Acute Central Hemodynamic Effects of a Volume Exchange in Peritoneal Dialysis

Background

Although peritoneal dialysis is considered to offer more hemodynamic stability than hemodialysis, the acute hemodynamic effects of peritoneal dialysis have only been investigated scarcely. The present study assesses the central hemodynamic impact of volume infusion using pH-adjusted icodextrin, thus avoiding interference of glucose, pH, and osmolarity.

Methods

Patients were randomized to 3 different starting volumes (A: 1000 mL, B: 1500 mL, and C: 2500 mL) of icodextrin, followed by addition (A and B) or drainage (C) of 200 mL every 10 minutes for 50 minutes. Local carotid systolic blood pressure (BP; as a surrogate for central BP), augmentation index, and augmentation pressure were measured by applanation tonometry before and after infusion of the starting volumes and after each volume change.

Results

We included 13 patients (median age 57 years). Baseline brachial BP was 126/77 mmHg. After infusion of the starting volume, carotid systolic BP and augmentation pressure increased by 4.7 mmHg ( p = 0.006) and 3.1 mmHg ( p = 0.015). Augmentation index increased by 5.7% ( p = 0.04) and heart rate decreased by 2.6/minute ( p = 0.006). Intraperitoneal pressure increased by 2.3 cm H2O ( p = 0.03). No additional hemodynamic changes except for a rise in diastolic BP with increasing volume ( p = 0.004) were observed after subsequent addition or removal of volumes.

Conclusions

Infusion of peritoneal dialysis fluids causes an acute increase in carotid systolic B P, followed by a progressive rise in diastolic BP. These effects persist until complete drainage of the abdomen and may be due to an enhanced preload, resulting from intraperitoneal venous compression, and/or increased wave reflection.

Reference values for local arterial stiffness. Part B: femoral artery

OBJECTIVE

Carotid-femoral pulse wave velocity (PWV) is considered the gold standard measure of arterial stiffness, representing mainly aortic stiffness. As compared with the elastic carotid and aorta, the more muscular femoral artery may be differently associated with cardiovascular risk factors (CV-RFs), or, as shown in a recent study, provide additional predictive information beyond carotid-femoral PWV. Still, clinical application is hampered by the absence of reference values. Therefore, our aim was to establish age and sex-specific reference values for femoral stiffness in healthy individuals and to investigate the associations with CV-RFs.

METHODS

Femoral artery distensibility coefficient, the inverse of stiffness, was calculated as the ratio of relative diastolic-systolic distension (obtained from ultrasound echo-tracking) and pulse pressure among 5069 individuals (49.5% men, age range: 15-87 years). Individuals without cardiovascular disease (CVD), CV-RFs and medication use (n = 1489; 43% men) constituted a healthy subpopulation used to establish sex-specific equations for percentiles of femoral artery distensibility coefficient across age.

RESULTS

In the total population, femoral artery distensibility coefficient Z-scores were independently associated with BMI, mean arterial pressure (MAP) and total to high-density lipoprotein (HDL) cholesterol ratio. Standardized βs, in men and women, respectively, were -0.18 [95% confidence interval (95% CI) -0.23 to -0.13] and -0.19 (-0.23 to -0.14) for BMI; -0.13 (-0.18 to -0.08) and -0.05 (-0.10 to -0.01) for MAP; and -0.07 (-0.11 to -0.02) and -0.16 (-0.20 to -0.11) for total-to-HDL cholesterol ratio.

CONCLUSION

In young and middle-aged men and women, normal femoral artery stiffness does not change substantially with age up to the sixth decade. CV-RFs related to metabolic disease are associated with femoral artery stiffness.

Vascular dysregulation in normal-tension glaucoma is not affected by structure and function of the microcirculation or macrocirculation at rest: a case-control study

In normal-tension glaucoma (NTG), optic nerve damage occurs despite a normal intraocular pressure. Studies implicating systemic blood pressure or, more recently, arterial stiffness in the pathophysiology of NTG have produced conflicting results. Our aim was to investigate whether NTG is associated with alterations in the macrocirculation or microcirculation, cardiac function, and peripheral and central hemodynamics. Thirty patients with NTG (mean age 65 years, range 46-79) and 33 healthy subjects (mean age 67 years, range 42-79) matched for age and sex were included in the study. Exclusion criteria (for both cases and controls) were history of cardiovascular disease, diabetes mellitus, severe hypertension, and hypercholesterolemia. Aortic stiffness was measured using carotid-femoral pulse wave velocity (PWV), central hemodynamics using carotid artery applanation tonometry, and diameter, stiffness, and intima-media thickness (IMT) of the carotid and femoral artery using echo-tracking. Total peripheral resistance index (TPRI) was derived from mean arterial pressure and cardiac index, measured using ultrasound. There were no statistically significant differences in arterial structure nor function between NTG patients and age and sex-matched controls. NTG versus controls, respectively: brachial blood pressure 126 ± 15/77 ± 8 versus 127 ± 16/76 ± 7 mm Hg, P = 0.81; carotid-femoral PWV 9.8 ± 2.1 versus 10.1 ± 1.9 m/s, P = 0.60; TPRI 1833 ± 609 versus 1779 ± 602 dyne.s/cm5/m2, P = 0.79; and carotid IMT 0.65 ± 0.14 versus 0.68 ± 0.13 mm, P = 0.39. This study could not show an association of NTG with altered IMT, arterial stiffness, total peripheral resistance, cardiac output, and peripheral or central hemodynamics at rest. Although the majority of these NTG patients do exhibit symptoms of vascular dysregulation, in the present study this was not translated into alterations in the microcirculation or macrocirculation at rest.

Barriers to antipsychotic discontinuation in nursing homes: an exploratory study

OBJECTIVES

Despite safety warnings on serious adverse effects and guidance advising discontinuation, antipsychotic use in nursing homes remains high. Studies documenting the barriers experienced to antipsychotic discontinuation are rare. This exploratory study investigates the willingness of nurses and general practitioners (GPs) as well as the barriers to undertake antipsychotic discontinuation.

DESIGN AND SETTING

A mixed-method study involving an expert meeting, followed by a survey using structured questionnaires distributed to responsible nurses (primary caregivers) and treating GPs on selected nursing home residents in Belgian nursing homes to generate case-specific information.

RESULTS

Antipsychotic users (n = 113) had a mean age of 81 years (range 57-97); 62% were female and 81% had moderate to severe cognitive impairment. Nurses and GPs indicated a willingness for antipsychotic discontinuation in a small proportion of residents, 13.8% and 12.2%, respectively, with a shared willingness in only 4.2%. Residents for whom there was a higher willingness to try antipsychotic discontinuation were generally older (mean age 84.6 vs. 80.3, p = 0.07), had high physical dependency (ADL > 14, 93.3% vs. 60.9%, p = 0.01) and resided on a ward with controlled access (80.0% vs. 45.7%, p = 0.02). In contrast, residents for whom there was a significant lower willingness for discontinuation already had a previously failed discontinuation effort, and may present risk of harm to themselves or to others. Nurses working longer on the ward, with lower education, presented higher barriers to discontinuation of antipsychotics.

CONCLUSION

Nurses and GPs share a very low willingness and high barriers to antipsychotic discontinuation. To implement discontinuation programs, complex multidisciplinary interventions should be offered taking existing barriers into account.

Moxifloxacin dosing in post-bariatric surgery patients

INTRODUCTION

Given the ever increasing number of obese patients and obesity related bypass surgery, dosing recommendations in the post-bypass population are needed. Using a population pharmacokinetic (PK) analysis and PK-pharmacodynamic (PD) simulations, we investigated whether adequate moxifloxacin concentrations are achieved in this population.

METHODS

In this modelling and simulation study we used data from a trial on moxifloxacin PK. In this trial, volunteers who had previously undergone bariatric surgery (at least 6 months prior to inclusion), received two doses (intravenous and oral) of 400 mg moxifloxacin administered on two occasions.

RESULTS

In contrast to other papers, we found that moxifloxacin PK were best described by a three compartmental model using lean body mass (LBM) as a predictor for moxifloxacin clearance. Furthermore, we showed that the probability of target attainment for bacterial eradication against a hypothetical Streptococcus pneumoniae infection is compromised in patients with higher LBM, especially when targeting microorganisms with minimum inhibitory concentrations (MICs) of 0.5 mg l(-1) or higher (probability of target attainment (PTA) approaching zero). When considering the targets for suppression of bacterial resistance formation, even at MIC values as low as 0.25 mg l(-1) , standard moxifloxacin dosing does not attain adequate levels in this population. Furthermore, for patients with a LBM of 78 kg or higher, the probability of hitting this target approaches zero.

CONCLUSIONS

Throughout our PK-PD simulation study, it became apparent that, whenever optimal bacterial resistance suppression is deemed necessary, the standard moxifloxacin dosing will not be sufficient. Furthermore, our study emphasizes the need for a LBM based individualized dosing of moxifloxacin in this patient population.

Cardiovascular risk assessment in low-resource settings: a consensus document of the European Society of Hypertension Working Group on Hypertension and Cardiovascular Risk in Low Resource Settings

The Global Burden of Diseases, Injuries, and Risk Factors Study 2010 confirms ischemic heart disease and stroke as the leading cause of death and that hypertension is the main associated risk factor worldwide. How best to respond to the rising prevalence of hypertension in resource-deprived settings is a topic of ongoing public-health debate and discussion. In low-income and middle-income countries, socioeconomic inequality and cultural factors play a role both in the development of risk factors and in the access to care. In Europe, cultural barriers and poor communication between health systems and migrants may limit migrants from receiving appropriate prevention, diagnosis, and treatment. To use more efficiently resources available and to make treatment cost-effective at the patient level, cardiovascular risk approach is now recommended. In 2011, The European Society of Hypertension established a Working Group on 'Hypertension and Cardiovascular risk in low resource settings', which brought together cardiologists, diabetologists, nephrologists, clinical trialists, epidemiologists, economists, and other stakeholders to review current strategies for cardiovascular risk assessment in population studies in low-income and middle-income countries, their limitations, possible improvements, and future interests in screening programs. This report summarizes current evidence and presents highlights of unmet needs.

Systematic appraisal of dementia guidelines for the management of behavioural and psychological symptoms

BACKGROUND

Within the treatment of dementia, management of behavioural and psychological symptoms (BPSD) is a complex component.

PURPOSE

We wanted to offer a pragmatic synthesis of existing specific practice recommendations for managing BPSD, based on agreement among systematically appraised dementia guidelines.

DATA SOURCES

We conducted a systematic search in MEDLINE and guideline organisation databases, supplemented by a hand search of web sites.

STUDY SELECTION

Fifteen retrieved guidelines were eligible for quality appraisal by the Appraisal of Guidelines Research and Evaluation instrument (AGREE), performed by 2 independent reviewers.

DATA EXTRACTION

From the 5 included guidelines, 18 specific practice recommendations for BPSD were extracted and compared for their level of evidence and strength.

DATA SYNTHESIS

No agreement was found among dementia guidelines for the majority of specific practice recommendations with regard to non-pharmacological interventions, although these were recommended as first-line treatment. Pharmacological specific practice recommendations were proposed as second-line treatment, with agreement for the use of a selection of antipsychotics based on strong supporting evidence, but with guidance for timely discontinuation.

LIMITATIONS

The appraisal of the level of agreement between guidelines for each specific practice recommendation was complicated by variation in grading systems, and was performed with criteria developed a posteriori.

CONCLUSION

Despite the limited number of recommendations for which agreement was found, guidelines did agree on careful antipsychotic use for BPSD. Adverse events might outweigh the supporting evidence of efficacy, weakening the recommendation. More pivotal trials on the effectiveness of non-pharmacological interventions, as well as guidelines specifically focusing on BPSD, are needed.

Aortic stiffness and central wave reflections predict outcome in renal transplant recipients

Although renal transplantation improves survival, cardiovascular morbidity and mortality remain significantly elevated compared with nonrenal populations. The negative impact of traditional, uremia-related, and transplantation-related risk factors in this process remains, however, largely unexplored. Surrogate markers such as aortic stiffness and central wave reflections may lead to more accurate cardiovascular risk stratification, but outcome data in renal transplant recipients are scarce. We aimed to establish the prognostic significance of these markers for fatal and nonfatal cardiovascular events in renal transplant recipients. Carotid-femoral pulse wave velocity, central augmentation pressure, and central augmentation index were measured in a cohort of 512 renal transplant recipients using the SphygmoCor system. After a mean follow-up of 5 years, 20 fatal and 75 nonfatal cardiovascular events were recorded. Using receiver operating characteristic curves, the area under the curve for predicting cardiovascular events was 0.718 (95% CI 0.659-0.776) for pulse wave velocity, 0.670 (95% CI 0.604-0.736) for central augmentation pressure, and 0.595 (95% CI 0.529-0.660) for central augmentation index. When we accounted for age, gender, and C-reactive protein in Cox-regression analysis, pulse wave velocity (hazard ratio: 1.349 per 1 SD increase; 95% CI 1.104-1.649; P=0.003) and central augmentation pressure (hazard ratio: 1.487 per 1 SD increase; 95% CI 1.219-1.814; P<0.001) remained independent predictors of outcome. Aortic stiffness and increased wave reflections are independent predictors of cardiovascular events in renal transplant recipients. As single parameter of wave reflection, central augmentation pressure was better than central augmentation index. Combined measurement of pulse wave velocity and central augmentation pressure may contribute to an accurate cardiovascular risk estimation in this heterogeneous population.

Telomere length and its associations with oxidized-LDL, carotid artery distensibility and smoking

Oxidative stress is a key factor driving the aging of cells and arteries. Studies suggest that white blood cell (WBC) telomere length is an index of systemic aging. We, therefore, investigated the association between WBC telomere length and oxidized-LDL, and vascular aging, expressed by the distensibility of the carotid artery. We studied a random population sample of 216 non-smokers and 89, smokers. In all subjects, age and gender- adjusted telomere length was inversely correlated with plasma oxidized-LDL (regression coefficient = -0.656 kb/mg/dL; p=0.0006). Independent of gender, age and mean blood pressure, carotid distensibility increased with telomere length (2.33+/- 1.18 10-3/kPa/kb; p=0.05) but decreased with higher plasma levels of oxidized LDL (-10.7+/- 3.91 10-3/kPa/ mg/dL; p=0.006). Adjusted for gender and age, smokers' telomere length was shorter (6.72 vs 6.91 kb; p=0.014) and plasma oxidized-LDL level higher (0.52 vs 0.46 mg/dL; p=0.03) than in non-smokers. Higher level of oxidized-LDL, is associated with shorter WBC telomeres and increased stiffness of the carotid artery. Smoking is marked by increased oxidative stress in concert with shortened WBC telomere length.

Evaluation of noninvasive methods to assess wave reflection and pulse transit time from the pressure waveform alone

Accurate quantification of pressure wave reflection requires separation of pressure in forward and backward components to calculate the reflection magnitude as the ratio of the amplitudes backward and forward pressure. To do so, measurement of aortic flow in addition to the pressure wave is mandatory, a limitation that can be overcome by replacing the unknown flow wave by an (uncalibrated) triangular estimate. Another extended application of this principle is the derivation of aortic pulse transit time from a single pulse recording. We verified these approximation techniques for reflection magnitude and transit time using carotid pressure and aortic flow waveforms measured noninvasively in the Asklepios Study (>2500 participants; 35 to 55 years of age). A triangular flow approximation using timing information from the measured aortic flow waveform yielded moderate agreement between reference and estimated reflection magnitude (R(2)=0.55). Approximating the flow by a more physiological waveform significantly improved these results (R(2)=0.74). Aortic transit time was assessed using pressure and measured or approximated flow waveforms, and results were compared with carotid-femoral transit times measured by Doppler ultrasound. Agreement between estimated and reference transit times was moderate (R(2)<0.29). Both for reflection magnitude and transit time, agreement between reference and approximated values further decreased when the approximated flow waveform was obtained using timing information from the pressure waveform. We conclude that, in our Asklepios population, results from pressure-based approximative methods to derive reflection magnitude or aortic pulse transit time differ substantially from the values obtained when using both measured pressure and flow information.

Acute central hemodynamic effects of a volume exchange in peritoneal dialysis

BACKGROUND

Although peritoneal dialysis is considered to offer more hemodynamic stability than hemodialysis, the acute hemodynamic effects of peritoneal dialysis have only been investigated scarcely. The present study assesses the central hemodynamic impact of volume infusion using pH-adjusted icodextrin, thus avoiding interference of glucose, pH, and osmolarity.

METHODS

Patients were randomized to 3 different starting volumes (A: 1000 mL, B: 1500 mL, and C: 2500 mL) of icodextrin, followed by addition (A and B) or drainage (C) of 200 mL every 10 minutes for 50 minutes. Local carotid systolic blood pressure (BP; as a surrogate for central BP), augmentation index, and augmentation pressure were measured by applanation tonometry before and after infusion of the starting volumes and after each volume change.

RESULTS

We included 13 patients (median age 57 years). Baseline brachial BP was 126/77 mmHg. After infusion of the starting volume, carotid systolic BP and augmentation pressure increased by 4.7 mmHg (p = 0.006) and 3.1 mmHg (p = 0.015). Augmentation index increased by 5.7% (p = 0.04) and heart rate decreased by 2.6/minute (p = 0.006). Intraperitoneal pressure increased by 2.3 cm H(2)O (p = 0.03). No additional hemodynamic changes except for a rise in diastolic BP with increasing volume (p = 0.004) were observed after subsequent addition or removal of volumes.

CONCLUSIONS

Infusion of peritoneal dialysis fluids causes an acute increase in carotid systolic BP, followed by a progressive rise in diastolic BP. These effects persist until complete drainage of the abdomen and may be due to an enhanced preload, resulting from intraperitoneal venous compression, and/or increased wave reflection.

Efficacy and tolerability of nebivolol compared with other antihypertensive drugs: a meta-analysis

BACKGROUND AND OBJECTIVE

Lowering BP to normal levels without quality of life deterioration is the most important means of reducing cardiovascular risk. Recent studies have challenged the position of beta-adrenoceptor antagonists (beta-blockers) as first-line antihypertensive drugs. Nebivolol is a third-generation, highly selective beta(1)-blocker that causes vasodilation through nitric oxide (NO) release. This meta-analysis investigates the efficacy and tolerability of nebivolol compared with other antihypertensive drugs and placebo in patients with hypertension.

METHODS

Twelve randomized controlled studies were included in which nebivolol 5 mg once daily was compared with the recommended clinical doses of other antihypertensive drugs (n = 9), placebo (n = 2), and both (n = 1). The clinical studies were selected after a MEDLINE search up to 2007 using the key words 'nebivolol' and 'hypertension.'

RESULTS

Antihypertensive response rates (the percentage of patients achieving target BP levels or a defined DBP reduction) were higher with nebivolol than with ACE inhibitors (odds ratio [OR] 1.92; p = 0.001) and all antihypertensive drugs combined (OR 1.41; p = 0.001) and similar to beta-blockers, calcium channel antagonists (CCAs) and the angiotensin receptor antagonist (ARA) losartan. Moreover, a higher percentage of patients receiving nebivolol achieved target BP levels compared with patients treated with losartan (OR 1.98; p = 0.004), CCAs (OR 1.44; p = 0.024), and all antihypertensive drugs combined (OR 1.35; p = 0.012). The percentage of patients experiencing adverse events did not differ between nebivolol and placebo; adverse event rates were significantly lower with nebivolol than losartan (OR 0.52; p = 0.016), other beta-blockers (OR 0.56; p = 0.007), nifedipine (OR 0.49; p < 0.001), and all antihypertensive drugs combined (OR 0.59; p < 0.001).

CONCLUSION

Results of previous pharmacokinetic studies suggest that nebivolol 5 mg may not conform completely to the definition of a classic beta-blocker demonstrating additional antihypertensive effect due to endothelial NO release-mediated vasodilation. This meta-analysis showed that nebivolol 5 mg achieved similar or better rates of treatment response and BP normalization than other drug classes and other antihypertensive drugs combined, with similar tolerability to placebo and significantly better tolerability than losartan, CCAs, other beta-blockers, and all antihypertensive drugs combined. Although not definitive, this meta-analysis suggests that nebivolol 5 mg is likely to have advantages over existing antihypertensives and may have a role in the first-line treatment of hypertension.

Assessment of pressure wave reflection: getting the timing right!

Assessment of timing and magnitude of wave reflection is ideally based on wave separation analysis (WSA). In clinical practice, however, waveform analysis (WFA) is often used to study wave reflection, with different coexisting approaches to assess 'landmarks' on the waveform which are indicative for return of the reflected wave. The aim of this work was to compare WSA and WFA. Data were obtained from 2132 subjects (1093 women) aged between 35 and 56 and free from overt cardiovascular disease. Carotid pressure and aortic flow waveforms, and carotid-femoral pulse wave velocity were measured non-invasively. WSA yielded the timing of return of reflected wave (T(f-b)), the ratio of forward and backward pressure wave (P(b)/P(f)), and the effective length of the arterial tree (L(eff)). WFA resulted in identification of the shoulder (T(sho)) or inflection point (T(inf)) as landmark points, with subsequently derived augmentation index and L(eff) (AIx(sho) and L(eff,sho), AIx(inf) and L(eff,inf), respectively). (i) Neither T(inf) nor T(sho) corresponded with the timing obtained from WSA. (ii) Measurements of L(eff) were found to decrease with age (conforming with current physiological insights) whilst L(eff,inf) was found to increase with age in women, and mixed results were obtained for L(eff,sho). (iii) Both AIx(inf) and AIx(sho) showed a persistent gender difference which was not present in P(b)/P(f). Using the pressure at T(f-b) to calculate AIx, the systematic gender difference in AIx(f-b) was greatly reduced. Analysis of pressure wave reflection is optimally based on measurement of pressure and flow, rather than on waveform analysis alone.

Arterial stiffness and wave reflections in renal transplant recipients

BACKGROUND

Arterial stiffness predicts cardiovascular disease (CVD) events and has been well documented in haemodialysis patients. Information in renal transplant recipients (RTR), however, remains limited despite their higher CVD risk compared to the general population. We aimed to assess arterial stiffening and wave reflections in RTR and healthy controls and to evaluate which factors could explain potential differences.

METHODS

Carotid augmentation index (AI) and carotid-femoral pulse wave velocity (PWV) were measured in 200 RTR and 44 controls using applanation tonometry. The impact of traditional and non-traditional CVD risk factors was assessed using linear regression analysis. Glomerular filtration rate (GFR) was measured by (51)Cr-EDTA (RTR) and estimated using the abbreviated Modification of Diet in Renal Disease formula (RTR and controls).

RESULTS

After correction for age, blood pressure and anthropometry, AI and PWV remained 7.4 +/- 3.6% (P = 0.04) and 0.7 +/- 0.3 m/s (P = 0.01) higher in RTR than controls, corresponding to a difference in vascular age of >10 years. In multivariate analysis, additional independent factors related to AI and PWV were GFR (-1.8% and -0.19 m/s per 10 ml/min) and C-reactive protein (3.2% and 0.21 m/s per logarithm increase).

CONCLUSIONS

Increased arterial stiffness and wave reflections in RTR are attributable to incomplete restoration of GFR and the presence of subclinical inflammation.

Is the Migraid device an asset in the non-pharmacologic treatment of migraine?

Non-pharmacologic treatment of migraine attacks is advised by guidelines to be considered. Some patients use digital massage of the temporal arteries. The Migraid device exerts a constant pressure on the temporal arteries and may be an alternative for the tiring digital massage. The present study investigates whether the new Migraid device may improve migraine symptoms. In a randomised multi-centre cross-over study the efficacy, safety and tolerability of a 1-hour use of the Migraid device at the start of the aura is compared with no-device in the treatment of migraine attacks with typical aura. Of the 134 patients who entered the study, 98 were suitable for the intention-to-treat analysis and 83 patients completed the study. Data on 94 Migraid treated and 87 non-treated attacks have been analysed. Twelve percent of patients (10/83) were pain-free at 2 hours in the Migraid group versus 1.6% (1/64) in the non-treated group (p = 0.02). After 24-hours 9.6% of patients were pain-free with the Migraid versus 0% with no treatment. After 2 hours 31.3% of patients perceived the migraine headache as severe using the Migraid versus 53.1% with no treatment. For nausea this was 6.1% and 15.6%, respectively (p = 0.01). The device was well tolerated. In conclusion, 1-hour use of the Migraid device at the start of the aura improved headache and other migraine symptoms compared to no treatment. Future research with a more appropriate control should determine whether the Migraid effects are going beyond unspecific placebo effects.

Altered arterial function in migraine of recent onset

OBJECTIVE

Migraine is associated with cardiovascular disorders but the underlying mechanisms are unknown. Arterial structure and function are important determinants of cardiovascular morbidity and mortality. The aim of the present study was to assess arterial properties in patients with migraine of recent onset.

METHODS

In a cross-sectional study, structural and functional arterial properties were assessed using ultrasound and applanation tonometry in 50 patients with a history of migraine >1 and <6 years during a headache-free interval and 50 age- and gender-matched subjects without a history of migraine.

RESULTS

Brachial artery diameter (4.82 +/- 0.93 mm vs 5.39 +/- 0.89 mm, p = 0.01) and compliance (0.30 +/- 0.17 mm(2)/kPa vs 0.37 +/- 0.19 mm(2)/kPa, p = 0.02) were decreased in migraine patients compared with controls. Femoral artery compliance was decreased in migraine patients (1.19 +/- 0.55 mm(2)/kPa vs 1.42 +/- 0.59 mm(2)/kPa, p = 0.04). Carotid arterial wall properties were similar between groups. Aortic augmentation index was increased in migraine patients (4 +/- 10% vs -1 +/- 10%, adjusted p = 0.04). Flow-mediated vasodilation of the brachial artery (normalized to peak shear rate) was decreased in patients with migraine (29 +/- 15 vs 37 +/- 15 10(-3)%. sec, p = 0.006).

CONCLUSION

Functional arterial properties are altered in patients with migraine of recent onset.

Noninvasive (input) impedance, pulse wave velocity, and wave reflection in healthy middle-aged men and women

The relation between arterial function indices, such as pulse wave velocity and augmentation index with parameters derived from input impedance analysis, is still incompletely understood. Carotid pressure, central flow waveforms, and pulse wave velocity were noninvasively acquired in 2026 apparently healthy, middle-aged subjects (1052 women and 974 men) 35 to 55 years old at inclusion. Input and characteristic impedance, reflection coefficient, the ratio of backward-to-forward pressure amplitude (reflection magnitude), and augmentation index were derived. Pulse wave velocity increased by 15% (from 6.1 to 7.0 m/s) both in men and women. In qualitative terms, input impedance evolved from a pattern indicative of wave transmission and reflection to a pattern more compatible with a windkessel-like system. In women, a decrease in total arterial compliance led to an increased input impedance in the low frequency range, whereas few changes were observed in men. Characteristic impedance did not change with age in women and even decreased in men (P<0.001) and could not be identified as the primary determinant of central pulse pressure. Augmentation index increased with age, as was expected, and was systematically higher in women (P<0.001). Reflection coefficient and reflection magnitude increased with age (P<0.001) without gender differences. We conclude that, in healthy middle-aged subjects, the age-related increase in arterial stiffness (pulse wave velocity) is not fully paralleled by an increase in arterial impedance, suggesting a role for age-dependent modulation of aortic cross-sectional area. Wave reflection increases with age and is not higher in women than in men.

Association Between Arterial Properties and Renal Sodium Handling in a General Population

Mean arterial pressure drives pressure-natriuresis and determines arterial structure and function. In a population sample, we investigated the relation between arterial characteristics and renal sodium handling as assessed by the clearance of endogenous lithium. We ultrasonographically measured diameter, cross-sectional compliance (CC) and distensibility (DC) of the carotid, brachial, and femoral arteries in 1069 untreated subjects (mean age: 41.6 years; 50.1% women; 18.8% hypertensive subjects). While accounting for covariates and standardizing for the sodium excretion rate in both sexes, CC and DC of the femoral artery increased with higher fractional distal sodium reabsorption. Differences associated with a 1-SD change in fractional distal reabsorption of sodium were 51.7 mm(2)/kPax10(-3) (95% CI: 23.9 to 79.5; P=0.0002) and 0.56x10(-3)/kPa (95% CI: 0.17 to 0.94; P=0.004) for femoral CC and DC, respectively. In women as well as in men, a 1-SD increment in fractional proximal sodium reabsorption was associated with decreases in femoral and brachial diameter, amounting to 111.6 mum (95% CI: 38.2 to 185.1; P=0.003) and 52.5 mum (95% CI: 10.0 to 94.9; P=0.016), respectively. There was no consistent association between the properties of the elastic carotid artery and renal sodium handling. In conclusion, higher fractional sodium reabsorption in the distal nephron is associated with higher femoral CC and DC, and higher proximal sodium reabsorption is associated with decreased brachial and femoral diameters. These findings demonstrate that there might be an influence of renal sodium handling on arterial properties or vice versa or that common mechanisms might influence both arterial and renal function.

Carotid Intima-Media Thickness and Antihypertensive Treatment

BACKGROUND AND PURPOSE

Hypertension promotes carotid intima-media thickening. We reviewed the randomized controlled trials that evaluated the effects of an antihypertensive drug versus placebo or another antihypertensive agent of a different class on carotid intima-media thickness.

METHODS

We searched the PubMed and the Web of Science databases for randomized clinical trials, published in English before 2005, and included 22 trials.

RESULTS

In 8 trials including 3329 patients with diabetes or coronary heart disease, antihypertensive treatment initiated with an angiotensin-converting enzyme (ACE) inhibitor, a beta-blocker, or a calcium-channel blocker (CCB), compared with placebo or no-treatment, reduced the rate of intima-media thickening by 7 microm/year (P=0.01). In 9 trials including 4564 hypertensive patients, CCBs, ACE inhibitors, an angiotensin II receptor blocker or an alpha-blocker, compared with diuretics or beta-blockers, in the presence of similar blood pressure reductions, decreased intima-media thickening by 3 microm/year (P=0.03). The overall beneficial effect of the newer over older drugs was largely attributable to the decrease of intima-media thickening by 5 microm/year (P=0.007) in 4 trials of CCBs involving 3619 patients. In 5 trials including 287 patients with hypertension or diabetes, CCBs compared with ACE inhibitors did not differentially affect blood pressure, but attenuated intima-media thickening by 23 microm/year (P=0.02). The treatment induced changes in carotid intima-media thickness correlated with the changes in lumen diameter (P=0.02), but not with the differences in achieved blood pressure (P>0.53).

CONCLUSIONS

CCBs reduce carotid intima-media thickening. This mechanism might contribute to their superior protection against stroke.

Reference values for SphygmoCor measurements in South Africans of African ancestry

BACKGROUND

Measurements of blood pressure (BP) together with applanation tonometry at the radial and femoral arteries allow for reproducible assessments of various indexes of arterial stiffness, including peripheral (PP(p)) and central (PP(c)) pulse pressures, peripheral (AI(p)) and central (AI(c)) augmentation indexes, and aortic pulse wave velocity (PWV). In the absence of an outcome-driven and ethnicity-specific reference frame, we defined preliminary diagnostic thresholds for subjects of African descent living in Africa, using the distributional characteristics of these hemodynamic measurements.

METHODS

We randomly recruited 347 subjects from a South African population of African origins. The PP(p) was the average difference between systolic and diastolic BP measured five times consecutively at one home visit. For measurement of PP(c), AI(p), AI(c), and PWV, we used a high-fidelity micromanometer interfaced with a laptop computer running the SphygmoCor software. For analyses we selected 185 subjects without hypertension, diabetes, and previous or concomitant cardiovascular disease.

RESULTS

Mean age (33.5 years) was similar in 77 men and 108 women. The PP(p), PP(c), AI(p), AI(c), and PWV significantly increased with age. The 95th prediction bands of this relation at age 30 years, approximated to 70 mm Hg for PP(p), 50 mm Hg for PP(c), 100% for AI(p), 40% for AI(c), and 8.0 m/sec for PWV. The aforementioned thresholds would need adjustment by approximately 2.5 mm Hg, 4.0 mm Hg, 10%, 6%, and 1.0 m/sec, respectively, for each decade that age differs from 30 years.

CONCLUSIONS

Pending validation in prospective outcome-based studies 70 mm Hg for PP(p), 50 mm Hg for PP(c), 100% for AI(p), 40% for AI(c), and 8.0 m/sec might be considered as preliminary thresholds to diagnose increased arterial stiffness in young adult subjects of African descent.

Obesity is associated with increased arterial stiffness from adolescence until old age

OBJECTIVE

To our knowledge, only two previous studies have investigated the age dependence of the relationship between the characteristics of large arteries and excessive body weight. We therefore investigated whether the relationship between arterial stiffness and body mass index (BMI) was consistent across an age range from 10 to 86 years.

METHODS

Using a cross-sectional population-based design, we randomly recruited 1306 individuals (median age 43.9 years; 50.5% women). Using a wall-tracking ultrasound system, we measured the properties of the carotid, femoral and brachial arteries and carotid-femoral pulse wave velocity. We analysed men and women separately while adjusting for significant covariates, including age, mean arterial pressure, heart rate, current smoking, alcohol intake and use of antihypertensive drugs.

RESULTS

Before and after adjustment, arterial diameter increased with BMI in all territories, with an opposite trend for arterial distensibility. In men and women, the relationships of brachial and femoral properties with BMI were consistent across the whole age range. In men and women, carotid distensibility decreased more with BMI at young than old age. In middle-aged and older women, but not in men of any age, pulse wave velocity increased with higher BMI.

CONCLUSIONS

Across a wide age range, the diameter and stiffness of muscular arteries increased with higher BMI. In elastic arteries, the relationship between arterial stiffness and BMI was more complex and varied with sex and age. The mechanisms underlying the influence of adiposity on the properties of muscular and elastic arteries and the reversibility of these associations by weight reduction at young age need further clarification.

Endothelial function and outdoor temperature

Studies within populations consistently showed that cardiovascular mortality increases with hot weather. However, the biological mechanisms underlying this association remain largely unknown. Endothelial function plays a pivotal role in the pathogenesis of cardiovascular disease. Therefore, we investigated the association between endothelial function and outdoor temperature. We measured flow-mediated vasodilatation (FMD) as index of endothelial function in 274 randomly recruited subjects (50% women, mean age 40.6 year). Both before (partial r = -0.14, p = 0.017) and after adjustment (partial r = -0.17, p = 0.006) for sex, age, body mass index, brachial artery diameter and current smoking, FMD was negatively associated with mean daily temperature. The odds of endothelial dysfunction increased by 58% (95% CI: 4-141%; p = 0.03) for each 10 degrees C increment in mean daily temperature during the week before the examination. Our findings suggest that endothelial dysfunction might contribute to the increase in cardiovascular morbidity and mortality associated with hot weather.

Quality of life and antihypertensive effect with nebivolol and losartan

BACKGROUND

Quality of life and antihypertensive effect, two important therapeutic goals, were determined with the third generation beta-blocker nebivolol and the angiotensin receptor blocker losartan are compared.

METHODS

In a double-blind, randomized, parallel group study 314 patients with hypertension were treated for 12 weeks with 5 mg of nebivolol or 50 mg of losartan once daily. If after 6 weeks diastolic blood pressure (BP) was not normalized 12.5 mg of hydrochlorothiazide once daily was added. Effects of treatment were compared using analysis of variance.

RESULTS

Both drugs decreased systolic BP similarly. The decrease in diastolic BP was greater (P < .0001) with nebivolol (-12 mm Hg after 6 and 12 weeks) than with losartan (-8 and -10 mm Hg after 6 and 12 weeks, respectively). Quality of life parameters did not differ between the two treatments. This was true after 6 and 12 weeks of treatment and results did not change when corrected for different effects on BP. Aspects of quality of life including questions on sexual function did not differ between the two treatments except for headache occurring less frequently (P < .05) in patients on nebivolol monotherapy at 6 weeks.

CONCLUSIONS

At advocated doses nebivolol and losartan decrease systolic BP similarly, whereas the decrease in diastolic BP was slightly greater with nebivolol. Overall quality of life parameters did not differ between nebivolol and losartan. The effect on sexual function did not differ between the two treatments and less patients had headache with nebivolol than with losartan after 6 weeks of monotherapy.

Noninvasive assessment of local pulse pressure: importance of brachial-to-radial pressure amplification

The advocated SphygmoCor procedure uses a radial-to-aorta transfer function with calibration on brachial instead of radial artery pressure to assess the central pulse pressure. We compared these values with carotid artery pulse pressures obtained from a validated calibration method, assuming mean minus diastolic blood pressure constant throughout the large artery tree. From 44 healthy subjects (21 males; 22 to 68 years) pressure waves were obtained at the radial, brachial, and carotid artery with applanation tonometry. Using the calibration method, radial and carotid artery pressures were assessed from brachial artery waves and pressures. The effect of brachial-to-radial pulse pressure amplification, brachial pulse pressure, mean pressure, age, gender, height, body mass index, and smoking on differences between the 2 methods was assessed. Brachial artery pressure was 118+/-12/72+/-10 mm Hg. SphygmoCor central pulse pressure was 9.7+/-4.6 mm Hg lower (P<0.001) than the carotid artery pulse pressure (33.0+/-6.8 versus 42.7+/-8.9 mm Hg). The difference between the 2 methods strongly depended (P<0.001) on brachial-to-radial artery pulse pressure amplification (5.8+/-5.1 mm Hg; 12+/-11%) and less on brachial artery pulse pressure (P=0.005). After calibration of the radial pressure wave with radial instead of brachial artery pressures, the difference between SphygmoCor central pulse pressure and carotid pulse pressure decreased with 4 mm Hg. The advocated SphygmoCor procedure systematically underestimates the central pulse pressure with brachial-to-radial pulse pressure amplification as important determinant. Therefore, calibration of radial artery pressure waves on brachial artery pressures should be avoided. The underestimation of central aortic pulse pressure caused by the radial-to-aorta transfer function itself is much less than previously reported.

Epistatic interaction between α- and γ-adducin influences peripheral and central pulse pressures in white Europeans

BACKGROUND

Adducin is a membrane skeleton protein consisting of alpha- and beta- or alpha- and gamma-subunits. Mutations in alpha- and beta-adducin are associated with hypertension. In the European Project on Genes in Hypertension, we investigated whether polymorphisms in the genes encoding alpha-adducin (Gly460Trp), beta-adducin (C1797T) and gamma-adducin (A386G), alone or in combination, affected pulse pressure (PP), an index of vascular stiffness.

METHODS

We measured peripheral and central PP by conventional sphygmomanometry and applanation tonometry, respectively. We randomly recruited 642 subjects (162 nuclear families and 70 unrelated individuals) from three European populations. In multivariate analyses, we used generalized estimating equations and the quantitative transmission disequilibrium test.

RESULTS

Peripheral and central PP averaged 46.1 and 32.6 mmHg, respectively. Among carriers of the alpha-adducin Trp allele, peripheral and central PP were 5.8 and 4.7 mmHg higher in gamma-adducin GG homozygotes than in their AA counterparts, due to an increase in systolic pressure. gamma-Adducin GG homozygosity was associated with lower urinary Na/K ratio among alpha-adducin Trp allele carriers and with higher urinary aldosterone excretion among alpha-adducin GlyGly homozygotes. Sensitivity analyses in founders and offspring separately, and tests based on the transmission of the gamma-adducin G allele across families, confirmed the interaction between the alpha- and gamma-adducin genes.

CONCLUSIONS

In alpha-adducin Trp allele carriers, peripheral and central PP increased with the gamma-adducin G allele. This epistatic interaction is physiologically consistent with the heterodimeric structure of the protein and its influence on transmembranous sodium transport.

Association of peripheral and central arterial wave reflections with the CYP11B2 ???344C allele and sodium excretion

OBJECTIVE

Angiotensin II and aldosterone, generated by the angiotensin-converting enzyme (ACE) and aldosterone synthase (CYP11B2), respectively, not only regulate sodium and water homeostasis, but also influence vascular remodeling in response to high blood pressure. In the European Project on Genes in Hypertension (EPOGH), we therefore investigated whether the ACE I/D and CYP11B2 C-344T polymorphisms influence early arterial wave reflections, a measure of vascular stiffness.

METHODS

We measured the peripheral and central augmentation index of systolic blood pressure by applanation tonometry at the level of the radial artery in 622 subjects (160 families and 64 unrelated individuals) randomly recruited from three European populations, whose average urinary sodium excretion ranged from 196 to 245 mmol/day. In multivariate analyses, with sodium excretion analyzed as a continuous variable, we explored the phenotype-genotype associations by means of generalized estimating equations and the quantitative transmission disequilibrium test.

RESULTS

The peripheral and central augmentation indexes were significantly higher in CYP11B2 -344C allele carriers than in -344T homozygotes. In offspring, early wave reflections increased with the transmission of the -344C allele. This effect of the CYP11B2 polymorphism occurred in subjects with a higher than median urinary sodium excretion (210 mmol/day). The ACE I/D polymorphism did not influence augmentation of systolic blood pressure.

CONCLUSIONS

The CYP11B2 C-344T polymorphism affects arterial stiffness. However, sodium intake seems to modulate this genetic effect.

Carotid and femoral intima-media thickness in relation to three candidate genes in a Caucasian population

BACKGROUND

In a Caucasian population, the prevalence and incidence of hypertension, renal function and large artery stiffness were significantly correlated with polymorphisms in the genes encoding the angiotensin-converting enzyme (ACE I/D), aldosterone synthase (-C344T) and the cytoskeleton protein alpha-adducin (Gly460Trp).

OBJECTIVE

This study investigated intima-media thickening, a precursor of atherosclerosis, in relation to these genetic polymorphisms.

METHODS

Carotid and femoral intima-media thickness were assessed with a wall-track system in 380 subjects enrolled in a population study. Subjects were genotyped for the presence of the ACE D, aldosterone synthase -344T and alpha-adducin 460Trp alleles. The statistical analysis allowed for confounders, interactions among genes, and the non-independence of the phenotypes within families.

RESULTS

The sample included 188 men (49.5%). Mean age was 39.8 years. Intima-media thickness of the carotid and femoral arteries averaged 575 and 719 microm, respectively. Intima-media thickness of the femoral-but not carotid-artery increased with the number of ACE D alleles. The effect of ACE genotype on femoral intima-media thickness was confined to carriers of the 460Trp allele and the -344T allele. Expressed as a percentage of the population mean, the mean differences between II and DD homozygotes averaged 13.4% (95% CI 5.6-21.2%) in all subjects, 21.2% (8.0-34.5%) in carriers of the 460Trp allele, 15.4% (4.1-26.8%) in carriers of the -344T allele, and 25.2% (10.7-39.7%) if the 460Trp and -344T alleles were both present.

CONCLUSION

This study shows that a relationship exists between the intima-media thickness of the large muscular femoral artery and the ACE gene. This relationship is only apparent in the presence of either the alpha-adducin 460Trp or the aldosterone synthase -344T allele. These findings may have clinical implications for the assessment of genetic cardiovascular risk.

Clinical applications of arterial stiffness, Task Force III: recommendations for user procedures

In vivo arterial stiffness is a dynamic property based on vascular function and structure. It is influenced by confounding factors like blood pressure (BP), age, gender, body mass index, heart rate, and treatment. As a consequence, standardization of the measurement conditions is imperative. General and method/device-specific user procedures are discussed. The subject's conditions should be standardized before starting measurements. These conditions include a minimal resting period of 10 min in a quiet room. It also includes prohibitions on smoking, meals, alcohol, and beverages containing caffeine before measurements. The position of the subject and time of measurements should be standardized. In comparative studies, corrections should be made for confounding factors. Repeated measurements are done preferably by the same investigator, and if available validated with user-independent automated procedures. As it is not feasible to discuss all methods or devices measuring arterial stiffness in one article, more attention is given to user procedures of commercially available devices, because these devices are of interest for a wider group of investigators. User procedures of methods/devices are discussed according to the nature of arterial stiffness measured: systemic, regional, or local arterial stiffness. Each section discusses general or method/device-specific user procedures and is followed by recommendations. Each recommendation discussed during the First International Consensus Conference on the Clinical Applications of Arterial Stiffness is quoted with the level of agreement reached during the conference. Also proposals for future research are made.