Variability of flow mediated dilation: consequences for clinical application

Cardiovascular health in people with perinatally acquired HIV - where do we stand?

PURPOSE OF REVIEW

HIV-associated cardiac disease was well recognized in the preantiretroviral (ART) era among children with perinatally-acquired HIV infection (PHIV). While ART has dramatically improved survival, it has become increasingly apparent that individuals with PHIV continue to experience multisystem co-morbidities. We review the cardiac and vascular manifestations in people growing up with PHIV in the ART era.

RECENT FINDINGS

ART has resulted in a drop in incidence of serious cardiac morbidity. However, there is a substantial body of evidence that demonstrates that cardiac and vascular structural and functional abnormalities, mostly subclinical, are common in people with PHIV taking ART. Studies have considerable heterogeneity with respect to types of cardiovascular assessments used. HIV-mediated chronic inflammation and potentially effects of ART contribute to these abnormalities. The long-term clinical significance of these abnormalities remains unknown as studies have mainly been cross-sectional, but it is likely that the burden of cardiovascular disease will grow as individuals with PHIV age and the prevalence of traditional risk factors increases.

SUMMARY

Understanding the pathogenesis of cardiovascular disease in PHIV, is critical to inform screening and interventional strategies. Longitudinal studies are also needed to understand the natural history of cardiovascular abnormalities and incidence of clinical outcomes.

The effect of cardiorespiratory fitness and habitual physical activity on cardiovascular responses to 2 h of uninterrupted sitting

Prolonged uninterrupted sitting of >3 h has been shown to acutely cause central and peripheral cardiovascular dysfunction. However, individuals rarely sit uninterrupted for >2 h, and the cardiovascular response to this time is currently unknown. In addition, while increased cardiorespiratory fitness (CRF) and habitual physical activity (HPA) are independently associated with improvements in central and peripheral cardiovascular function, it remains unclear whether they influence the response to uninterrupted sitting. This study sought to 1) determine whether 2 h of uninterrupted sitting acutely impairs carotid-femoral pulse wave velocity (cfPWV), femoral ankle PWV (faPWV), and central and peripheral blood pressure and 2) investigate the associations between CRF and HPA versus PWV changes during uninterrupted sitting. Following 2 h of uninterrupted sitting, faPWV significantly increased [mean difference (MD) = 0.26 m·s-1, standard error (SE) = 0.10, P = 0.013] as did diastolic blood pressure (MD = 2.83 mmHg, SE = 1.08, P = 0.014), however, cfPWV did not significantly change. Although our study shows 2 h of uninterrupted sitting significantly impairs faPWV, neither CRF (r = 0.105, P = 0.595) nor HPA (r = -0.228, P = 0.253) was associated with the increases.NEW & NOTEWORTHY We demonstrate that neither cardiorespiratory fitness nor habitual physical activity influence central and peripheral cardiovascular responses to a 2-h bout of uninterrupted sitting in healthy young adults.

Metabolic Factors Predict Changes in Endothelial Function During the Early Course of Type 1 and Type 2 Diabetes

CONTEXT

Endothelial dysfunction may occur early in the development of cardiovascular and metabolic diseases; however, it remains often underestimated and studies rarely discriminate between diabetes types. We have examined endothelial function and its determinants during the early course of type 1 and type 2 diabetes.

METHODS

Caucasian participants of the prospective German Diabetes Study (GDS) with known diabetes duration <1 year (n = 398) or without diabetes, but of similar age, body mass index (BMI) and sex distribution (n = 109), underwent measurements of flow-mediated dilation (FMD) and nitroglycerin-mediated dilatation (NMD). Whole-body insulin sensitivity (M-value) was assessed by hyperinsulinemic-euglycemic clamps and physical fitness (VO2max) by spiroergometry. A subset of individuals with type 1 or type 2 diabetes (n = 108) was re-evaluated after 5 years.

RESULTS

At baseline, neither FMD nor NMD differed between people with diabetes and the matched glucose-tolerant groups. At the 5-year follow-up, decline in FMD (-13.9%, P = .013) of persons with type 2 diabetes was independent of age, sex, and BMI, but associated with baseline adipose tissue insulin resistance and indices of liver fibrosis. The M-value decreased in both type 1 and type 2 diabetes groups by 24% and 15% (both P < .001, respectively) over 5 years. Higher HbA1c, lower M-value, and lower VO2max at baseline was associated with lower FMD in both type 1 and type 2 diabetes.

CONCLUSION

Endothelial function decreases during the early course of type 2 diabetes. In addition to age and BMI, insulin sensitivity at diagnosis was the best predictor of progressive impairment in endothelial function in type 2 diabetes.

Defining cardiovascular toxicities of cancer therapies: an International Cardio-Oncology Society (IC-OS) consensus statement

The discipline of Cardio-Oncology has seen tremendous growth over the past decade. It is devoted to the cardiovascular (CV) care of the cancer patient, especially to the mitigation and management of CV complications or toxicities of cancer therapies, which can have profound implications on prognosis. To that effect, many studies have assessed CV toxicities in patients undergoing various types of cancer therapies; however, direct comparisons have proven difficult due to lack of uniformity in CV toxicity endpoints. Similarly, in clinical practice, there can be substantial differences in the understanding of what constitutes CV toxicity, which can lead to significant variation in patient management and outcomes. This document addresses these issues and provides consensus definitions for the most commonly reported CV toxicities, including cardiomyopathy/heart failure and myocarditis, vascular toxicity, and hypertension, as well as arrhythmias and QTc prolongation. The current document reflects a harmonizing review of the current landscape in CV toxicities and the definitions used to define these. This consensus effort aims to provide a structure for definitions of CV toxicity in the clinic and for future research. It will be important to link the definitions outlined herein to outcomes in clinical practice and CV endpoints in clinical trials. It should facilitate communication across various disciplines to improve clinical outcomes for cancer patients with CV diseases.

Short-Term Treatment with Alirocumab, Flow-Dependent Dilatation of the Brachial Artery and Use of Magnetic Resonance Diffusion Tensor Imaging to Evaluate Vascular Structure: An Exploratory Pilot Study

Background: Short-term effects of alirocumab on vascular function have hardly been investigated. Moreover, there is a scarce of reliable non-invasive methods to evaluate atherosclerotic changes of the vasculature. The ALIROCKS trial was performed to address these issues using standard ultrasound-based procedures and a completely novel magnetic resonance-based imaging technique. Methods: A total of 24 patients with an indication for treatment with PCSK9 antibodies were recruited. There were 2 visits to the study site, the first before initiation of treatment with alirocumab and the second after 10 weeks of treatment. The key outcome measures included the change of carotid vessel wall fractional anisotropy, a novel magnetic resonance-based measure of vascular integrity, and the changes of carotid intima-media thickness and flow-dependent dilatation of the brachial artery measured with ultrasound. Results: A total of 19 patients completed the trial, 2 patients stopped treatment, 3 patients did not undergo the second visit due to the COVID pandemic. All of them had atherosclerotic vascular disease. Their mean (standard deviation) LDL-cholesterol concentration was 154 (85) mg/dL at baseline and was reduced by 76 (44) mg/dL in response to alirocumab treatment (p < 0.001, n = 19). P-selectin and vascular endothelial growth factors remained unchanged. Flow-dependent dilatation of the brachial artery (+41%, p = 0.241, n = 18), carotid intima-media thickness (p = 0.914, n = 18), and fractional anisotropy of the carotid artery (p = 0.358, n = 13) also did not significantly change. Conclusion: Despite a nominal amelioration for flow-dependent dilatation, significant effects of short-term treatment with alirocumab on vascular function were not detectable. More work would be needed to evaluate, whether fractional anisotropy may be useful in clinical atherosclerosis research.

Cardiometabolic Complications in Youth With Perinatally Acquired HIV in the Era of Antiretroviral Therapy

PURPOSE OF REVIEW

Antiretroviral therapy (ART) scale-up has dramatically reduced rates of pediatric HIV mortality and morbidity. Children living with perinatally acquired HIV (PHIV) are now expected to live through adolescence and well into adulthood, such that adolescents now represent the largest growing population living with HIV. This review aims to discuss the prevalence and mechanisms for cardiometabolic comorbidities in the setting of newer ART regimens and the research gaps that remain.

RECENT FINDINGS

Data highlight the continued risks of subclinical cardiometabolic complications in PHIV in the setting of newer ART. Novel techniques in imaging and omics may help identify early cardiometabolic abnormalities in this young population and potentially identify early changes in the mechanistic pathways related to these changes. Further studies to determine risk and management strategies of the cardiometabolic effects in PHIV adolescents, beyond ART, are warranted. Focus should be on prevention of these complications in youth to avoid new epidemic of diabetes and cardiovascular disease when these youths become aging adults.

Impaired vascular endothelial function as a perioperative risk predictor - a prospective observational trial

Background

In the recent years, an increasing number of patients with multiple comorbidities (e.g. coronary artery disease, diabetes, hypertension) presents to the operating room. The clinical risk factors are accompanied by underlying vascular-endothelial dysfunction, which impairs microcirculation and may predispose to end-organ dysfunction and impaired postoperative outcome. Whether preoperative endothelial dysfunction identifies patients at risk of postoperative complications remains unclear. In this prospective observational study, we tested the hypothesis that impaired flow-mediated dilation (FMD), a non-invasive surrogate marker of endothelial function, correlates with Days at Home within 30 days after surgery (DAH30). DAH30 is a patient-centric metric that captures postoperative complications and importantly also hospital re-admissions.

Methods

Seventy-one patients scheduled for major abdominal surgery were enrolled. FMD was performed pre-operatively prior to major abdominal surgery and patients were dichotomised at a threshold value of 10%. FMD was then correlated with DAH30 (primary endpoint) and postoperative complications (secondary endpoints).

Results

DAH30 did not differ between patients with reduced FMD and normal FMD (14 (4) (median (IQR)) vs. 15 (8), P = 0.8). Similary, no differences between both groups were found for CCI (normal FMD: 21 (30) (median (IQR)), reduced FMD: 26 (38), P = 0.4) or frequency of major complications (normal FMD: 7 (19%) (n (%)), reduced FMD: 12 (35%), P = 0.12). The regression analyses revealed that FMD in combination with ASA status and surgery duration had no additional significant predictive effect for DAH30, CCI or Clavien-Dindo score.

Conclusion

FMD does not add predictive value with regards to DAH30, CCI or Clavien-Dindo score within our study cohort of patients undergoing abdominal surgery.

Trial registration

The study was registered in the German Clinical Trials Register (DRKS00005472), prospectively registered on 25/11/2013.

Impact of presymptomatic COVID-19 on vascular and skeletal muscle function: a case study

The impact of COVID-19 has been largely described after symptom development. Although the SARS-CoV-2 virus elevates heart rate (HR) prior to symptom onset, whether this virus evokes other presymptomatic alterations is unknown. This case study details the presymptomatic impact of COVID-19 on vascular and skeletal muscle function in a young woman [24 yr, 173.5 cm, 89 kg, body mass index (BMI): 29.6 kg·m^-2]. Vascular and skeletal muscle function were assessed as part of a separate study with the first and second visits separated by 2 wk. On the evening following the second visit, the participant developed a fever and a rapid antigen test confirmed a positive COVID-19 diagnosis. Compared with the first visit, the participant presented with a markedly elevated HR (∼30 beats/min) and a lower mean blood pressure (∼8 mmHg) at the second visit. Vascular function measured by brachial artery flow-mediated dilation, reactive hyperemia, and passive leg movement were all noticeably attenuated (25%-65%) as was leg blood flow during knee extension exercise. Muscle strength was diminished as was ADP-stimulated respiration (30%), assessed in vitro, whereas there was a 25% increase in the apparent Km. Lastly, an elevation in IL-10 was observed prior to symptom onset. Notably, 2.5 mo after diagnosis symptoms of fatigue and cough were still present. Together, these findings provide unique insight into the physiological responses immediately prior to onset of COVID-19 symptoms; they suggest that SARS-CoV-2 negatively impacts vascular and skeletal muscle function prior to the onset of common symptoms and may set the stage for the widespread sequelae observed following COVID-19 diagnosis.NEW & NOTEWORTHY This unique case study details the impact of SARS-CoV-2 infection on vascular and skeletal muscle function in a young predominantly presymptomatic woman. Prior to COVID-19 diagnosis, substantial reductions in vascular, skeletal muscle, and mitochondrial function were observed along with an elevation in IL-10. This integrative case study indicates that the presymptomatic impact of COVID-19 is widespread and may help elucidate the acute and long-term sequelae of this disease.

Endothelial Dysfunction in South African Youth Living With Perinatally Acquired Human Immunodeficiency Virus on Antiretroviral Therapy

BACKGROUND

Human immunodeficiency virus (HIV) and antiretroviral therapy (ART) confer cardiovascular disease (CVD) risk in adults with HIV. Few studies have assessed endothelial dysfunction (ED), an early marker of subclinical CVD risk, in youth living with perinatally acquired HIV (YLPHIV).

METHODS

Using peripheral arterial tonometry, we compared ED in YLPHIV and age-matched youth without HIV. A reactive hyperemic index ≤1.35 was defined as ED. Eligible participants included those aged 9-14 years and on ART ≥6 months at enrollment.

RESULTS

Overall, 431 YLPHIV and 93 youth without HIV with a median age of 14.1 versus 13.9 years, respectively, were included. YLPHIV had a lower BMI z score (BMIZ; -0.2 vs 0.4; P < .01) but higher rates of hypercholesterolemia (10% vs 1%; P = .01) than youth without HIV. Among YLPHIV, mean log viral load (VL) was 4.83 copies/mL with 21.7% having a CD4 count <500 cell/mm3; median duration on ART was 9.8 years with 38% initiating at <2 years of age. YLPHIV had higher rates of ED than youth without HIV (50% vs 34%; P = .01); this relationship persisted after adjusting for age, sex, BMIZ, elevated BP, and hypercholesterolemia (RR, 1.43; P = .02). Among YLPHIV, CD4 count >500 cell/mm3 (RR, 1.04; P = .76), VL (RR, 1.01; P = .78), and current ART class (protease inhibitor based vs nonnucleoside inhibitor based: relative risk, 0.90; P = .186) were not associated with ED after adjustment.

CONCLUSIONS

Even after adjusting for physiologic differences, YLPHIV appear to be at increased risk of ED compared with age-matched youth without HIV. These findings have important implications for the life course of YLPHIV who may be at increased risk of premature CVD and complications.

Maintenance of endothelial function following acute resistance exercise in females is associated with a tempered blood pressure response

Acute resistance exercise-induced hypertensive stimulus impairs endothelial function in males. Because prior work indicates that female subjects have a tempered blood pressure response to acute resistance exercise, we hypothesized that, compared with males, females would better maintain endothelial function following resistance exercise and that this preservation would be associated with a lower hypertensive stimulus. Twenty-nine young healthy males (n = 16) and females (n = 13) participated in this study. All subjects performed a session of resistance exercise (leg extension) at the same relative workload [65% of one repetition maximum (1RM)]. The blood pressure response to exercise was characterized, and brachial artery flow-mediated dilation (FMD) was measured before and after. Males performed a second experimental trial in which the blood pressure response to resistance exercise was matched to that of females. This was accomplished by reducing the workload (~25% of 1RM). When resistance exercise was performed at the same relative workload, the systolic blood pressure was greater in males compared with females. Congruently, resistance exercise caused a significant impairment in FMD in males but not in females (P < 0.001). When the exercise workload was reduced in males, they no longer displayed an impairment in FMD following resistance exercise and, as such, the sex difference was abolished (P > 0.05). The present study reveals that acute resistance exercise transiently impairs endothelial function in young, healthy males but not in age-matched females. Notably, the maintenance of endothelial function in females is associated with a lower blood pressure response during resistance exercise.NEW & NOTEWORTHY The present data demonstrate for the first time that acute resistance exercise impairs endothelial function in young, healthy male but not female subjects. In addition, we show that the preservation of endothelial function in females is associated with a mitigated blood pressure response during resistance exercise. Accordingly, this work portrays a sexual dimorphism in the barostress response, and ensuing vascular effects, to resistance exercise.

Decreased resting coronary flow and impaired endothelial function in patients with vasospastic angina

OBJECTIVES

Coronary endothelial and circulatory dysfunction plays important roles in the pathogenesis of vasospastic angina (VSA). However, a complete understanding of the entire coronary circulation including microvasculature in patients with VSA is lacking.

PATIENTS AND METHODS

A total of 32 patients without obstructive coronary artery disease in the left descending coronary artery, who underwent an intracoronary acetylcholine (ACh) provocation test for diagnosis of VSA, were enrolled prospectively. A positive diagnosis of the ACh test was defined as total/subtotal coronary artery narrowing accompanied by chest pain and/or ischemic ECG changes. Angina frequency and severity at baseline, and 1 and 3 months were recorded. Coronary circulation was evaluated invasively using a thermodilution method by obtaining the mean transit time (Tmn) at rest and hyperemia, coronary flow reserve, and index of microcirculatory resistance. Systemic endothelial function was assessed by the reactive hyperemia index.

RESULTS

There were 14 (44%) and 18 (56%) patients with and without a positive ACh provocation test. The baseline characteristics did not differ significantly between the two groups. Patients with VSA had a significantly lower reactive hyperemia index compared with those without VSA (1.70±0.33 vs. 2.12±0.53, P=0.02). Coronary flow reserve, index of microcirculatory resistance, and hyperemic Tmn were not different between the two groups, whereas resting Tmn was significantly longer in patients with VSA (1.20±0.44 vs. 0.71±0.37, P=0.002). Although the frequency and severity of angina improved from baseline to 1 and 3 months in patients with both positive and negative ACh tests, there was no difference between the two groups.

CONCLUSION

Patients with VSA had decreased resting coronary flow and impaired endothelial function.

Brachial flow-mediated dilation by continuous monitoring of arterial cross-section with ultrasound imaging

Objective

Impairment of flow-mediated dilation of the brachial artery is a marker of endothelial dysfunction and often predisposes atherosclerosis and cardiovascular events. In this study, we propose a user-guided automated approach for monitoring arterial cross-section during hyperemic response to improve reproducibility and sensitivity of flow-mediated dilation.

Material and methods

Ultrasound imaging of the brachial artery was performed in 11 volunteers in cross-sectional and in 5 volunteers in longitudinal view. During each examination, images were recorded continuously before and after inducing ischemia. Time-dilation curves of the brachial lumen cross-section were measured by user-guided automated segmentation of brachial images with the feed-forward active contour (FFAC) algorithm. %FMD was determined by the ratio of peak dilation to the baseline value. Each measurement was repeated twice in two sessions 1 h apart on the same arm to evaluate the reproducibility of the measurements. The intra-subject variation in flow-mediated dilation between two sessions (subject-specific) and inter-group variation in flow-mediated dilation with all the subjects within a session grouped together (group-specific) were measured for FFAC. The FFAC measurements were compared with the conventional diameter measurements made using echo tracking in longitudinal views.

Results

Flow-mediated dilation values for cross-sectional area were greater than those measured by diameter dilation: 33.1% for cross-sectional area compared to 22.5% for diameter. Group-specific flow-mediated dilation measurements for cross-sectional area were highly reproducible: 33.2% vs. 33.0% (p > 0.05) with coefficient of variation CV of 0.4%. The group-specific flow-mediated dilations measured by echo tracking for the two sessions were 21.1 vs. 23.9% with CV of 9%. Subject-specific CV for cross-sectional area by FFAC was 10% ± 2% versus 24% ± 10% for the conventional approach. Using correlation as a metric of evaluation also showed better performance for cross-sectional imaging: correlation coefficient, R, between two sessions for cross-sectional area was 0.92 versus 0.72 for the conventional approach based on diameter measurements.

Conclusion

Peak dilation area measured by continuous automated monitoring of cross-sectional area of the brachial artery provides more reproducible and higher-sensitivity measurement of flow-mediated dilation compared to the conventional approach of using vascular diameter measured using longitudinal imaging.

Reliability of microvascular responsiveness measures derived from near-infrared spectroscopy across a variety of ischemic periods in young and older individuals

BACKGROUND

Cardiovascular disease (CVD) is associated with impairments in microvascular responsiveness. Therefore, reliably assessing microvascular function is clinically relevant. Thus, this study aimed to examine the reliability of the near-infrared spectroscopy (NIRS)-derived oxygen saturation (StO₂) reperfusion slope, a measure of microvascular responsiveness, to four different vascular occlusion tests (VOT) of different durations in young and older participants.

METHODS

Eight healthy young (29 ± 5 yr) and seven older (67 ± 4 yr) men participated in four NIRS combined with VOT (NIRS-VOT; 30 s, 1, 3, and 5 min) in the leg microvasculature on two visits separated by 1-2 weeks. Vascular responsiveness was determined by the StO₂ reperfusion slope. The coefficient of variation (CV), repeatability, reliability (ICC), and the limits of agreement (LOA) were calculated for the NIRS-derived reperfusion slopes for each occlusion duration and visit.

RESULTS

CV for the StO₂ reperfusion slope following 30 s, 1, 3 and 5 min of occlusion were 33 ± 29%, 19 ± 21%, 14 ± 12%, and 12 ± 10%, respectively. Repeatability values following 30 s, 1, 3 and 5 min occlusions were 20%, 1%, 4% and 21%, respectively. The ICC for the StO₂ reperfusion slopes for each occlusion duration were 0.29, 0.42, 0.84, and 0.88 following 30 s, 1, 3 and 5 min of occlusion, respectively. LOA values between visit 1 and 2 for occlusions were not different from zero. There were no age-related differences for all variables of the study.

CONCLUSION

NIRS-derived StO₂ reperfusion slope, has good reliability across a range of occlusion durations with the strongest reliability during longer occlusion durations.

Reactive hyperemia index (RHI) and cognitive performance indexes are associated with histologic markers of liver disease in subjects with non-alcoholic fatty liver disease (NAFLD): a case control study

Background

No study evaluated vascular health markers in subjects with non-alcoholic fatty liver disease (NAFLD) through a combined analysis of reactive hyperemia peripheral arterial tonometry (RH-PAT) and arterial stiffness indexes.

Aim of the study

We aimed to assess whether NAFLD and its histological severity are associated with impairment of arterial stiffness and RH-PAT indexes in a mixed cohort of patients with biopsy-proven NAFLD.

Materials and methods

The Kleiner classification was used to grade NAFLD grade. Pulse wave velocity (PWV) and augmentation index (Aix) were used as markers of arterial stiffness, whereas endothelial function was assessed using reactive hyperemia index (RHI). The mini-mental state examination (MMSE) was administered to test cognitive performance.

Results

80 consecutive patients with biopsy-proven NAFLD and 83 controls without fatty liver disease. NAFLD subjects showed significantly lower mean RHI, higher mean arterial stiffness indexes and lower mean MMSE score. Multivariable analysis after correction for BMI, dyslipidaemia, hypertension, sex, diabetes, age and cardiovascular disease showed that BMI, diastolic blood pressure and RHI are significantly associated to NAFLD. Simple linear regression analysis showed among non-alcoholic steatohepatitis (NASH) subjects a significant negative relationship between ballooning grade and MMSE and a significant positive association between Kleiner steatosis grade and augmentation index.

Conclusions

Future research will be addressed to evaluate the relationship between inflammatory markers and arterial stiffness and endothelial function indexes in NAFLD subjects. These study will evaluate association between cardiovascular event incidence and arterial stiffness, endothelial and cognitive markers, and they will address the beneficial effects of cardiovascular drugs such as statins and ACE inhibitors on these surrogate markers in NAFLD subjects.

HIV-positive youth who are perinatally infected have impaired endothelial function

OBJECTIVE

Evaluating cardiovascular disease risk in children and youth 13 to 24 years old who are facing a life time exposure to both HIV and antiretroviral therapy is a research priority. This study compares endothelial function measured by peripheral arterial tonometry in HIV-positive youth infected perinatally and behaviorally as well as HIV-negative controls.

METHODS

Three groups of participants aged 8-30 year were enrolled; HIV-positive perinatally infected, HIV-positive behaviorally infected on antiretroviral therapy with HIV-1 RNA less than 1000 copies/ml, and HIV-negative controls. We measured the reactive hyperemic index, a measure of endothelial function, using endoPAT (Caesarea, Israel). Markers of systemic inflammation, monocyte activation, and gut integrity were also assessed. Spearman correlations and regression analyses were used to explore relationships between endothelial function measures and other measured variables.

RESULTS

Overall, 119 participants were enrolled: 53 HIV-positive behaviorally infected, 18 HIV-positive perinatally infected, and 48 controls. Overall, 71% were men; 77% African Americans and median age was 22 years old. Median (interquartile range) reactive hyperemic index was lower in the HIV-positive perinatally infected group [1.34 (1.20, 1.42)], compared with the behaviorally infected group [1.52 (1.34, 1.75)] and the control group [1.52 (1.27, 1.80; P < 0.01)]. Soluble CD14, a marker of monocyte activation, intestinal fatty acid-binding protein, a marker of gut integrity and soluble vascular cell adhesion molecule, a marker of vascular dysfunction, were different among the three groups (P ≤ 0.01).

CONCLUSION

HIV-positive youth infected perinatally appear to have higher levels of endothelial dysfunction and immune activation when compared with behaviorally infected youth. Further longitudinal studies are needed to determine whether perinatally infected youth have higher risks of cardiovascular disease.

Arterial stiffness in symptomatic smokers with normal lung function

Chronic obstructive pulmonary disease (COPD) is associated with cardiovascular morbidity and mortality. Arterial stiffness and endothelial dysfunction index are validated surrogate cardiovascular markers and are increased in subjects with COPD. We tested whether increased arterial stiffness and endothelial dysfunction occur in symptomatic smokers with no evidence of bronchial obstruction. Clinical and lung functional assessments were conducted in smoker subjects with chronic respiratory symptoms and in COPD patients. Pulse wave velocity (PWV), aortic augmentation index (AIx) and reactive hyperaemia index (RHI) were measured to estimate the cardiovascular risk. 48 smokers (male n=37, female n=11; mean age 70±8.4 years) were studied. Smokers with respiratory symptoms without bronchial obstruction (n=13) did not differ from COPD patients (n=35) in terms of mean±sd PWV (12±3.2 m·s-1versus 14±3.8 m·s-1; p=0.10), aortic AIx (25.2±11.8% versus 24.8±9.7%, p=0.89) and RHI (1.66±1.49 versus 1.62±1.43; p=0.79). The current investigation shows that the cardiovascular risk occurs in smokers with respiratory symptoms in the absence of bronchial obstruction. These findings need to be confirmed in larger populations in order to inform the design of intensive preventive programmes.

Arterial stiffness, endothelial and cognitive function in subjects with type 2 diabetes in accordance with absence or presence of diabetic foot syndrome

Background

Endothelial dysfunction is an early marker of cardiovascular disease so endothelial and arterial stiffness indexes are good indicators of vascular health. We aimed to assess whether the presence of diabetic foot is associated with arterial stiffness and endothelial function impairment.

Methods

We studied 50 subjects with type 2 diabetes mellitus and diabetic foot syndrome (DFS) compared to 50 diabetic subjects without diabetic foot, and 53 patients without diabetes mellitus, by means of the mini mental state examination (MMSE) administered to evaluate cognitive performance. Carotid-femoral pulse wave velocity (PWV) and augmentation index (Aix) were also evaluated by Applanation tonometry (SphygmoCor version 7.1), and the RH-PAT data were digitally analyzed online by Endo-PAT2000 using reactive hyperemia index (RHI) values.

Results

In comparison to diabetic subjects without diabetic foot the subjects with diabetic foot had higher mean values of PWV, lower mean values of RHI, and lower mean MMSE. At multinomial logistic regression PWV and RHI were significantly associated with diabetic foot presence, whereas ROC curve analysis had good sensitivity and specificity in arterial PWV and RHI for diabetic foot presence.

Conclusions

Pulse wave velocity and augmentation index, mean RHI values, and mean MMSE were effective indicators of diabetic foot. Future research could address these issues by means of longitudinal studies to evaluate cardiovascular event incidence in relation to arterial stiffness, endothelial and cognitive markers.

Intra- and interday reproducibility of high-flow-mediated constriction response in young adults

BACKGROUND

Previously, we have demonstrated that high-flow-mediated constriction (H-FMC) of the brachial artery has been shown to negatively affect flow-mediated dilation (FMD). However, the reproducibility of an H-FMC response is unknown.

OBJECTIVE

The aim of this study was to determine the intra- and interday reproducibility of H-FMC in young adults.

METHODS

Thirty young adults (15 male, 15 female; 24 ± 3 years) were assessed for H-FMC reproducibility via high-resolution ultrasound imaging of the brachial artery during and after forearm occlusion of a normal FMD procedure. Two vascular assessments were conducted for all participants during two separate visits with a minimum of 7 days in between. H-FMC was characterized as the greatest 10-s average constriction occurring after 3-s postocclusion compared to baseline brachial artery diameter and considered present if the percent change was <-0·1%.

RESULTS

Of the 120 total vascular assessments performed in this study, 98 of the assessments (80·3%) displayed an H-FMC. H-FMC diameter was not statistically different for intraday comparisons for visit 1 (P = 0·39) or visit 2 (P = 0·55) or interday comparisons between the first (P = 0·61) or second (P = 0·10) assessments. H-FMC percentage was also not statistically different for intra-day comparison for visit 1 (P = 0·94) or visit 2 (P = 0·15) or interday comparisons between the first (P = 0·63) or second (P = 0·16) assessments.

CONCLUSION

These data are supportive of H-FMC being reproducible in young adults and included in future FMD studies. The impact of H-FMC on future CVD risk and development warrants evaluation.

Endothelial function and arterial stiffness indexes in subjects with acute ischemic stroke: Relationship with TOAST subtype

BACKGROUND AND AIMS

Only one study has examined endothelial function in subjects with acute ischemic stroke and no study has yet assessed arterial stiffness and reactive hyperemia peripheral arterial tonometry (RH-PAT) in ischemic stroke and its clinical subtypes. Our study aimed to evaluate arterial stiffness and endothelial dysfunction indexes in patients with acute ischemic stroke and the relationship between endothelial dysfunction indexes and arterial stiffness markers and stroke subtypes according to Trial of Org 10172 in Acute Stroke Treatment (TOAST) Classification.

METHODS

We enrolled 98 patients with a diagnosis of acute ischemic stroke and 105 hospitalized patients without a diagnosis of acute ischemic stroke. Arterial stiffness analysis was conducted by applanation tonometry to record radial artery pressure waveform continuously; augmentation index (Aix) and pulse wave velocity (PWV) were calculated. The reactive hyperemia index (RHI) was assessed by peripheral arterial tonometry.

RESULTS

In comparison to controls, ischemic stroke subjects had higher mean levels of PWV, Aix, and significantly lower mean RHI values. Compared to subjects with lacunar and cardioembolic stroke, those with Large Artery AtheroSclerosis (LAAS) subtype of stroke had higher median levels of PWV and significantly lower median levels of RHI. On multinomial logistic regression analysis of predictive variables of stroke subtype (lacunar vs. LAAS and lacunar vs. cardioembolic), we observed a negative association between RHI value and LAAS subtype and a negative association of PWV with cardioembolic subtype.

CONCLUSIONS

Our findings underline the relationship between endothelial and arterial stiffness index correlations in patients with acute ischemic stroke, also suggesting the use of a combination of PAT and arterial stiffness indexes to better categorize patients with ischemic stroke.

Radial artery vasomotor function following transradial cardiac catheterisation

Aims

To determine the reproducibility of flow-mediated dilation (FMD) and nitrate-mediated dilation (NMD) in the assessment of radial artery vasomotor function, and to examine the effect of transradial catheterisation on radial artery injury and recovery.

Methods

Radial artery FMD and NMD were examined in 20 volunteers and 20 patients on four occasions (two visits at least 24 hours apart, with two assessments at each visit). In a further 10 patients, radial artery FMD was assessed in the catheterised arm prior to, at 24 hours and 3 months following cardiac catheterisation.

Results

There were no differences in baseline radial artery diameter (2.7±0.4 mm vs 2.7±0.4 mm), FMD (13.4±6.4 vs 12.89±5.5%) or NMD (13.6±3.8% vs 10.1±4.3%) between healthy volunteers and patients (p>0.05 for all comparisons). Mean differences for within and between day FMD were 2.53% (95% CIs −15.5% to 20.5%) and −4.3% (−18.3% to 9.7%) in patients. Compared to baseline, radial artery FMD was impaired at 24 hours (8.7±4.1% vs 3.9±2.9%, p=0.015) but not 3 months (8.7±4.1% vs 6.2±4.4, p=0.34) following transradial catheterisation.

Conclusions

Radial FMD is impaired early after transradial catheterisation but appears to recover by 3 months. While test–retest variability was demonstrated, our findings suggest that transradial access for cardiac catheterisation may afford a potential model of vascular injury and repair in vivo in man.

Vascular responsiveness measured by tissue oxygen saturation reperfusion slope is sensitive to different occlusion durations and training status

What is the central question of this study? Is the near-infrared spectroscopy-derived measure of tissue oxygen saturation (StO2) reperfusion slope sensitive to a range of ischaemic conditions, and do differences exist between trained and untrained individuals? What is the main finding and its importance? The StO2 reperfusion rate is sensitive to different occlusion durations, and changes in the reperfusion slope in response to a variety of ischaemic challenges can be used to detect differences between two groups. These data indicate that near-infrared spectroscopy-derived measures of StO2, specifically the reperfusion slope following a vascular occlusion, can be used as a sensitive measure of vascular responsiveness. The reperfusion rate of near-infrared spectroscopy-derived measures of tissue oxygen saturation (StO2) represents vascular responsiveness. This study examined whether the reperfusion slope of StO2 is sensitive to different ischaemic conditions (i.e. a dose-response relationship) and whether differences exist between two groups of different fitness levels. Nine healthy trained (T; age 25 ± 3 years; maximal oxygen uptake 63.4 ± 6.7 ml kg^-1  min^-1 ) and nine healthy untrained men (UT; age 21 ± 1 years; maximal oxygen uptake 46.6 ± 2.5 ml kg^-1  min^-1 ) performed a series of vascular occlusion tests of different durations (30 s, 1, 2, 3 and 5 min), each separated by 30 min. The StO2 was measured over the tibialis anterior using near-infrared spectroscopy, with the StO2 reperfusion slope calculated as the upslope during 10 s following cuff release. The reperfusion slope was steeper in T compared with UT at all occlusion durations (P < 0.05). For the T group, the reperfusion slopes for 30 s and 1 min occlusions were less than for all longer durations (P < 0.05). The reperfusion slope following 2 min occlusion was similar to that for 3 min (P > 0.05), but both were less steep than for 5 min of occlusion. In UT, the reperfusion slope at 30 s was smaller than for all longer occlusion durations (P < 0.05), and 1 min occlusion resulted in a reperfusion slope that was less steep than following 2 and 3 min (P < 0.05), albeit not different from 5 min (P > 0.05). The present study demonstrated that the reperfusion rate of StO2 is sensitive to different occlusion durations, and that changes in the reperfusion rate in response to a variety of ischaemic challenges can be used to detect differences in vascular responsiveness between trained and untrained groups.

Impaired Peripheral Endothelial Function Assessed by Digital Reactive Hyperemia Peripheral Arterial Tonometry and Risk of In-Stent Restenosis

Background

Drug‐eluting stents are replacing bare‐metal stents, but in‐stent restenosis (ISR) remains a problem. Reactive hyperemia index (RHI) assessed by peripheral arterial tonometry evaluates endothelial function noninvasively. We prospectively assessed the prognostic value of RHI in predicting ISR after percutaneous coronary intervention.

Methods and Results

RHI was measured before percutaneous coronary intervention and at follow‐up (F/U) angiography (F/U RHI; 6 and 9 months post bare‐metal stents– and drug‐eluting stents– percutaneous coronary intervention, respectively) in 249 consecutive patients. At F/U, ISR (stenosis >50% of diameter) was seen in 68 patients (27.3%). F/U natural logarithm (RHI) was significantly lower in patients with ISR than in those without (0.52±0.23 versus 0.65±0.27, P<0.01); no between‐group difference in initial natural logarithm (RHI) (0.60±0.26 versus 0.62±0.25, P=0.56) was seen. By multivariate logistic regression analysis, even after adjusting for other significant parameters in univariate analysis, F/U natural logarithm (RHI) independently predicted ISR (odds ratio: 0.13; 95% CI: 0.04–0.48; P=0.002). In receiver operating‐characteristic analysis, F/U RHI was the strongest predictor of ISR (area under the curve: 0.67; 95% CI: 0.60–0.75; P<0.01; RHI <1.73 had 67.6% sensitivity, 64.1% specificity); area under the curve significantly improved from 0.62 to 0.70 when RHI was added to traditional ISR risk factors (P=0.02). Net reclassification index was significant after addition of RHI (26.5%, P=0.002).

Conclusions

Impaired RHI at F/U angiography independently correlated with ISR, adding incremental prognostic value to the ISR‐risk stratification following percutaneous coronary intervention.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov/. Unique identifier: NCT02131935.

A Comparison of Measures of Endothelial Function in Patients with Peripheral Arterial Disease and Age and Gender Matched Controls

This study compared flow-mediated dilatation (FMD), peripheral artery tonometry (PAT), and serum nitric oxide (NO) measures of endothelial function in patients with peripheral artery disease (PAD) against age/gender matched controls. 25 patients (mean age: 72.4 years, M : F 18 : 7) with established PAD and an age/gender matched group of 25 healthy controls (mean age: 72.4 years, M : F 18 : 7) were studied. Endothelial function was measured using the % FMD, reactive hyperemia index (RHI) using PAT and serum NO (μmol). Difference for each method between PAD and control patients and correlation between the methods were investigated. FMD and RHI were lower in patients with PAD (median FMD for PAD = 2.16% versus control = 3.77%, p = 0.034 and median RHI in PAD = 1.64 versus control = 1.92, p = 0.005). NO levels were not significantly different between the groups (PAD median = 7.70 μmol, control median = 13.05 μmol, p = 0.662). These results were obtained in elderly patients and cannot be extrapolated to younger individuals. FMD and PAT both demonstrated a lower hyperaemic response in patients with PAD; however, FMD results in PAD patients were unequivocally reduced whereas half the PAD patients had RHI values above the established threshold for endothelial dysfunction. This suggests that FMD is a more appropriate method for the measurement of NO-mediated endothelial function.

Vascular responsiveness determined by near-infrared spectroscopy measures of oxygen saturation

Vascular impairments at the macro- and microcirculatory levels are associated with increased risk for cardiovascular disease. Flow-mediated dilation (FMD) is currently the most widely used method for non-invasive assessment of vascular endothelial function. Recently, near-infrared spectroscopy (NIRS)-derived measures of tissue oxygen saturation (StO2) have been used to characterize the dynamic response of local tissue perfusion to a brief period of ischaemia. The purpose of the present study was to establish correlations between the reperfusion rate of StO2 and FMD. Ultrasound-derived FMD was quantified after 5 min of distal cuff occlusion of the popliteal artery in 20 healthy young men (26 ± 3 years old). Triplicate measurements of end-diastolic arterial diameter were made every 15 s after cuff release, and FMD response was calculated as the greatest percentage change in diameter from baseline (%FMD). The StO2 was measured using NIRS throughout the duration of each test. Two consecutive FMD tests were performed, separated by 30 min of rest, and were averaged for %FMD and StO2. The %FMD was significantly correlated with the reperfusion slope of StO2 after cuff release (slope 2 StO2; r = 0.63, P = 0.003). In conclusion, the present study established a correlation between slope 2 StO2 and %FMD in healthy young men. These data suggest that NIRS-derived slope 2 StO2 can be used as a measure of vascular endothelial function.

Prognostic Value of Flow-Mediated Vasodilation in Brachial Artery and Fingertip Artery for Cardiovascular Events: A Systematic Review and Meta-Analysis

BACKGROUND

Endothelial dysfunction plays a pivotal role in cardiovascular disease progression, and is associated with adverse events. The purpose of this systematic review and meta-analysis was to investigate the prognostic magnitude of noninvasive peripheral endothelial function tests, brachial artery flow-mediated dilation (FMD), and reactive hyperemia--peripheral arterial tonometry (RH-PAT) for future cardiovascular events.

METHODS AND RESULTS

Databases of MEDLINE, EMBASE, and the Cochrane Library were systematically searched. Clinical studies reporting the predictive value of FMD or RH-PAT for cardiovascular events were identified. Two authors selected studies and extracted data independently. Pooled effects were calculated as risk ratio (RR) for continuous value of FMD and natural logarithm of RH-PAT index (Ln_RHI) using random-effects models. Thirty-five FMD studies of 17 280 participants and 6 RH-PAT studies of 1602 participants were included in the meta-analysis. Both endothelial function tests significantly predicted cardiovascular events (adjusted relative risk [95% CI]: 1% increase in FMD 0.88 [0.84-0.91], P<0.001, 0.1 increase in Ln_RHI 0.79 [0.71-0.87], P<0.001). There was significant heterogeneity in the magnitude of the association across studies. The magnitude of the prognostic value in cardiovascular disease subjects was comparable between these 2 methods; a 1 SD worsening in endothelial function was associated with doubled cardiovascular risk.

CONCLUSIONS

Noninvasive peripheral endothelial function tests, FMD and RH-PAT, significantly predicted cardiovascular events, with similar prognostic magnitude. Further research is required to determine whether the prognostic values of these 2 methods are independent of each other and whether an endothelial function-guided strategy can provide benefit in improving cardiovascular outcomes.

Assessments of endothelial function and arterial stiffness are reproducible in patients with COPD

Background

Elevated cardiovascular disease risk is observed in patients with COPD. Non-invasive assessments of endothelial dysfunction and arterial stiffness have recently emerged to provide mechanistic insight into cardiovascular disease risk in COPD; however, the reproducibility of endothelial function and arterial stiffness has yet to be investigated in this patient population.

Objectives

This study sought to examine the within-day and between-day reproducibility of endothelial function and arterial stiffness in patients with COPD.

Methods

Baseline diameter, peak diameter, flow-mediated dilation, augmentation index, augmentation index at 75 beats per minute, and pulse wave velocity were assessed three times in 17 patients with COPD (six males, eleven females, age range 47–75 years old; forced expiratory volume in 1 second =51.5% predicted). Session A and B were separated by 3 hours (within-day), whereas session C was conducted at least 7 days following session B (between-day). Reproducibility was assessed by: 1) paired t-tests, 2) coefficients of variation, 3) coefficients of variation prime, 4) intra-class correlation coefficient, 5) Pearson’s correlations (r), and 6) Bland–Altman plots. Five acceptable assessments were required to confirm reproducibility.

Results

Six out of six within-day criteria were met for endothelial function and arterial stiffness outcomes. Six out of six between-day criteria were met for baseline and peak diameter, augmentation index and pulse wave velocity, whereas five out of six criteria were met for flow-mediated dilation.

Conclusion

The present study provides evidence for within-day and between-day reproducibility of endothelial function and arterial stiffness in patients with COPD.

A methodological approach to non-invasive assessments of vascular function and morphology

The endothelium is the innermost lining of the vasculature and is involved in the maintenance of vascular homeostasis. Damage to the endothelium may predispose the vessel to atherosclerosis and increase the risk for cardiovascular disease. Assessments of peripheral endothelial function are good indicators of early abnormalities in the vascular wall and correlate well with assessments of coronary endothelial function. The present manuscript details the important methodological steps necessary for the assessment of microvascular endothelial function using laser Doppler imaging with iontophoresis, large vessel endothelial function using flow-mediated dilatation, and carotid atherosclerosis using carotid artery ultrasound. A discussion on the methodological considerations for each of the techniques is also presented, and recommendations are made for future research.

Ultrasound in preoperative evaluation for dialysis-access placement

US vessel mapping for vascular access creation has evolved as standard practice in the preoperative evaluation of an ESRD patient. The best yield from this technology is when it is used to compliment physical examination and viewed in realtime by the operating physician. It is important to evaluate both arterial and venous systems during vessel mapping. While minimum diameters have been associated with an increased chance of maturation of an AV access, the quality of the vessel wall also plays an important role in maturation. US has a distinct advantage of being a noninvasive modality that can evaluate both structural and functional aspects of vessels that play an important role in access maturation.

Mediation of cardiovascular risk factor effects through subclinical vascular disease: the Multi-Ethnic Study of Atherosclerosis

OBJECTIVE

It is unclear to what extent subclinical cardiovascular disease (CVD) such as coronary artery calcium (CAC), carotid intima-media thickness (CIMT), and brachial flow-mediated dilation (FMD) are mediators of the known associations between traditional cardiovascular risk factors and incident CVD events. We assessed the portion of the effects of risk factors on incident CVD events that are mediated through CAC, CIMT, and FMD.

APPROACH AND RESULTS

Six thousand three hundred fifty-five of 6814 Multi-Ethnic Study of Atherosclerosis participants were included. Nonlinear implementation of structural equation modeling (STATA mediation package) was used to assess whether CAC, CIMT, or FMD are mediators of the association between traditional risk factors and incident CVD event. Mean age was 62 years, with 47% men, 12% diabetics, and 13% current smokers. After a mean follow-up of 7.5 years, there were 539 CVD adjudicated events. CAC showed the highest mediation while FMD showed the least. Age had the highest percent of total effect mediated via CAC for CVD outcomes, whereas current cigarette smoking had the least percent of total effect mediated via CAC (percent [95% confidence interval]: 80.2 [58.8-126.7] versus 10.6 [6.1-38.5], respectively). Body mass index showed the highest percent of total effect mediated via CIMT (17.7 [11.6-38.9]); only a negligible amount of the association between traditional risk factors and CVD was mediated via FMD.

CONCLUSIONS

Many of the risk factors for incident CVD (other than age, sex, and body mass index) showed a modest level of mediation via CAC, CIMT, and FMD, suggesting that current subclinical CVD markers may not be optimal intermediaries for gauging upstream risk factor modification.

Intermediate end point cardiovascular clinical trials: an excellent idea based on an obsolete paradigm

Intermediate end points are widely used in cardiovascular clinical trials mainly to forecast/foreshadow actual clinical cardiovascular outcomes. This approach is based on the historical atherosclerosis paradigm which states in part that the effects of traditional cardiovascular risk factors on clinical cardiovascular disease (CVD) events are solely mediated through subclinical cardiovascular disease/atherosclerosis. The utility of intermediate end point CVD clinical trials using either historical subclinical CVD markers such as quantitative angiography or current sophisticated markers such as coronary artery calcium, carotid intima-media thickness or brachial flow mediated dilation has been variable. Discoveries of other pathways pertinent to the pathogenesis of atherosclerosis calls for a new conceptual model or paradigm and helps explain the discordance in results from prior and ongoing intermediate end point-clinical CVD event trial pairs.

New methodological approach to improve reproducibility of brachial artery flow-mediated dilatation

BACKGROUND

Measurement of flow-mediated dilation (FMD) is well known as a noninvasive method for an assessment of vascular endothelial function. However, the reproducibility is a major issue of FMD measurement. The purpose of this study is to examine the reproducibility of the new FMD measurement with medial epicondyle method.

METHODS

First, to evaluate the variability of the brachial artery diameter, 23 volunteers recruited from 32 healthy volunteers were examined for a brachial artery diameter at rest using with FMD equipment. Second, to evaluate the reproducibility of the FMD measurement, all volunteers underwent the FMD measurement, which was repeated at 2-week interval using the traditional method and the medial epicondyle method. The reproducibility in both methods was evaluated by 2 independent observers who measured on the same subject to assess the inter-observer reproducibility, and 1 observer who measured the same subject twice to assess the intra-observer reproducibility regarding the baseline value of arterial diameter and FMD.

RESULTS

The variability of brachial artery diameter was 0.57 ± 0.27 mm in 23 healthy volunteers. In the study of inter- and intra-observer reproducibility, 2 parameters including intra-class correlation coefficient and Pearson's correlation coefficient by medial epicondyle method are superior to those by traditional method.

CONCLUSIONS

These results suggest that medial epicondyle methodological approach to measure FMD is superior to traditional method.

An anxious heart: anxiety and the onset of cardiovascular diseases

The public health burden of cardiovascular disease (CVD) is high both in terms of economic and social costs. Key modifiable factors identified for CVD prevention include health behaviors and health risk factors (e.g., cholesterol, blood pressure). However, a substantial body of research has also identified stress, anxiety, and depression as potentially modifiable CVD risk factors. Here we focus on the role of anxiety in the development of CVD and consider its potential as a key target for primordial prevention strategies. First, we highlight important findings and summarize the latest research on anxiety and incident CVD. We also review and summarize the findings to date on subclinical CVD outcomes and briefly consider mechanisms by which anxiety may influence CVD. We identify key issues and consider how these issues may inform our understanding of the anxiety-CVD relationship. Finally, we briefly discuss the clinical implications of this work, with specific recommendations for providers.

Very rapid effect of pitavastatin on microvascular function in comparison to rosuvastatin: reactive hyperemia peripheral arterial tonometric study

BACKGROUND

It has been reported that pitavastatin improves endothelial function faster than other statins. Recently introduced reactive hyperemia peripheral arterial tonometry (RH-PAT) provides objective and quantitative assessment of peripheral microvascular function.

PURPOSE

This study aimed to investigate whether peripheral microvascular function improved 2 hours after pitavastatin in subjects with coronary artery disease (CAD) using RH-PAT, and the results were compared with those of rosuvastatin.

METHODS

This study included 94 subjects with CAD, assigned to a group given 2 mg of pitavastatin (n = 36), a group given 2.5 mg of rosuvastatin (n = 38), and a control group (n = 20). RH-PAT examinations were performed before and 2 hours after statin administration.

RESULTS

The RH-PAT index increased 2 hours after pitavastatin administration from 1.82 ± 0.45 to 2.16 ± 0.62 (P = 0.02), whereas there were no differences in the RH-PAT index in the rosuvastatin group (1.79 ± 0.71 to 1.91 ± 0.53, P = 0.09) and the control group (1.68 ± 0.36 to 1.84 ± 0.58, P = 0.4). No significant changes were observed at 2 hours in serum cholesterol levels in each group.

CONCLUSION

The present study demonstrated that peripheral microvascular function improved 2 hours after a single clinical dose of pitavastatin, but not after rosuvastatin.

Non Contrast-Enhanced MRA versus Ultrasound Blood Vessel Assessment to determine the Choice of Hemodialysis Vascular Access

Purpose

The aim of this work was to establish the relationship between traditional blood vessel mapping for vascular access (VA) creation by B-mode ultrasound (US) and novel non contrast-enhanced magnetic resonance angiography (NCE-MRA), and to study the potential influence of the diameter assessment technique on the choice of hemodialysis vascular access.

Methods

A total of 27 end-stage renal-disease patients were included. They received routine US and a NCE-MRA examination of the upper extremity. Diameters were measured manually on US and semi-automatically on NCE-MRA. These measurements were statistically compared for the arteries and veins and for each measurement location. Furthermore, sensitivity and specificity of both modalities to predict VA location was investigated by comparison with an experienced surgeon. This analysis gave insight into the potential influence of vessel mapping modality on decision-making.

Results

Comparison of NCE-MRA with US for the arteries and veins, demonstrated a bias of 9% (limits −33%-78%) and 38% (limits −36%-198%), respectively. Statistically significant differences between the modalities on the individual locations were mainly found for the venous locations. The sensitivity and specificity for US to predict VA location was 1.0 and 0.74, respectively, while for NCE-MRA this was 0.88 and 0.39, respectively.

Conclusions

The results obtained indicate that extreme caution should be exercised when replacing one diameter measurement modality with the other. A further need exists to improve both vessel mapping protocols to obtain a geometric description of the upper extremity vasculature regardless of acquisition modality.

Differential short-term repeated forearm hyperaemic reactivity in coronary artery disease patients compared to healthy low risk participants

The hyperaemic response of the forearm is a widely used technique to assess the vascular reactivity. Little is known about the short-term reproducibility and the possible exhaustion of this response in normal or diseased states. As such, the current study was conducted to assess this phenomenon using a unique nuclear medicine- (NM-) based technique. 19 patients with coronary artery disease (CAD) undergoing NM exercise stress tests and 15 low risk (LR) participants completed 2 reactive hyperaemia tests, using a SPECT-based technique, separated by 15  min. Analyses revealed that CAD patients had lower hyperaemic responses than LR participants (P < .001), and that there was a significant group × time interaction (P < .005), such that LR participants showed a larger decrease in the reactivity (5.2 ± 0.4 to 3.6 ± 0.4) than the CAD patients (2.9 ± 0.3 to 2.6 ± 0.3). These results suggest that there is a variability, due to disease states, in the reproducibility of the hypaeremic reactivity. This needs to be taken into account in short-term repeated measure studies.

Evaluation of a technique for measurement of flow-mediated vasodilation in healthy ponies

OBJECTIVE

To determine between-pony and within-pony variations and interobserver and intraobserver agreements of a technique for measurement of flow-mediated vasodilation (FMD) in healthy ponies.

ANIMALS

6 healthy pony mares (weight range, 236 to 406 kg; body condition score range, 3/9 to 7/9; age range, 14 to 25 years).

PROCEDURES

In each pony, the left median artery was occluded with a blood pressure cuff (inflated to > 300 mm Hg for 5 minutes). Two-dimensional ultrasonographic images of the artery were recorded for 30 seconds before cuff inflation and for 2 minutes after cuff deflation. Maximum luminal diameters of arteries were compared with their baseline diameters to calculate FMD (relative percentage increase in luminal size). Images were obtained from 6 ponies 1 time and from 1 pony 6 times. Independent analysis of images was performed by 2 investigators, 1 of whom analyzed images on 2 occasions.

RESULTS

Mean ± SD FMD in 6 ponies (1 time) was 12.57 ± 4.28% and in 1 pony (6 times) was 7.30 ± 2.11%. Between-pony and within-pony coefficients of variation were 34.09% and 28.84%, respectively. Interobserver agreement was fair (intraclass correlation coefficient, 0.47); intraobserver agreement was poor (intraclass correlation coefficient, 0.30).

CONCLUSIONS AND CLINICAL RELEVANCE

FMD was identified and measured in ponies. Measurement of FMD is used to assess endothelial function in humans and has been investigated in dogs. Measurement of FMD in ponies appeared to be feasible and could be used to assess endothelial function (to determine predisposition for development of laminitis or cardiovascular diseases).

Intervention to improve adherence to lipid-lowering medication and lipid-levels in patients with an increased cardiovascular risk

Low levels of statin adherence may compromise treatment outcomes. The aim of this study was to investigate whether nurse-led cardiovascular risk-factor counseling could improve statin adherence and lipid levels without increasing patients' anxiety. Patients with indications for statin therapy for primary or secondary prevention of cardiovascular disease were randomly assigned to receive routine care or extended care (EC) at baseline and at months 3, 9, and 18. Patients in the EC group received a personalized risk-factor passport, showing modifiable and unmodifiable individual risk factors and a graphical presentation of their calculated absolute 10-year cardiovascular disease risk as well as the target risk that could be reached if all modifiable risk factors were optimally treated. Lipid levels were assessed at each visit. Carotid intima-media thickness was measured at baseline and at month 18. Adherence, anxiety, quality of life, symptoms, and smoking status were assessed using a self-administered questionnaire at each visit. A total of 201 patients were included in the study. Statin adherence was significantly higher (p <0.01) and anxiety was significantly lower (p <0.01) in the EC group than in the routine care group. Low-density lipoprotein cholesterol was statistically significantly lower in the EC group than in the routine group (2.66 vs 3.00 mmol/L, respectively, p = 0.024) in primary prevention patients only. Intima-media thickness improved significantly from baseline (p <0.01) in all patients, irrespective of group assignment. In conclusion, cardiovascular risk-factor counseling resulted in improved lipid profiles in primary prevention patients and higher levels of adherence to statins and lower levels of anxiety in all patients.

Assessments of arterial stiffness and endothelial function using pulse wave analysis

Conventionally, the assessments of endothelial function and arterial stiffness require different sets of equipment, making the inclusion of both tests impractical for clinical and epidemiological studies. Pulse wave analysis (PWA) provides useful information regarding the mechanical properties of the arterial tree and can also be used to assess endothelial function. PWA is a simple, valid, reliable, and inexpensive technique, offering great clinical and epidemiological potential. The current paper will outline how to measure arterial stiffness and endothelial function using this technique and include discussion of validity and reliability.

Use of ultrasound for non-invasive assessment of flow-mediated dilation

The pathological complications of atherosclerosis, namely heart attacks and strokes, remain the leading cause of mortality in the Western world. Preceding atherosclerosis is endothelial dysfunction. There is therefore interest in the application of non-invasive clinical tools to assess endothelial function. The flow-mediated dilation (FMD) test is the standard tool used to assess endothelial function. Reduced FMD is an early marker of atherosclerosis and has been noted for its capacity to predict future cardiovascular disease events. This review discusses the measurement of endothelial function using ultrasound, with a focus on the FMD technique.

Augmentation index association with reactive hyperemia as assessed by peripheral arterial tonometry in hypertension

BACKGROUND

Augmentation pressure has emerged as a surrogate marker for cardiovascular disease, and endothelial dysfunction has been proposed as related factor. However, the relationship between augmentation pressure and digital endothelial function has not yet been well defined. We investigated the relationship between augmentation pressure and digital reactive hyperemia (RH) in patients with hypertension using peripheral arterial tonometry (PAT), which is regarded as being representative of endothelial function.

METHODS

One hundred hypertensive patients (64 males; mean age, 49 ± 12 years) without a history of taking antihypertensive medication were enrolled in this study.

RESULTS

The mean augmentation pressure and augmentation index (AIx) normalized for a heart rate of 75 beats/min (AIx75) were 15 ± 8 mm Hg and 26 ± 11%, respectively. The mean RH-PAT index and log transformed PAT ratio were 2.24 ± 0.55 and 0.62 ± 0.30. There was an inverse relationship between the RH-PAT index and age, male sex, and body mass index. The log transformed PAT ratio also showed inverse relationship with age and male sex. The RH-PAT index and the log transformed PAT ratio showed no relationship with augmentation pressure or AIx75. In a multiple linear regression analysis, age, height, and central systolic BP demonstrated an independent association with augmentation pressure and AIx75.

CONCLUSION

In patients with hypertension, the RH-PAT index determined using PAT was not associated with augmentation pressure or AIx75. Digital vascular function may be a less important factor for pressure augmentation in patients with hypertension.