Biochemical changes associated with thermal biofeedback treatment of hypertension

Fifty-two hypertensive patients whose blood pressure (BP) was controlled on two medications received either 16 sessions of thermal biofeedback (n = 30) for hand warming or 8 sessions of progressive muscle relaxation (n = 22) prior to medication withdrawal. A number of biochemical measures, including plasma norepinephrine (NEPI) (supine and standing), plasma renin activity, plasma aldosterone, and urinary sodium and potassium, were taken before treatment and after treatment while medication remained constant. Results for the biofeedback-treated patients showed significant reductions in mean arterial pressure as well as in both supine and standing NEPI, while the other biochemical measures were unchanged. There were no significant changes on any variable for the relaxation-treated patients. Although the group data support a reduction in peripheral sympathetic tone as associated with the decrease in BP for the thermal biofeedback condition, dose-response relations were not significant.     

Biochemical changes associated with thermal biofeedback treatment of hypertension

Fifty-two hypertensive patients whose blood pressure (BP) was controlled on two medications received either 16 sessions of thermal biofeedback (n=30) for hand warming or 8 sessions of progressive muscle relaxation (n=22) prior to medication withdrawal. A number of biochemical measures, including plasma norepinephrine (NEPI) (supine and standing), plasma renin activity, plasma aldosterone, and urinary sodium and potassium, were taken before treatment and after treatment while medication remained constant. Results for the biofeedback-treated patients showed significant reductions in mean arterial pressure as well as in both supine and standing NEPI, while the other biochemical measures were unchanged. There were no significant changes on any variable for the relaxation-treated patients. Although the group data support a reduction in peripheral sympathetic tone as associated with the decrease in BP for the thermal biofeedback condition, dose-response relations were not significant.This research was supported by a grant from NHLBI, HL-27622.     

Relationships between high-sensitive C-reactive protein and markers of arterial stiffness in hypertensive patients. Differences by sex

ABSTRACT: BACKGROUND: The present study was designed to evaluate the relationship between high-sensitivity Creactive protein (hs-CRP) and arterial stiffness according to sex in patients with arterial hypertension. METHODS: A case-series study was carried out in 258 hypertensive patients without antecedents of cardiovascular disease or diabetes mellitus. Nephelometry was used to determine hs-CRP. Office or clinical and home blood pressures were measured with a validated OMRON model M10 sphygmomanometer. Ambulatory blood pressure monitoring was performed with the SpaceLabs 90207 system. Pulse wave velocity (PWV) and central and peripheral augmentation index (AIx) were measured with the SphygmoCor system, and a Sonosite Micromax ultrasound unit was used for automatic measurements of carotid intima-media thickness (IMT). Ambulatory arterial stiffness index and home arterial stiffness index were calculated as "1-slope" from the within-person regression analysis of diastolic-on-systolic ambulatory blood pressure. RESULTS: Central and peripheral AIx were greater in women than in men: 35.31 +/- 9.95 vs 26.59 +/- 11.45 and 102.06 +/- 20.47 vs 85.97 +/- 19.13, respectively. IMT was greater in men (0.73 +/- 0.13 vs 0.69 +/- 0.10). hs-CRP was positively correlated to IMT (r = 0.261), maximum (r = 0.290) and to peripheral AIx (r = 0.166) in men, and to PWV in both men (r = 0.280) and women (r = 0.250). In women, hs-CRP was negatively correlated to central AIx (r = 0.222). For each unit increase in hs-CRP, carotid IMT would increase 0.05 mm in men, and PWV would increase 0.07 m/sec in men and 0.08 m/sec in women, while central AIx would decrease 2.5 units in women. In the multiple linear regression analysis, hs-CRP explained 10.2 % and 6.7 % of PWV variability in women and men, respectively, 8.4 % of carotid IMT variability in men, and 4.9 % of central AIx variability in women. CONCLUSIONS: After adjusting for age, other cardiovascular risk factors and the use of antihypertensive and lipid-lowering drugs, hs-CRP was seen to be positively correlated to carotid IMT in men, and negatively correlated to central AIx in women. The association of hs-CRP to arterial stiffness parameters differs between men and women.     

Plasma Homocysteine Is Associated with Aortic Arterial Stiffness but not Wave Reflection in Chinese Hypertensive Subjects

Objective

Elevated plasma total homocysteine (tHcy) acts synergistically with hypertension to exert a multiplicative effect on cardiovascular diseases risk. The aim of this study was to determine the relationship between tHcy concentration and blood pressure, and to evaluate the role of plasma tHcy in arterial stiffness and wave reflection in hypertension.

Methods

In this cross-sectional study, a community-based sample of 1680 subjects (mean age 61.6 years) was classified into four groups according to tHcy level (<21.6 vs. ≥21.6 µmol/l) and blood pressure (hypertensive vs. normotensive). Levels of plasma tHcy and other biochemical parameters (e.g., lipids, glucose) were determined. Central arterial blood pressure, reflected pressure wave, and carotid-femoral pulse wave velocity (cf-PWV) were assessed by tonometry within 2 days of obtaining the blood specimen.

Results

Neither peripheral nor central blood pressure differed according to tHcy levels in normotensive and hypertensive subjects. Differences in cf-PWV according to tHcy were observed only in hypertensive subjects; differences in cf-PWV in normotensive subjects were not significant after adjusting for confounding factors. Central augmentation index did not differ according to tHcy level in either normotensive or hypertensive subjects. Results of univariate analysis revealed significant correlations between blood pressure parameters and tHcy concentration only among normotensive subjects; however, these correlations were not significant in a partial correlation analysis. Results of multiple regression analysis showed that plasma tHcy levels were independently correlated with cf-PWV in hypertensive subjects (β = 0.713, P = 0.004). The independent relationship between tHcy and central augmentation index was not significant by further multiple analyses in normotensive or hypertensive individuals.

Conclusions

Plasma tHcy level is strongly and independently correlated with arterial stiffness measured as cf-PWV only in hypertensive subjects. Thus, hypertension is a major link between tHcy and aortic arterial stiffness.     

Oral glucose tolerance test reduces arterial baroreflex sensitivity in older adults

Although postprandial decreases in blood pressure are a common cause of syncope in the older adult population, the postprandial effects of the oral glucose tolerance test on blood pressure and the arterial baroreflex remain poorly characterized in older adults. Therefore, arterial blood pressure and the arterial baroreflex were studied in 19 healthy older adults (mean age 71.7 +/- 1.1 years) who were given a standardized oral glucose load (75 g) or an isovolumetric sham drink during 2 separate sessions. All measures were taken for 120 min after treatment. Baroreflex function was assessed by using the spontaneous baroreflex method (baroreflex sensitivity, BRS). Subjects demonstrated a decrease in BRS after oral glucose that was not seen in the placebo session (two-way analysis of variance, p = 0.04). There was no significant change in systolic, mean, or diastolic blood pressure; together with a drop in BRS, this resulted in a significant tachycardia post glucose (two-way analysis of variance, p < 0.001). We conclude that healthy older adults can successfully maintain blood pressure during an oral glucose tolerance test despite a decrease in arterial BRS. Decreased BRS resulted in a tachycardic response to glucose.     

Biological aortic age derived from the arterial pressure waveform

Indexes for arterial stiffness are, by their nature, influenced by the ambient blood pressure due to the curvilinear nature of arterial compliance. We developed a new concept of the "Modelflow aortic age," which is, theoretically, not influenced by the ambient blood pressure and provides an easily understood context (biological vs. chronological age) for measures of arterial stiffness. The purpose of the present study was to validate this pressure-independent index for aortic stiffness in humans. Twelve sedentary elderly (65-77 yr), 11 Masters athletes (65-73 yr), and 12 sedentary young individuals (20-42 yr) were studied. Modelflow aortic ages were comparable with chronological ages in both sedentary groups, indicating that healthy sedentary individuals have age-appropriate aortas. In contrast, Masters athletes showed younger Modelflow aortic ages than their chronological ages. The coefficient of variation of sedentary subjects was three times smaller with the Modelflow aortic age (21%) than with other indexes, such as static systemic arterial stiffness (61%), central pulse wave velocity (61%), or carotid β-stiffness index (58%). The typical error was very small and two times smaller in the Modelflow aortic age (<7%) than in static systemic arterial stiffness (>13%) during cardiac unloading by lower body negative pressure. The Modelflow aortic age can more precisely and reliably estimate aortic stiffening with aging and modifiers, such as life-long exercise training compared with the pressure-dependent index of static systemic arterial stiffness, and provides a physiologically relevant and clinically compelling context for such measurements.     

Progressive resistance training without volume increases does not alter arterial stiffness and aortic wave reflection

Endurance exercise is efficacious in reducing arterial stiffness. However, the effect of resistance training (RT) on arterial stiffening is controversial. High-intensity, high-volume RT has been shown to increase arterial stiffness in young adults. We tested the hypothesis that an RT protocol consisting of progressively higher intensity without concurrent increases in training volume would not elicit increases in either central or peripheral arterial stiffness or alter aortic pressure wave reflection in young men and women. The RT group (n = 24; 21 +/- 1 years) performed two sets of 8-12 repetitions to volitional fatigue on seven exercise machines on 3 days/week for 12 weeks, whereas the control group (n = 18; 22 +/- 1 years) did not perform RT. Central and peripheral arterial pulse wave velocity (PWV), aortic pressure wave reflection (augmentation index; AIx), brachial flow-mediated dilation (FMD), and plasma levels of nitrate/nitrite (NOx) and norepinephrine (NE) were measured before and after RT. RT increased the one-repetition maximum for the chest press and the leg extension (P < 0.001). RT also increased lean body mass (P < 0.01) and reduced body fat (%; P < 0.01). However, RT did not affect carotid-radial, carotid-femoral, and femoral-distal PWV (8.4 +/- 0.2 vs. 8.0 +/- 0.2 m/sec; 6.5 +/- 0.1 vs. 6.3 +/- 0.2 m/sec; 9.5 +/- 0.3 vs. 9.5 +/- 0.3 m/sec, respectively) or AIx (2.5% +/- 2.3% vs. 4.8% +/- 1.8 %, respectively). Additionally, no changes were observed in brachial FMD, NOx, NE, or blood pressures. These results suggest that an RT protocol consisting of progressively higher intensity without concurrent increases in training volume does not increase central or peripheral arterial stiffness or alter aortic pressure wave characteristics in young subjects.     

Increased arterial stiffness in children treated with anthracyclines for malignant disease

Survivors of childhood cancer have a significantly higher late morbidity and mortality from cardiovascular diseases. The aim of this study was to determine whether anthracyclines used in childhood could increase arterial stiffness, a well-known independent predictor of cardiovascular diseases. The study included 53 children and adolescents aged 6-20 years having completed anthracycline treatment for a malignant disease according to various protocols at least a year before. The patients were free from clinical or laboratory signs of the underlying disease or cardiac disease. Control group consisted of 45 age- and sex-matched healthy children. Arterial stiffness was determined by measuring aortic pulse wave velocity (PWVao) using oscillometric method (Arteriograph TensioMed device). PWVao value was significantly increased (6.24 +/- 1.34 m/s vs. 5.42 +/- 0.69 m/s; p < 0.001) in patients having received anthracyclines as compared to control group. Increased arterial stiffness was present irrespective of the following parameters: age, sex, body mass index, systolic and diastolic blood pressure, mean arterial pressure and heart rate. It is possible that the effect of anthracycline on increased cardiovascular morbidity and mortality in long-term childhood cancer survivors is associated not only with cardiotoxicity, but also with increased arterial stiffness.     

Thyroid Feedback Quantile-Based Index Is Associated With Blood Pressure and Other Hemodynamic Measures: A Cross-sectional Study

ObjectivePrevious studies have reported inconsistent relationships between thyroid function and blood pressure (BP) levels. We aimed to explore the associations between thyroid hormone sensitivity and BP parameters.MethodsThis retrospective study included 6272 participants who underwent a health examination at the First Hospital of China Medical University between January 2017 and December 2018. The Thyroid Feedback Quantile-based Index (TFQI), Parametric TFQI, thyroid-stimulating hormone index, and thyrotroph thyroxine resistance index were calculated to reflect thyroid hormone sensitivity. Mean arterial pressure, pulse pressure, and rate-pressure product were used to indirectly represent arterial stiffness.ResultsThe TFQI was positively associated with systolic BP (β = 3.22), diastolic BP (β =2.32), and mean arterial pressure (β = 2.62) (P < .001, for all). Analyses of the Parametric TFQI, thyroid-stimulating hormone index, and thyrotroph thyroxine resistance index yielded similar results. The TFQI was positively related to pulse pressure and rate-pressure product. With a 1 SD increase in the TFQI, the adjusted odds ratio for hypertension was 1.11 (95% CI 1.04-1.18). When comparing the fourth quartile of the TFQI with the first, the odds ratio for hypertension was 1.27 (95% CI 1.07-1.51, P_{for trend} = .006). These relationships remained significant when stratified by age, sex, and body mass index. Similar results were observed in a euthyroid or normotensive population.ConclusionThe TFQI was positively associated with BP and markers of arterial stiffness. Impaired thyroid hormone sensitivity was related to increased risk for hypertension.     

Evaluation of Cardiovascular Risk With Arterial Stiffness in Patients With Nonfunctioning Pituitary Adenoma

Objective: Nonfunctioning pituitary adenoma (NFPA) accounts for 30% of all pituitary adenomas, and its incidence has been increasing compared to previous years. Increased risk of cardiovascular effects shown in recent studies is noteworthy in patients with NFPA diagnosis, but the number of studies on the subject is limited. In this study, we aimed to assess possible cardiovascular effects and risk via arterial stiffness measurements in patients diagnosed with NFPA.Methods: We performed arterial stiffness measurements for 30 patients diagnosed with NFPA and 30 healthy volunteers and compared the results to explore the relationship between arterial stiffness parameters, hormone levels, and adenoma size.Results: Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP), central SBP, central DBP, augmentation index corrected for a heart rate of 75 beats per minute (AIx@75), and pulse wave velocity (PWV) values of the patients with NFPA diagnosis were significantly higher than the control group. PWV was found to have a significant and negative correlation with growth hormone and insulin-like growth factor 1 (IGF-1). A significant and positive correlation was found between adenoma median short-axis length and PWV. IGF-1 was found to have a significant and negative correlation with adenoma median long- and short-axis length. In multivariate linear regression analysis, we found that IGF-1 was an independent predictor of PWV.Conclusion: Both arterial stiffness parameters such as AIx@75 and PWV and peripheral SBP, DBP, and MBP values were found to be high in NFPA patients with no cardiovascular risk factors. Our findings suggest increased cardiovascular effect and risk in patients with NFPA diagnosis, and therefore, we recommend that patients are monitored closely in this respect.Abbreviations: ACTH = adrenocorticotropic hormone; AIx@75 = augmentation index corrected for a heart rate of 75 beats per minute; BMI = body mass index; CVD = cardiovascular disease; DBP = diastolic blood pressure; FSH = follicle-stimulating hormone; GH = growth hormone; HT = hypertension; IGF-1 = insulin-like growth factor 1; LH = luteinizing hormone; MBP = mean blood pressure; MRI = magnetic resonance imaging; NFPA = nonfunctioning pituitary adenoma; PP = pulse pressure; PWA = pulse wave analysis; PWV = pulse wave velocity; SBP = systolic blood pressure; TSH = thyroid-stimulating hormone     

The plasma concentration of advanced oxidation protein products and arterial stiffness in apparently healthy adults

BACKGROUND: Oxidative stress plays an important role in the pathogenesis of atherosclerosis. Advanced oxidation protein products (AOPP) are markers of oxidative stress and mediators of inflammation. Increased arterial stiffness is associated with increased risk of cardiovascular mortality and morbidity. The aim of this study was to evaluate the relationship between an indirect marker of arterial stiffness and the AOPP level in apparently healthy individuals. METHODS AND RESULTS: Arterial stiffness was estimated with the use of the stiffness index (SI(DVP)) which significantly correlated with age, mean blood pressure, body fat content and AOPP. The SI(DVP) was associated with AOPP concentration in both single (R = 0.22, p = 0.03) and multiple regression models adjusted for age, sex, mean blood pressure and body fat content (R(2) = 42%, p < 0.0001). CONCLUSIONS: The AOPP concentration is elevated in healthy people with increased values of stiffness index. This finding supports the concept that oxidative stress may contribute to arterial stiffening in humans.     

Abnormal arterial flows by a distributed model of the fetal circulation

Modeling the propagation of blood pressure and flow along the fetoplacental arterial tree may improve interpretation of abnormal flow velocity waveforms in fetuses. The current models, however, either do not include a wide range of gestational ages or do not account for variation in anatomical, vascular, or rheological parameters. We developed a mathematical model of the pulsating fetoumbilical arterial circulation using Womersley's oscillatory flow theory and viscoelastic arterial wall properties. Arterial flow waves are calculated at different arterial locations from which the pulsatility index (PI) can be determined. We varied blood viscosity, placental and brain resistances, placental compliance, heart rate, stiffness of the arterial wall, and length of the umbilical arteries. The PI increases in the umbilical artery and decreases in the cerebral arteries, as a result of increasing placental resistance or decreasing brain resistance. Both changes in resistance decrease the flow through the placenta. An increased arterial stiffness increases the PIs in the entire fetoplacental circulation. Blood viscosity and peripheral bed compliance have limited influence on the flow profiles. Bradycardia and tachycardia increase and decrease the PI in all arteries, respectively. Umbilical arterial length has limited influence on the PI but affects the mean arterial pressure at the placental cord insertion. The model may improve the interpretation of arterial flow pulsations and thus may advance both the understanding of pathophysiological processes and clinical management.     

Reduction of blood pressure by indirect biofeedback

Forty-five randomly assigned subjects served in either a relaxation control, an EMG plus thermal, or a thermal biofeedback group. All groups received the same relaxation manipulation. Experimental results demonstrated a significant drop in both diastolic and systolic blood pressure for the feedback treatment. Diastolic measures showed a somewhat greater decrease for the EMG plus thermal treatment condition. A learning effect was demonstrated both within and across the three experimental sessions. Given that the sample was normotensive, the 20% reduction in blood pressure was notable. The results support the idea that blood pressure biofeedback is not a necessary condition for reduction of arterial blood pressure.     

Relationship between androgenic hormones and arterial stiffness, based on longitudinal hormone measurements

Circulating testosterone levels (T) decrease with age in men. Low T has been associated with coronary disease and with risk factors for atherosclerosis. This study examines the relationship in men between androgenic hormones and arterial stiffness, a major risk factor for cardiovascular events. T, sex hormone-binding globulin (SHBG), and dehydroepiandrosterone sulfate (DHEAS) were measured longitudinally over 33 yr (follow-up 11.8 +/- 8.3 yr) in 901 men from the Baltimore Longitudinal Study of Aging, of whom 206 (68.1 +/- 13.7 yr) underwent carotid duplex ultrasonography. The 901 men were used to characterize age-associated hormone levels by means of mixed-effects models. Hormone values were estimated for the 206 men at the time of ultrasonography. Free T index (FTI) was calculated by dividing T by SHBG. The arterial stiffness index was calculated from peak systolic and end diastolic diameters of the common carotid artery and simultaneous brachial artery blood pressure. T, FTI, and DHEAS were correlated negatively with age, pulse pressure (PP), and stiffness index (each P < 0.01), whereas SHBG was correlated positively with age and stiffness index (P < 0.01). However, T was the only hormone that predicted the stiffness index after adjustment for age, PP, fasting plasma glucose, body mass index, and total cholesterol. T values 5-10 yr before the carotid study also predicted the stiffness index (P < 0.05). Thus the adverse influence of low T on the cardiovascular system in men may be mediated in part via the effects of T on vascular structure and function.     

Decreased aortic diameter and compliance precedes blood pressure increases in postnatal development of elastin-insufficient mice

Increased arterial stiffness and blood pressure are characteristic of humans and adult mice with reduced elastin levels caused by aging or genetic disease. Direct associations have been shown between increased arterial stiffness and hypertension in humans, but it is not known whether changes in mechanical properties or increased blood pressure occur first. Using genetically modified mice with elastin haploinsufficiency (Eln(+/-)), we investigated the temporal relationship between arterial mechanical properties and blood pressure throughout postnatal development. Our results show that some mechanical properties are maintained constant regardless of elastin amounts. The peak diameter compliance for both genotypes occurs near the physiologic pressure at each age, which acts to provide maximum pulse dampening. The stress-strain relationships are similar between genotypes and become nonlinear near the systolic pressure for each age, which serves to limit distension under high pressure. Our results also show that some mechanical properties are affected by reduced elastin levels and that these changes occur before measurable changes in blood pressure. Eln(+/-) mice have decreased aortic diameter and compliance in ex vivo tests that are significant by postnatal day 7 and increased blood pressure that is not significant until postnatal day 14. This temporal relationship suggests that targeting large arteries to increase diameter or compliance may be an effective treatment for human hypertension.     

有创动脉压监测在危重肝胆手术患者中的应用

目的:探讨有创动脉压监测在危重肝胆手术患者中的应用方法与价值。方法:选择2011年2月到2015年4月在我院进行危重肝胆手术的患者110例,随机分为治疗组与对照组各55例,治疗组在围手术期给予有创动脉压监测,对照组在围手术期给予无创动脉压监测。除所用传感器不一样,均采用监护仪检测患者在围手术期内血压异常、血流动力学参数变化以及并发症发生情况。结果:治疗组围手术期的血压异常率为36.4%,对照组为12.7%,治疗组的血压异常率明显高于对照组(P0.05)。治疗组术中的平均动脉压(MAP)、每搏出量(SV)、每搏指数(SI)、心输出量(CO)和心脏指数(CI)都明显高于对照组(P0.05)。两组围手术期的感染、血肿、神经损伤、皮肤坏死等并发症发生情况对比差异无统计学意义(P0.05)。结论:有创动脉压监测在危重肝胆手术患者中的应用可有效反映血压异常情况,有利于进行心功能的判定,安全性好,有很好的应用价值。     

Exercise reduces arterial pressure augmentation through vasodilation of muscular arteries in humans

Exercise markedly influences pulse wave morphology, but the mechanism is unknown. We investigated whether effects of exercise on the arterial pulse result from alterations in stroke volume or pulse wave velocity (PWV)/large artery stiffness or reduction of pressure wave reflection. Healthy subjects (n = 25) performed bicycle ergometry. with workload increasing from 25 to 150 W for 12 min. Digital arterial pressure waveforms were recorded using a servo-controlled finger cuff. Radial arterial pressure waveforms and carotid-femoral PWV were determined by applanation tonometry. Stroke volume was measured by echocardiography, and brachial and femoral artery blood flows and diameters were measured by ultrasound. Digital waveforms were recorded continuously. Other measurements were made before and after exercise. Exercise markedly reduced late systolic and diastolic augmentation of the peripheral pressure pulse. At 15 min into recovery, stroke volume and PWV were similar to baseline values, but changes in pulse wave morphology persisted. Late systolic augmentation index (radial pulse) was reduced from 54 +/- 3.9% at baseline to 42 +/- 3.7% (P < 0.01), and diastolic augmentation index (radial pulse) was reduced from 37 +/- 1.8% to 25 +/- 2.9% (P < 0.001). These changes were accompanied by an increase in femoral blood flow (from 409 +/- 44 to 773 +/- 48 ml/min, P < 0.05) and an increase in femoral artery diameter (from 8.2 +/- 0.4 to 8.6 +/- 0.4 mm, P < 0.05). In conclusion, exercise dilates muscular arteries and reduces arterial pressure augmentation, an effect that will enhance ventricular-vascular coupling and reduce load on the left ventricle.     

Reflex control of vascular capacitance during hypoxia, hypercapnia, or hypoxic hypercapnia

We tested the hypothesis that the changes in venous tone induced by changes in arterial blood oxygen or carbon dioxide require intact cardiovascular reflexes. Mongrel dogs were anesthetized with sodium pentobarbital and paralyzed with veruronium bromide. Cardiac output and central blood volume were measured by indocyanine green dilution. Mean circulatory filling pressure, an index of venous tone at constant blood volume, was estimated from the central venous pressure during transient electrical fibrillation of the heart. With intact reflexes, hypoxia (arterial PaO2 = 38 mmHg), hypercapnia (PaCO2 = 72 mmHg), or hypoxic hypercapnia (PaO2 = 41; PaCO2 = 69 mmHg) (1 mmHg = 133.32 Pa) significantly increased the mean circulatory filling pressure and cardiac output. Hypoxia, but not normoxic hypercapnia, increased the mean systemic arterial pressure and maintained the control level of total peripheral resistance. With reflexes blocked with hexamethonium and atropine, systemic arterial pressure supported with a constant infusion of norepinephrine, and the mean circulatory filling pressure restored toward control with 5 mL/kg blood, each experimental gas mixture caused a decrease in total peripheral resistance and arterial pressure, while the mean circulatory filling pressure and cardiac output were unchanged or increased slightly. We conclude that hypoxia, hypercapnia, and hypoxic hypercapnia have little direct influence on vascular capacitance, but with reflexes intact, there is a significant reflex increase in mean circulatory filling pressure.     

Increased Arterial Stiffness in Systemic Lupus Erythematosus (SLE) Patients at Low Risk for Cardiovascular Disease: A Cross-Sectional Controlled Study

Cardiovascular disease (CVD) is a major cause of death in systemic lupus erythematosus (SLE) patients. Although the risk for cardiovascular events in patients with SLE is significant, the absolute number of events per year in any given cohort remains small. Thus, CVD risks stratification in patients with SLE focuses on surrogate markers for atherosclerosis at an early stage, such as reduced elasticity of arteries. Our study was designed to determine whether arterial stiffness is increased in SLE patients at low risk for CVD and analyze the role for traditional and non-traditional CVD risk factors on arterial stiffness in SLE. Carotid-femoral pulse wave velocity (PWV) was prospectively assessed as a measure of arterial stiffness in 41 SLE patients and 35 controls (CTL). Adjustment on age or Framingham score was performed using a logistic regression model. Factors associated with PWV were identified separately in SLE patients and in controls using Pearson''s correlation coefficient for univariate analysis and multiple linear regression for multivariate analysis. SLE patients and controls displayed a low 10-year risk for CVD according to Framingham score (1.8±3.6% in SLE vs 1.6±2.8% in CTL, p = 0.46). Pulse wave velocity was, however, higher in SLE patients (7.1±1.6 m/s) as compared to controls (6.3±0.8 m/s; p = 0.01, after Framingham score adjustment) and correlated with internal carotid wall thickness (p = 0.0017). In multivariable analysis, only systolic blood pressure (p = 0.0005) and cumulative dose of glucocorticoids (p = 0.01) were associated with PWV in SLE patients. Interestingly, the link between systolic blood pressure (SBP) and arterial stiffness was also confirmed in SLE patients with normal systolic blood pressure. In conclusion, arterial stiffness is increased in SLE patients despite a low risk for CVD according to Framingham score and is associated with systolic blood pressure and glucocorticoid therapy.