| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
(Hypertension. 2004;43:1239.)
© 2004 American Heart Association, Inc.
Scientific Contributions |
From Cardiovascular Engineering, Inc (G.F.M.), Holliston, Mass; the Department of Mathematics and Statistics (H.P.), Evans Department of Medicine (E.J.B., J.A.V., R.S.V.), Whitaker Cardiovascular Institute (E.J.B., J.A.V., R.S.V.), and Section of Preventive Medicine (E.J.B., M.G.L., R.S.V.), Boston University School of Medicine, Mass; and the National Heart, Lung, and Blood Institutes Framingham Study (E.J.B., M.G.L., M.J.K., R.S.V., D.L.), Framingham, Mass.
Correspondence to Gary F. Mitchell, MD, Cardiovascular Engineering, Inc, 327 Fiske St, Holliston, MA 01746. E-mail GaryFMitchell{at}mindspring.com
| Abstract |
|---|
|
|
|---|
Key Words: aging aorta arteries arteriosclerosis elasticity elderly vasculature
| Introduction |
|---|
|
|
|---|
Pressure wave reflection in the arterial system serves 2 beneficial purposes. When normally timed, the reflected wave returns to the central aorta in diastole and therefore enhances diastolic perfusion pressure in the coronary circulation.9 Partial wave reflection also returns a portion of the pulsatile energy content of the wave form to the central aorta where it is dissipated by viscous damping. Thus, wave reflection limits transmission of pulsatile energy into the periphery where it might otherwise damage the microcirculation.10 Loss of this apparently protective function of wave reflection could contribute to the pathogenesis of a growing spectrum of cardiovascular and noncardiovascular accompaniments of aging that share a potential microvascular etiology,11 including white matter lesions of the brain12 and renal dysfunction.13,14
In the normal arterial system, there is a steep gradient of increasing arterial stiffness moving outward from the heart. In a young adult, pulse wave velocity (PWV), a close correlate of arterial wall stiffness, is only 4 to 6 m/s in the highly compliant proximal aorta and increases to 8 to 10 m/s in the stiffer peripheral muscular arteries. This progressive increase in regional arterial stiffness, together with branching and narrowing of the lumen, creates an impedance mismatch and leads to a partial reflection of the advancing pressure wave.15,16 Prior studies have shown that central arterial stiffness increases to a far greater extent than peripheral arterial stiffness with advancing age.1719 As a result, aortic stiffness may equal or exceed peripheral arterial stiffness in the elderly. This reversal of the normal arterial stiffness gradient may diminish wave reflections and therefore increase transmission of pulsatile energy into the periphery and microcirculation.
To test these hypotheses, we designed the present study to evaluate changes in central and peripheral arterial stiffness and wave reflection with advancing age in a healthy subset of the community-based Framingham Heart Study.
| Methods |
|---|
|
|
|---|
140 mm Hg, diastolic blood pressure [DBP]
90 mm Hg, or drug treatment for hypertension, n=1233), diabetes (defined as a fasting blood glucose
126 mg/dL or treatment with insulin or an oral hypoglycemic agent, n=359), treatment for dyslipidemia (n=548), cardiovascular disease (coronary heart disease, congestive heart failure, stroke, transient ischemic attack, or intermittent claudication, n=366), current smoking (defined as smoking within the 12 months before the index examination, n=354), or obesity (defined as a body mass index [BMI]
30 kg/m2, n=784). Of the remaining 667 eligible individuals, optimal tonometry at all 4 pulse sites (brachial, radial, femora,l and carotid) and results of a submaximal walk test were available in 188 men and 333 women.
Noninvasive Hemodynamic Data Acquisition
Participants were studied in the supine position after approximately 5 minutes of rest. Supine brachial SBP and DBP were obtained using an oscillometric device. Arterial tonometry with simultaneous ECG was obtained from brachial, radial, femoral, and carotid arteries using a commercially available tonometer (SPT-301, Millar Instruments, Houston, Tex). Transit distances were assessed by body surface measurements from the suprasternal notch to each pulse-recording site. Tonometry and ECG data were digitized during the primary acquisition (1000 Hz), transferred to CD-ROMs, and shipped to the core laboratory (Cardiovascular Engineering, Inc, Holliston, Mass) for analysis blinded to all clinical data.
Tonometry Data Analysis
Tonometry waveforms were signal-averaged using the ECG R-wave as a fiducial point.21 Average systolic and diastolic cuff pressures were used to calibrate the peak and trough of the signal-averaged brachial pressure waveform. Diastolic and integrated mean brachial pressures were then used to calibrate carotid, radial, and femoral pressure tracings.22 Calibrated carotid pressure was used as a surrogate for central pressure.22 Carotid-brachial pulse wave velocity (CBPWV) and CFPWV were calculated from tonometry waveforms and body surface measurements as previously described.23 Systolic ejection period (SEP) was measured from the foot of the carotid pressure waveform to the dicrotic notch (Figure 1). Reflected wave transit time (RWTT) was measured from the foot of the carotid pressure waveform to the first inflection point, which corresponds to the foot of the global reflected pressure wave (Figure 1).24 The effective reflecting distance (ERD) was calculated from RWTT and CFPWV: ERD=(RWTTxCFPWV)/2.24 Effective reflecting distance calculated in this manner correlates well with values obtained from impedance spectra.9 Augmentation index was calculated as previously described.24 The central forward wave amplitude was defined as the difference between pressure at the waveform foot and pressure at the first systolic inflection point or peak of the carotid pressure waveform (Figure 1). Reflected wave pressure was defined as the difference between central systolic pressure and pressure at the forward wave peak (Figure 1).
|
We evaluated analysis reproducibility of key tonometry measures in a random sample of 50 cases that were blindly reanalyzed by a second observer. Correlation coefficients for key variables were: CFPWV, r=0.972; RWTT, r=0.968; augmentation index, r=0.997; and SEP, r=0.999.
Statistical Analysis
Baseline characteristics and tonometry variables were tabulated separately for men and women. Correlations between tonometry variables and blood pressure, heart rate, anthropometric and metabolic variables were calculated. Multivariable correlates25 of tonometry variables were assessed using sex-pooled stepwise regression analysis that always included terms for sex, age, and age-squared. Regression was performed using the SAS REG procedure with a P
0.10 inclusion criterion.26 For age and mean arterial pressure (MAP), linear and quadratic terms were used together as a paired variable to evaluate potential nonlinearity in these relations. The quadratic terms were centered to minimize collinearity. Participants also underwent a submaximal walk test either before or after the tonometry evaluation. A walk test status variable (before versus after tonometry) was also offered as a covariate. Values are presented as mean±SD except as noted. There was no adjustment for multiple testing. A 2-sided P<0.05 was considered significant.
| Results |
|---|
|
|
|---|
|
|
|
Correlations of key tonometry variables with anthropometric (height, weight, and BMI) and metabolic (total/HDL cholesterol ratio, triglycerides, and glucose) variables were also assessed. Despite exclusion of individuals with diabetes, hyperglycemia, or treated dyslipidemia, CFPWV was related to total/HDL cholesterol ratio (r=0.242 in women, r=0.126 in men), triglycerides (r=0.244 in women, r=0.260 in men), and fasting glucose (r=0.172 in women, r=0.204 in men). All values P<0.05 except total/HDL cholesterol ratio in men.
We performed stepwise regression analyses with key tonometry variables as dependent variables and with age, age-squared, sex, heart rate, MAP, MAP-squared, height, weight, body mass index, total/HDL cholesterol ratio, triglycerides, glucose, and walk test timing as potential covariates (Table 4). There was a strong, nonlinear increase in CFPWV with advancing age, as indicated by the significant age and age-squared terms (Table 4). Higher MAP, heart rate and triglycerides, and walk test before tonometry were associated with higher CFPWV. The model for CBPWV was similar, although the increase in CBPWV with age was markedly attenuated (Table 4). Forward wave amplitude was related to increasing age and MAP and was higher in women. Reflected wave pressure was higher in women than men, increased with age and MAP, and decreased with increasing heart rate and height. The model for augmentation index resembled the model for reflected wave pressure although there was a highly significant age-squared term indicating a convex upward relation (Table 4).
|
The relations of age to arterial stiffness measures in this healthy cohort are presented in Figures 2 and 3. CFPWV increased with advancing age, whereas CBPWV did not differ in these unadjusted analyses (Figure 2). The initial increase in CFPWV with age (<60 years), at a time when CFPWV was less than CBPWV, was accompanied by a reciprocal decrease in RWTT, no change in the location of major reflecting sites, as assessed by ERD (Figure 2), and an increase in augmentation index (Figure 3). However, after age 60 years, CFPWV equaled and then exceeded CBPWV. Further reductions in RWTT were attenuated and reflecting sites shifted to more distal locations (increased ERD, Figure 2). Forward wave amplitude continued to increase, whereas the relative amplitude of the reflected wave (augmentation index) reached a maximum (in men) or fell (in women), even though reflected wave timing remained premature (Figure 3).
|
|
| Discussion |
|---|
|
|
|---|
As in prior studies,17,18 we found regional heterogeneity in arterial stiffening with advancing age in our cohort. The marked increase in aortic stiffness with age with little change in peripheral arterial stiffness resulted in a reversal of the gradient of arterial stiffness from the youthful pattern of a compliant proximal aorta, which was evident in individuals aged <50 years, to a pattern of greater aortic stiffness in older participants. This transition to higher central as compared with peripheral arterial stiffness was marked by a turning point in the absolute and relative amplitude of the reflected pressure wave. These changes in wave reflection with advancing age are consistent with the hypothesis that a marked increase in CFPWV with little change in CBPWV leads to impedance matching between central aorta and proximal muscular arteries, which reduces proximal wave reflection and shifts reflecting sites distally.
These data provide new insights into the variable mechanisms of age-related loss of peripheral pressure amplification, which has been shown to portend an adverse clinical outcome.27 In young adults with a reflected pressure wave arriving centrally during diastole, pulse pressure is substantially higher in the periphery as compared with the central aorta.28 This amplification of the pressure waveform as it propagates distally represents the dual effects of progressive stiffening of vessels with increasing distance from the heart and relatively earlier timing of local reflections as the advancing wave approaches reflecting sites.15 In middle-age, increasing pulse wave velocity leads to premature return of the reflected pressure wave to the central aorta during systole, which augments central systolic and pulse pressure and reduces peripheral amplification.29 Finally, in the elderly, we have shown that central arterial stiffness exceeds peripheral arterial stiffness. This loss of the normal arterial stiffness gradient may reduce amplification and reflection and increase transmission of a larger potentially harmful forward pressure wave into the microcirculation.
Prior studies evaluated changes in pressure waveform morphology and pulse wave velocity with advancing age and demonstrated that central aortic stiffness increases with advancing age even in relatively healthy individuals.7,8,10,29,30 The present study, however, is the first to describe the changes in wave reflection and pulse waveform morphology that follow from these differential changes in regional arterial properties. It is important to note that we measured arterial stiffness in the arms but not in the legs. However, prior studies have shown a similar pattern of minimal stiffening with advancing age in the legs.17,18 We modeled wave reflections as though they arose from a single "effective" reflecting site. Actually, there are innumerable reflecting sites that produce a summated reflected wave that appears to arise from a single "effective" reflecting site (Figure 1).
We found several additional correlates of wave reflection, including a prominent sex difference and relations with height and heart rate, which have been observed in prior studies.3134 The reductions in reflected wave amplitude and augmentation index with increasing heart rate in the multivariable models are consistent with a shorter SEP at higher heart rate resulting in less overlap between forward and reflected waves. Women had larger reflected waves than men, in part due to shorter height and closer physical proximity between heart and reflecting sites. However, height was not sufficient to fully explain higher reflected wave pressure in women in multivariable analyses (Table 4), which is consistent with findings of a prior study of elderly men and women who were matched for height.33 Thus, there are unexplained differences in arterial structure or function between men and women that lead to increased wave reflection in women.
We found significant correlations between heart rate and several tonometry variables, including positive relationships with CFPWV and CBPWV and negative relationships with reflected wave pressure and augmentation index as described above. Increased heart rate may be an indicator of increased sympathetic tone, which may increase the stiffness of large arteries directly.35 Alternatively, increased large artery stiffness is associated with reduced baroreceptor sensitivity, which could alter sympathetic tone and heart rate.36,37 Chronically elevated heart rate may increase large artery stiffness by accelerating elastin breakdown in the arterial wall38 or because wall stiffness is modestly frequency dependent.39 In paced animal models, increased heart rate was shown to increase stiffness of large elastic arteries while having a variable effect on muscular arteries.40,41 We also found that the heart rate-PWV relationship was steeper for CFPWV, which encompasses a substantial segment of elastic aorta, as compared with CBPWV, which encompasses predominantly muscular arteries.42 Although the mechanism remains incompletely defined, there is clearly a modest relationship between heart rate and PWV that should be considered when interpreting PWV values.
There are limitations to our study that should be considered. To determine systolic and diastolic pressure for calibration of tonometry data, we used an oscillometric blood pressure device, which may have introduced calibration errors. However, it is important to note that many of the measures that we have reported, such as regional pulse wave velocities, timing of wave reflection, and augmentation index are independent of pressure calibration. Furthermore, the pattern of relative change in forward versus reflected wave is not affected by calibration errors because the effects on forward and reflected waves are proportional. We estimated forward wave amplitude from the carotid pressure waveform without measuring the corresponding aortic flow, which is needed to separate forward and reflected waves. To test the validity of this approach, we analyzed pressure and flow data from a previously reported cohort43 and found that forward wave amplitude estimated from the carotid pressure waveform alone provided a robust estimate of forward wave amplitude estimated from carotid pressure and aortic flow (n=158, R=0.879, P<0.001).
Perspectives
We have shown that in a healthy, community-based sample of middle-aged and elderly individuals with no known cardiovascular disease and a low burden of conventional cardiovascular disease risk factors, aortic stiffness increases dramatically with advancing age. Our findings are consistent with the hypothesis that changes in central aortic stiffness and forward wave amplitude, rather than wave reflection, are responsible for most of the increase in pulse pressure in the elderly. In contrast, the stiffness of second and third generation muscular arteries increases minimally with age, leading to reversal of the normal central-to-peripheral arterial stiffness gradient, a shift of reflecting sites to more distal locations and a reduction in relative amplitude of the reflected pressure wave. Increased forward transmission of a larger forward wave may expose the peripheral small arteries and microvessels to damaging levels of pressure pulsatility and may contribute to an emerging spectrum of microvascular disorders that are common in the elderly.
| Acknowledgments |
|---|
Received December 16, 2003; first decision January 9, 2004; accepted April 6, 2004.
| References |
|---|
|
|
|---|
2. Chae CU, Pfeffer MA, Glynn RJ, Mitchell GF, Taylor JO, Hennekens CH. Increased pulse pressure and risk of heart failure in the elderly. JAMA. 1999; 281: 634639.
3. Franklin SS, Khan SA, Wong ND, Larson MG, Levy D. Is pulse pressure useful in predicting risk for coronary heart disease? The Framingham heart study. Circulation. 1999; 100: 354360.
4. Domanski M, Norman J, Wolz M, Mitchell G, Pfeffer M. Cardiovascular risk assessment using pulse pressure in the first national health and nutrition examination survey (NHANES I). Hypertension. 2001; 38: 793797.
5. Laurent S, Boutouyrie P, Asmar R, Gautier I, Laloux B, Guize L, Ducimetiere P, Benetos A. Aortic stiffness is an independent predictor of all-cause and cardiovascular mortality in hypertensive patients. Hypertension. 2001; 37: 12361241.
6. Meaume S, Benetos A, Henry OF, Rudnichi A, Safar ME. Aortic pulse wave velocity predicts cardiovascular mortality in subjects >70 years of age. Arterioscler Thromb Vasc Biol. 2001; 21: 20462050.
7. Avolio AP, Deng FQ, Li WQ, Luo YF, Huang ZD, Xing LF, ORourke MF. Effects of aging on arterial distensibility in populations with high and low prevalence of hypertension: comparison between urban and rural communities in China. Circulation. 1985; 71: 202210.
8. Vaitkevicius PV, Fleg JL, Engel JH, OConnor FC, Wright JG, Lakatta LE, Yin FC, Lakatta EG. Effects of age and aerobic capacity on arterial stiffness in healthy adults. Circulation. 1993; 88: 14561462.
9. Nichols WW, ORourke MF. Chapter 9. Wave Reflections. In: McDonalds Blood Flow in Arteries: Theoretical, Experimental and Clinical Principles. London: Arnold, 1998: 203222.
10. Safar ME, Levy BI, Struijker-Boudier H. Current perspectives on arterial stiffness and pulse pressure in hypertension and cardiovascular diseases. Circulation. 2003; 107: 28642869.
11. Rizzoni D, Porteri E, Boari GE, De Ciuceis C, Sleiman I, Muiesan ML, Castellano M, Miclini M, Agabiti-Rosei E. Prognostic significance of small-artery structure in hypertension. Circulation. 2003; 108: 22302235.
12. Liao D, Cooper L, Cai J, Toole J, Bryan N, Burke G, Shahar E, Nieto J, Mosley T, Heiss G. The prevalence and severity of white matter lesions, their relationship with age, ethnicity, gender, and cardiovascular disease risk factors: the ARIC Study. Neuroepidemiology. 1997; 16: 149162.[Medline] [Order article via Infotrieve]
13. Safar ME, London GM, Plante GE. Arterial stiffness and kidney function. Hypertension. 2004; 43: 163168.
14. Mitchell GF. Increased aortic stiffness: an unfavorable cardiorenal connection. Hypertension. 2004; 43: 151153.
15. Taylor MG. Wave-travel in a non-uniform transmission line, in relation to pulses in arteries. Phys Med Biol. 1965; 539550.
16. London GM, Asmar RG, ORourke MF, Safar ME. Mechanism(s) of selective systolic blood pressure reduction after a low-dose combination of perindopril/indapamide in hypertensive subjects: comparison with atenolol. J Am Coll Cardiol. 2004; 43: 9299.
17. Boutouyrie P, Laurent S, Benetos A, Girerd XJ, Hoeks AP, Safar ME. Opposing effects of ageing on distal and proximal large arteries in hypertensives. J Hypertens Suppl. 1992; 10: S87S91.[CrossRef][Medline] [Order article via Infotrieve]
18. Benetos A, Laurent S, Hoeks AP, Boutouyrie PH, Safar ME. Arterial alterations with aging and high blood pressure. A noninvasive study of carotid and femoral arteries. Arterioscler Thromb. 1993; 13: 9097.
19. van der Heijden-Spek JJ, Staessen JA, Fagard RH, Hoeks AP, Boudier HA, van Bortel LM. Effect of age on brachial artery wall properties differs from the aorta and is gender dependent: a population study. Hypertension. 2000; 35: 637642.
20. Kannel WB, Feinleib M, McNamara PM, Garrison RJ, Castelli WP. An investigation of coronary heart disease in families. The Framingham offspring study. Am J Epidemiol. 1979; 110: 281290.
21. Mitchell GF, Pfeffer MA, Westerhof N, Pfeffer JM. Measurement of aortic input impedance in rats. Am J Physiol. 1994; 267: H1907H1915.[Medline] [Order article via Infotrieve]
22. Kelly R, Fitchett D. Noninvasive determination of aortic input impedance and external left ventricular power output: a validation and repeatability study of a new technique. J Am Coll Cardiol. 1992; 20: 952963.[Abstract]
23. Mitchell GF, Izzo JL, Jr., Lacourciere Y, Ouellet JP, Neutel J, Qian C, Kerwin LJ, Block AJ, Pfeffer MA. Omapatrilat reduces pulse pressure and proximal aortic stiffness in patients with systolic hypertension: results of the conduit hemodynamics of omapatrilat international research study. Circulation. 2002; 105: 29552961.
24. Murgo JP, Westerhof N, Giolma JP, Altobelli SA. Aortic input impedance in normal man: relationship to pressure wave forms. Circulation. 1980; 62: 105116.
25. Kleinbaum DG, Kupper LL, Muller KE. Applied Regression Analysis and Other Multivariable Methods. Second edition. Boston: PWS-Kent Publishing Company, 1988: 718.
26. SAS Institute Inc. SAS/STAT Users Guide, Version 8. Cary, NC: SAS Institute Inc, 1999.
27. Safar ME, Blacher J, Pannier B, Guerin AP, Marchais SJ, Guyonvarch PM, London GM. Central pulse pressure and mortality in end-stage renal disease. Hypertension. 2002; 39: 735738.
28. ORourke MF, Blazek JV, Morreels CL, Jr, Krovetz LJ. Pressure wave transmission along the human aorta. Changes with age and in arterial degenerative disease. Circ Res. 1968; 23: 567579.
29. Kelly R, Hayward C, Avolio A, ORourke M. Noninvasive determination of age-related changes in the human arterial pulse. Circulation. 1989; 80: 16521659.
30. Lakatta EG, Levy D. Arterial and cardiac aging: major shareholders in cardiovascular disease enterprises: Part I: aging arteries: a "set up" for vascular disease. Circulation. 2003; 107: 139146.
31. Hayward CS, Kelly RP. Gender-related differences in the central arterial pressure waveform. J Am Coll Cardiol. 1997; 30: 18631871.[Abstract]
32. Smulyan H, Asmar RG, Rudnicki A, London GM, Safar ME. Comparative effects of aging in men and women on the properties of the arterial tree. J Am Coll Cardiol. 2001; 37: 13741380.
33. Gatzka CD, Kingwell BA, Cameron JD, Berry KL, Liang YL, Dewar EM, Reid CM, Jennings GL, Dart AM. Gender differences in the timing of arterial wave reflection beyond differences in body height. J Hypertens. 2001; 19: 21972203.[CrossRef][Medline] [Order article via Infotrieve]
34. Gatzka CD, Cameron JD, Dart AM, Berry KL, Kingwell BA, Dewar EM, Reid CM, Jennings GL. Correction of carotid augmentation index for heart rate in elderly essential hypertensives. ANBP2 Investigators. Australian Comparative Outcome Trial of Angiotensin-Converting Enzyme Inhibitor- and Diuretic-Based Treatment of Hypertension in the Elderly. Am J Hypertens. 2001; 14: 573577.[CrossRef][Medline] [Order article via Infotrieve]
35. Mahmud A, Feely J. Acute effect of caffeine on arterial stiffness and aortic pressure waveform. Hypertension. 2001; 38: 227231.
36. Kingwell BA, Cameron JD, Gillies KJ, Jennings GL, Dart AM. Arterial compliance may influence baroreflex function in athletes and hypertensives. Am J Physiol. 1995; 268: H411H418.[Medline] [Order article via Infotrieve]
37. Monahan KD, Tanaka H, Dinenno FA, Seals DR. Central arterial compliance is associated with age- and habitual exercise-related differences in cardiovagal baroreflex sensitivity. Circulation. 2001; 104: 16271632.
38. Avolio A, Jones D, Tafazzoli-Shadpour M. Quantification of alterations in structure and function of elastin in the arterial media. Hypertension. 1998; 32: 170175.
39. Lantelme P, Mestre C, Lievre M, Gressard A, Milon H. Heart rate: an important confounder of pulse wave velocity assessment. Hypertension. 2002; 39: 10831087.
40. Mangoni AA, Mircoli L, Giannattasio C, Ferrari AU, Mancia G. Heart rate-dependence of arterial distensibility in vivo. J Hypertens. 1996; 14: 897901.[CrossRef][Medline] [Order article via Infotrieve]
41. Mircoli L, Mangoni AA, Giannattasio C, Mancia G, Ferrari AU. Heart rate-dependent stiffening of large arteries in intact and sympathectomized rats. Hypertension. 1999; 34: 598602.
42. Sa Cunha R, Pannier B, Benetos A, Siche JP, London GM, Mallion JM, Safar ME. Association between test high heart rate and high arterial rigidity in normotensive and hypertensive subjects. J Hypertens. 1997; 15: 14231430.[CrossRef][Medline] [Order article via Infotrieve]
43. Mitchell GF, Lacourciere Y, Ouellet JP, Izzo JL, Jr., Neutel J, Kerwin LJ, Block AJ, Pfeffer MA. Determinants of elevated pulse pressure in middle-aged and older subjects with uncomplicated systolic hypertension: the role of proximal aortic diameter and the aortic pressure-flow relationship. Circulation. 2003; 108: 15921598.
This article has been cited by other articles:
![]() |
F. Fantin, C. J. Bulpitt, S. Bonapace, J. D. Cameron, and C. Rajkumar Is vascular stiffness associated with the diameter of the abdominal aorta? Age Ageing, July 1, 2009; 38(4): 466 - 469. [Full Text] [PDF] |
||||
![]() |
M. Namasivayam, B. J. McDonnell, C. M. McEniery, M. F. O'Rourke, and on behalf of the Anglo-Cardiff Collaborative Trial Does Wave Reflection Dominate Age-Related Change in Aortic Blood Pressure Across the Human Life Span? Hypertension, June 1, 2009; 53(6): 979 - 985. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Gomberg-Maitland Something Subtle About Death: Isolated Systolic Pulmonary Pressure Circulation, May 26, 2009; 119(20): 2647 - 2649. [Full Text] [PDF] |
||||
![]() |
C. S.P. Lam, B. A. Borlaug, G. C. Kane, F. T. Enders, R. J. Rodeheffer, and M. M. Redfield Age-Associated Increases in Pulmonary Artery Systolic Pressure in the General Population Circulation, May 26, 2009; 119(20): 2663 - 2670. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. A. Chirinos, S. S. Franklin, R. R. Townsend, and L. Raij Body Mass Index and Hypertension Hemodynamic Subtypes in the Adult US Population Arch Intern Med, March 23, 2009; 169(6): 580 - 586. [Abstract] [Full Text] [PDF] |
||||
![]() |
W. K. Laskey, W. G. Kussmaul III, and A. Noordergraaf Systemic Arterial Response to Exercise in Patients With Aortic Valve Stenosis Circulation, February 24, 2009; 119(7): 996 - 1004. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. Williams The aorta and resistant hypertension. J. Am. Coll. Cardiol., February 3, 2009; 53(5): 452 - 454. [Full Text] [PDF] |
||||
![]() |
J. G. Kips, E. R. Rietzschel, M. L. De Buyzere, B. E. Westerhof, T. C. Gillebert, L. M. Van Bortel, and P. Segers Evaluation of Noninvasive Methods to Assess Wave Reflection and Pulse Transit Time From the Pressure Waveform Alone Hypertension, February 1, 2009; 53(2): 142 - 149. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. C. Iliopoulos, E. P. Kritharis, A. T. Giagini, S. A. Papadodima, and D. P. Sokolis Ascending thoracic aortic aneurysms are associated with compositional remodeling and vessel stiffening but not weakening in age-matched subjects. J. Thorac. Cardiovasc. Surg., January 1, 2009; 137(1): 101 - 109. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. E. Westerhof, J. P. van den Wijngaard, J. P. Murgo, and N. Westerhof Response to Uncertainties in Estimating the Site of Arterial Wave Reflection Hypertension, January 1, 2009; 53(1): e8 - e8. [Full Text] [PDF] |
||||
![]() |
J. E Davies, K. H Parker, D. P Francis, A. D Hughes, and J. Mayet What is the role of the aorta in directing coronary blood flow? Heart, December 1, 2008; 94(12): 1545 - 1547. [Full Text] [PDF] |
||||
![]() |
K. S. Heffernan, S. Y. Jae, K. R. Wilund, J. A. Woods, and B. Fernhall Racial differences in central blood pressure and vascular function in young men Am J Physiol Heart Circ Physiol, December 1, 2008; 295(6): H2380 - H2387. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Sugawara, K. Hayashi, T. Yokoi, and H. Tanaka Age-associated elongation of the ascending aorta in adults. J. Am. Coll. Cardiol. Img., November 1, 2008; 1(6): 739 - 748. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. F. Mitchell Effects of central arterial aging on the structure and function of the peripheral vasculature: implications for end-organ damage J Appl Physiol, November 1, 2008; 105(5): 1652 - 1660. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. D. Smith and P. J. Levy Review: New techniques for assessment of vascular function Therapeutic Advances in Cardiovascular Disease, October 1, 2008; 2(5): 373 - 385. [Abstract] [PDF] |
||||
![]() |
D. R. Seals, C. A. DeSouza, A. J. Donato, and H. Tanaka Habitual exercise and arterial aging J Appl Physiol, October 1, 2008; 105(4): 1323 - 1332. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. E. Westerhof, J. P. van den Wijngaard, J. P. Murgo, and N. Westerhof Location of a Reflection Site Is Elusive: Consequences for the Calculation of Aortic Pulse Wave Velocity Hypertension, September 1, 2008; 52(3): 478 - 483. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. D. Chantler, V. Melenovsky, S. P. Schulman, G. Gerstenblith, L. C. Becker, L. Ferrucci, J. L. Fleg, E. G. Lakatta, and S. S. Najjar The sex-specific impact of systolic hypertension and systolic blood pressure on arterial-ventricular coupling at rest and during exercise Am J Physiol Heart Circ Physiol, July 1, 2008; 295(1): H145 - H153. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Pini, M. C. Cavallini, V. Palmieri, N. Marchionni, M. Di Bari, R. B. Devereux, G. Masotti, and M. J. Roman Central but not brachial blood pressure predicts cardiovascular events in an unselected geriatric population: the ICARe Dicomano Study. J. Am. Coll. Cardiol., June 24, 2008; 51(25): 2432 - 2439. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Schnabel, M. G. Larson, J. Dupuis, K. L. Lunetta, I. Lipinska, J. B. Meigs, X. Yin, J. Rong, J. A. Vita, C. Newton-Cheh, et al. Relations of Inflammatory Biomarkers and Common Genetic Variants With Arterial Stiffness and Wave Reflection Hypertension, June 1, 2008; 51(6): 1651 - 1657. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. R. Malik, V. Kondragunta, and I. J. Kullo Forearm Vascular Reactivity and Arterial Stiffness in Asymptomatic Adults From the Community Hypertension, June 1, 2008; 51(6): 1512 - 1518. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. F. Mitchell, P. R. Conlin, M. E. Dunlap, Y. Lacourciere, J. M. O. Arnold, R. I. Ogilvie, J. Neutel, J. L. Izzo Jr, and M. A. Pfeffer Response to Wave Reflection in Systolic Hypertension: Smaller Stature, Shorter Aorta: Higher Pulse Pressure? and Questions Regarding the Aortic Measurements of Mitchell et al Hypertension, May 1, 2008; 51(5): e39 - e40. [Full Text] [PDF] |
||||
![]() |
J C Ferreira, E L Gastal, and O J Ginther Uterine blood flow and perfusion in mares with uterine cysts: effect of the size of the cystic area and age Reproduction, April 1, 2008; 135(4): 541 - 550. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. J. Lester, A. J. Tajik, R. A. Nishimura, J. K. Oh, B. K. Khandheria, and J. B. Seward Unlocking the Mysteries of Diastolic Function Deciphering the Rosetta Stone 10 Years Later. J. Am. Coll. Cardiol., February 19, 2008; 51(7): 679 - 689. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Shimizu and K. Kario Review: Role of the augmentation index in hypertension Therapeutic Advances in Cardiovascular Disease, February 1, 2008; 2(1): 25 - 35. [Abstract] [PDF] |
||||
![]() |
R. S. Vasan Pathogenesis of Elevated Peripheral Pulse Pressure: Some Reflections and Thinking Forward Hypertension, January 1, 2008; 51(1): 33 - 36. [Full Text] [PDF] |
||||
![]() |
G. F. Mitchell, P. R. Conlin, M. E. Dunlap, Y. Lacourciere, J. M. O. Arnold, R. I. Ogilvie, J. Neutel, J. L. Izzo Jr, and M. A. Pfeffer Aortic Diameter, Wall Stiffness, and Wave Reflection in Systolic Hypertension Hypertension, January 1, 2008; 51(1): 105 - 111. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. K. Sweitzer, M. Shenoy, J. H. Stein, S. Keles, M. Palta, T. LeCaire, and G. F. Mitchell Increases in Central Aortic Impedance Precede Alterations in Arterial Stiffness Measures in Type 1 Diabetes Diabetes Care, November 1, 2007; 30(11): 2886 - 2891. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Benjo, R. E. Thompson, D. Fine, C. W. Hogue, D. Alejo, A. Kaw, G. Gerstenblith, A. Shah, D. E. Berkowitz, and D. Nyhan Pulse Pressure Is an Age-Independent Predictor of Stroke Development After Cardiac Surgery Hypertension, October 1, 2007; 50(4): 630 - 635. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Walsh, T. Donnelly, and D. Lyons Why a Sex Difference in Age-Adjusted Relationship Between Height and Stroke Mortality? Stroke, September 1, 2007; 38(9): e92 - e92. [Full Text] [PDF] |
||||
![]() |
M. F. O'Rourke and J. Hashimoto Mechanical Factors in Arterial Aging: A Clinical Perspective J. Am. Coll. Cardiol., July 3, 2007; 50(1): 1 - 13. [Abstract] [Full Text] [PDF] |
||||
![]() |
F. Fantin, A. Mattocks, C. J. Bulpitt, W. Banya, and C. Rajkumar Reply Age Ageing, July 1, 2007; 36(4): 476 - 476. [Full Text] [PDF] |
||||
![]() |
A. M. Briones, M. Salaices, and E. Vila Mechanisms Underlying Hypertrophic Remodeling and Increased Stiffness of Mesenteric Resistance Arteries From Aged Rats J. Gerontol. A Biol. Sci. Med. Sci., July 1, 2007; 62(7): 696 - 706. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. E. Safar and P. Lacolley Disturbance of macro- and microcirculation: relations with pulse pressure and cardiac organ damage Am J Physiol Heart Circ Physiol, July 1, 2007; 293(1): H1 - H7. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. Agabiti-Rosei, G. Mancia, M. F. O'Rourke, M. J. Roman, M. E. Safar, H. Smulyan, J.-G. Wang, I. B. Wilkinson, B. Williams, and C. Vlachopoulos Central Blood Pressure Measurements and Antihypertensive Therapy: A Consensus Document Hypertension, July 1, 2007; 50(1): 154 - 160. [Full Text] [PDF] |
||||
![]() |
D. Levy, S.-J. Hwang, A. Kayalar, E. J. Benjamin, R. S. Vasan, H. Parise, M. G. Larson, T. J. Wang, J. Selhub, P. F. Jacques, et al. Associations of Plasma Natriuretic Peptide, Adrenomedullin, and Homocysteine Levels With Alterations in Arterial Stiffness: The Framingham Heart Study Circulation, June 19, 2007; 115(24): 3079 - 3085. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. D. Reesink, E. Hermeling, M. C. Hoeberigs, R. S. Reneman, and A. P. G. Hoeks Carotid artery pulse wave time characteristics to quantify ventriculoarterial responses to orthostatic challenge J Appl Physiol, June 1, 2007; 102(6): 2128 - 2134. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. F. Mitchell, C.-Y. Guo, S. Kathiresan, R. S. Vasan, M. G. Larson, J. A. Vita, M. J. Keyes, M. Vyas, C. Newton-Cheh, S. L. Musone, et al. Vascular Stiffness and Genetic Variation at the Endothelial Nitric Oxide Synthase Locus: The Framingham Heart Study Hypertension, June 1, 2007; 49(6): 1285 - 1290. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. Segers, E. R. Rietzschel, M. L. De Buyzere, S. J. Vermeersch, D. De Bacquer, L. M. Van Bortel, G. De Backer, T. C. Gillebert, P. R. Verdonck, and on behalf of the Asklepios investigators Noninvasive (Input) Impedance, Pulse Wave Velocity, and Wave Reflection in Healthy Middle-Aged Men and Women Hypertension, June 1, 2007; 49(6): 1248 - 1255. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. F. Mitchell Impedance Progress: Aortic Diameter Rears Its Head Again? Hypertension, June 1, 2007; 49(6): 1207 - 1209. [Full Text] [PDF] |
||||
![]() |
G. F. Mitchell, M. E. Dunlap, W. Warnica, A. Ducharme, J. M. O. Arnold, J.-C. Tardif, S. D. Solomon, M. J. Domanski, K. A. Jablonski, M. M. Rice, et al. Long-Term Trandolapril Treatment Is Associated With Reduced Aortic Stiffness: The Prevention of Events With Angiotensin-Converting Enzyme Inhibition Hemodynamic Substudy Hypertension, June 1, 2007; 49(6): 1271 - 1277. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. F. Mitchell, C.-Y. Guo, E. J. Benjamin, M. G. Larson, M. J. Keyes, J. A. Vita, R. S. Vasan, and D. Levy Cross-Sectional Correlates of Increased Aortic Stiffness in the Community: The Framingham Heart Study Circulation, May 22, 2007; 115(20): 2628 - 2636. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. Aznaouridis, C. Vlachopoulos, I. Dima, N. Ioakeimidis, and C. Stefanadis Triglyceride level is associated with wave reflections and arterial stiffness in apparently healthy middle-aged men Heart, May 1, 2007; 93(5): 613 - 614. [Abstract] [Full Text] [PDF] |
||||
![]() |
I. J. Kullo and A. R. Malik Arterial Ultrasonography and Tonometry as Adjuncts to Cardiovascular Risk Stratification J. Am. Coll. Cardiol., April 3, 2007; 49(13): 1413 - 1426. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. F. Mitchell, R. S. Vasan, M. J. Keyes, H. Parise, T. J. Wang, M. G. Larson, R. B. D'Agostino Sr, W. B. Kannel, D. Levy, and E. J. Benjamin Pulse Pressure and Risk of New-Onset Atrial Fibrillation JAMA, February 21, 2007; 297(7): 709 - 715. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. D. Achimastos, S. P. Efstathiou, T. Christoforatos, T. N. Panagiotou, G. S. Stergiou, and T. D. Mountokalakis Arterial Stiffness: Determinants and Relationship to the Metabolic Syndrome Angiology, February 1, 2007; 58(1): 11 - 20. [Abstract] [PDF] |
||||
![]() |
J. Cameron Ageing and central aortic pulse wave analysis. Commentary on 'Is Augmentation Index a Good Measure of Vascular Stiffness in the Elderly?' by Fantin et al. Age Ageing, January 1, 2007; 36(1): 3 - 5. [Full Text] [PDF] |
||||
![]() |
F. Fantin, A. Mattocks, C. J. Bulpitt, W. Banya, and C. Rajkumar Is augmentation index a good measure of vascular stiffness in the elderly? Age Ageing, January 1, 2007; 36(1): 43 - 48. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. F. Mitchell Response to Timing and Amplitude of Wave Reflection Hypertension, January 1, 2007; 49(1): E4 - E4. [Full Text] [PDF] |
||||
![]() |
N Bjarnegard, C Bengtsson, J Brodszki, G Sturfelt, O Nived, and T Lanne Increased aortic pulse wave velocity in middle aged women with systemic lupus erythematosus Lupus, October 1, 2006; 15(10): 644 - 650. [Abstract] [PDF] |
||||
![]() |
K. Hirata, T. Yaginuma, M. F. O'Rourke, and M. Kawakami Age-Related Changes in Carotid Artery Flow and Pressure Pulses: Possible Implications for Cerebral Microvascular Disease Stroke, October 1, 2006; 37(10): 2552 - 2556. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. F. Mitchell Triangulating the Peaks of Arterial Pressure Hypertension, October 1, 2006; 48(4): 543 - 545. [Full Text] [PDF] |
||||
![]() |
B. E. Westerhof, I. Guelen, N. Westerhof, J. M. Karemaker, and A. Avolio Quantification of Wave Reflection in the Human Aorta From Pressure Alone: A Proof of Principle Hypertension, October 1, 2006; 48(4): 595 - 601. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Murakami Reply Ann. Thorac. Surg., June 1, 2006; 81(6): 2341 - 2342. [Full Text] [PDF] |
||||
![]() |
Y. Li, J.-G. Wang, E. Dolan, P.-J. Gao, H.-F. Guo, T. Nawrot, A. V. Stanton, D.-L. Zhu, E. O'Brien, and J. A. Staessen Ambulatory Arterial Stiffness Index Derived From 24-Hour Ambulatory Blood Pressure Monitoring Hypertension, March 1, 2006; 47(3): 359 - 364. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. E. Davies, Z. I. Whinnett, D. P. Francis, K. Willson, R. A. Foale, I. S. Malik, A. D. Hughes, K. H. Parker, and J. Mayet Use of simultaneous pressure and velocity measurements to estimate arterial wave speed at a single site in humans Am J Physiol Heart Circ Physiol, February 1, 2006; 290(2): H878 - H885. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. H. Freitag, R. Peila, K. Masaki, H. Petrovitch, G. W. Ross, L. R. White, and L. J. Launer Midlife Pulse Pressure and Incidence of Dementia: The Honolulu-Asia Aging Study Stroke, January 1, 2006; 37(1): 33 - 37. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. F. Mitchell, J. A. Vita, M. G. Larson, H. Parise, M. J. Keyes, E. Warner, R. S. Vasan, D. Levy, and E. J. Benjamin Cross-Sectional Relations of Peripheral Microvascular Function, Cardiovascular Disease Risk Factors, and Aortic Stiffness: The Framingham Heart Study Circulation, December 13, 2005; 112(24): 3722 - 3728. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. M. McEniery, Yasmin, I. R. Hall, A. Qasem, I. B. Wilkinson, J. R. Cockcroft, and on behalf of the ACCT Investigators Normal Vascular Aging: Differential Effects on Wave Reflection and Aortic Pulse Wave Velocity: The Anglo-Cardiff Collaborative Trial (ACCT) J. Am. Coll. Cardiol., November 1, 2005; 46(9): 1753 - 1760. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. F. O'Rourke, A. Adji, S. Hoegler, F. Verbeke, P. Segers, R. Vanholder, P. Verdonck, and L. M. Van Bortel Calibration of Noninvasively Recorded Upper-Limb Pressure Waves Hypertension, November 1, 2005; 46(5): e15 - e16. [Full Text] [PDF] |
||||
![]() |
G. F. Mitchell, Y. Lacourciere, J. M. O. Arnold, M. E. Dunlap, P. R. Conlin, and J. L. Izzo Jr Changes in Aortic Stiffness and Augmentation Index After Acute Converting Enzyme or Vasopeptidase Inhibition Hypertension, November 1, 2005; 46(5): 1111 - 1117. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. M. Redfield, S. J. Jacobsen, B. A. Borlaug, R. J. Rodeheffer, and D. A. Kass Age- and Gender-Related Ventricular-Vascular Stiffening: A Community-Based Study Circulation, October 11, 2005; 112(15): 2254 - 2262. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. R. Sankatsing, S. W. Fouchier, S. de Haan, B. A. Hutten, E. de Groot, J. J.P. Kastelein, and E. S.G. Stroes Hepatic and Cardiovascular Consequences of Familial Hypobetalipoproteinemia Arterioscler. Thromb. Vasc. Biol., September 1, 2005; 25(9): 1979 - 1984. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. A. Khalil Sex Hormones as Potential Modulators of Vascular Function in Hypertension Hypertension, August 1, 2005; 46(2): 249 - 254. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. F. Mitchell, A. L. DeStefano, M. G. Larson, E. J. Benjamin, M.-H. Chen, R. S. Vasan, J. A. Vita, and D. Levy Heritability and a Genome-Wide Linkage Scan for Arterial Stiffness, Wave Reflection, and Mean Arterial Pressure: The Framingham Heart Study Circulation, July 12, 2005; 112(2): 194 - 199. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. Mazzaro, S. J. Almasi, R. Shandas, D. R. Seals, and P. E. Gates Aortic Input Impedance Increases With Age in Healthy Men and Women Hypertension, June 1, 2005; 45(6): 1101 - 1106. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. H. Dao, R. Essalihi, C. Bouvet, and P. Moreau Evolution and modulation of age-related medial elastocalcinosis: Impact on large artery stiffness and isolated systolic hypertension Cardiovasc Res, May 1, 2005; 66(2): 307 - 317. [Abstract] [Full Text] [PDF] |
||||
![]() |
W. Ahn and J. Hyon Bahk Letters to the Editor: Calculation of Reflection Wave Transit Time and Paired Data Analysis Hypertension, May 1, 2005; 45(5): e13 - e13. [Full Text] [PDF] |
||||
![]() |
M. F. O'Rourke and W. W. Nichols Aortic Diameter, Aortic Stiffness, and Wave Reflection Increase With Age and Isolated Systolic Hypertension Hypertension, April 1, 2005; 45(4): 652 - 658. [Full Text] [PDF] |
||||
![]() |
M. F. O'Rourke, W. W. Nichols, G. F. Mitchell, H. Parise, E. J. Benjamin, M. G. Larson, M. J. Keyes, J. A. Vita, R. S. Vasan, and D. Levy Changes in Wave Reflection With Advancing Age in Normal Subjects * Response Hypertension, December 1, 2004; 44(6): e10 - e11. [Full Text] [PDF] |
||||
![]() |
M. E. Safar Peripheral Pulse Pressure, Large Arteries, and Microvessels Hypertension, August 1, 2004; 44(2): 121 - 122. [Full Text] [PDF] |
||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Hypertension Home | Subscriptions | Archives | Feedback | Authors | Help | AHA Journals Home | Search Copyright © 2004 American Heart Association, Inc. All rights reserved. Unauthorized use prohibited. |