Exercise SBP response and incident depressive symptoms: The Maastricht Study

Objective : An exaggerated exercise SBP, which is potentially modifiable, may be associated with incident depressive symptoms via an increased pulsatile pressure load on the brain. However, the association between exaggerated exercise SBP and incident depressive symptoms is unknown. Therefore, we examined whether exaggerated exercise SBP is associated with a higher risk of depressive symptoms over time. Methods : We used longitudinal data from the population-based Maastricht Study, with only individuals free of depressive symptoms at baseline included (n = 2121; 51.3% men; age 59.5 +/- 8.5 years). Exercise SBP was measured at baseline with a submaximal exercise cycle test. We calculated a composite score of exercise SBP based on four standardized exercise SBP measures: SBP at moderate workload, SBP at peak exercise, SBP change per minute during exercise and SBP 4 min after exercise. Clinically relevant depressive symptoms were determined annually at follow-up and defined as a Patient Health Questionnaire score of at least 10. Results : After a mean follow-up of 3.9 years, 175 participants (8.3%) had incident clinically relevant depressive symptoms. A 1 SD higher exercise SBP composite score was associated with a higher incidence of clinically relevant depressive symptoms [hazard ratio: 1.27 (95% confidence interval: 1.04-1.54)]. Results were adjusted for age, sex, education level, glucose metabolism status, lifestyle, cardiovascular risk factors, resting SBP and cardiorespiratory fitness. Conclusion : A higher exercise SBP response is associated with a higher incidence of clinically relevant depressive symptoms

Orthogonal B-Mode Evaluation of Common Carotid Artery Plaques Reveals the Absence of Outward Remodeling

Item does not contain fulltextTo properly assess morphologic and dynamic parameters of arteries and plaques, we propose the concept of orthogonal distance measurements, that is, measurements made perpendicular to the local lumen axis rather than along the ultrasound beam (vertical direction for a linear array). The aim of this study was to compare orthogonal and vertical artery and lumen diameters at the site of a plaque in the common carotid artery (CCA). Moreover, we investigated the interrelationship of orthogonal diameters and plaque size and the association of artery parameters with plaque echogenicity. In 29 patients, we acquired a longitudinal B-mode ultrasound recording of plaques at the posterior CCA wall. After semi-automatic segmentation of end-diastolic frames, diameters were extracted orthogonally along the lumen axis. To establish inter-observer variability of diameters obtained at the location of maximal plaque thickness, a second observer repeated the analysis (subset N = 21). Orthogonal adventitia-adventitia and lumen diameters could be determined with good precision (coefficient of variation: 1%-5%. However, the precision of the change in lumen diameter from diastole to systole (distension) at the site of the plaque was poor (21%-50%). The orthogonal lumen diameter was significantly smaller than the vertical lumen diameter (p <0.001). Surprisingly, the plaques did not cause outward remodeling, that is, a local increase in adventitia-adventitia distance at the site of the plaque. The intra- and inter-observer precision of diastolic-systolic plaque compression was poor and of the same order as the standard deviation of plaque compression. The orthogonal relative lumen distension was significantly lower for echogenic plaques, indicating a higher stiffness, than for echolucent plaques (p <0.01). In conclusion, we illustrated the feasibility of extracting orthogonal CCA and plaque dimensions, albeit that the proposed approach is inadequate to quantify plaque compression

Noninvasive estimation of the blood pressure waveform in the carotid artery using continuous finger blood pressure monitoring

Item does not contain fulltextTo noninvasively estimate the blood pressure continuously in the common carotid artery (CCA), we obtained the distension waveform of the CCA from seven healthy volunteers and 20 hypertensive patients using radio-frequency ultrasound. Consequently, it was calibrated by the mean and diastolic pressure measured in the finger artery and compared with applanation tonometry, calibrated using the systolic and diastolic pressure in the brachial artery. The mean difference in estimating the mean blood pressure was 0.3 mm Hg (limits of agreement: -11.7 to 12.3 mm Hg). In estimating the systolic blood pressure, the mean difference was 8.0 mm Hg (limits of agreement: -29.8 to 45.8 mm Hg) and showed increasing variation with blood pressure. The systolic blood pressure values can be expected between 0.83 and 1.35 times the control method. In this study, we obtained proof-of-principle for noninvasively measuring blood pressure in the CCA using continuous finger blood pressure monitoring. This opens the way to estimating location specific arterial stiffness and intra-plaque elasticity

Wall shear rates in human and mouse arteries: Standardization of hemodynamics for in vitro blood flow assays: Communication from the ISTH SSC subcommittee on biorheology

Hemodynamics play a central role in hemostasis and thrombosis by affecting all aspects linked to platelet functions and coagulation. In vitro flow devices are extensively used in basic research, pharmacological studies, antiplatelet agent screening, and development of diagnostic tools. Because hemodynamic conditions vary tremendously throughout the vascular tree and among different (patho)physiological processes, it is important to use flow conditions based on relevant biorheological reference ranges. Surprisingly, it is particularly difficult to find a concise overview of relevant hemodynamic parameters in various human and mouse vessels. To our knowledge, this is the first time an inventory of flow conditions in healthy, non-diseased, human and mouse vessels has been created. The objective of providing such a repertoire is to aid researchers in the field of hemostasis and thrombosis in choosing rheological conditions relevant in in vitro flow experiments and to promote harmonization of flow-based assays to facilitate comparative evaluations between studies. With reference to the human, we discuss relevant similarities and discrepancies in wall shear rates in the mouse, which are typically one order of magnitude greater in agreement with allometric scaling laws between species. Importantly, we bring the attention of the researchers to the fact that the relevant range of average wall shear rates in human arteries where clinically relevant arterial thrombosis occurs may fall as low as 100 to 200 s−1, thus significantly overlapping with what are considered “venous” shear rates. The same range for the murine arteries used for arterial thrombosis models may significantly exceed 1000 s−1 reaching values considered to be “pathological.”

CSF alpha-synuclein does not discriminate dementia with lewy bodies from Alzheimer's disease.

Contains fulltext : 88288.pdf (publisher's version ) (Open Access)In this study, we assessed whether cerebrospinal fluid (CSF) levels of the biomarker alpha-synuclein have a diagnostic value in differential diagnosis of dementia with Lewy bodies (DLB) and Alzheimer's disease (AD). We also analyzed associations between CSF biomarkers and cognitive performance in DLB and in AD. We included 35 DLB patients, 63 AD patients, 18 patients with Parkinson's disease (PD), and 34 patients with subjective complaints (SC). Neuropsychological performance was measured by means of the Mini-Mental Status Examination (MMSE), Visual Association Test (VAT), VAT object-naming, Trail Making Test, and category fluency. In CSF, levels of alpha-synuclein, amyloid-beta 1-42 (Abeta1-42), total tau (tau), and tau phosphorylated at threonine 181 (ptau-181) were measured. CSF alpha-synuclein levels did not differentiate between diagnostic groups (p=0.16). Higher ptau-181 and higher tau levels differentiated AD from DLB patients (p< 0.05). In DLB patients, lower Abeta1-42 and higher total tau levels were found than in SC and PD patients (p< 0.05). In DLB patients, linear regression analyses of CSF biomarkers showed that lower alpha-synuclein was related to lower MMSE-scores (beta (SE) = 6(2) and p< 0.05) and fluency (beta (SE) = 4(2), p< 0.05). Ultimately, CSF alpha-synuclein was not a useful diagnostic biomarker to differentiate DLB and/or PD (alpha-synucleinopathies) from AD or SC. In DLB patients maybe lower CSF alpha-synuclein levels are related to worse cognitive performance

Single M-Line Is as Reliable as Multiple M-Line Ultrasound for Carotid Artery Screening

Purpose: Carotid artery properties can be evaluated with high accuracy and reproducibility using multiple M-line ultrasound. However, the cost of multiple M-line-based imaging modalities and the extensive operator expertise requirements hamper the large-scale application for arterial properties assessment, particularly in resource-constrained settings. This study is aimed to assess the performance of a single M-line approach as an affordable and easy-to-use alternative to multiple M-line imaging for screening purposes. Methods: We used triplicate longitudinal common carotid artery (CCA) ultrasound recordings (17 M-lines covering about 16 mm, at 500 frames per second) of 500 subjects from The Maastricht Study to assess the validity and reproducibility of a single against multiple M-line approach. The multiple M-line measures were obtained by averaging over all available 17 lines, whereas the middle M-line was used as a proxy for the single M-line approach. Results: Diameter, intima-media thickness (IMT), and Young's elastic modulus (YEM) were not significantly different between the single and multiple M-line approaches (p > 0.07). Distension and distensibility coefficient (DC) did differ significantly (p < 0.001), however, differences were technically irrelevant. Similarly, Bland-Altman analysis revealed good agreement between the two approaches. The single M-line approach, compared to multiple M-line, exhibited an acceptable reproducibility coefficient of variation (CV) for diameter (2.5 vs. 2.2%), IMT (11.9 vs. 7.9%), distension (10 vs. 9.4%), DC (10.9 vs. 10.2%), and YEM (26.5 vs. 20.5%). Furthermore, in our study population, both methods showed a similar capability to detect age-related differences in arterial stiffness. Conclusion: Single M-line ultrasound appears to be a promising tool to estimate anatomical and functional CCA properties with very acceptable validity and reproducibility. Based on our results, we might infer that image-free, single M-line tools could be suited for screening and for performing population studies in low-resource settings worldwide. Whether the comparison between single and multiple M-line devices will yield similar findings requires further study

Complementing sparse vascular imaging data by physiological adaptation rules

Mathematical modeling of pressure and flow waveforms in blood vessels using pulse wave propagation (PWP) models has tremendous potential to support clinical decision making. For a personalized model outcome, measurements of all modeled vessel radii and wall thicknesses are required. In clinical practice, however, data sets are often incomplete. To overcome this problem, we hypothesized that the adaptive capacity of vessels in response to mechanical load could be utilized to fill in the gaps of incomplete patient-specific data sets. We implemented homeostatic feedback loops in a validated PWP model to allow adaptation of vessel geometry to maintain physiological values of wall stress and wall shear stress. To evaluate our approach, we gathered vascular MRI and ultrasound data sets of wall thicknesses and radii of central and arm arterial segments of 10 healthy subjects. Reference models (i.e., termed RefModel, n = 10) were simulated using complete data, whereas adapted models (AdaptModel, n = 10) used data of one carotid artery segment only, and the remaining geometries in this model were estimated using adaptation. We evaluated agreement between RefModel and AdaptModel geometries, as well as that between pressure and flow waveforms of both models. Limits of agreement (bias +/- 2 SD of difference) between AdaptModel and RefModel radii and wall thicknesses were 0.2 +/- 2.6 mm and -140 +/- 557 mu m, respectively. Pressure and flow waveform characteristics of the AdaptModel better resembled those of the RefModels as compared with the model in which the vessels were not adapted. Our adaptation-based PWP model enables personalization of vascular geometries even when not all required data are available.NEW & NOTEWORTHY To benefit personalized pulse wave propagation (PWP) modeling, we propose a novel method that, instead of relying on extensive data sets on vascular geometries, incorporates physiological adaptation rules. The developed vascular adaptation model adequately predicted arterial radius and wall thickness compared with ultrasound and MRI estimates, obtained in humans. Our approach could be used as a tool to facilitate personalized modeling, notably in case of missing data, as routinely found in clinical settings