CARDIOTRACK
Home Professional Information Theory Publications Contact Us Order
THEORY
Pulse Contour Analysis
Cardiovascular disease (CVD) is the leading cause of death and serious illness and in 1948, the
Framingham Heart Study embarked on an ambitious project in health research. Pulse wave shape
was one of the parameters collected during the study. The tools available to the investigators
at that time precluded a detailed analysis of the waveform, but visual inspection of waveform
changes correlated with increased risk of developing CVD (Ref.1 & 20). It is only recently that
research workers from around the world have revisited this exciting observation (Ref. 2 to 5,
28, 29, 31) and in particular the research group at St Thomas hospital showed that the finger
volume pulse derived from a digital photoplethysmographic probe is directly related to the radial
and brachial artery pressure pulse (Ref. 6).
The Digital Volume Pulse (DVP)
The digital volume pulse (DVP) is recorded by measuring the transmission of infra-red light
absorbed through the finger. The amount of light is directly proportional to the volume of blood in
the finger pulp.
To minimise the occurrence of poor signals from vasoconstricted and poorly perfused subjects,
a unique control system maintains the light transmission at the optimum level to accurately
follow blood volume changes, independent of the subjects finger size to obtain an extremely
accurate and noise free signal.
How the Digital Volume Pulse (DVP) is formed?
The first part of the waveform (systolic component) is formed as a result of pressure transmission
along a direct path from the aortic root to the finger. The second part (diastolic component) is
formed by pressure transmitted from the ventricle along the aorta to the lower body where it
is reflected back along the aorta to the finger. The upper limb provides a common channel for
both the directly transmitted pressure wave and the reflected wave and, therefore, has little
influence on the contour of the DVP.
Indices derived from the Digital Volume Pulse (DVP)
The height of the diastolic component of the DVP relates to the amount of pressure wave
reflection. This in turn relates mainly to the tone of small arteries.
The timing of the diastolic component relative to the systolic component depends on the pulse
wave velocity (PWV) of pressure waves in the aorta and large arteries. This in turn depends upon
large artery stiffness.
Indices derived from the Digital Volume Pulse (DVP)
Reflection Index
of the systolic peak and is a measure of the amount of pulse wave reflection and the tone of
small arteries:
The Stiffness Index SI is an estimate of pulse wave velocity in large arteries and is obtained
from subject height divided by the time between the systolic and diastolic peaks of the DVP.
It is a measure of large artery stiffness
The Digital Volume Pulse (DVP) is 'the same' as the pressure pulse in the wrist
It has been known for some time that the peripheral pressure pulse contains information on
arterial stiffness and vascular tone and that increased arterial stiffness correlates with increased
risk of a major cardiovascular event (Ref. 5 and 7, 8, 22, 23, 26, 28, 29, 30 and 32). The specific
validation of Pulse Trace was done at St Thomas' Hospital and has been published (Ref.3, 6 and
9 ). These papers demonstrated: A simple linear relationship between the shape of the Digital
Volume Pulse and that of the peripheral pressure pulse, which remains constant irrespective of
the effects of hypertension or effects of vasodilatation produced by NTG and that the Stiffness
Index (SI) parameter correlates with PWV the gold standard for arterial stiffness (see below).
It is stable, simple, easy to use device with a low Coefficient of Variation
In comparison to other methods to measure arterial stiffness and vascular tone Pulse Trace is
the only one that is operator independent with a Coefficient of Variation equivalent or better
than the other established techniques. This has been demonstrated in a number of independent
studies (Ref. 9 to 11)
The Stiffness Index (SI) parameter correlates with the 'gold
standard' measurement for arterial stiffness PWVcf
The Stiffness Index (SI) is calculated from the time it takes the reflected pressure wave to
travel from the lower body back to the finger divided into the subject's height. Whilst many
factors influence the volume pulse contour, arterial stiffness is the dominant factor. This
was clearly demonstrated in a comparison of the 'gold' standard method of measuring arterial
stiffness using the PWV (carotid - femoral) with the Pulse Trace SI parameter (Ref. 9 and 3).
This paper and others show that SI is a measure of arterial stiffness. The link between arterial
stiffness and the risk of a major cardiovascular event is well established and SI can be used to
measure and monitor arterial stiffness in a simple, non-operator dependant, and reproducible manner.
The Reflection Index (RI) parameter measures vessel tone and can be
used to assess endothelial function.
The Reflection Index (RI) is calculated as the % ratio of the height of the diastolic notch to
the peak pulse height. In numerous studies it has been shown to correlate with vascular tone
(large vessel diameter) and can be used as a bases for a non invasive test for endothelial function
(Ref. 3, and 11 to 14, 24 ,25, 27)and in other studies where the disease process or drug action
is known to modify vascular tone e.g. PIH (Ref. 15)
Bibliography
1 Kannel WB, Dawber TR, McGee DL Perspectives on systolic hypertension. The Framingham study.Circulation 1980
Jun 61:1179-1182
2 Takazawa K, Tanaka N, Fujita M, Matsuoka O, Saiki T, Aikawa M, Tamura S, Ibukiyama CAssessment of vasoactive
agents and vascular aging by the second derivative of photoplethysmogram waveform Hypertension 1998 Aug 32:365-70
3 Chowienczyk PJ, Kelly RP, MacCallum H, Millasseau SC, Andersson TLG, Gosling RG, Ritter JM, Änggård EE.
Photoplethysmographic assessment of pulse wave reflection. Blunted response to endothelium-dependent
beta2-adrenergic vasodilation in type II diabetes mellitus. J Am Coll Cardiol 1999; 34: 2007-2014.
4 Iketani T, Iketani Y, Takazawa K, Yamashina A The influence of the peripheral reflection wave on left ventricular
hypertrophy in patients with essential hypertension. Hypertens Res 2000 Sep 23:451-8
5 John R Cockcroft and Ian B Wilkinson Arterial stiffness and pulse contour analysis: an age old concept revisited
Clinical Science (2002) 103, 379-380
6 Millasseau SC, Guigui FG, Kelly RP, Prasad K, Cockcroft JR, Ritter JM, Chowienczyk PJ. Non-invasive assessment
of the digital volume pulse: comparison with the peripheral pressure pulse. Hypertension 2000; 36:952-956
7 Pierre Boutouyrie, Anne Isabelle Tropeano, Roland Asmar, Isabelle Gautier, Athanase Benetos,
Patrick Lacolley, Stephane Laurent Aortic Stiffness Is an Independent Predictor of Primary Coronary Events in
Hypertensive Patients. A Longitudinal Study Hypertension. 2002;39:10-15.
8 Alain P. Guerin, MD; Jacques Blacher, MD, PhD; Bruno Pannier, MD; Sylvain J. Marchais, MD; Michel E. Safar,
MD; Gerard M. London, MDImpact of Aortic Stiffness Attenuation on Survival of Patients in End-Stage Renal
Failure Circulation. 2001;103:987-992.
9 Millasseau
stiffness by digital pulse contour analysis Clinical Science (2002) 103, 371-377
10 R.J. Woodman, G.F. Watts, B.A. Kingwell, L.J. Beilin1, S.E. Hamilton, A.M. DartTechnical Comparison of Methods
for Measuring Arterial Compliance Poster presentation, 73rd EAS 2002
11 Aleksandras Laucevicius, Ligita Ryliskyte, Zaneta Petruioniene, Milda Kovaite, Nerijus MisonisFirst Experience With
Salbutomol - Induced Changes In The Photoplethysmogaphic Digital Volume Pulse Seminars in Cardiology. 2002;
8(1):87-93
12 Gopaul N.K, Manraj M.D, Hebe A, Lee Kwai,Yan S, Johnston A, Carrier,M.J, Änggård EE. Oxidative stress could
precede endothelial dysfunction and insulin resistance in Indian Mauritians with impaired glucose metabolism.
Diabetologia; 2001; 44: 706-712.
13 Beeton I, Leatham E. Bedside digital plethysmography detects endothelial dysfunction in recent onset angina.
Eur Heart J 2001; 22: 170-170 Suppl. S (Abstract).
14 Wilkinson IB, Hall IR, MacCallum H, Mackenzie IS, McEniery CM, van der Arend BJ, ShuYE, MacKay LS, Webb
DJ, Cockcroft JR. Pulse-wave analysis: clinical evaluation of a noninvasive, widely applicable method for
assessing endothelial function. Arterioscler Thromb Vasc Biol 2002; 22: 147-152.
15 Melson LC, Millasseau SC, Chowienczyk PJ, Poston L, Shennan A Rapid non-invasive analysis of vascular
function in pre-eclampsia Hypertension in Pregnancy Journal 2000 Vol 19 Sup 1
16 Millasseau SCComparison of central aortic augmentation index obtained from radial and carotid tonometry
Presented at the BHS 2002
17 R.J. Woodman, G.F. Watts, B.A. Kingwell, L.J. Beilin, S.E. Hamilton, A.M. Dart Comparison of central
pulse pressure and augmentation index derived from analyses of carotid and radial artery waveforms Presented
at the 73rd EASC, Salzburg 2002
18 Michael F. O'Rourke, Alfredo Pauca & Xiong-Jing JiangPulse wave analysis Br J Clin Pharmacol, 51, 507± 522
19 Glasser, S. P., Arnett, D. K., McVeigh, G. E., Finkelstein, S. M., Bank, A. J., Morgan, D. J. and Cohn, J. N. Vascular
compliance and cardiovascular disease: a risk factor or a marker? Am. J. Hypertens. 1997, 10, 1175±1189
20 Thomas R. Dawber, H. Emerson Thomas Jr, Patricia M. Mcnamara Characteristics of the dicrotic notch of the arterial
pulse wave in coronary heart disease Angiology 1973, Vol 24, p 244-255
21 R.P. Kelly, S.C. Millasseau, J.M. Ritter, P.J. Chowienczyk Vasoactive Drugs Influence Aortic Augmentation Index
Independently of Pulse-Wave Velocity in Healthy Men Hypertension. 2001;37:1429-1433.
22 Cruickshank K, Riste L, Anderson SG et al. Aortic pulse-wave velocity and its relationship to mortality in
diabetes and glucose intolerance: an integrated index of vascular function? Circulation.2002;106:2085-2090.
23 Meaume S, Benetos A, Henry OF et al. Aortic pulse wave velocity predicts cardiovascular mortality in subjects
>70 years of age. Arterioscler Thromb Vasc Biol. 2001;21:2046-2050.
24 Lind L, Pettersson K, Johansson K. Analysis of endothelium-dependent vasodilation by use of the radial
artery pulse wave obtained by applanation tonometry.Clin Physiol & Func Im, 2003; 23:50–57
25 Hayward CS, Kraidly M, Webb CM, Collins P. Assessment of Endothelial Function Using Peripheral Waveform
Analysis. J Am Coll Cardiol 2002; 40:521-528
26 Stefanadis C, Dernellis J, Tsiamis E et al. Aortic stiffness as a risk factor for recurrent acute coronary events
in patients with ischaemic heart disease. Eur Heart J. 2000;21:390-396.
27 D. Darko, A. Dornhorst, F. J. Kelly, J. M. Ritters and P. J. Chowienczyk Lack of effect of oral vitamin C on
blood pressure, oxidative stress and endothelialfunction in Type II diabetes Clinical Science (2002) 103, 339–344
28 Yamashina A, Tomiyama H, Takeda K, et al. Validity, Reproducibility, and Clinical Significance of Noninvasive
Brachial-Ankle Pulse Wave Velocity Measurement. Hypertension Res.2002, Vol. 25. No. 3 ;359-364
29 Suzuki E, Kashiwagi A, Nishio A et al. Increased Arterial Wall Stiffness Limits Flow Volume in the Lower
Extremities in Type 2 Diabetic Patients.Diabetic Care 2001, Vol. 24, No. 12 2107-2114.
30 Laurent S, Boutouyrie P, Asmar R et al. Aortic stiffness is an independent predictor of all-cause and cardiovascular
mortality in hypertensive patients. Hypertension. 2001;37:1236-1241
31 Roland Asmar. Efect of Antihypertensive Agents on Arterial Stiffness as evaluated by Pulse Wace
Velocity – Clinical Implications.Am. J. Cardiovasc. Drugs 2001:1 (5) 387-397
32 J Amar. JB Ruidavets, B Chamontin et al. Arterial stiffness and cardiovascular risk factors in a population-based
study. Journal of Hypertension 2001, Vol 19 No 3 381-387
33 Bramwell JC, Hill AV. The velocity of the pulse wave in man. Proceedings of the Royal Society, London, Ser B.
1922;93:298-306.
34 Moens AI. Die Pulskurve. Leiden ed. 1878.
35 Korteweg DJ. Über die Fortpflanzungsgesschwindigkeit des Schalles in elastischen Rohren. Annals of Physics and
Chemistry (NS). 1878;5:520-537.
36 O’Rourke MF, Staessen JA, Vlachopoulos C, et al. Clinical Applications of Arterial Stiffness; Definitions and Reference
Values. Am. Journal of Hypert. 2002; 5; 426-444
37 Hallock P. Arterial elasticity in man in relation to age as evaluated by the pulse wave velocity method.
Arch Inter Med. 1934;54:770-798.
38 Haynes F, Ellis LB, Weiss S. Pulse wave velocity and arterial elasticity in arterial hypertension, arteriosclerosis
and related conditions. Am Heart J. 1936;11:385-401.
39 Avolio AP, Chen S-G, Wang R-P et al. Effects of aging on changing arterial compliance and left ventricular load
in a northern Chinese urban community. Circulation. 1983;68:50-58.
40 Avolio AP, Fa-Quan D, Wei-Qiang L et al. Effects of aging on arterial distensibility in populations with high and
low prevelance of hypertension: comparison between urban and rural communities in China. Circulation. 1985;71:202-210.
41 Asmar R. Arterial Stiffness and Pulse Wave Velocity: clinical applications. Elsevier, 1999.