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Background Carotid artery applanation tonometry is widely used in estimating local carotid artery pressure waveforms and carotid-femoral pulse wave velocity. However, the substantial pressure applied locally to the carotid artery with applanation tonometry might well evoke a baroreceptor response, resulting in bradycardia and hypotension. Therefore, when carotid and femoral tonometry are performed sequentially, baroreceptor activation could lead to different hemodynamic conditions between carotid and femoral acquisitions. Combining those acquisitions into one pulse wave velocity measure would be erroneous. In this study, we assessed whether carotid applanation tonometry has an influence on heart rate and blood pressure. Methods In 26 hypertensive subjects, heart rate and blood pressure were assessed by continuous finger pulse waveform recording during carotid as well as femoral applanation tonometry. Both carotid and femoral acquisitions were measured in alternation and in triplicate. Median averaging over the 3 carotid and femoral measurements, respectively, was used to obtain a subject's median heart rate and blood pressure during carotid as well as femoral tonometry. Results Difference in heart rate during carotid and femoral tonometry was -0.7±2.2 bpm. Differences in systolic, pulse, and diastolic blood pressure were -0.7±6.8, -0.1±3.8, and -0.3±3.5mm Hg, respectively. All differences were statistically nonsignificant. Confidence intervals were used to calculate the maximum absolute difference at 95% certainty, which was 1.6 bpm for heart rate and ≤3.5mm Hg for all blood pressures. Conclusions We conclude that in our study, carotid artery applanation tonometry as performed by an experienced researcher did not cause clinically significant baroreceptor activation.

Although aortic wave reflection may be inherited, the extent to which indexes of wave reflection derived from wave separation analysis (reflected (backward) wave index (RI) and pressure (Pb)) show intrafamilial aggregation and heritability is uncertain. We therefore aimed to determine the intrafamilial aggregation and heritability of RI and Pb and compare these with indexes of pressure augmentation.Aortic Pb, RI, augmented pressure (Pa), and augmentation index (AIx) were determined using radial applanation tonometry and SphygmoCor software in 1,152 participants of 315 families (111 father-mother, 705 parent-child, and 301 sibling-sibling pairs) from an urban developing community of black Africans. Heritability estimates were determined from Statistical Analysis for Genetic Epidemiology software.With appropriate adjustments, significant correlations were noted between parent-child pairs for Pb and Pa (P0.05 for all), but not for RI (P = 0.50) or AIx (P = 0.90) and between sib-sib pairs for Pb and Pa (P0.05), but not for RI (P = 0.54) or AIx (P = 0.14). No correlations for indexes of wave reflection were noted between fathers and mothers (P0.57). After adjustments, Pb (h2 = 0.24±0.07) and Pa (h2 = 0.23±0.07) (P0.001 for both) but not RI (h2 = 0.04±0.06, P = 0.27) or AIx (h2 = 0.10±0.07, P = 0.07) showed significant heritability.Aortic reflected (backward) waves derived from either wave separation (Pb) or pulse wave analysis (Pa) show a similar degree of intrafamilial aggregation and heritability, but the use of RI or AIx may underestimate reflected wave effects.

BACKGROUND Telomere length predicts cardiovascular disease (CVD) possibly through an impact of telomere attrition on aortic stiffness. Whether reduced biological aging and a lack of telomere length-aortic stiffness relationships in women contribute to the lower prevalence of CVD in women, prior to menopause, is uncertain. METHODS We evaluated the relationship between telomere length and carotid-femoral (aortic) pulse wave velocity (PWV) in 580 randomly recruited participants of Black African descent (age = 44 ± 19 years; women: n = 361; premenopausal: n = 195). PWV was determined using carotid and femoral applanation tonometry (SphygmoCor). Relative leukocyte telomere length (T/S) was measured using quantitative real-time polymerase chain reaction assays. RESULTS Men and women had similar T/S. T/S was inversely correlated with age (r = -0.14, P < 0.001) and this association was similar in all (r = -0.14, P < 0.01) and premenopausal (r = -0.17, P < 0.05) women as in men (r = -0.14, P < 0.05). An inverse relationship between T/S and PWV was noted both before (r = -0.20, P < 0.0001) and after (partial r = -0.14, P < 0.001) adjustments for confounders. No interaction between T/S and either sex or menopausal status was independently associated with PWV, and T/S was independently correlated with PWV in all (partial r = -0.14, P < 0.01) and premenopausal (partial r = -0.18, P < 0.05) women and in men (partial r = -0.15, P < 0.05). CONCLUSIONS Gender and premenopausal status do not affect age-related decreases in T/S and associations between T/S and PWV. In participants of African descent in whom telomere length did not differ by gender, the impact of gender prior to menopause on CVD is unlikely to be attributed to differences in the effect of biological aging on aortic stiffness.

BACKGROUND Short- and long-term exposures to cold increase blood pressure and may explain the higher wintertime cardiovascular morbidity and mortality. Hypertensive subjects may be more susceptible to adverse cold-related cardiovascular health effects. The aim of our study was to assess the effect of short-term cold exposure on central aortic blood pressure among untreated hypertensive men. METHODS We conducted a population-based recruitment of 41 hypertensive men and a control group of 20 men without hypertension (aged 55-65 years) who underwent whole-body cold exposure (15-minute exposure to temperature -10 °C, wind 3 m/s, winter clothes). Central aortic blood pressure, augmentation index, and subendocardial viability ratio were measured by radial artery applanation tonometry. RESULTS Short-term cold exposure increased the central aortic blood pressure similarly both in both hypertensive men, from 130/93 to 162/107 mm Hg (P < 0.001) and men in the control group, from 114/81 to 142/91 mmHg (P < 0.001). Augmentation index increased by 12% (from 10% to 22%, P < 0.001; and from 16% to 28%, P < 0.001, respectively), whereas subendocardial viability ratio decreased 10% (from 188% to 177%, P = 0.001; and from 203% to 193%, P = 0.01, respectively) during cold exposure in both hypertensive men and control subjects. CONCLUSIONS Short-term cold exposure increases central aortic blood pressure and cardiac workload, and myocardial oxygen demand slightly increases in relation to blood supply in untreated hypertensive middle-aged men. Because of the higher baseline blood pressure among hypertensive subjects, the cold-induced rise in central aortic blood pressure may increase the risk of adverse cardiovascular health effects.

BACKGROUND As groups of African descent may have higher nocturnal blood pressure (BP) for a given day BP than other ethnic groups, we ascertained whether this translates into differences in conventional (CBP) and 24-h ambulatory (ABP) BP control at a community level. METHODS Ambulatory 24-h, day and night BP (model 90207; SpaceLabs, Issaquah, WA) and CBP (mean of five values) control rates were determined in 689 randomly selected participants (>1 6 years) of African ancestry in South Africa.Target organ effects were determined from urinary microalbumin-to-creatinine ratios (ACR) and aortic pulse wave velocity (PWV, applanation tonometry). RESULTS Of the participants 45.7% were hypertensive and 22.6% were receiving antihypertensive medication. More participants had uncontrolled BP at night (34.0%) than during the day (22.6%, P < 0.0001). Uncontrolled CBP was noted in 37.2% of participants, while a much lower proportion had uncontrolled ABP (24.1 %) (P < 0.0001). Marked differences in the proportion of hypertensive participants with uncontrolled CBP and ABP were noted (treated: CBP = 62.2%, ABP = 33.3%, P < 0.0001; all: CBP = 81.3%, ABP = 44 . 4% , P < 0.0001 ).These differences were accounted for by a high prevalence of isolated increases in CBP (white-coat effects) (treated = 35.9%; all = 39.4%). Indeed, after censoring data from participants with white-coat effects, similar CBP and ABP control rates were noted. Participants with white-coat effects had similar ACR and PWV values as participants with normal ABP and CBP. CONCLUSIONS In communities of African descent, despite worse BP control at night than during the day, a high prevalence of white-coat effects translates into a striking underestimation of BP control in hypertensives when employing CBP rather than ABP measurements.

BACKGROUND We aimed to clarify whether age influences the independent relationship between adiposity and pulse-wave velocity (PWV). METHODS We explored the effect of age on the independent relationships between indexes of central adiposity (waist circumference (WC) and waist-to-hip ratio (WHR)) and carotid-femoral PWV, central augmentation index (AIc), or pressure wave amplification assessed from applanation tonometry measurements obtained at the radial, carotid, and femoral arteries in 508 randomly selected subjects >16 years of age in a population sample of African ancestry with a high prevalence of excess adiposity ( approximately 63% overweight or obese). RESULTS In women a strong interaction between age and either WC or WHR was associated with logPWV independent of confounders and the individual terms (r = 0.68, P < 0.0001). This translated into a markedly greater increase in logPWV with increases in either WC or WHR in women older than the median age as compared to women younger (slopes of WC-logPWV relationships = 0.0031 +/- 0.0009 vs. -0.0007 +/- 0.0007, P < 0.002). In women older than the median age for the group, a one s.d. increase in WC (12.8 cm) translated into a 0.70 m/s increase in PWV as compared to a 0.14 m/s decrease in PWV for each one s.d. increase in WC (13.0 cm) in women younger than the median age (P < 0.001). No index of adiposity was independently associated with the log of AIc or aortic-brachial wave amplification. CONCLUSION In women of African ancestry, a greater independent effect of adiposity on PWV is noted in older as compared to younger women.

Background Pulse wave velocity (PWV) is an indicator of aortic stiffness and a predictor of cardiovascular risk. Applanation tonometry (e.g., SphygmoCor) is a well-established method to measure aortic PWV (aPWV). The Vicorder, a new oscillometric device, has not been validated in children and adolescents. Methods We performed intra- and interobserver repeatability studies in 14 individuals using the Vicorder. Vicorder and SphygmoCor measurements were compared in 156 healthy children (6-18 years) using two different path length measurements. Results Intra- and interobserver repeatabilities of the Vicorder were excellent with coefficients of variation of 5.6% and 5.8% and intraclass correlation coefficients (ICCs) of 0.8 and 1.0. aPWV calculated using the distances (suprasternal notch-to-femoral recording point) - (suprasternal notch-to-carotid artery), the path length most commonly used in adults, revealed a mean of 4.8 ± 0.7 m/s for SphygmoCor and 4.9 ± 0.6 m/s for Vicorder. The percentage deviation between both devices was 13.0% and the limit of agreement (LoA) ranged from -1.0 to 1.7 m/s reflecting a good concordance. Using a path length that measured the distance from suprasternal notch to femoral recording point via the umbilicus (Umb), an even better agreement was found (percentage deviation: 11.8%, LoA: -1.0 to 1.6 m/s). Conclusions Vicorder aPWV values are similar to those obtained by SphygmoCor applanation tonometry. The best agreement between devices was obtained with the path length that most accurately describes the aortic tree. Excellent intra- and interobserver repeatability and ease of measurements make Vicorder appropriate for large multicentre studies in children and adolescents.

BACKGROUND The time from carotid to femoral pulse wave propagation (pulse transit time (PTT)) is required to estimate the carotid-femoral pulse wave velocity (PWV), a reliable index for evaluating large artery stiffness. METHODS In this work, we propose a novel, noncontact laser-based technique, named optical vibrocardiography (VCG), for evaluating PTT from synchronous recordings of the motion of the skin on the neck and the groin. These measurements, which have been demonstrated to be related to the radial displacement of the underlying blood vessels, were performed on 14 healthy subjects. As validation, applanation tonometry was performed to determine PTT between the carotid and the femoral artery. RESULTS PTT evaluated by VCG was not different from applanation tonometry (74.86 +/- 8.63 ms vs. 75.85 +/- 8.61 ms, P = 0.377). CONCLUSIONS Our preliminary results demonstrate that laser-based noncontact measurement in young healthy volunteers is feasible, and yields PTTs that are equivalent to those measured using arterial applanation tonometry. Its clinical application can overcome limitations inherent to a contact method like arterial tonometry.

Pulse wave velocity (PWV) is correlated with cardiovascular risk. This study presents a new method for measuring the arterial PWV by simultaneously recording the digital volume pulse through the finger and the toe by way of dual-channel photoplethysmography (PPG).In this study, 100 asymptomatic subjects (54 men and 46 women, 19 to 64 years of age) were enrolled. The PWV was measured both by dual-channel PPG (PWV-DVP) and by the standard method that current used applanation tonometry (PWV-AT). The developed dual-channel PPG system recorded digital volume pulse simultaneously from both the finger and toe. Time of pulse transition was measured on the time delay difference between two digital volume pulses. The PWV was calculated by dividing the distance between finger and toe by that of transit time.The PWV-DVP was significantly correlated with PWV-AT (r = 0.678, P.01). With multivariate analysis controlled for age, heart rate, systolic blood pressure, and diastolic blood pressure, PWV-DVP was still significantly correlated with PWV-AT (r = 0.669, P.01). Subjects with hypertension and dyslipidemia had significant higher PWV detected by both methods.This study showed that PWV measured with dual-channel PPG system correlated very well with that measured using the traditional method.

To study the effects of alcohol on large artery function we measured arterial wave reflection in the aorta as augmentation index (AI%) by applanation tonometry in 324 subjects (18 to 86 years, 223 male). In eight subjects, when ingested acutely, red wine containing alcohol (0.8 g/kg), but not dealcoholized wine, reduced (P.01) blood pressure (BP), pulse wave velocity, and AI%. Men with an excessive alcohol consumption (21 units/week) had a higher AI% (12 +/- 2 v 5 +/- 2, P.05) and BP, particularly aortic systolic, than did those with a lesser intake. This study suggests that alcohol when ingested acutely may reduce arterial stiffness, although alcohol when ingested chronically, in excess, increases it.