SphygmoCor Pulse Wave Analysis Research Articles

Acute cognitive, mood and cardiovascular effects of green and black tea

AbstractTea is often described as having “refreshing” properties. Indeed, components of both green and black tea have been shown to acutely improve aspects of cognition and mood and to affect cardiovascular function. There is, however, surprising little research directly comparing these effects between different types of tea. This study therefore examined acute cognitive, mood, and cardiovascular effects of green tea and black tea.A double blind, randomised, placebo-controlled,balanced, three-way cross-over study was conducted. Fourteen healthy young adults (M = 23.8, SD = 3 years) consumed placebo (water), green tea and black tea in balanced order at least 24 h apart.The drinks were prepared according to standardised procedures and consumed under double-blind conditions (in opaque containers with lemon cordial added for taste-masking). Mood and cognition were measured at baseline then 90 min post-treatment, cardiovascular function was assessed post-dose only. Mood was evaluated using a series of visual analogue scales, cognitive performance was assessed using a suite of standardised tests from the Computerised Mental Performance Assessment System (COMPASS), gauging performance on aspects of attention, memory and executive function.Peripheral and central systolic and diastolic pressure,augmentation pressure, augmentation index,and blood flow velocity were measured via Sphygmocor pulse wave analysis and Doppler ultrasound, respectively. There were a number of significant effects associated with the active treatments. Compared with placebo, black tea and green tea was associated with significantly improved digit vigilance accuracy (p < .01), while green tea was associated with higher alertness (p < .05).Regarding cardiovascular outcomes, black tea and green tea significantly increased central diastolic pressure, and peripheral diastolic pressure in comparison to placebo (P < .01). Black tea also significantly increased central systolic pressure compared to green tea and placebo (p < .05). Analysis of treatment guessing suggested that the masking procedure was highly effective. In conclusion, the present study shows that green tea improves alertness. Since black tea contains higher levels of caffeine, this effect is likely underpinned by non-caffeine mechanisms or caffeine/non-caffeine compound interactions.Improved vigilance is consistent with caffeine effects which may be modulated by cardiovascular effects. Interestingly the cardiovascular effects are opposite to those reported for chronic tea interventions. These results suggest that acute cognitive and cardiovascular components of tea merit further investigation both in the presence and absence of caffeine.

A14232 Correlation between urinary albuminto-creatinine ratio and Central Arterial pressure in patients with essential Hypertension

Objectives: To investigate the correlation between urinary albuminto-creatinine ratio and central arterial pressure in patients with essential hypertension (EP) Methods: A total of 673 EP were divided into normal ACR group (ACR < 30 mg/g, n = 485) and abnormal group (ACR ≥ 30 mg/g, n = 188), the clinical data of all patients were collected, Sphygmocor pulse wave analysis system was used to determine central artery related indicators such as central systolic pressure (CSP), central diastolic pressure (CDP), central pulse pressure (CPP), augmentation pressure (AP), reflected wave augmentation index, Their correlation with ACR and influencing factors were analyzed. Results: There was significant difference in SBP, DBP, PP, TC, HDL-C, apolipoprotein B, CSP, CDP, CPP, AP, creatinine level between 2 groups (P < 0. 05). By Pearson correlation analysis, ACR was positively correlated with AIX, CSP, CDP, CPP, AP, SBP, DBP, fasting blood-glucose, TC, urea nitrogen (r = 0.075, P < 0. 05; r = 0. 290, P < 0. 01; r = 0. 078, P < 0. 05; r = 0.116, P < 0. 01; r = 0.142, P < 0. 01; r = 0.123, P < 0. 01; r = 0. 110, P < 0. 01; r = 0. 100, P < 0. 01; r = 0.077, P < 0. 05; r = 0.086, P < 0. 05); By multiple regression analysis, CSP, AP, SBP entered into the regression equation. Conclusion: CSP, AP, SBP, risk factors of ACR, can lead to elevated ACR when they increase.

Aortic stiffness and its influencing factors in patients with chronic kidney disease

Objective: To investigate the changes of aortic stiffness and its influencing factors in patients with chronic kidney diseases (CKD). Methods: Eightyfour patients with CKD from Department of Nephrology, Zhejiang Provincial People's Hospital were divided into the dialysis group (CKD stage 5, n=48) and non-dialysis group (CKD stage 3-5, n=36). Clinical data, biochemical parameters and echocardiography findings were collected. SphygmoCor pulse wave analysis system was used to obtain pulse wave analysis (PWA) parameters including central aortic systolic blood pressure (CSP), central pulse pressure (CPP), augmented pressure (AP), augmentation index (AIX), and heart rate 75-adjusted augmentation index (HR75AIX). The influencing factors of aortic stiffness were analyzed by spearman correlation analysis and multiple regression analysis. Results: CSP, CPP, AP, AIX and HR75AIX in dialysis patients had no significant differences compared with those in non-dialysis group (all P>0.05). Spearman correlation analysis showed that CSP was positively correlated with systolic blood pressure, diastolic blood pressure, cholesterol, low-density lipoprotein cholesterol, left atrial diameter (LA),left ventricular systolic diameter (LVDs), left ventricular diastolic diameter (LVDd), and negatively correlated with calcium and hemoglobin levels. CPP was positively correlated with systolic blood pressure, age, LA, LVDd, and negatively correlated with diastolic blood pressure and hemoglobin levels. AP was positively correlated with systolic blood pressure, age, LA, LVDd, and negatively correlated with hemoglobin levels. AIX was positively correlated with systolic blood pressure, age, sodium, and negatively correlated with phosphorus levels. HR75AIX was positively correlated with systolic blood pressure, sodium, cholesterol, and negatively correlated with hemoglobin and albumin levels. Multiple regression analysis showed that higher systolic blood pressure was the independent risk factor for CSP (β=0.944, P<0.01); lower diastolic blood pressure (β=0.939, P<0.01) and higher systolic blood pressure (β=-1.010, P<0.01) were the independent risk factors for CPP; older age (β=0.237, P<0.01) and higher systolic blood pressure (β=0.200, P<0.01) were the independent risk factors for AP; higher systolic blood pressure (β=0.163 and 0.115, P<0.05 and P<0.01) and higher sodium (β=0.646 and 0.625, all P<0.05) were independent risk factors for both AIX and HR75AIX. Conclusions: No significant correlation is observed between aortic stiffness and CKD of different stages. Control blood pressure and restrict sodium intake may be effective means of delaying arterial stiffness in patients with CKD.

Repeatability of SphygmoCor pulse wave analysis in assessing arterial wave reflection in pregnancy using applanation tonometry

Objective: To estimate clinical agreement in relation to measuring aortic augmentation index (AIX-75) in pregnancy in a routine clinical setting. Methods: A hospital-based clinical agreement study of 20 women in which two trained nurses alternated in measuring arterial function (AIX standardized to a heart rate of 75 beats-per-minute, AIX-75) on a single occasion in triplicate, after participants had rested semi-recumbent for 15 min. Right brachial blood pressure (BP) was measured using the Microlife 3BTO-A oscillometric device. Radial applanation pulse wave analysis (PWA) was undertaken according to current guidelines using the SphygmoCor device with a hand-held Millar tonometer applanated at the right radial artery. Each nurse was blinded to others PWA results. Observer agreement was assessed using the Bland–Altman “limits of agreement” (LOA, mean difference ±2 SD) approach. Results: Median gestation was 37 weeks (range: 12–42), mean age 31 years, 30% nulliparous, mean brachial BP 128/79 mm Hg. Based on all six PWA measurements, mean AIX-75 was 11.7 (range: −18 to +35). The between-observer LOA was 0.1 ± 11.0 and the within-observer LOA’s were 1 ± 10 and −2 ± 8 for the two nurses. Observer differences did not vary systematically with the magnitude of AIX-75. Conclusion: AIX-75 can be measured by nurses using PWA in pregnancy with a high level of observer agreement.

Reduction in arterial stiffness and vascular age by naltrexone-induced interruption of opiate agonism: a cohort study

ObjectiveTo prospectively assess if opiate antagonist treatment or the opiate-free status could reverse opiate-related vasculopathy.DesignLongitudinal Open Observational, Serial ‘N of One’, over 6.5 years under various treatment conditions: opiate dependence,...

Arterial dysfunction in patients with rheumatoid arthritis and the consumption of daily fruits and daily vegetables

Rheumatoid arthritis (RA) is associated with increased arterial dysfunction and increased risk of cardiovascular disease. Regular fruit and vegetable consumption prevents cardiovascular disease, but their influence on arterial dysfunction in RA has not been investigated. We assessed the relationship between daily fruit-vegetable consumption and arterial dysfunction in this high-risk group. Participants were recruited from a consecutive series of RA patients aged 40-65 years without overt cardiovascular disease attending rheumatology clinics. Standardised research nurse assessment included SphygmoCor pulse wave analysis using radial applanation tonometry (a higher augmentation index (AIX%) indicates arterial dysfunction), fasting blood sample, patient questionnaire and medical record review. Multivariable analysis was used to adjust for age, sex, cholesterol, mean arterial blood pressure, smoking habit, alcohol consumption, physical activity, cumulative inflammatory burden, rheumatoid nodules, disability and education. We recruited 114 RA patients: 81% female, mean age 54 years, median arthritis duration 10 years and mean AIX% 31.5 (s.d. 7.7). Fruit and vegetable consumption were significantly correlated (Spearman's rho 0.54, P≪0.0001) and on unadjusted analysis daily fruit and vegetable consumption was associated with a lower AIX% (-3.2; 95% CI -6.4 to -0.1, P=0.05). On adjusted analysis AIX% was lower with daily vegetable (-4.2; 95% CI -7.9 to -0.5; P=0.003), but not with daily fruit (-0.02; 95% CI -3.9 to 3.8; P=0.99) consumption. Daily vegetable consumption, but not daily fruit consumption, was independently associated with more favourable arterial function in patients with RA. These findings are consistent with the enterosalivary circulation of nitrate having an influence on arterial function.

Influence of the daily consumption of vegetables and fruits on arterial dysfunction in patients with rheumatoid arthritis: A cross-sectional study employing pulse wave analysis

BackgroundRegular vegetable-fruit consumption maintains cardiovascular (CV) health in the general population, but their effects are not explained by ‘antioxidation’. Based on the ‘Bradford-Hill guidelines’ there is stronger evidence for the...

E0268 Subendocardial viability ratios in residents of a community in Jinan City, Shandong Province

ObjectiveThe subendocardial viability ratio (SEVR) measures myocardial perfusion related to cardiac workload. The chief aim of this work was to investigate the relationship between SEVR and cardiovascular risk factors.MethodsThis study...

Effects of salt substitute on pulse wave analysis among individuals at high cardiovascular risk in rural China: a randomized controlled trial

Reduced-sodium, increased-potassium salt substitutes lower blood pressure but may also have direct effects on vascular structure and arterial function. This study aimed to test the effects of long-term salt substitution on indices of these outcomes. The China Salt Substitute Study was a randomized, controlled trial designed to establish the effects of salt substitute (65% sodium chloride, 25% potassium chloride, 10% magnesium sulfate) compared with regular salt (100% sodium chloride) on blood pressure among 600 high-risk individuals living in six rural areas in northern China over a 12-month intervention period. Data on central aortic blood pressure, aortic pressure augmentation (AUG), augmentation index (AIx), the differences of the peak of first and baseline waves (P(1)-P(0)) and pulse wave reflection time (RT) were collected at randomization and at the completion of follow-up in 187 participants using the Sphygmocor pulse wave analysis system. Mean baseline blood pressure was 150.1/91.4 mm Hg, mean age was 58.4 years, 41% were male and three quarters had a history of vascular disease. After 12 months of intervention, there were significant net reductions in peripheral (7.4 mm Hg, P=0.009) and central (6.9 mm Hg, P=0.011) systolic blood pressure levels and central pulse pressure (4.5 mm Hg, P=0.012) and correspondingly there was a significant net reduction in P(1)-P(0) (3.0 mm Hg, P=0.007), borderline significant net reduction in AUG (1.5 mm Hg, P=0.074) and significant net increase in RT (2.59 ms, P=0.001). There were no detectable reductions in peripheral (2.8 mm Hg, P=0.14) or central (2.4 mm Hg, P=0.13) diastolic blood pressure levels or AIx (0.06%, P=0.96). In conclusion, over the 12-month study period the salt substitute significantly reduced not only peripheral and central systolic blood pressure but also reduced arterial stiffness.

Repeatability of central aortic blood pressures measured non‐invasively using radial artery applanation tonometry and peripheral pulse wave analysis

Objective. To estimate the repeatability of radial pulse wave analysis (PWA) in measuring central systolic and diastolic blood pressures (cSBP/cDBP), pulse pressure (cPP), augmentation pressure (cAP) and pulse pressure amplification (PPA). Methods. After 15 min supine rest, 20 ambulant patients (aged 27–82 years; four female) underwent four SphygmoCor PWA measurements on a single occasion. Two nurses independently undertook two measurements in alternate order, blind to their colleague's measurements. Analysis was by Bland–Altman limits of agreement (LOA). Results. Heart rate and brachial blood pressure (BP) were stable during assessment. Based on the average of two PWA measurements between‐observer differences (LOA, mean difference±2SD) were small (cSBP 1.5±10.9 mmHg; cDBP 0.4±5.2 mmHg; cAP 0.5±4.5 mmHg; cPP 1.1±10.5 mmHg; PPA −0.5%±5.6%). Between‐observer differences were much greater for single/initial PWA measurement (cSBP 3.6±15.9 mmHg; cDBP 2.8±8.8 mmHg; cAP 0.7±5.8 mmHg; cPP 0.8±13.6 mmHg; PPA −1.2±9.4%). Within‐observer LOA were very similar for both nurse A (cSBP −4.2±14.1 mmHg; cDBP −4.6±13.1 mmHg; cAP −0.4±4.4 mmHg; cPP 0.5±11.0 mmHg; PPA 0.7%±9.0%) and nurse B (cSBP 0.0±12.1 mmHg; cDBP 0.2±8.5 mmHg; cAP −0.1±4.4 mmHg; cPP −0.2±11.9 mmHg; PPA −0.7%±10.6%). Conclusion. Non‐invasive assessment of central aortic pressures using PWA on a single occasion is highly repeatable in ambulant patients even when used by relatively inexperienced staff.

Protective effects of ascorbic acid on arterial hemodynamics during acute hyperglycemia

Mortality increases when acute coronary syndromes are complicated by stress-induced hyperglycemia. Early pulse wave reflection can augment central aortic systolic blood pressure and increase left ventricular strain. Altered pulse wave reflection may contribute to the increase in cardiac risk during acute hyperglycemia. Chronic ascorbic acid (AA) supplementation has recently been shown to reduce pulse wave reflection in diabetes. We investigated the in vivo effects of acute hyperglycemia, with and without AA pretreatment, on pulse wave reflection and arterial hemodynamics. Healthy male volunteers were studied. Peripheral blood pressure (BP) was measured at the brachial artery, and the SphygmoCor pulse wave analysis system was used to derive central BP, the aortic augmentation index (AIx; measure of systemic arterial stiffness), and the time to pulse wave refection (Tr; measure of aortic distensibility) from noninvasively obtained radial artery pulse pressure (PP) waveforms. Hemodynamics were recorded at baseline and then every 30 min during a 120-min systemic hyperglycemic clamp (14 mmol/l). The subjects, studied on two separate occasions, were randomized in a double-blind, crossover manner to placebo or 2 g intravenous AA before the initiation of hyperglycemia. During hyperglycemia, AIx increased and Tr decreased. Hyperglycemia did not change peripheral PP but did magnify central aortic PP and diminished the normal physiological amplification of PP from the aorta to the periphery. Pulse wave reflection, as assessed from peripheral pulse wave analysis, is enhanced during acute hyperglycemia. Pretreatment with AA prevented the hyperglycemia-induced hemodynamic changes. By protecting hemodynamics during acute hyperglycemia, AA may have therapeutic use.

Similarities and differences between augmentation index and pulse wave velocity in the assessment of arterial stiffness.

We investigated whether there was a correlation between the simultaneous assessments of augmentation index (AI) and pulse wave velocity (PWV), undertaken by the SphygmoCor system, and what were the principal factors responsible for differences in these two putative assessments of arterial stiffness, in 105 offspring (41 men, 64 women) aged 19-71 years, of patients with familial hypertension. Arterial stiffness was measured using the SphygmoCor pulse wave analysis system. AI and PWV correlated significantly and positively (r = 0.29, p < 0.005) and the strength of the correlation was greater when each gender was examined separately. This led us to observe several-fold higher AI in women (22.04 +/- 12) than in men (8.59 +/- 13) (p < 0.001); the difference could be explained only in part by an inverse regression correlation between AI and height (r = -0.45; p < 0.001), but not PWV. AI was also more influenced than PWV by heart rate and blood pressure. AI is strongly correlated with a previously validated estimate of arterial stiffness, PWV. It is probable that separate normal ranges should be established for men and women, while further studies determine what parameters other than height are responsible for the gender difference.