Pulse wave analysis and pulse wave velocity techniques: are they ready for the clinic&quest (original) (raw)
Related papers
2009
The most common method of clinical measurement of arterial blood pressure is by means of the cuff sphygmomanometer. This instrument has provided fundamental quantitative information on arterial pressure in individual subjects and in populations and facilitated estimation of cardiovascular risk related to levels of blood pressure obtained from the brachial cuff. Although the measurement is taken in a peripheral limb, the values are generally assumed to reflect the pressure throughout the arterial tree in large conduit arteries. Since the arterial pressure pulse becomes modified as it travels away from the heart towards the periphery, this is generally true for mean and diastolic pressure, but not for systolic pressure, and so pulse pressure. The relationship between central and peripheral pulse pressure depends on propagation characteristics of arteries. Hence, while the sphygmomanometer gives values of two single points on the pressure wave (systolic and diastolic pressure), there is additional information that can be obtained from the time-varying pulse waveform that enables an improved quantification of the systolic load on the heart and other central organs. This topical review will assess techniques of pressure measurement that relate to the use of the cuff sphygmomanometer and to the non-invasive registration and analysis of the peripheral and central arterial pressure waveform. Improved assessment of cardiovascular function in relation to treatment and management of high blood pressure will result from future developments in the indirect measurement of arterial blood pressure that involve the conventional cuff sphygmomanometer with the addition of information derived from the peripheral arterial pulse. R2 Topical Review analysis, transfer function, radial pulse, carotid pulse, central aortic pressure, arterial impedance, pulse wave velocity, arterial stiffness, pulse amplification, vascular haemodynamics Baumann M, Dan L, Nurnberger J, Heemann U and Witzke O 2008 Association of ambulatory arterial stiffness index and brachial pulse pressure is restricted to dippers J. Hypertens. 26 210-4 Belani K, Ozaki M, Hynson J, Hartmann T, Reyford H, Martino J M, Poliac M and Miller R 1999a A new noninvasive method to measure blood pressure: results of a multicenter trial Anesthesiology 91 686-92 Belani K G, Buckley J J and Poliac M O 1999b Accuracy of radial artery blood pressure determination with the Vasotrac Can. J. Anaesth. 46 488-96 Benetos A, Safar M, Rudnichi A, Smulyan H, Richard J L, DucimetieÃre P and Guize L 1997 Pulse pressure: a predictor of long-term cardiovascular mortality in a French male population Hypertension 30 1410-5 Birch A A and Morris S L 2003 Do the finapres and colin radial artery tonometer measure the same blood pressure changes following deflation of thigh cuffs? Physiol. Meas. 24 653-60 Blacher J, Staessen J A, Girerd X, Gasowski J, Thijs L, Liu L, Wang J G, Fagard R H and Safar M E 2000 Pulse pressure not mean pressure determines cardiovascular risk in older hypertensive patients Arch. Intern. Med. Continuous positive airway pressure treatment improves baroreflex control of heart rate during sleep in severe obstructive sleep apnea syndrome Am. J. Respir. Crit. Care. Med. 166 279-86 Borow K M and Newburger J W 1982 Noninvasive estimation of central aortic pressure using the oscillometric method for analyzing systemic artery pulsatile blood flow: comparative study of indirect systolic, diastolic, and mean brachial artery pressure with simultaneous direct ascending aortic pressure measurements Am. Heart J. 103 879-86 Bortolotto L A, Blacher J, Kondo T, Takazawa K and Safar M E 2000 Assessment of vascular aging and atherosclerosis in hypertensive subjects: second derivative of photoplethysmogram versus pulse wave velocity Am. J. Hypertens. 13 Photoplethysmographic assessment of pulse wave reflection: blunted response to endothelium-dependent beta2-adrenergic vasodilation in type II diabetes mellitus J. Am. Coll. Cardiol. 34 2007-14 Ciaccio E J and Drzewiecki G M 2008 Tonometric arterial pulse sensor with noise cancellation IEEE Trans. Biomed. Eng. 55 2388-96 Cloud G C, Rajkumar C, Kooner J, Cooke J and Bulpitt C J 2003 Estimation of central aortic pressure by SphygmoCor R requires intra-arterial peripheral pressures Clin. Sci. 105 219-25 Cohn J N 1999 Pathophysiologic and prognostic implications of measuring arterial compliance in hypertensive disease Prog. Cardiovasc. Dis. 41 441-50 Conrad W A, McQueen D M and Yellin E L 1980 Steady pressure flow relations in compressed arteries: possible origin of Korotkoff sounds Med. Biol. Eng. Comput. 18 419-26 Cook J N, DeVan A E, Schleifer J L, Anton M M, Cortez-Cooper M Y and Tanaka H 2006 Arterial compliance of rowers: implications for combined aerobic and strength training on arterial elasticity Am. J. Physiol. Heart Circ. Physiol. 290 H1596-600 Cornolo J, Fouillot J P, Schmitt L, Povea C, Robach P and Richalet J P 2006 Interactions between exposure to hypoxia and the training-induced autonomic adaptations in a 'live high-train low' session Eur. J. Appl. Physiol. 96 389-96 Cortez-Cooper M Y, Supak J A and Tanaka H 2003 A new device for automatic measurements of arterial stiffness and ankle-brachial index Am. J. Cardiol. 91 1519-22, A9 Crilly M, Coch C, Bruce M, Clark H and Williams D 2007 Indices of cardiovascular function derived from peripheral pulse wave analysis using radial applanation tonometry: a measurement repeatability study Vasc.
2008
Aortic pulse wave velocity (PWV), calculated from pulse transit time (PTT) using 2 separate pulse recordings over a known distance, is a significant biomarker of cardiovascular risk. This study evaluates a novel method of determining PTT from waveform decomposition of central aortic pressure using a single pulse measurement. Aortic pressure was estimated from a transformed radial pulse and decomposed into forward and backward waves using a triangular flow wave. Pulse transit time was determined from cross-correlation of forward and backward waves. Pulse transit time, representing twice the PTT between 2 specific sites, was compared with independent measurements of carotid-femoral PTT in a cohort of 46 subjects (23 females; age 57Ϯ14 years). Linear regression between measured PTT (y; milliseconds) and calculated PTT (x; milliseconds) was yϭ1.05xϪ2.1 (rϭ0.67; PϽ0.001). This model was tested in a separate group of 44 subjects (21 females; age 55Ϯ14 years) by comparing measured carotid-femoral PWV (y; meters per second) and PWV calculated using the estimated value of PTT (eTR/2) and carotid femoral distance (x; meters per second; yϭ1.21xϪ2.5; rϭ0.82; PϽ0.001). Findings indicate that the time lag between the forward and backward waves obtained from the decomposition of aortic pressure wave can be used to determine PWV along the aortic trunk and shows good agreement with carotid-femoral PWV. This technique can be used as a noninvasive and nonintrusive method for measurement of aortic PWV using a single pressure recording. (Hypertension. 2008;51:188-195.)
Quantification of wave reflection in the human aorta from pressure alone: a proof of principle
…, 2006
Wave reflections affect the proximal aortic pressure and flow waves and play a role in systolic hypertension. A measure of wave reflection, receiving much attention, is the augmentation index (AI), the ratio of the secondary rise in pressure and pulse pressure. AI can be limiting, because it depends not only on the magnitude of wave reflection but also on wave shapes and timing of incident and reflected waves. More accurate measures are obtainable after separation of pressure in its forward (P f ) and reflected (P b ) components. However, this calculation requires measurement of aortic flow. We explore the possibility of replacing the unknown flow by a triangular wave, with duration equal to ejection time, and peak flow at the inflection point of pressure (F tIP ) and, for a second analysis, at 30% of ejection time (F t30 ). Wave form analysis gave forward and backward pressure waves. Reflection magnitude (RM) and reflection index (RI) were defined as RMϭP b /P f and RIϭP b /(P f ϩP b ), respectively. Healthy subjects, including interventions such as exercise and Valsalva maneuvers, and patients with ischemic heart disease and failure were analyzed. RMs and RIs using F tIP and F t30 were compared with those using measured flow (F m ). Pressure and flow were recorded with high fidelity pressure and velocity sensors. Relations are: RM tIP ϭ0.82RM mf ϩ0.06 (R 2 ϭ0.79; nϭ24), RM t30 ϭ0.79RM mf ϩ0.08 (R 2 ϭ0.85; nϭ29) and RI tIP ϭ0.89RI mf ϩ0.02 (R 2 ϭ0.81; nϭ24), RI t30 ϭ0.83RI mf ϩ0.05 (R 2 ϭ0.88; nϭ29). We suggest that wave reflection can be derived from uncalibrated aortic pressure alone, even when no clear inflection point is distinguishable and AI cannot be obtained. Epidemiological studies should establish its clinical value. (Hypertension. 2006;48:1-7.) Key Words: aorta Ⅲ blood flow Ⅲ blood flow velocity Ⅲ blood pressure Ⅲ pulse
Physiological Measurement, 2010
The most common method of clinical measurement of arterial blood pressure is by means of the cuff sphygmomanometer. This instrument has provided fundamental quantitative information on arterial pressure in individual subjects and in populations and facilitated estimation of cardiovascular risk related to levels of blood pressure obtained from the brachial cuff. Although the measurement is taken in a peripheral limb, the values are generally assumed to reflect the pressure throughout the arterial tree in large conduit arteries. Since the arterial pressure pulse becomes modified as it travels away from the heart towards the periphery, this is generally true for mean and diastolic pressure, but not for systolic pressure, and so pulse pressure. The relationship between central and peripheral pulse pressure depends on propagation characteristics of arteries. Hence, while the sphygmomanometer gives values of two single points on the pressure wave (systolic and diastolic pressure), there is additional information that can be obtained from the time-varying pulse waveform that enables an improved quantification of the systolic load on the heart and other central organs. This topical review will assess techniques of pressure measurement that relate to the use of the cuff sphygmomanometer and to the non-invasive registration and analysis of the peripheral and central arterial pressure waveform. Improved assessment of cardiovascular function in relation to treatment and management of high blood pressure will result from future developments in the indirect measurement of arterial blood pressure that involve the conventional cuff sphygmomanometer with the addition of information derived from the peripheral arterial pulse. R2 Topical Review analysis, transfer function, radial pulse, carotid pulse, central aortic pressure, arterial impedance, pulse wave velocity, arterial stiffness, pulse amplification, vascular haemodynamics Baumann M, Dan L, Nurnberger J, Heemann U and Witzke O 2008 Association of ambulatory arterial stiffness index and brachial pulse pressure is restricted to dippers J. Hypertens. 26 210-4 Belani K, Ozaki M, Hynson J, Hartmann T, Reyford H, Martino J M, Poliac M and Miller R 1999a A new noninvasive method to measure blood pressure: results of a multicenter trial Anesthesiology 91 686-92 Belani K G, Buckley J J and Poliac M O 1999b Accuracy of radial artery blood pressure determination with the Vasotrac Can. J. Anaesth. 46 488-96 Benetos A, Safar M, Rudnichi A, Smulyan H, Richard J L, DucimetieÃre P and Guize L 1997 Pulse pressure: a predictor of long-term cardiovascular mortality in a French male population Hypertension 30 1410-5 Birch A A and Morris S L 2003 Do the finapres and colin radial artery tonometer measure the same blood pressure changes following deflation of thigh cuffs? Physiol. Meas. 24 653-60 Blacher J, Staessen J A, Girerd X, Gasowski J, Thijs L, Liu L, Wang J G, Fagard R H and Safar M E 2000 Pulse pressure not mean pressure determines cardiovascular risk in older hypertensive patients Arch. Intern. Med. Continuous positive airway pressure treatment improves baroreflex control of heart rate during sleep in severe obstructive sleep apnea syndrome Am. J. Respir. Crit. Care. Med. 166 279-86 Borow K M and Newburger J W 1982 Noninvasive estimation of central aortic pressure using the oscillometric method for analyzing systemic artery pulsatile blood flow: comparative study of indirect systolic, diastolic, and mean brachial artery pressure with simultaneous direct ascending aortic pressure measurements Am. Heart J. 103 879-86 Bortolotto L A, Blacher J, Kondo T, Takazawa K and Safar M E 2000 Assessment of vascular aging and atherosclerosis in hypertensive subjects: second derivative of photoplethysmogram versus pulse wave velocity Am. J. Hypertens. 13 Photoplethysmographic assessment of pulse wave reflection: blunted response to endothelium-dependent beta2-adrenergic vasodilation in type II diabetes mellitus J. Am. Coll. Cardiol. 34 2007-14 Ciaccio E J and Drzewiecki G M 2008 Tonometric arterial pulse sensor with noise cancellation IEEE Trans. Biomed. Eng. 55 2388-96 Cloud G C, Rajkumar C, Kooner J, Cooke J and Bulpitt C J 2003 Estimation of central aortic pressure by SphygmoCor R requires intra-arterial peripheral pressures Clin. Sci. 105 219-25 Cohn J N 1999 Pathophysiologic and prognostic implications of measuring arterial compliance in hypertensive disease Prog. Cardiovasc. Dis. 41 441-50 Conrad W A, McQueen D M and Yellin E L 1980 Steady pressure flow relations in compressed arteries: possible origin of Korotkoff sounds Med. Biol. Eng. Comput. 18 419-26 Cook J N, DeVan A E, Schleifer J L, Anton M M, Cortez-Cooper M Y and Tanaka H 2006 Arterial compliance of rowers: implications for combined aerobic and strength training on arterial elasticity Am. J. Physiol. Heart Circ. Physiol. 290 H1596-600 Cornolo J, Fouillot J P, Schmitt L, Povea C, Robach P and Richalet J P 2006 Interactions between exposure to hypoxia and the training-induced autonomic adaptations in a 'live high-train low' session Eur. J. Appl. Physiol. 96 389-96 Cortez-Cooper M Y, Supak J A and Tanaka H 2003 A new device for automatic measurements of arterial stiffness and ankle-brachial index Am. J. Cardiol. 91 1519-22, A9 Crilly M, Coch C, Bruce M, Clark H and Williams D 2007 Indices of cardiovascular function derived from peripheral pulse wave analysis using radial applanation tonometry: a measurement repeatability study Vasc.
Hypertension, 2008
Accurate quantification of pressure wave reflection requires separation of pressure in forward and backward components to calculate the reflection magnitude as the ratio of the amplitudes backward and forward pressure. To do so, measurement of aortic flow in addition to the pressure wave is mandatory, a limitation that can be overcome by replacing the unknown flow wave by an (uncalibrated) triangular estimate. Another extended application of this principle is the derivation of aortic pulse transit time from a single pulse recording. We verified these approximation techniques for reflection magnitude and transit time using carotid pressure and aortic flow waveforms measured noninvasively in the Asklepios Study (Ͼ2500 participants; 35 to 55 years of age). A triangular flow approximation using timing information from the measured aortic flow waveform yielded moderate agreement between reference and estimated reflection magnitude (R 2 ϭ0.55). Approximating the flow by a more physiological waveform significantly improved these results (R 2 ϭ0.74). Aortic transit time was assessed using pressure and measured or approximated flow waveforms, and results were compared with carotid-femoral transit times measured by Doppler ultrasound. Agreement between estimated and reference transit times was moderate (R 2 Ͻ0.29). Both for reflection magnitude and transit time, agreement between reference and approximated values further decreased when the approximated flow waveform was obtained using timing information from the pressure waveform. We conclude that, in our Asklepios population, results from pressure-based approximative methods to derive reflection magnitude or aortic pulse transit time differ substantially from the values obtained when using both measured pressure and flow information. (Hypertension. 2009;53:142-149.)
Quantification of Wave Reflection in the Human Aorta From Pressure Alone
Hypertension, 2006
Wave reflections affect the proximal aortic pressure and flow waves and play a role in systolic hypertension. A measure of wave reflection, receiving much attention, is the augmentation index (AI), the ratio of the secondary rise in pressure and pulse pressure. AI can be limiting, because it depends not only on the magnitude of wave reflection but also on wave shapes and timing of incident and reflected waves. More accurate measures are obtainable after separation of pressure in its forward (P f ) and reflected (P b ) components. However, this calculation requires measurement of aortic flow. We explore the possibility of replacing the unknown flow by a triangular wave, with duration equal to ejection time, and peak flow at the inflection point of pressure (F tIP ) and, for a second analysis, at 30% of ejection time (F t30 ). Wave form analysis gave forward and backward pressure waves. Reflection magnitude (RM) and reflection index (RI) were defined as RM=P b /P f and RI=P b /(P f +P...
Hypertension, 2008
Aortic pulse wave velocity (PWV), calculated from pulse transit time (PTT) using 2 separate pulse recordings over a known distance, is a significant biomarker of cardiovascular risk. This study evaluates a novel method of determining PTT from waveform decomposition of central aortic pressure using a single pulse measurement. Aortic pressure was estimated from a transformed radial pulse and decomposed into forward and backward waves using a triangular flow wave. Pulse transit time was determined from cross-correlation of forward and backward waves. Pulse transit time, representing twice the PTT between 2 specific sites, was compared with independent measurements of carotid-femoral PTT in a cohort of 46 subjects (23 females; age 57Ϯ14 years). Linear regression between measured PTT (y; milliseconds) and calculated PTT (x; milliseconds) was yϭ1.05xϪ2.1 (rϭ0.67; PϽ0.001). This model was tested in a separate group of 44 subjects (21 females; age 55Ϯ14 years) by comparing measured carotid-femoral PWV (y; meters per second) and PWV calculated using the estimated value of PTT (eTR/2) and carotid femoral distance (x; meters per second; yϭ1.21xϪ2.5; rϭ0.82; PϽ0.001). Findings indicate that the time lag between the forward and backward waves obtained from the decomposition of aortic pressure wave can be used to determine PWV along the aortic trunk and shows good agreement with carotid-femoral PWV. This technique can be used as a noninvasive and nonintrusive method for measurement of aortic PWV using a single pressure recording. (Hypertension. 2008;51:188-195.)
Pressure wave reflection assessed from the peripheral pulse: is a transfer function necessary?
…, 2003
Synthesis of the aortic pressure waveform by application of a transfer function to the radial pulse allows the estimation of aortic systolic blood pressure and aortic augmentation index, an index of pressure wave reflection derived from the early systolic component of the waveform. The accuracy of this approach for determining the aortic augmentation index has been questioned, however, and it may be possible to derive similar information without using a transfer function. We compared aortic systolic blood pressure and the aortic augmentation index obtained from carotid and radial arteries with the use of transfer functions. We examined the correlation between the aortic augmentation index and a radial augmentation index obtained without use of a transfer function. Arterial tonometry (Sphygmocor) was performed in 84 subjects including healthy volunteers (nϭ30), subjects with essential hypertension (nϭ30), and patients with coronary artery disease (nϭ24). Effects of nitroglycerine and norepinephrine on aortic and radial augmentation index were examined in 12 healthy volunteers. Values of aortic systolic pressure obtained from radial and carotid arteries by using transfer functions were in acceptable agreement (Rϭ0.98, differenceϭϪ0.9Ϯ4.6 mm Hg; meanϮSD, nϭ84), but those of aortic augmentation index differed especially in control subjects (Rϭ0.47, differ-enceϭϪ3.8Ϯ12.4%). Aortic augmentation index was, however, closely correlated with radial augmentation index (Rϭ0.96, nϭ84). Nitroglycerine and norepinephrine produced parallel changes in the aortic and radial augmentation index. Our findings question the use of a transfer function to obtain the aortic augmentation index but suggest that similar information on central pressure wave reflection can be obtained directly from the radial pulse. (Hypertension. 2003;41:1016-1020.
Artery Research, 2007
It has been recognised for nearly 200 years that the human pressure waveform changes in shape with ageing and disease. The shape of the pressure waveform has been explained in terms of two fundamental models: the Windkessel (reservoir) and wave theory. In its simplest form the Windkessel model satisfactorily explains the pressure waveform in diastole but cannot model pressure changes in systole. Wave theory satisfactorily models the pressure waveform but predicts the existence of 'self-cancelling' forward and backward waves in diastole which are difficult to explain in biological terms. We propose that a hybrid reservoire wave model better describes the pressure waveform and may enable assessment of aortic function from pressure measurements made at any large systemic artery. ª a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / a r t r e s Artery Research (2007) 1, 40e45