ASTRALogy: Unrealistic Expectations?

Revascularization versus medical therapy for renal-arter

Baroreflex Activation Therapy for the Treatment of Drug-Resistant Hypertension: New Developments

In the past few years, novel accomplishments have been obtained in carotid baroreflex activation therapy (BAT) for the treatment of resistant hypertension. In addition, this field is still evolving with promising results in the reduction of blood pressure and heart rate. This overview addresses the latest developments in BAT for the treatment of drug-resistant hypertension. Although not totally understood considering the working mechanisms of BAT, it appeared to be possible to achieve at least as much efficacy of single-sided as bilateral stimulation. Therefore unlike the first-generation Rheos system, the second-generation Barostim neo operates by unilateral baroreflex activation, using a completely different carotid electrode. Also significant improvements in several cardiac parameters have been shown by BAT in hypertensive patients, which set the basis for further research to evaluate BAT as a therapy for systolic heart failure. Yet important uncertainties need to be clarified to guarantee beneficial effects; hence not all participants seem to respond to BAT

The applicability of home blood pressure measurement in clinical practice: A review of literature

Willem J Verberk, Abraham A Kroon, Heidi A Jongen-Vancraybex, Peter W de LeeuwUniversity Hospital Maastricht, Department of Internal Medicine and Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, The NetherlandsPurpose: To review the literature on home blood pressure measurement (HBPM), to examine its validity and applicability for clinical practice and to provide recommendations regarding HBPM assessment.Findings: HBPM can eliminate the white coat effect and offers the possibility to obtain multiple measurements under standardized conditions, which increases knowledge of overall blood pressure value. Although it is not entirely capable of replacing ambulatory blood pressure measurement (ABPM), HBPM correlates better with target organ damage and cardiovascular mortality than office blood pressure measurement (OBPM), it enables prediction of sustained hypertension in patients with borderline hypertension, and proves to be an appropriate tool for assessing drug efficacy. Additional advantages of HBPM are that it may increase drug compliance and patient’s awareness of hypertension. Overall, OBPM yield higher blood pressure values than HBPM. Differences between OBPM and HBPM tend to increase with age and are generally higher in patients without antihypertensive treatment than in patients with antihypertensive treatment.Recommendations: Measurements should be performed according to accepted guidelines and recordings should be performed with a memory equipped automatic validated device. From the data reviewed here, we recommend that HBPM be assessed monthly by taking two measurements in the morning within 1 hour after awakening and two in the evening for three consecutive days, the data from the first day should be dismissed. A subject should be labeled hypertensive if his/her HBPM value is equal to or greater than 137 mmHg systolic and/or 84 mmHg diastolic.Keywords: blood pressure, hypertension, self-measurement, home measurement, ambulatory measurement, adherenc

Repeated automatic versus ambulatory blood pressure measurement:the effects of age and sex in a normal ageing population

Objectives To study blood pressure adaptation in relation to age and sex, In a subsample, laboratory blood pressure measurements were compared with ambulatory daytime blood pressure measurements to determine the degree of agreement between the two methods, The night-time blood pressure reduction was analysed as a function of blood pressure status, age and sex.Design A cross-sectional study in 469 healthy volunteers, aged 23-82 years, stratified for age, sex and educational level.Methods Laboratory blood pressure was measured automatically (Dinamap 8100) five times during a 20min recording session, Cardiovascular events in the medical history were identified in order to treat the cardiovascular event-free group separately in subsequent analyses, Within 3 weeks after laboratory blood pressure measurement, ambulatory blood pressure was measured for 24h in 135 volunteers from the main study.Results Both diastolic and systolic blood pressure varied markedly in a single measurement session as a function of age, independent of mean pressure level, After 15min no further blood pressure decrease was observed, On the basis of the average of the final two blood pressure measurements, 18.8% of the subjects were in the hypertensive range (WHO/ISH guidelines). Ambulatory blood pressure measurements were in accord with earlier findings and correlated 0.74 and 0.73 with laboratory diastolic and systolic blood pressure, respectively, but weighted kappa values indicated only moderate agreement (0.42 and 0.51), Women showed a more profound reduction in cnight-time blood pressure than did men.Conclusions There is a substantial change in blood pressure during a single measurement session which is greater in older age groups, The moderate agreement between the two methods of blood pressure measurement supports the notion that blood pressure measured in a single session has limited generalizability to average daytime levels in a population sample

Differences in renal hemodynamics and renin secretion between patients with unifocal and multifocal fibromuscular dysplasia

Objective: Fibromuscular dysplasia (FMD) can be classified in a multifocal and a unifocal subtype. As unifocal FMD generally leads to more severe hypertension at younger age, we hypothesized that renal hemodynamics are more disturbed in unifocal renal artery FMD as compared with multifocal FMD, leading to increased renin secretion. Methods: We measured renal blood flow ((133)Xenon washout method), renin secretion, and glomerular filtration rate per kidney in 101 patients with FMD (26 unifocal and 75 multifocal), all off medication and prior to balloon angioplasty. Results: We found that renal blood flow and glomerular filtration were substantially lower in kidneys with unifocal FMD as compared with multifocal FMD. In the affected kidney from patients with unilateral FMD for example, mean renal blood flow was 173 +/- 77 in unifocal vs. 244 +/- 79 ml/100 g kidney/min in multifocal FMD (P=0.013). Moreover, lateralization in renin secretion was only observed in a subset of patients with unifocal FMD, but not in any of the patients with multifocal FMD. Conclusion: These findings suggest that the impact of unifocal FMD lesions on the kidney is more severe, resulting in a classical pattern of renovascular hypertension. In multifocal FMD, however, renal blood flow is more preserved, local renin secretion is not increased, and the association between renin levels and blood pressure is inverse. These differences may explain the often more severe clinical presentation and higher success rate of revascularization in unifocal FMD, but also suggest that the pathophysiological mechanisms leading to hypertension may differ between these two disease entities

Total Cerebral Small Vessel Disease MRI Score Is Associated with Cognitive Decline in Executive Function in Patients with Hypertension

Objectives: Hypertension is a major risk factor for white matter hyperintensities (WMH), lacunes, cerebral microbleeds, and perivascular spaces, which are MRI markers of cerebral small vessel disease (SVD). Studies have shown associations between these individual MRI markers and cognitive functioning and decline. Recently, a “total SVD score” was proposed in which the different MRI markers were combined into one measure of SVD, to capture total SVD-related brain damage. We investigated if this SVD score was associated with cognitive decline over 4 years in patients with hypertension. Methods: In this longitudinal cohort study, 130 hypertensive patients (91 patients with uncomplicated hypertension and 39 hypertensive patients with a lacunar stroke) were included. They underwent a neuropsychological assessment at baseline and after 4 years. The presence of WMH, lacunes, cerebral microbleeds, and perivascular spaces were rated on baseline MRI. Presence of each individual marker was added to calculate the total SVD score (range 0–4) in each patient. Results: Uncorrected linear regression analyses showed associations between SVD score and decline in overall cognition (p = 0.017), executive functioning (p < 0.001) and information processing speed (p = 0.037), but not with memory (p = 0.911). The association between SVD score and decline in overall cognition and executive function remained significant after adjustment for age, sex, education, anxiety and depression score, potential vascular risk factors, patient group, and baseline cognitive performance. Conclusion: Our study shows that a total SVD score can predict cognitive decline, specifically in executive function, over 4 years in hypertensive patients. This emphasizes the importance of considering total brain damage due to SVD

Peroxisome proliferator-activated receptor gamma-2 P12A polymorphism and risk of acute myocardial infarction, coronary heart disease and ischemic stroke: A case-cohort study and meta-analyses

The alanine allele of P12A polymorphism in PPARG gene in a few studies has been associated with a reduced or increased risk of acute myocardial infarction (AMI). Yet, the risk relation has not been confirmed, and data on ischemic stroke (IS) is scarce. We therefore investigated the role of this polymorphism on occurrence of AMI, coronary heart disease (CHD) and IS. We performed a case-cohort study in 15,236 initially healthy Dutch women and applied a Cox proportional hazards model to study the relation of the P12A polymorphism and AMI (n = 71), CHD (n = 211), and IS (n = 49) under different inheritance models. In addition, meta-analyses of published studies were performed. Under the dominant inheritance model, carriers of the alanine allele compared with those with the more common genotype were not at increased or decreased risk of CHD (hazard ratio [HR] = 0.82; 95% confidence interval [CI], 0.58 to 1.17) and of IS (HR = 1.03; 95% CI, 0.14 to 7.74). In addition no relations were found under the recessive and additive models. Our meta-analyses corroborated these findings by showing no significant association. For AMI we found a borderline significant association under dominant (HR = 0.49; 95% CI, 0.26 to 0.94), and additive (HR = 0.51; 95% CI, 0.26 to 1.00) models which could be due to chance, because of small cases in this subgroup. The meta-analysis did not show any association between the polymorphism and risk of AMI under the different genetic models. Our study in healthy Dutch women in combination with the meta-analyses of previous reports does not provide support for a role of P12A polymorphism in PPARG gene in MI and CHD risk. Also our study shows that the polymorphism has no association with IS ris

The atomic-to-molecular hydrogen transition in the TNG50 simulation:Using realistic UV fields to create spatially resolved H i maps

Cold gas in galaxies provides a crucial test to evaluate the realism of cosmological hydrodynamical simulations. To extract the atomic and molecular hydrogen properties of the simulated galaxy population, post-processing methods taking the local UV field into account are required. We improve upon previous studies by calculating realistic UV fields with the dust radiative transfer code SKIRT to model the atomic-to-molecular transition in TNG50, the highest-resolution run of the IllustrisTNG suite. Comparing integrated quantities such as the H i mass function, we study to what detail the UV field needs to be modelled in order to calculate realistic cold gas properties. We then evaluate new, spatially resolved comparisons for cold gas in galaxies by exploring synthetic maps of atomic hydrogen at redshift zero and compare them to 21-cm observations of local galaxies from the WHISP survey. In terms of non-parametric morphologies, we find that TNG50 H i maps are less concentrated than their WHISP counterparts (median ΔC ≈ 0.3), due in part to central H i deficits related to the ejective character of supermassive black hole feedback in TNG. In terms of the H i column density distribution function, we find discrepancies between WHISP and IllustrisTNG that depend on the total H i abundance in these data sets as well as the post-processing method. To fully exploit the synergy between cosmological simulations and upcoming deep H i/H2 data, we advocate the use of accurate methods to estimate the UV radiation field and to generate mock maps.</p

Vascular compliance in sodium-sensitive and sodium-resistant borderline hypertensive patients

Vascular compliance in sodium-sensitive and sodium-resistant borderline hypertensive patients. Recently, we demonstrated a reduction in the compliance of the carotid, femoral and brachial arteries in sodiumsensitive subjects who had consumed a regular sodium intake of approximately 120 mmol per day, as compared to both sodium-resistant borderline hypertensive subjects and normotensive controls. Venous compliance was not different between the two borderline hypertensive groups and was only slightly lesser than in controls. Large artery compliance was studied using a non-invasive ultrasound vessel wall movement detector system, while venous compliance was determined by means of strain gauge plethysmography. The borderline hypertensive subjects were subsequently treated with enalapril 10 mg/day, felodipine 5 mg/day or placebo during six months. Despite similar reductions in blood pressure, enalapril induced a significant increase of the muscular femoral and brachial artery compliance, but not of the elastic carotid artery, while felodipine did not influence large artery compliance at all in the sodium-sensitive group. The effect of enalapril on muscular artery compliance was established through a dose-dependent increase in distension and not through a change in arterial diameter. Arterial compliance was not influenced by either of the drugs in the resistant group. Venous compliance was also not altered by the medication. In conclusion, femoral and brachial artery compliance in sodium-sensitive borderline hypertensive subjects, which was found to be lower than that of sodium-resistant subjects, improved with antihypertensive treatment with enalapril but not with felodipine, despite the similar reductions in blood pressure induced by both drugs. This finding implies that firstly, reduced arterial compliance is caused by more than just blood pressure elevation, and secondly, the renin-angiotensin system may play a role in the reduced arterial compliance of sodium-sensitive subjects

Bias-induced threshold voltages shifts in thin-film organic transistors

An investigation into the stability of metal-insulator-semiconductor (MIS) transistors based on alpha-sexithiophene is reported. In particular, the kinetics of the threshold voltage shift upon application of a gate bias has been determined. The kinetics follow stretched-hyperbola-type behavior, in agreement with the formalism developed to explain metastability in amorphous-silicon thin-film transistors. Using this model, quantification of device stability is possible. Temperature-dependent measurements show that there are two processes involved in the threshold voltage shift, one occurring at Tapproximate to220 K and the other at Tapproximate to300 K. The latter process is found to be sample dependent. This suggests a relation between device stability and processing parameters. (C) 2004 American Institute of Physics