Noninvasive measurements of arterial stiffness: Repeatability and interrelationships with endothelial function and arterial morphology measures

Corey J Huck1, Ulf G Bronas1, Eric B Williamson1, Christopher C Draheim1, Daniel A Duprez2, Donald R Dengel1,31School of Kinesiology, University of Minnesota, Minneapolis, MN, USA; 2Cardiovascular Division, Department of Medicine, University of Minnesota, Minneapolis, MN; 3Research Service, Minneapolis Veterans Affairs Medical Center, Minneapolis, MN, USABackground: Many noninvasive arterial assessment techniques have been developed, measuring different parameters of arterial stiffness and endothelial function. However, there is little data available comparing different devices within the same subject. Therefore, the purpose of this study was to examine the repeatability and interrelationships between 3 different techniques to measure arterial stiffness and to compare this with forearm-mediated dilation.Methods: Carotid-radial pulse wave velocity was measured by the Sphygmocor (SPWV) and Complior (CPWV) devices, cardio-ankle vascular index (CAVI) was measured by the VaSera device, vascular structure and function was assessed using ultrasonography and evaluated for reliability and compared in 20 apparently healthy, college-aged men and women.Results: The intraclass correlation coefficient and standard error of the mean for the Sphygmocor (R = 0.56, SEM = 0.69), Complior (R = 0.62, SEM = 0.69), and VaSera (R = 0.60, SEM = 0.56), indicated moderate repeatability. Bland-Altman plots indicated a mean difference of 0.11 ± 0.84 for SPWV, 0.13 ± 1.15 for CPWV, and –0.43 ± 0.90 for CAVI. No significant interrelationships were found among the ultrasound measures and SPWV, CPWV, and CAVI.Conclusions: The three noninvasive modalities to study arterial stiffness reliably measures arterial stiffness however, they do not correlate with ultrasound measures of vascular function and structure in young and apparently healthy subjects.Keywords: Pulse wave velocity, intima-media thickness, flow-mediated dilatio

Modes of exercise training for intermittent claudication

Background According to international guidelines and literature, all patients with intermittent claudication should receive an initial treatment of cardiovascular risk modification, lifestyle coaching, and supervised exercise therapy. In the literature, supervised exercise therapy often consists of treadmill or track walking. However, alternative modes of exercise therapy have been described and yielded similar results to walking. This raises the following question: which exercise mode produces the most favourable results? This is the first update of the original review published in 2014.ObjectivesTo assess the effects of alternative modes of supervised exercise therapy compared to traditional walking exercise in patients with intermittent claudication.Search methodsThe Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 4 March 2019. We also undertook reference checking, citation searching and contact with study authors to identify additional studies. No language restriction was applied.Selection criteriaWe included parallel-group randomised controlled trials comparing alternative modes of exercise training or combinations of exercise modes with a control group of supervised walking exercise in patients with clinically determined intermittent claudication. The supervised walking programme needed to be supervised at least twice a week for a consecutive six weeks of training.Data collection and analysisTwo review authors independently selected studies, extracted data, and assessed the risk of bias for each study. As we included studies with different treadmill test protocols and different measuring units (metres, minutes, or seconds), the standardised mean difference (SMD) approach was used for summary statistics of mean walking distance (MWD) and pain-free walking distance (PFVVD). Summary estimates were obtained for all outcome measures using a random-effects model. We used the GRADE approach to assess the certainty of the evidence.Main results For this update, five additional studies were included, making a total of 10 studies that randomised a total of 527 participants with intermittent claudication (IC). The alternative modes of exercise therapy included cycling, lower-extremity resistance training, upper-arm ergometry, Nordic walking, and combinations of exercise modes. Besides randomised controlled trials, two quasi-randomised trials were included.Overall risk of bias in included studies varied from high to low. According to GRADE criteria, the certainty of the evidence was downgraded to low, due to the relatively small sample sizes, clinical inconsistency, and inclusion of three studies with risk of bias concerns. Overall, comparing alternative exercise modes versus walking showed no clear differences for MVVD at 12 weeks (standardised mean difference (SMD)-0.01, 950/o confidence interval (CI)-0.29 to 0.27; P = 0.95; 6 studies; 274 participants; low-certainty evidence); or at the end of training (SMD-0.11, 95% CI-0.33 to 0.11; P = 0.32; 9 studies; 412 participants; low-certainty evidence). Similarly, no clear differences were detected in PFWD at 12 weeks (SMD-0.01, 950/o CI-0.26 to 0.25; P= 0.97; 5 studies; 249 participants; low-certainty evidence); or at the end of training (SMD-0.06, 95% CI-0.30 to 0.17; P = 0.59; 8 studies, 382 participants; low-certainty evidence). Four studies reported on health-related quality of life (HR-QoL) and three studies reported on functional impairment. As the studies used different measurements, meta-analysis was only possible for the walking impairment questionnaire (WIQ) distance score, which demonstrated little or no difference between groups (MD-5.52, 95% CI-17A1 to 6.36; P = 0.36; 2 studies; 96 participants; low-certainty evidence).Authors' conclusionsThis review found no clear difference between alternative exercise modes and supervised walking exercise in improving the maximum and pain-free walking distance in patients with intermittent claudication. The certainty of this evidence was judged to be low, due to clinical inconsistency, small sample size and risk of bias concerns. The findings of this review indicate that alternative exercise modes may be useful when supervised walking exercise is not an option. More RCTs with adequate methodological quality and sufficient power are needed to provide solid evidence for comparisons between each alternative exercise mode and the current standard of supervised treadmill walking. Future RCTs should investigate outcome measures on walking behaviour, physical activity, cardiovascular risk, and HRQoL, using standardised testing methods and reporting of outcomes to allow meaningful comparison across studies.</p

Unionization structure, licensing and innovation

Closed access. This article was published in the International Journal of Industrial Organization and the definitive version is available at: http://dx.doi.org/10.1016/j.ijindorg.2010.06.001We show the effects of the unionization structure (viz., decentralized and centralized unions) on a firm's incentive for technology licensing and innovation. The incentive for technology licensing is stronger under decentralized unions. We identify circumstances under which the benefit from licensing creates a stronger incentive for innovation under decentralized unions. If the union's preference for employment is high, the benefit from licensing may create higher incentive for innovation under decentralized unions. However, if the union's preference for wage is high enough, the incentive for innovation is higher under a centralized union irrespective of licensing ex-post innovation. If the centralized union decides whether or not to supply workers to all firms, the possibility of higher innovation under decentralized unions increases. We further show that perfectly substitutable workers can be better off under decentralized unions if the labor productivity depends on the unionization structure, which occurs in our analysis when, e.g., licensing after innovation occurs only under decentralized unions or innovation (with no licensing) occurs only under a centralized union

Cognitive Impairment in Chronic Kidney Disease: Vascular Milieu and the Potential Therapeutic Role of Exercise

Chronic kidney disease (CKD) is considered a model of accelerated aging. More specifically, CKD leads to reduced physical functioning and increased frailty, increased vascular dysfunction, vascular calcification and arterial stiffness, high levels of systemic inflammation, and oxidative stress, as well as increased cognitive impairment. Increasing evidence suggests that the cognitive impairment associated with CKD may be related to cerebral small vessel disease and overall impairment in white matter integrity. The triad of poor physical function, vascular dysfunction, and cognitive impairment places patients living with CKD at an increased risk for loss of independence, poor health-related quality of life, morbidity, and mortality. The purpose of this review is to discuss the available evidence of cerebrovascular-renal axis and its interconnection with early and accelerated cognitive impairment in patients with CKD and the plausible role of exercise as a therapeutic modality. Understanding the cerebrovascular-renal axis pathophysiological link and its interconnection with physical function is important for clinicians in order to minimize the risk of loss of independence and improve quality of life in patients with CKD

Relationships Among Heart Rate Variability, Perceived Social Support, and Hopelessness in Adults With Ischemic Heart Disease.

BACKGROUND: Lower perceived social support is associated with hopelessness in patients with ischemic heart disease (IHD). Higher perceived social support is associated with higher heart rate variability (HRV) in adults following a stressful event, but the relationship between HRV and hopelessness has not been examined in patients with IHD. The purpose of this research was to evaluate the relationships among HRV, perceived social support, and hopelessness in patients with IHD. METHODS AND RESULTS: Ninety-four participants were enrolled while hospitalized for an IHD event at a large hospital in the United States. Data collection occurred 2 weeks after hospital discharge and included the State-Trait Hopelessness Scale, ENRICHD Social Support Inventory, Patient Health Questionnaire-9, a demographic form, and a short-term HRV measurement taken at rest. Linear models were used to assess associations between variables in unadjusted and adjusted models. Most participants were men (67%), married (75%), and non-Hispanic White (96%) and underwent coronary artery bypass surgery (57%). There were inverse correlations between high frequency HRV and state hopelessness (r=-0.21, P=0.008) and root mean square of successive differences between normal heartbeats HRV and state hopelessness (r=-0.20, P=0.012) after adjusting for important covariates. High frequency and root mean square of successive differences between normal heartbeats did not show evidence of mediating the relationship between perceived social support and hopelessness. CONCLUSIONS: There were significant inverse correlations between parasympathetic measures of HRV and hopelessness. Assessing high frequency and root mean square of successive differences between normal heartbeats during early recovery following an IHD event could provide promising evidence for understanding a possible precursor to hopelessness and targets for future interventions. Registration Information: clinicaltrials.gov. Identifiers: NCT03907891, NCT05003791