Ultrasound assessment of endothelial-dependent flow-mediated vasodilation of the brachial artery in clinical research

Advancements in risk stratification and management strategies in primary cardiovascular prevention

Atherosclerotic cardiovascular disease (ASCVD) remains a leading cause of morbidity and mortality worldwide, highlighting the urgent need for advancements in risk assessment and management strategies. Although significant progress has been made recently, identifying and managing apparently healthy individuals at a higher risk of developing atherosclerosis and those with subclinical atherosclerosis still poses significant challenges. Traditional risk assessment tools have limitations in accurately predicting future events and fail to encompass the complexity of the atherosclerosis trajectory. In this review, we describe novel approaches in biomarkers, genetics, advanced imaging techniques, and artificial intelligence that have emerged to address this gap. Moreover, polygenic risk scores and imaging modalities such as coronary artery calcium scoring, and coronary computed tomography angiography offer promising avenues for enhancing primary cardiovascular risk stratification and personalised intervention strategies. On the other hand, interventions aiming against atherosclerosis development or promoting plaque regression have gained attention in primary ASCVD prevention. Therefore, the potential role of drugs like statins, ezetimibe, proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, omega-3 fatty acids, antihypertensive agents, as well as glucose-lowering and anti-inflammatory drugs are also discussed. Since findings regarding the efficacy of these interventions vary, further research is still required to elucidate their mechanisms of action, optimize treatment regimens, and determine their long-term effects on ASCVD outcomes. In conclusion, advancements in strategies addressing atherosclerosis prevention and plaque regression present promising avenues for enhancing primary ASCVD prevention through personalised approaches tailored to individual risk profiles. Nevertheless, ongoing research efforts are imperative to refine these strategies further and maximise their effectiveness in safeguarding cardiovascular health.

Positron Emission Tomography of Nitric Oxide by a Specific Radical-Generating Dihydropyridine Tracer

Nitric oxide (NO) plays a pivotal role as a biological signaling molecule, presenting challenges in its specific detection and differentiation from other reactive nitrogen and oxygen species within living organisms. Herein, a 18F-labeled (fluorine-18, t1/2 = 109.7 min) small-molecule tracer dimethyl 4-(4-(4-[18F]fluorobutoxy)benzyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate ([18F]BDHP) is developed based on the dihydropyridine scaffold for positron emission tomography (PET) imaging of NO in vivo. [18F]BDHP exhibits a highly sensitive and efficient C-C cleavage reaction specifically triggered by NO under physiological conditions, leading to the production of a 18F-labeled radical that is readily retained within the cells. High uptakes of [18F]BDHP are found within and around NO-generating cells, such as macrophages treated with lipopolysaccharide or benzo(a)pyrene. MicroPET/CT imaging of arthritic animal model mice reveals distinct tracer accumulation in the arthritic legs, showcasing a higher distribution of NO compared with the control legs. In summary, a specific radical-generating dihydropyridine tracer with a unique radical retention strategy has been established for the marking of NO in real-time in vivo.

Effect of Yoga on Endothelial Function: A Systematic Review and Meta-Analysis

Introduction: Endothelial dysfunction is the initial step in the pathogenesis of atherosclerosis; and it plays a central role in the development of cardiovascular diseases and many types of human diseases (diabetes, kidney failure, cancer, and viral infections). Strategies that are effective in protecting vascular endothelial function and retard or reversing endothelial dysfunction in the early stage appear to be potential in the prevention of vascular, cardiac, and many human diseases. Several studies have been carried out on the effects of yoga on endothelial function, but the results of these studies have not been synthesized. This study aimed at conducting a systematic review and meta-analysis to determine the effectiveness of yoga on endothelial function. Methods: A systematic review and meta-analysis of studies that assessed the effect of yoga practice on vascular endothelial function was done as per the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The PubMed, Scopus, Google Scholar, and Cochrane controlled register of trials (CENTRAL) were searched from inception to August 2022. The search strategy was constructed around yoga-based techniques and endothelial function. All the yoga-based interventional studies on endothelial function or dysfunction were included in this review. A narrative synthesis and descriptive analysis were done due to the diverse methodology of selected studies. We carried out a formal meta-analysis of controlled trials that assessed the effect of yoga on flow-mediated dilatation (FMD), a measure of endothelial function. Results: A total of 18 studies were included for review involving 1043 participants. Yoga training showed improved endothelial function in 12 studies, whereas 6 studies did not find any statistically robust effect. Meta-analysis (n = 395 participants, 6-studies, 7 comparisons) showed an increase in brachial FMD by yoga practice (mean difference = -1.23%; 95% confidence interval -2.23 to -0.23; p = 0.02). The heterogeneity between the studies was 43% (Tau2 = 0.70, χ2 = 10.49). The risk of bias was low to moderate in these studies. No adverse effects were reported. Conclusions: Yoga practice improved endothelial function. Yoga could be a safe and potential integrative medicine to improve endothelial function. However, as the statistical heterogeneity, that is, variation in the FMD among the studies was moderate, large clinical trials are necessary for its clinical recommendations.

Flow-mediated Dilation of the Brachial Artery in Women with Hypertensive Disorders of Pregnancy

Background

Hypertensive disorder of pregnancy (HDP) comprise chronic hypertension, gestational hypertension, preeclampsia/eclampsia, and preeclampsia superimposed on chronic hypertension. HDP complicate up to 10% of pregnancies worldwide and carry significant risks of maternal and perinatal morbidity and mortality. The aim of this study was to evaluate the derangement and characteristics of brachial artery flow-mediated dilation (BAFMD) in women with HDP.

Methods

The BAFMD of the right brachial artery of 80 women with HDP (pregnant HDP), 80 normotensive pregnant women (pregnant non-HDP), and 80 healthy nonpregnant women (nonpregnant controls) was evaluated with B-mode ultrasound. The age, blood pressure, body mass index (BMI), brachial artery diameter, and BAFMD of the participants were compared. P ≤ 0.05 was statistically significant.

Results

The pregnant HDP group had significantly lower mean BAFMD compared to pregnant non-HDP and nonpregnant controls (6.9% ± 2.53% vs. 8.32% ± 3.4% vs. 9.4% ± 2.68%; P < 0.001). There was no significant difference between the mean BAFMD of the pregnant HDP subgroups: preeclampsia (5.81% ± 1.7%) versus gestational hypertension (6.43% ± 3.02%); P = 0.57. BAFMD diminished with advancing gestational age in both the pregnant HDP and pregnant non-HDP groups. On regression analysis, BAFMD was a poor marker for HDP, while BMI was an independent predictor for HDP.

Conclusion

Even though HDP were associated with significantly diminished BAFMD, it was not a good marker for HDP.

Vascular mechanisms of post-COVID-19 conditions: Rho-kinase is a novel target for therapy

BACKGROUND

In post-coronavirus disease-19 (post-COVID-19) conditions (long COVID), systemic vascular dysfunction is implicated, but the mechanisms are uncertain, and the treatment is imprecise.

METHODS AND RESULTS

Patients convalescing after hospitalization for COVID-19 and risk factor matched controls underwent multisystem phenotyping using blood biomarkers, cardiorenal and pulmonary imaging, and gluteal subcutaneous biopsy (NCT04403607). Small resistance arteries were isolated and examined using wire myography, histopathology, immunohistochemistry, and spatial transcriptomics. Endothelium-independent (sodium nitroprusside) and -dependent (acetylcholine) vasorelaxation and vasoconstriction to the thromboxane A2 receptor agonist, U46619, and endothelin-1 (ET-1) in the presence or absence of a RhoA/Rho-kinase inhibitor (fasudil), were investigated. Thirty-seven patients, including 27 (mean age 57 years, 48% women, 41% cardiovascular disease) 3 months post-COVID-19 and 10 controls (mean age 57 years, 20% women, 30% cardiovascular disease), were included. Compared with control responses, U46619-induced constriction was increased (P = 0.002) and endothelium-independent vasorelaxation was reduced in arteries from COVID-19 patients (P < 0.001). This difference was abolished by fasudil. Histopathology revealed greater collagen abundance in COVID-19 arteries {Masson's trichrome (MT) 69.7% [95% confidence interval (CI): 67.8-71.7]; picrosirius red 68.6% [95% CI: 64.4-72.8]} vs. controls [MT 64.9% (95% CI: 59.4-70.3) (P = 0.028); picrosirius red 60.1% (95% CI: 55.4-64.8), (P = 0.029)]. Greater phosphorylated myosin light chain antibody-positive staining in vascular smooth muscle cells was observed in COVID-19 arteries (40.1%; 95% CI: 30.9-49.3) vs. controls (10.0%; 95% CI: 4.4-15.6) (P < 0.001). In proof-of-concept studies, gene pathways associated with extracellular matrix alteration, proteoglycan synthesis, and viral mRNA replication appeared to be upregulated.

CONCLUSION

Patients with post-COVID-19 conditions have enhanced vascular fibrosis and myosin light change phosphorylation. Rho-kinase activation represents a novel therapeutic target for clinical trials.

The state of platelet and plasma hemostasis as a predictor of coronary blood flow in patients with acute myocardial infarction

Aim      To study the relationship of the platelet function and plasma homeostasis with the blood flow in the infarct-related artery (IRA) and with the course of acute myocardial infarction (AMI).Material and methods  This study included 93 patients with AMI (75 patients with ST-elevation AMI and 18 patients without ST segment elevation). 63 patients had TIMI 0-1 blood flow in the IRA and 30 patients had TIMI 2-3. Rotational thromboelastometry, impedance aggregometry, the endothelium-dependent vasodilation (EDVD) test, and the thrombodynamics test were performed for all patients. The primary clinical endpoint included the totality of in-hospital complications of AMI, and the secondary endpoint included the totality of out-of-hospital complications of AMI. Major bleedings (BARC 3-5) and minor bleedings (BARC 1-2) were evaluated separately.Results Patients with IRA TIMI 0-1 flow were characterized by a shorter blood clotting time (BCT), larger thrombus size and density, more intense platelet aggregation induced by arachidonic acid and ADP, and lower values of the EDVD test. It was found that the parameters of platelet aggregation induced by arachidonic acid (AUC Asa) in combination with BCT allowed assessment of the severity of IRA blood flow disorder (sensitivity 76 %, specificity 71 %) in patients with AMI, regardless of the presence of ST segment elevation on the ECG. In addition, the incidence of the primary endpoint was greater in patients with IRA TIMI 0-1 flow (41.3% and 16.7%, respectively; p=0.015). In patients with TIMI 2-3 flow in the long-term period of the disease, the incidence of minor bleedings was significantly higher (8.5% and 30.4 %, respectively; p=0.045).Conclusion      Compared to patients with preserved blood flow, patients with AMI and IRA TIMI 0-1 flow are characterized by endothelial dysfunction and more intense processes of thrombogenesis and platelet aggregation. It has been shown for the first time that the combination of two simple criteria for assessing hemostasis (AUC Asa; BCT) allows assessment of the degree of IRA blood flow disorder in patients with AMI.

Comparison of experiences and preferences following non-invasive cardiovascular risk procedures: a cross-sectional survey in participants with and without diabetes mellitus

Aims

Endothelial dysfunction is an early risk marker of cardiovascular disease in diabetes mellitus. Timely screening is important in reducing cardiovascular disease-associated morbidity and mortality. This cross-sectional study investigates the acceptability and preferability of non-invasive cardiovascular risk procedures (EndoPAT2000 system and the ECG-gated fundoscope) in participants with diabetes mellitus compared to controls.

Methods

A self-administered Likert scale-based questionnaire was completed by 106 controls and 117 participants with diabetes mellitus, identified through stratified random sampling, upon conclusion of an Australian Heart Eye sub-study conducted at Westmead Hospital, NSW, Australia from 2012 to 2014. Pearson’s χ² test, independent-samples t-test and regression analysis were performed.

Results

Study participants who responded to the questionnaire had no preference for procedures (controls: 2.4 ± 1.1 vs diabetes mellitus: 2.5 ± 0.9, p = 0.38) but had an overall more negative experience with most aspects of the ECG-gated fundoscope than the EndoPAT2000 system. Of those with diabetes mellitus, participants who provided poorer self-rated health expressed discomfort with the mydriatic drops (ß 0.27, 95%CI 0.001 - 0.54, p = 0.049) and the fundoscope’s green light filter (ß 0.27, 95%CI 0.07 - 0.47, p = 0.009), as well as maintaining still (ß 0.40, 95%CI 0.08 - 0.72, p = 0.02) and not blinking (ß 0.38, 95%CI 0.07 - 0.70, p = 0.02) during photo acquisition. These participants were also less willing to repeat the ECG-gated fundoscope procedure (ß 0.29, 95%CI 0.07 - 0.52, p = 0.01).

Conclusions

Participants with diabetes mellitus, especially with poorer self-rated health, had a more negative experience with the ECG-gated fundoscope than the EndoPAT2000 system. Difficulties experienced under examination by the ECG-gated fundoscope appear related to the procedural design, which requires amendments improving patient comfort and compliance.

LPA Genotypes and Haplotypes Are Associated with Lipoprotein(a) Levels but Not Arterial Wall Properties in Stable Post-Coronary Event Patients with Very High Lipoprotein(a) Levels

Lipoprotein(a) [Lp(a)] levels are an independent risk factor for coronary artery disease (CAD). Two single-nucleotide polymorphisms (rs10455872, rs3798220) and number of KIV-2 repeats in the gene encoding Lp(a) (LPA) are associated with Lp(a) and CAD. Our aim was to investigate whether in patients with stable CAD and high Lp(a) levels these genetic variants are associated with increased Lp(a) and arterial wall properties. Blood samples underwent biochemical and genetic analyses. Ultrasound measurements for the functional and morphological properties of arterial wall were performed. Genotypes of rs10455872 and haplotypes AT and GT showed significant association with Lp(a) levels. Patients with GG showed significantly higher Lp(a) levels compared with those with AG genotype (2180 vs. 1391 mg/L, p = 0.045). Patients with no AT haplotype had significantly higher Lp(a) compared to carriers of one AT haplotype (2158 vs. 1478 mg/L, p = 0.023) or two AT haplotypes (2158 vs. 1487 mg/L, p = 0.044). There were no significant associations with the properties of the arterial wall. Lp(a) levels significantly correlated also with number of KIV-2 repeats (r = -0.601; p < 0.0001). In our patients, these two LPA polymorphisms and number of KIV-2 repeats are associated with Lp(a), but not arterial wall properties.

Low Brachial Artery Flow-Mediated Dilation Predicts Worse Prognosis in Hospitalized Patients with COVID-19

Background: Endothelial injury can be induced by coronavirus disease 2019 (COVID-19) and seems to exert a crucial pathogenic role in its most severe clinical manifestations. We aimed to investigate the association between brachial artery flow-mediated dilation (bFMD), a potential clinical and non-invasive measure of endothelial function, and in-hospital prognosis of COVID-19 patients. Methods: Brachial artery flow-mediated dilation was assessed in hospitalized COVID-19 patients within 48 h of hospital admission. The association between bFMD and either intensive care unit (ICU) admission or in-hospital death was explored using univariable and multivariable analyses. Results: Four hundred and eight patients were enrolled. Significantly lower bFMD values emerged in COVID-19 patients with either radiographic signs of pneumonia, respiratory distress, or the need for non-invasive ventilation compared with patients without these signs (p < 0.001, p = 0.001, and p < 0.001, respectively). Forty-two (10%) patients were admitted to the ICU, 76 (19%) patients died, and 118 (29%) patients met the composite endpoint of ICU admission/in-hospital death. At unadjusted Cox regression analysis showed that low bFMD (<4.4%, the median value) was associated with a higher risk for the composite endpoint of ICU admission/in-hospital death compared with high bFMD (≥4.4%, the median value) (HR 1.675, 95% CI 1.155–2.428, p = 0.007). Multi-adjusted Cox regression analyses showed that low bFMD was independently associated with a 1.519- to 1.658-fold increased risk for the composite endpoint of ICU admission/in-hospital death. Conclusions: Low bFMD predicts an unfavorable in-hospital prognosis in COVID-19 patients. The measurement of bFMD may be clinically useful in the prognostic stratification of COVID-19 patients upon hospital admission.

Cytomegalovirus may influence vascular endothelial health in Indonesian HIV-infected patients after 5 years on ART

Objectives

Accelerated atherosclerosis in older HIV-infected patients has been attributed to persistent immune activation and high burden cytomegalovirus (CMV), as demonstrated in transplant recipients and the general population. Here we assess CMV and inflammatory markers linked with vascular health in young adult patients treated in Indonesia.

Study design

HIV-infected adults (n = 32) were examined when they began antiretroviral therapy (ART) with < 200 CD4 T-cells/µl (V0) and after 60 months (V60). Age-matched healthy controls (HC, n = 32) were assessed once.

Methods

Flow Mediated Dilatation (FMD) was assessed by ultrasound on brachial arteries at V60 and in HC. Plasma markers of immune activation and endothelial activation, and CMV antibodies (lysate, gB, IE-1) were assessed in all samples. Results were assessed using bivariate (non-parametric) and multivariable analyses.

Results

Levels of inflammatory biomarkers and CMV antibodies declined on ART, but the antibodies remained higher than in HC. FMD values were similar in patients and HC at V60. In HIV patients, levels of CMV lysate antibody correlated inversely (r = − 0.37) with FMD. The optimal model predicting lower FMD values (adjusted R² = 0.214, p = 0.012) included CMV lysate antibodies and chondroitin sulphate. In HC, levels of sTNFR correlated inversely with FMD (r = − 0.41) and remained as a risk factor in the optimal multivariable model, with CMV glycoprotein-B (gB) antibody predicting a healthier FMD (adjusted R² = 0.248, p = 0.013).

Conclusions

Higher levels CMV antibodies optimally predict vascular health measured by FMD in HIV patients. However in healthy controls, sTNFR marks risk and CMV gB antibody may be protective.

Cardiovascular Risk and Endothelial Dysfunction in Primary Sjogren Syndrome Is Related to the Disease Activity

The aim of our study was to evaluate if endothelial-dysfunction (ED) occurs in patients with primary Sjogren syndrome (pSS) and whether it is associated with the disease characteristics and activity. A total of 46 patients with pSS and 30 controls, without known cardiovascular disease, were enrolled in this study. A flow-mediated-dilation (FMD) of the brachial artery, plasma concentrations of the nitric oxide (NO) metabolic pathway (ADMA, L-arginine, SDMA, cGMP), and markers of endothelial inflammatory function (PAI-1, sE-selectin) and angiogenesis (angiostatin, VEGF) were analyzed. The FMD was significantly lower in pSS patients (7.56 ± 3.08 vs. 10.91 ± 1.02%, p = 0.043) and positively correlated with the Ro/SS-A-antibodies (r = 0.34, p = 0.03), pulmonary involvement (r = 0.52, p = 0.001) and inversely with ADMA (r = −0.35, p = 0.04). Plasma ADMA, L-arginine and angiostatin levels were significantly higher in pSS patients (0.39 ± 0.08 vs. 0.36 ± 0.06 µmol/L, p = 0.05; 29.07 ± 6.7 vs. 25.4 ± 5.23 µmol/L, p = 0.01; 152.25 ± 60.99 vs. 120.07 ± 38.7 pg/mL, p = 0.0, respectively). ADMA was associated with ESSDAI (r = 0.33, p = 0.02), SCORE (r = 0.57, p = 0.00003) and focus score (r = 0.38, p = 0.04). In the multiple regression analysis, the ESSDAI was significantly and independently associated with plasma ADMA levels (β = 0.24, p = 0.04). Moreover, plasma cGMP concentrations were negatively correlated with the disease duration (r = −0.31, p = 0.03). Endothelial function is impaired in patients with pSS and associated with the measures of disease activity, which supports the key-role of inflammation in developing and maintaining accelerated atherosclerosis.

The effects of acute and sustained cannabidiol dosing for seven days on the haemodynamics in healthy men: A randomised controlled trial

BACKGROUND

In vivo studies show that cannabidiol (CBD) acutely reduces blood pressure (BP) in men. The aim of this study was to assess the effects of repeated CBD dosing on haemodynamics.

METHODS

Twenty-six healthy males were given CBD (600 mg) or placebo orally for seven days in a randomised, placebo-controlled, double-blind, parallel study (n = 13/group). Cardiovascular parameters were assessed at rest and in response to isometric exercise after acute and repeated dosing using Finometer®, Vicorder® and Duplex ultrasound.

RESULTS

Compared to placebo, CBD significantly reduced resting mean arterial pressure (P = .04, two-way ANOVA, mean difference (MD) -2 mmHg, 95% CI -3.6 to -0.3) after acute dosing, but not after repeated dosing. In response to stress, volunteers who had taken CBD had lower systolic BP after acute (P = .001, two-way ANOVA, MD -6 mmHg, 95% CI -10 to -1) and repeated (P = .02, two-way ANOVA, MD -5.7 mmHg, 95% CI -10 to -1) dosing. Seven days of CBD increased internal carotid artery diameter (MD +0.55 mm, P = .01). Within the CBD group, repeated dosing reduced arterial stiffness by day 7 (pulse wave velocity; MD -0.44 m/s, P = .05) and improved endothelial function (flow mediation dilatation, MD +3.5%, P = .02, n = 6 per group), compared to day 1.

CONCLUSION

CBD reduces BP at rest after a single dose but the effect is lost after seven days of treatment (tolerance); however, BP reduction during stress persists. The reduction in arterial stiffness and improvements in endothelial function after repeated CBD dosing are findings that warrant further investigation in populations with vascular diseases.

Effects of Resistance Training on Vascular and Hemodynamic Responses in Patients With Coronary Artery Disease

PURPOSE

The purpose of this study was to determine the impact of adjunctive resistance training (RT) in aerobically trained patients with coronary artery disease on systolic blood pressure (SBP), heart rate (HR), rating of perceived exertion (RPE; using the traditional 6-to-20 scale), and rate-pressure product (RPP) responses to lifting fixed submaximal workloads. Additionally, pretest and posttest RT measures of brachial artery reactivity were obtained.

METHOD

Fifteen patients with coronary artery disease (M_age = 66.1 ± 5.1 years) who were already performing regular aerobic exercise completed an adjunctive 12-week progressive RT program. Prior to and immediately after the training period, hemodynamic responses and RPE were obtained while participants performed one set of exercises including the bicep curl (BC), shoulder press (SP), and leg press (LP) at individually determined fixed submaximal loads, using ~ 60% to 80% of estimated maximal voluntary contraction. Vascular function was assessed by flow-mediated vasodilation (FMD) testing before and after training.

RESULTS

Attenuated hemodynamic and RPE responses for all variables were observed. Meaningful changes were attained for RPP ([HR × SBP] / 100) during BC (106 ± 27 mmHg × beats/min × 10^-2 to 91 ± 22 mmHg × beats/min × 10^-2, d = 0.6, p < .05) and SP (102 ± 24 mmHg × beats/min × 10^-2 to 86 ± 17 mmHg × beats/min × 10^-2, d = 0.8, p < .05). Rating of perceived exertion decreased significantly during all exercises (d ranging from 1.8 to 3.1, p < .05): BC (14.3 ± 2.6 to 9.7 ± 1.6), SP (13.9 ± 1.6 to 9.2 ± 1.5), and LP (14.3 ± 1.4 to 10.3 ± 1.6). Peak group FMD responses were 12.8% and 10.3% dilation at pretraining and posttraining, respectively (p > .05). Five of the 15 participants showed modest improvements in their posttraining time to achieve maximum dilation from a mean of 117 s to 81 s, although this change was not statistically significant (p > .05).

CONCLUSION

Among aerobically trained cardiac patients, a supplemental RT program resulted in decreased hemodynamic and RPE responses to lifting fixed submaximal workloads.

Imaging in Vascular Access

This review examines four imaging modalities; ultrasound (US), digital subtraction angiography (DSA), magnetic resonance imaging (MRI) and computed tomography (CT), that have common or potential applications in vascular access (VA). The four modalities are reviewed under their primary uses, techniques, advantages and disadvantages, and future directions that are specific to VA. Currently, US is the most commonly used modality in VA because it is cheaper (relative to other modalities), accessible, non-ionising, and does not require the use of contrast agents. DSA is predominantly only performed when an intervention is indicated. MRI is limited by its cost and the time required for image acquisition that mainly confines it to the realm of research where high resolution is required. CT’s short acquisition times and high resolution make it useful as a problem-solving tool in complex cases, although accessibility can be an issue. All four imaging modalities have advantages and disadvantages that limit their use in this particular patient cohort. Current imaging in VA comprises an integrated approach with each modality providing particular uses dependent on their capabilities. MRI and CT, which currently have limited use, may have increasingly important future roles in complex cases where detailed analysis is required.

Ultrasound Assessment of Flow-Mediated Dilation of the Brachial and Superficial Femoral Arteries in Rats

Arterial vasodilation to increases in wall shear rate is indicative of vascular endothelial function. In humans, the non-invasive measurement of endothelial function can be achieved by employing the flow-mediated dilation technique, typically performed in the brachial or superficial femoral artery. Briefly, a blood pressure cuff placed distal to an ultrasound probe is inflated to a suprasystolic pressure, which results in limb ischemia. After 5 min of occlusion the cuff is deflated, resulting in reactive hyperemia and increases in wall shear rate that signal vasodilatory molecules to be released from the endothelium eliciting vasodilation. Despite the thousands of studies performing flow-mediated dilation in humans, surprisingly, no studies have performed this technique non-invasively in living rats. Considering the recent shift in focus to translational research, the establishment of guidelines for non-invasive measurement of flow-mediated dilation in rats and other rodents would be extremely valuable. In the following article, a protocol is presented for the non-invasive measurement of flow-mediated dilation in brachial and superficial femoral arteries of rats, as those sites are most commonly measured in humans.

Posttraumatic Stress Disorder Is Associated With Worse Endothelial Function Among Veterans

Background

Current research in behavioral cardiology reveals a significant association between posttraumatic stress disorder (PTSD) and increased risk for cardiovascular disease and mortality; however, the underlying mechanisms remain poorly understood. We hypothesized that patients with PTSD would exhibit endothelial dysfunction, a potential mechanism involved in the development and progression of cardiovascular disease.

Methods and Results

A total of 214 outpatients treated at the San Francisco Veterans Affairs Medical Center underwent tests of endothelial function and evaluation for PTSD. Flow‐mediated vasodilation of the brachial artery was performed to assess endothelial function, and current PTSD status was defined by the PTSD Checklist, based on the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition), with a score ≥40. Multivariable linear regression models were used to estimate the association between PTSD status and endothelial function. Patients with PTSD (n=67) were more likely to be male (99% versus 91%, P=0.04) and to have depression (58% versus 8%, P<0.0001) and were less likely to be on an angiotensin‐converting enzyme inhibitor (17% versus 36%, P=0.007) or β‐blocker treatment (25% versus 41%, P=0.03). Univariate analysis demonstrated that patients with PTSD had significantly lower flow‐mediated vasodilation (5.8±3.4% versus 7.5±3.7%; P=0.003); furthermore, lower flow‐mediated vasodilation was associated with increasing age (P=0.008), decreasing estimated glomerular filtration rate (P=0.003), hypertension (P=0.002), aspirin (P=0.03), and β‐blocker treatments (P=0.01). In multivariable analysis, PTSD remained independently associated with lower flow‐mediated vasodilation (P=0.0005).

Conclusions

After adjusting for demographic, comorbidity, and treatment characteristics, PTSD remained associated with worse endothelial function in an outpatient population. Whether poor endothelial function contributes to the higher risk of cardiovascular disease in patients with PTSD deserves further study.

Short-Term, High-Dose Fish Oil Supplementation Increases the Production of Omega-3 Fatty Acid-Derived Mediators in Patients With Peripheral Artery Disease (the OMEGA-PAD I Trial)

BACKGROUND

Patients with peripheral artery disease (PAD) experience significant morbidity and mortality. The OMEGA-PAD I Trial, a randomized, double-blinded, placebo-controlled trial, addressed the hypothesis that short-duration, high-dose n-3 polyunsaturated fatty acids (n-3 PUFA) oral supplementation improves endothelial function and inflammation in PAD.

METHODS AND RESULTS

Eighty patients with stable claudication received 4.4 g of fish oil or placebo for 1 month. The primary end point was endothelial function as measured by brachial artery flow-mediated vasodilation. Secondary end points included biomarkers of inflammation, n-3 polyunsaturated fatty acids metabolome changes, lipid profile, and walking impairment questionnaires. Although there was a significant increase in FMD in the fish oil group following treatment (0.7±1.8% increase from baseline, P=0.04), this response was not different then the placebo group (0.6±2.5% increase from baseline, P=0.18; between-group P=0.86) leading to a negative finding for the primary endpoint. There was, however, a significant reduction in triglycerides (fish oil: -34±46 mg/dL, P<0.001; placebo -10±43 mg/dL, P=0.20; between-group differential P-value: 0.02), and an increase in the omega-3 index of 4±1% (P<0.001) in the fish oil group (placebo 0.1±0.9%, P=0.49; between-group P<0.0001). We observed a significant increase in the production of pathway markers of specialized pro-resolving mediators generated from n-3 polyunsaturated fatty acids in the fish oil group.

CONCLUSIONS

High-dose, short-duration fish oil supplementation did not lead to a different response in the primary end point of endothelial function between the treatment and placebo group, but improved serum triglycerides and increased the production of downstream n-3 polyunsaturated fatty acids-derived products and mediators in patients with PAD.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov/. Unique identifier: NCT01310270.