clinical use were evaluated and their sensitivity to RH was established. Among the parameters presented, temperature rebound (TR) was shown to have the best correlation with the level of RH with good sensitivity for the range of flow rates studied. It was shown that both TR and the equilibrium start temperature (representing the baseline flow rate) are necessary to identify the amount of RH and, thus, to establish criteria for predicting the state of specific patient’s cardiovascular health.

1.
World Health Organization
, 2007, “
Health Topics, Cardiovascular Diseases
,” Fact Sheet No. 317.
2.
Labarthe
,
D. R.
, 1998,
Epidemiology and Prevention of Cardiovascular Diseases, A Global Challenge
,
Aspen Publishers Inc.
,
Gaithersburg, Maryland
.
3.
Maciejko
,
J.
, 2004,
Atherosclerosis Risk Factors
,
American Association for Clinical Chemistry Press
,
Washington, DC
.
4.
Kannel
,
W. B.
, 1976, “
Some Lessons in Cardiovascular Epidemiology From Framingham
,”
Am. J. Cardiol.
0002-9149,
37
(
2
), pp.
269
282
.
5.
Tuzcu
,
E. M.
,
Kapadia
,
S. R.
,
Tutar
,
E.
,
Ziada
,
K. M.
,
Hobbs
,
R. E.
,
McCarhty
,
P. M.
,
Young
,
J. B.
, and
Nissen
,
S. E.
, 2001, “
High Prevalence of Coronary Atherosclerosis in Asymptomatic Teenagers and Young Adults Evidence From Intravascular Ultrasound
,”
Circulation
0009-7322,
103
, pp.
2705
2710
.
6.
Bernstein
,
E. F.
, 1993,
Vascular Diagnosis
,
Mosby
,
St. Louis
.
7.
Grundy
,
S. M.
,
Pasternak
,
R.
,
Greenland
,
P.
,
Smith
,
J. S.
, and
Fuster
,
V.
, 1999, “
Assessment of Cardiovascular Risk by Use of Multiple-Risk-Factor Assessment Equations: A Statement for Healthcare Professionals From the American Heart Association and the American College of Cardiology
,”
Circulation
0009-7322,
100
, pp.
1481
1492
.
8.
Grundy
,
S. M.
,
Balady
,
G. J.
,
Criqui
,
M. H.
,
Fletcher
,
G.
,
Greenland
,
P.
,
Hiratzka
,
L. F.
,
Houston-Miller
,
N.
,
Kris-Etherton
,
P.
,
Krumholz
,
H. M.
,
LaRosa
,
J.
,
Ockene
,
I. S.
,
Pearson
,
T. A.
,
Reed
,
J.
,
Washington
,
R.
, and
Smith
,
S. C.
, Jr.
, 1998, “
Primary Prevention of Coronary Heart Disease: Guidance From Framingham: A Statement for Healthcare Professionals From the AHA Task Force on Risk Reduction
,”
Circulation
0009-7322,
97
, pp.
1876
1887
.
9.
Akosah
,
K. O.
,
Schaper
,
A.
,
Cogbill
,
C.
, and
Schoenfeld
,
P.
, 2003, “
Preventing Myocardial Infarction in the Young Adult in the First Place: How Do the National Cholesterol Education Panel III Guidelines Perform?
,”
J. Am. Coll. Cardiol.
0735-1097,
41
(
9
), pp.
1475
1479
.
10.
Sibley
,
C.
,
Blumenthal
,
R. S.
,
Merz
,
C. N. B.
, and
Mosca
,
L.
, 2006, “
Limitations of Current Cardiovascular Disease Risk Assessment Strategies in Women
,”
J. Womens Health
1059-7115,
15
(
1
), pp.
54
56
.
11.
Michos
,
E. D.
,
Nasir
,
K.
,
Braunstein
,
J. B.
,
Rumberger
,
J. A.
,
Budoff
,
M. J.
,
Post
,
W. S.
, and
Blumenthal
,
R. S.
, 2006, “
Framingham Risk Equation Underestimates Subclinical Atherosclerosis Risk in Asymptomatic Women
,”
Atherosclerosis
0021-9150,
184
, pp.
201
206
.
12.
Giannotti
,
G.
, and
Landmesser
,
U.
, 2007, “
Endothelial Dysfunction as an Early Sign of Atherosclerosis
,”
Herz
0340-9937,
32
, pp.
568
572
.
13.
Ross
,
R.
, 1993, “
The Pathogenesis of Atherosclerosis: A Perspective for the 1990s
,”
Nature (London)
0028-0836,
362
, pp.
801
809
.
14.
Moncada
,
S.
, and
Higgs
,
A.
, 1993, “
The L-Arginine-Nitric Oxide Pathway
,”
N. Engl. J. Med.
0028-4793,
329
(
27
), pp.
2002
2012
.
15.
Moens
,
A. L.
,
Goovaerts
,
I.
,
Claeys
,
M. J.
, and
Vrints
,
C. J.
, 2005, “
Flow-Mediated Vasodilation: A Diagnostic Instrument, or an Experimental Tool?
Chest
0012-3692,
127
, pp.
2254
2263
.
16.
Charakida
,
M.
,
Deanfield
,
J. E.
, and
Halcox
,
J.
, 2007, “
Childhood Origins of Arterial Disease
,”
Curr. Opin. Pediatr.
1040-8703,
19
, pp.
538
545
.
17.
Nadar
,
S.
,
Blann
,
A. D.
, and
Gregory
,
Y. H. L.
, 2004, “
Endothelial Dysfunction: Methods of Assessment and Application to Hypertension
,”
Curr. Pharm. Des.
1381-6128,
10
, pp.
3591
3605
.
18.
Farouque
,
H. M. O.
, and
Meredith
,
I.
, 2001, “
The Assessment of Endothelial Function in Humans
,”
Coron. Artery Dis.
0954-6928,
12
, pp.
445
454
.
19.
Sinoway
,
L. I.
,
Hendrickson
,
C.
,
Davidson
,
W. R. J.
,
Prophet
,
S.
, and
Zelis
,
R.
, 1989, “
Characteristics of Flow-Mediated Brachial Artery Vasodilation in Human Subjects
,”
Circ. Res.
0009-7330,
64
, pp.
32
42
.
20.
Celermajer
,
D. S.
,
Sorensen
,
K. E.
,
Gooch
,
V. M.
,
Spiegelhalter
,
D. J.
,
Miller
,
O. I.
,
Sullivan
,
I. D.
,
Lloyd
,
J. K.
, and
Deanfield
,
J. E.
, 1992, “
Non-Invasive Detection of Endothelial Dysfunction in Children and Adults at Risk of Atherosclerosis
,”
Lancet
0140-6736,
340
(
8828
), pp.
1111
1115
.
21.
Joannides
,
R.
,
Haefeli
,
W. E.
,
Linder
,
L.
,
Richard
,
V.
,
Bakkali
,
E. H.
,
Thuillez
,
C.
, and
Lüscher
,
T. F.
, 1995, “
Nitric Oxide Is Responsible for Flow-Dependent Dilatation of Human Peripheral Conduit Arteries In Vivo
,”
Circulation
0009-7322,
91
, pp.
1314
1319
.
22.
Neunteufl
,
T.
,
Heher
,
S.
,
Katzenschlager
,
R.
,
Wölfl
,
G.
,
Kostner
,
K.
,
Maurer
,
G.
, and
Weidinger
,
F.
, 2000, “
Late Prognostic Value of Flow-Mediated Dilation in the Brachial Artery of Patients With Chest Pain
,”
Am. J. Cardiol.
0002-9149,
86
, pp.
207
210
.
23.
Heitzer
,
T.
,
Schlinzig
,
T.
,
Krohn
,
K.
,
Meinertz
,
T.
, and
Münzel
,
T.
, 2001, “
Endothelial Dysfunction, Oxidative Stress, and Risk of Cardiovascular Events in Patients With Coronary Artery Disease
,”
Circulation
0009-7322,
104
, pp.
2673
2678
.
24.
Perticone
,
F.
,
Ceravolo
,
R.
,
Pujia
,
A.
,
Ventura
,
G.
,
Iacopino
,
S.
,
Scozzafava
,
A.
,
Ferraro
,
A.
,
Chello
,
M.
,
Mastroroberto
,
P.
,
Verdecchia
,
P.
, and
Schillaci
,
G.
, 2001, “
Prognostic Significance of Endothelial Dysfunction in Hypertensive Patients
,”
Circulation
0009-7322,
104
(
2
), pp.
191
196
.
25.
Lieberman
,
E. H.
,
Gerhard
,
M. D.
,
Uehata
,
A.
,
Selwyn
,
A. P.
,
Ganz
,
P.
,
Yeung
,
A. C.
, and
Creager
,
M. A.
, 1996, “
Flow-Induced Vasodilation of the Human Brachial Artery Is Impaired in Patients <40 years of Age With Coronary Artery Disease
,”
Am. J. Cardiol.
0002-9149,
78
, pp.
1210
1214
.
26.
Higashi
,
Y.
,
Sasaki
,
S.
,
Nakagawa
,
K.
,
Matsuura
,
H.
,
Kajiyama
,
G.
, and
Oshima
,
T.
, 2001, “
A Noninvasive Measurement of Reactive Hyperemia That Can Be Used to Assess Resistance Artery Endothelial Function in Humans
,”
Am. J. Cardiol.
0002-9149,
87
(
1
), pp.
121
125
.
27.
Mitchell
,
G. F.
,
Parise
,
H.
,
Vita
,
J. A.
,
Larson
,
M. G.
,
Warner
,
E.
,
Keaney
,
J. J. F.
,
Keyes
,
M. J.
,
Levy
,
D.
,
Vasan
,
R. S.
, and
Benjamin
,
E. J.
, 2004, “
Local Shear Stress and Brachial Artery Flow-Mediated Dilation: The Framingham Heart Study
,”
Hypertension
0194-911X,
44
, pp.
134
139
.
28.
Vita
,
J. A.
,
Keaney
,
J. F. J.
,
Larson
,
M. G.
,
Keyes
,
M. J.
,
Massaro
,
J. M.
,
Lipinska
,
I.
,
Lehman
,
B. T.
,
Fan
,
S.
,
Osypiuk
,
E.
,
Wilson
,
P. W. F.
,
Vasan
,
R. S.
,
Mitchell
,
G. F.
, and
Benjamin
,
E. J.
, 2004, “
Brachial Artery Vasodilator Function and Systemic Inflammation in the Framingham Offspring Study
,”
Circulation
0009-7322,
110
, pp.
3604
3609
.
29.
Huang
,
A. L.
,
Silver
,
A. E.
,
Shvenke
,
E.
,
Schopfer
,
D. W.
,
Jahangir
,
E.
,
Titas
,
M. A.
,
Shpilman
,
A.
,
Menzoian
,
J. O.
,
Watkins
,
M. T.
,
Raffetto
,
J. D.
,
Gibbons
,
G.
,
Woodson
,
J.
,
Shaw
,
P. M.
,
Dhadly
,
M.
,
Eberhardt
,
R. T.
,
Keaney
,
J. J. F.
,
Gokce
,
N.
, and
Vita
,
J. A.
, 2007, “
Predictive Value of Reactive Hyperemia for Cardiovascular Events in Patients With Peripheral Arterial Disease Undergoing Vascular Surgery
,”
Arterioscler., Thromb., Vasc. Biol.
1079-5642,
27
, pp.
2113
2119
.
30.
Philpott
,
A.
, and
Anderson
,
T. J.
, 2007, “
Reactive Hyperemia and Cardiovascular Risk
,”
Arterioscler., Thromb., Vasc. Biol.
1079-5642,
27
, pp.
2065
2067
.
31.
Bonetti
,
P. O.
,
Pumper
,
G. M.
,
Higano
,
S. T.
,
Holmes
,
J. D. R.
,
Kuvin
,
J. T.
, and
Lerman
,
A.
, 2004, “
Noninvasive Identification of Patients With Early Coronary Atherosclerosis by Assessment of Digital Reactive Hyperemia
,”
J. Am. Coll. Cardiol.
0735-1097,
44
(
11
), pp.
2137
2141
.
32.
Kistler
,
A.
,
Mariauzouls
,
C.
, and
von Berlepsch
,
K.
, 1998, “
Fingertip Temperature as an Indicator for Sympathetic Responses
,”
Int. J. Psychophysiol
0167-8760,
29
(
1
), pp.
35
41
.
33.
Pennes
,
H. H.
, 1948, “
Analysis of Tissue and Arterial Blood Temperatures in the Resting Human Forearm
,”
J. Appl. Physiol.
8750-7587,
1
(
2
), pp.
93
122
.
34.
Shitzer
,
A.
,
Stroschein
,
L. A.
,
Vital
,
P.
,
Gonalez
,
R. R.
, and
Pandolf
,
K. B.
, 1997, “
Numerical Analysis of an Extremity in a Cold Environment Including Countercurrent Arterio-Venous Heat Exchange
,”
ASME J. Biomech. Eng.
0148-0731,
119
, pp.
179
186
.
35.
Hutchinson
,
M.
,
Mallat
,
J.
, and
Mareib
,
E. N.
, 2003,
A Brief Atlas of the Human Body
,
Pearson Education
,
San Francisco
.
36.
Pedley
,
T. J.
, 1980,
The Fluid Mechanics of Large Blood Vessels
,
Cambridge Univeristy Press
,
New York
.
37.
Chato
,
J. C.
, 1990,
Fundamentals of Bioheat Transfer
,
Springer-Verlag
,
New York
.
38.
Curry
,
D. M.
, 1970,
Multi-Dimensional Analysis of Heat and Mass Transfer in Porous Media
,
University of Houston
,
Houston, TX
.
39.
Whitaker
,
S.
, 1966, “
The Equations of Motion in Porous Media
,”
Chem. Eng. Sci.
0009-2509,
21
, pp.
291
300
.
40.
Batchelor
,
G. K.
, 1967,
An Introduction to Fluid Dynamics
,
Cambridge University Press
,
Cambridge, England
.
41.
Cheng
,
P.
, 1964, “
Two-Dimensional Radiating Gas Flow by a Moment Method
,”
AIAA J.
0001-1452,
2
, pp.
1662
1664
.
42.
Siegel
,
R.
, and
Howell
,
J. R.
, 1992,
Thermal Radiation Heat Transfer
,
Hemisphere
,
Washington, DC
.
43.
Issa
,
I. R.
, 1986, “
Solution of Implicitly Discretized Fluid Flow Equations by Operator Splitting
,”
J. Comput. Phys.
0021-9991,
62
, pp.
40
65
.
44.
Nield
,
D. A.
, and
Bejan
,
A.
, 1998,
Convection in Porous Media
,
Springer-Verlag
,
New York
.
45.
He
,
Y.
,
Liu
,
H.
,
Himeno
,
R.
,
Sunaga
,
J.
,
Kakusho
,
N.
, and
Yokota
,
H.
, 2008, “
Finite Element Analysis of Blood Flow and Heat Transfer in an Image-Based Human Finger
,”
Comput. Biol. Med.
0010-4825,
38
, pp.
555
562
.
46.
Agarwal
,
K.
,
Lange
,
A. C.
, and
Beck
,
H.
, 2007, “
Thermal Imaging in Healthy Humans. What is Normal Skin Temperature?
,”
InrfaMation Proceedings
, Vol.
121A
.
47.
Morgan
,
V. T.
, 1975,
The Overall Convective Heat Transfer From Smooth Circular Cylinders
,
Academic
,
New York
.
48.
Gebhart
,
B.
,
Jaluria
,
Y.
,
Mahajan
,
R. L.
, and
Sammakia
,
B.
, 1988,
Buoyancy-Induced Flows and Transport
,
Hemisphere
,
New York
.
49.
Burton
,
A. C.
, 1939, “
The Range and Variability of the Blood Flow in the Human Fingers and the Vasomotor Regulation of Body Temperature
,”
Am. J. Physiol.
0002-9513,
127
, pp.
437
453
.
50.
Krogstad
,
A. L.
,
Elam
,
M.
,
Karlsson
,
T.
, and
Wallin
,
B. G.
, 1995, “
Arteriovenous Anastomoses and the Thermoregulatory Shift Between Cutaneous Vasoconstrictor and Vasodilator Reflexes
,”
J. Auton Nerv. Syst.
0165-1838,
53
(
2–3
), pp.
215
222
.
51.
Ahmadi
,
N.
,
Hajsadeghi
,
F.
,
Gul
,
K.
,
Vane
,
J.
,
Usman
,
N.
,
Flores
,
F.
,
Nasir
,
K.
,
Hecht
,
H.
,
Naghavi
,
M.
, and
Budoff
,
M.
, 2008, “
Relations Between Digital Thermal Monitoring of Vascular Function, the Framingham Risk Score, and Coronary Artery Calcium Score
,”
Journal of Cardiovascular Computed Tomography
1934-5925,
2
, pp.
382
388
.
You do not currently have access to this content.