Assessment of vascular endothelial function with peripheral arterial tonometry: information at your fingertips?

Exploring the perspectives of pharmaceutical experts and healthcare practitioners on senolytic drugs for vascular aging-related disorder: a qualitative study

Objective: The field of targeting cellular senescence with drug candidates to address age-related comorbidities has witnessed a notable surge of interest and research and development. This study aimed to gather valuable insights from pharmaceutical experts and healthcare practitioners regarding the potential and challenges of translating senolytic drugs for treatment of vascular aging-related disorders. Methods: This study employed a qualitative approach by conducting in-depth interviews with healthcare practitioners and pharmaceutical experts. Participants were selected through purposeful sampling. Thematic analysis was used to identify themes from the interview transcripts. Results: A total of six individuals were interviewed, with three being pharmaceutical experts and the remaining three healthcare practitioners. The significant global burden of cardiovascular diseases presents a potentially large market size that offer an opportunity for the development and marketability of novel senolytic drugs. The pharmaceutical sector demonstrates a positive inclination towards the commercialization of new senolytic drugs targeting vascular aging-related disorders. However potential important concerns have been raised, and these include increasing specificity toward senescent cells to prevent off-site targeting, thus ensuring the safety and efficacy of these drugs. In addition, novel senolytic therapy for vascular aging-related disorders may encounter competition from existing drugs that treat or manage risk factors of cardiovascular diseases. Healthcare practitioners are also in favor of recommending the novel senolytic drugs for vascular aging-related disorders but cautioned that its high cost may hinder its acceptance among patients. Besides sharing the same outcome-related concerns as with the pharmaceutical experts, healthcare practitioners anticipated a lack of awareness among the general public regarding the concept of targeting cellular senescence to delay vascular aging-related disorders, and this knowledge gap extends to healthcare practitioner themselves as well. Conclusion: Senolytic therapy for vascular aging-related disorders holds great promise, provided that crucial concerns surrounding its outcomes and commercial hurdles are effectively addressed.

Impaired Peripheral Microvascular Function and Risk of Major Adverse Cardiovascular Events in Patients With Coronary Artery Disease

[Figure: see text].

Improved metabolic fitness, but no cardiovascular health effects, of a low-frequency short-term combined exercise programme in 50-70-year-olds with low fitness: A randomized controlled trial

We evaluated the cardiometabolic effects of a 15-week combined exercise programme, implemented in sports clubs, for 50-70-year-olds with low aerobic fitness. In a randomized controlled trial, 45 participants (26 women) with low fitness were randomly assigned (2:1-ratio) to a training group (TG, n = 30) or inactive control group (CG, n = 15). TG had 15 weeks with one weekly 90-min supervised group-based session in a recreational sports club with combined aerobic exercise and strength training and were encouraged to perform home-based training 30 min/wk. Evaluations of relative VO_2max (mLO₂/min/kg), blood pressure, resting heart rate (HR), echocardiography, peripheral arterial tonometry, body composition, lipid profile and HbA1c were performed at 0 and 15 wks. Average HR during supervised training was 113 ± 13 bpm (68.6 ± 7.0%HR_max), with 4.3 ± 6.6% spent >90%HR_max. At 15-wk follow-up, intention-to-treat analyses revealed no between-group difference for VO_2max/kg (0.4 mLO₂/min/kg, 95%CI -0.8-1.5, P = 0.519; -3 mL/min, 95%CI -123-118, P = 0.966) or other cardiovascular outcomes (all P > 0.05). Compared to CG, total fat mass (-1.9 kg; 95%CI -3.2 to -0.5, P = 0.005), total fat percentage (-1.3%, 95%CI -2.2 to -0.3, P = 0.01) and total/HDL cholesterol ratio (P = 0.032) decreased in TG. Regular adherence to supervised training was high (81%), but 0% for home-based exercise. In conclusion, the group-based supervised training was associated with high adherence and moderate exercise intensity, whereas insufficiently supported home-based training was not feasible. Together, 15 wks of combined exercise training did not improve aerobic fitness or affected cardiovascular function in 50-70-yr-olds with low aerobic fitness, whereas some positive effects were observed in metabolic parameters.HighlightsCombined exercise training implemented in a sports club elicited moderate aerobic intensity in 50-70-year-old untrained individuals.Supervised group-based training had high adherence whereas unsupported home-based training had very low adherence.15 weeks of low-frequency combined moderate intensity exercise training improved lipid profile and fat mass, but had no effect on cardiovascular fitness.

Effect of early sleep apnoea treatment with adaptive servo-ventilation in acute stroke patients on cerebral lesion evolution and neurological outcomes: study protocol for a multicentre, randomized controlled, rater-blinded, clinical trial (eSATIS: early Sleep Apnoea Treatment in Stroke)

BACKGROUND

Sleep-disordered breathing (SDB) is highly prevalent in acute ischaemic stroke and is associated with worse functional outcome and increased risk of recurrence. Recent meta-analyses suggest the possibility of beneficial effects of nocturnal ventilatory treatments (continuous positive airway pressure (CPAP) or adaptive servo-ventilation (ASV)) in stroke patients with SDB. The evidence for a favourable effect of early SDB treatment in acute stroke patients remains, however, uncertain.

METHODS

eSATIS is an open-label, multicentre (6 centres in 4 countries), interventional, randomized controlled trial in patients with acute ischaemic stroke and significant SDB. Primary outcome of the study is the impact of immediate SDB treatment with non-invasive ASV on infarct progression measured with magnetic resonance imaging in the first 3 months after stroke. Secondary outcomes are the effects of immediate SDB treatment vs non-treatment on clinical outcome (independence in daily functioning, new cardio-/cerebrovascular events including death, cognition) and physiological parameters (blood pressure, endothelial functioning/arterial stiffness). After respiratory polygraphy in the first night after stroke, patients are classified as having significant SDB (apnoea-hypopnoea index (AHI) > 20/h) or no SDB (AHI < 5/h). Patients with significant SDB are randomized to treatment (ASV+ group) or no treatment (ASV- group) from the second night after stroke. In all patients, clinical, physiological and magnetic resonance imaging studies are performed between day 1 (visit 1) and days 4-7 (visit 4) and repeated at day 90 ± 7 (visit 6) after stroke.

DISCUSSION

The trial will give information on the feasibility and efficacy of ASV treatment in patients with acute stroke and SDB and allows assessing the impact of SDB on stroke outcome. Diagnosing and treating SDB during the acute phase of stroke is not yet current medical practice. Evidence in favour of ASV treatment from a randomized multicentre trial may lead to a change in stroke care and to improved outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02554487 , retrospectively registered on 16 September 2015 (actual study start date, 13 August 2015), and www.kofam.ch (SNCTP000001521).

The effect of dietary nitrate and vitamin C on endothelial function, oxidative stress and blood lipids in untreated hypercholesterolemic subjects: A randomized double-blind crossover study

BACKGROUND

Vitamin C may enhance nitric oxide (NO) production through stepwise reduction of dietary nitrate (NO₃) to nitrite (NO₂) to NO. The combined effect of vitamin C and NO₃ supplementation is relatively unexplored in untreated hypercholesterolemia.

AIMS

We aimed to examine whether co-administration of vitamin C and nitrate for 4-weeks would improve endothelial function (primary outcome), plasma NO metabolites, oxidative stress, and blood lipids (secondary outcomes).

METHODS

Subjects 50-70 years of age with low density lipoprotein (LDL) > 130 mg/dL and RHI ≤2 were enrolled in this randomized double-blind crossover study. Subjects were assigned to two 4-week supplementation treatments starting with 70 ml of concentrated beetroot juice (CBJ) with 1000 mg of vitamin C (NC) or CBJ with matched placebo (N), then switched to alternate treatment following 2-week washout. The change in reactive hyperemia index (RHI), sum of plasma NO metabolites (NO₂ + NO₃ (NOx)), oxidized LDL (oxLDL), and serum lipids were assessed at baseline and at 4-weeks of each treatment period.

RESULTS

Eighteen subjects (11M:7F) completed all study visits. No significant treatment differences were observed in RHI change (N: 0.21 ± 0.12; NC: 0.20 ± 0.17; p = 0.99). Secondary analysis revealed that a subgroup of NC subjects who started with a baseline RHI of <1.67 (threshold value for ED) had greater improvements in RHI compared to subjects with RHI >1.67 (1.23 ± 0.15 to 1.96 ± 0.19; n = 8 vs. 1.75 ± 0.11 to 1.43 ± 0.10; n = 8; p = 0.02). Compared to N, NC experienced a significant increase in plasma NOx (N: 94.2 ± 15.5 μmol/L; NC: 128.7 ± 29.1 μmol/L; p = 0.01). Although there was no significant difference in oxLDL change between treatments (N: -1.08 ± 9.8 U/L; NC: -6.07 ± 9.14 U/L; p = 0.19), NC elicited significant reductions in LDL (N: 2.2 ± 2; NC: -10.7 ± 23; p = 0.049), triglycerides (N: 14.6 ± 43; NC: -43.7 ± 45; p = 0.03), and no change in serum high density lipoprotein. Within treatment group comparisons showed that only NC reduced oxLDL significantly from baseline to 4 weeks (p = 0.01).

CONCLUSIONS

No between intervention differences were observed in RHI. RHI only improved in NC subjects with ED at intervention baseline. Four weeks of NC enriched the NO pool and promoted reduction of blood lipids and oxidative stress in subjects with hypercholesterolemia. These preliminary findings highlight a supplementation strategy that may reduce the progression of atherosclerotic disease and deserves further attention in studies using flow mediated dilation methods.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov (NCT04283630).

Photoplethysmographic Waveform Analysis for Autonomic Reactivity Assessment in Depression

OBJECTIVE

In the present study, a photoplethysmographic (PPG) waveform analysis for assessing differences in autonomic reactivity to mental stress between patients with Major Depressive Disorder (MDD) and healthy control (HC) subjects is presented.

METHODS

PPG recordings of 40 MDD and 40 HC subjects were acquired at basal conditions, during the execution of cognitive tasks, and at the post-task relaxation period. PPG pulses are decomposed into three waves (a main wave and two reflected waves) using a pulse decomposition analysis. Pulse waveform characteristics such as the time delay between the position of the main wave and reflected waves, the percentage of amplitude loss in the reflected waves, and the heart rate (HR) are calculated among others. The intra-subject difference of a feature value between two conditions is used as an index of autonomic reactivity.

RESULTS

Statistically significant individual differences from stress to recovery were found for HR and the percentage of amplitude loss in the second reflected wave ( A₁₃) in both HC and MDD group. However, autonomic reactivity indices related to  A₁₃ reached higher values in HC than in MDD subjects (Cohen's [Formula: see text]), implying that the stress response in depressed patients is reduced. A statistically significant ( ) negative correlation ( r=-0.5) between depression severity scores and A₁₃ was found.

CONCLUSION

A decreased autonomic reactivity is associated with higher degree of depression.

SIGNIFICANCE

Stress response quantification by dynamic changes in PPG waveform morphology can be an aid for the diagnosis and monitoring of depression.

An exploratory, randomised, placebo-controlled, 14 day trial of the soluble guanylate cyclase stimulator praliciguat in participants with type 2 diabetes and hypertension

AIMS/HYPOTHESIS

Praliciguat (IW-1973), a soluble guanylate cyclase stimulator, amplifies nitric oxide signalling. This exploratory trial investigated the safety, tolerability, pharmacokinetic profile and pharmacodynamic effects of praliciguat in individuals with type 2 diabetes and hypertension.

METHODS

This Phase IIA, double-blind, placebo-controlled trial investigated praliciguat in 26 participants with type 2 diabetes and hypertension on stable glucose- and BP-lowering therapies. Participants were randomly allocated in a 3:5:5 ratio to three groups: placebo (n = 6), praliciguat 40 mg once daily for days 1-14 (n = 10), or praliciguat 20 mg twice daily for days 1-7 then 40 mg once daily for days 8-14 (n = 10). Assessments were made in clinic and included treatment-emergent adverse events, pharmacokinetics, metabolic variables, 24 h BP and heart rate, platelet function, reactive hyperaemia index (RHI) and plasma biomarkers. Participants, the sponsor, the investigator and clinic study staff (except designated pharmacy personnel) were blinded to group assignment.

RESULTS

Participants treated for 14 days with praliciguat had least-square mean change-from-baseline differences vs placebo (95% CI) of -0.7 (-1.8, 0.4) mmol/l for fasting plasma glucose, -0.7 (-1.1, -0.2) mmol/l for total cholesterol, -0.5 (-1.0, -0.1) mmol/l for LDL-cholesterol, -23 (-56, 9) for HOMA-IR in those not being treated with insulin, and -5 (-10, 1) mmHg and 3 (-1, 6) beats/min for average 24 h mean arterial pressure and heart rate, respectively. Apart from one serious adverse event (SAE; upper gastrointestinal haemorrhage), praliciguat was well tolerated. Praliciguat did not affect platelet function or RHI. Among exploratory biomarkers, plasma levels of asymmetric dimethylarginine decreased in praliciguat vs placebo recipients.

CONCLUSIONS/INTERPRETATION

In participants with type 2 diabetes and hypertension on standard therapies, over 14 days praliciguat was well tolerated, except for a single SAE, and showed positive trends in metabolic and BP variables. These results support further clinical investigation of praliciguat.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03091920.

FUNDING

This trial was funded by Cyclerion Therapeutics.

The effect of melatonin on endothelial dysfunction in patients after acute coronary syndrome: The MEFACS randomized clinical trial

Endothelial dysfunction (ED) precedes acute coronary syndrome. Oxidative stress results in ED but is reversible. Melatonin is aside from being a circadian hormone, also an antioxidant. The aim of this study was to investigate whether 25 mg melatonin administered for twelve weeks following acute coronary syndrome (ACS) could improve ED. In this placebo-controlled randomized trial, ED was measured as reactive hyperemia index (RHI) at baseline, day 14, and day 84. The effect was assessed using a generalized estimating equation adjusted for the baseline RHI. As secondary outcome, the concentrations of three biomarkers were measured: l-arginine, asymmetric dimethylarginine, and uric acid. Thirty-one patients were included in the study. The intention-to-treat analysis of the primary outcome had 26 patients due to missing data. The estimated marginal mean difference in RHI at day 14 and day 84 between the groups was 0.15 (95% CI: 0.29-0.01, P = .039) in favor of the placebo group. No significant differences in the biomarker concentrations were found. Melatonin treatment after ACS did not improve but may have aggravated ED. The significant difference between groups was in favor of placebo, but this might be due to the effect of missing data or uneven distribution of comorbidities.

Cardiovascular adaptations after 10 months of intense school-based physical training for 8- to 10-year-old children

This study examined cardiovascular adaptations in 8- to 10-year-old schoolchildren after 10 months (a full school year) of 3 × 40 minute per week of small-sided ball games (SSG, including football, basketball, and/or floorball) or circuit strength training (CST). The study involved 291 Danish schoolchildren, 8-10 years old, cluster-randomized to SSG (n = 93, 4 schools, 5 classes), CST (n = 83, 4 schools, 4 classes), or a control group (CON, n = 115, 2 schools, 5 classes). Before and after the 10-month intervention, resting heart rate and blood pressure measurements were performed as well as comprehensive transthoracic echocardiography and peripheral arterial tonometry (PAT). Analysis of baseline-to-10-months changes showed between-group differences (P < 0.05) after both training interventions in diastolic blood pressure (delta scores: SSG -2.1 ± 6.0 mm Hg; CST -3.0 ± 7.1 mm Hg; CON 0.2 ± 5.3 mm Hg). Moreover, there were between-group differences in delta scores (P < 0.05) in interventricular septum thickness (SSG 0.17 ± 0.87 mm; CST 0.30 ± 0.94 mm; CON -0.15 ± 0.68 mm), left-atrial volume index (SSG 0.32 ± 5.13 mL/m² ; CON 2.60 ± 5.94 mL/m² ), and tricuspid annular plane systolic excursion (SSG -0.4 ± 3.3 mm; CON: 0.1 ± 3.6 mm). No significant between-group differences were observed for the PAT-derived reactive hyperemia index. In conclusion, 10 months of 3 × 40 minutes per week of SSG and CST in 8- to 10-year-old children decreased diastolic blood pressure and elicited discrete cardiac adaptations, suggesting that intense physical exercise in school classes can have effects on cardiovascular health in children.

Microvascular endothelial function in Japanese early adolescents

Endothelial dysfunction is the early predictive factor for the development of atherosclerosis and future cardiovascular diseases in adulthood. The prevalence of endothelial dysfunction in children and early adolescents is increasing worldwide. Peripheral arterial tonometry is a noninvasive technique for assessing peripheral microvascular function and is used as a validated marker of endothelial function. We assessed anthropometric parameters, blood pressure, arterial stiffness, and peripheral endothelial function in 157 Japanese early adolescents (75 boys and 82 girls). We measured peripheral endothelial function by using peripheral arterial tonometry to determine the reactive hyperemia index, and assessed the association of reactive hyperemia index with parameters of anthropometry and arterial stiffness. The mean reactive hyperemia index of all subjects was 1.85 ± 0.6, and there was no difference of reactive hyperemia index according to sex. Reactive hyperemia index was significantly associated with systolic and diastolic blood pressures, and had no correlation with anthropometric parameters and arterial stiffness markers. The reactive hyperemia index values among Japanese early adolescents were similar to those reported in previous studies on children and early adolescents. This noninvasive technique may be useful for the assessment of microvascular endothelial function among children and early adolescents.

Endothelial dysfunction in cardiovascular disease and Flammer syndrome-similarities and differences

The endothelium has increasingly been recognized as a smart barrier and a key regulator of blood flow in micro- and macrovascular beds. Endothelial dysfunction marks a stage of atherosclerosis and is an important prognostic marker for cardiovascular disease. Yet, some people who tend to be slim and physically active and with rather low blood pressure show a propensity to respond to certain stimuli such as emotional stress with endothelial-mediated vascular dysregulation (Flammer syndrome). This leads to characteristic vascular symptoms such as cold hands but also a risk for vascular-mediated diseases such as normal-tension glaucoma. It is the aim of this review to delineate the differences between Flammer syndrome and its "counterpart" endothelial dysfunction in the context of cardiovascular diseases.

Peripheral Endothelial Function After Arterial Switch Operation for D-looped Transposition of the Great Arteries

Coronary artery re-implantation during arterial switch operation in patients with D-looped transposition of the great arteries (D-TGA) can alter coronary arterial flow and increase shear stress, leading to local endothelial dysfunction, although prior studies have conflicting results. Endothelial pulse amplitude testing can predict coronary endothelial dysfunction by peripheral arterial testing. This study tested if, compared to healthy controls, patients with D-TGA after arterial switch operation had peripheral endothelial dysfunction. Patient inclusion criteria were (1) D-TGA after neonatal arterial switch operation; (2) age 9-29 years; (3) absence of known cardiovascular risk factors such as hypertension, diabetes, hypercholesterolemia, vascular disease, recurrent vasovagal syncope, and coronary artery disease; and (4) ability to comply with overnight fasting. Exclusion criteria included (1) body mass index ≥85th percentile, (2) use of medications affecting vascular tone, or (3) acute illness. We assessed endothelial function by endothelial pulse amplitude testing and compared the results to our previously published data in healthy controls (n = 57). We tested 20 D-TGA patients (16.4 ± 4.8 years old) who have undergone arterial switch operation at a median age of 5 days (0-61 days). Endothelial pulse amplitude testing indices were similar between patients with D-TGA and controls (1.78 ± 0.61 vs. 1.73 ± 0.54, p = 0.73).In our study population of children and young adults, there was no evidence of peripheral endothelial dysfunction in patients with D-TGA who have undergone arterial switch operation. Our results support the theory that coronary arterial wall thickening and abnormal vasodilation reported in these patients is a localized phenomenon and not reflective of overall atherosclerotic burden.

Cold-induced sympathetic tone modifies the impact of endothelium-dependent vasodilation in the finger pulp

OBJECTIVE

In thermoneutral and cold subjects, the sympathetic nervous system regulates skin blood flow by adjusting frequency of the tonic vasoconstrictor impulses. However, the way these thermoregulatory impulses influence the vascular endothelium is not well known. We studied how the sympathetic nervous system influences endothelium-dependent vasodilation (EDV) caused by shear stress in skin containing arteriovenous anastomoses (AVAs) and arterioles in healthy subjects.

METHODS

Thirteen healthy subjects were exposed to thermoneutral (29°C) and cold (22°C) ambient temperatures on separate days. EDV was induced by releasing suprasystolic pressure cuff applied to the forearm or third finger after 4min. Bilateral laser Doppler flux from the finger pulp, dorsal finger and dorsal wrist was measured together with ultrasound Doppler from the right radial artery. Absolute EDV response (EDV peak minus baseline) and normalized relative EDV response (ratio EDV peak/baseline) were calculated (median, 95% confidence interval). The relative EDV response reflect the size of EDV response independent of the baseline level and is thus used to compare the EDV responses in the finger pulp and wrist skin in the two temperature conditions.

RESULTS

In finger pulp (dominated by AVAs), the absolute EDV response (flux, au) in thermoneutral (137.8 (67.5, 168.8)) and cold (130.3 (97.2, 154.9)) was the same (p=0.85), whereas the relative EDV response was significantly higher in cold (3.6 (2.5, 5.9)) than in thermoneutral (1.4 (1.1, 1.6), p=0.002). The same patterns were found in the radial artery. In the dorsal wrist (dominated by arterioles) the absolute EDV response (flux, au) was smaller in cold (30.9 (15.91, 38.0)) than in thermoneutral (52.1 (38.4, 57.8), p=0.04), whereas the relative EDV responses in cold (3.5 (2.3, 4.2)), and thermoneutral (2.3 (1.6, 2.7)) were equal (p=0.16).

CONCLUSIONS

The relative EDV responses show that the impact of EDV on skin perfusion in cold conditions is significantly greater in the finger pulp than in wrist skin. However, the absolute EDV responses indicate that vascular smooth muscle relaxation during EDV is probably not affected by higher mild cold-induced sympathetic activity either in AVAs or in arterioles.

Arterial pressure beat to beat characterization during post-occlusive reactive hyperemia

INTRODUCTION

In recent years, peripheral arterial tonometry (PAT, a non-invasive and reproducible technique) has gained considerable interest. In this sense, arterial capacity to react to vasoactive stimulus (induced by reactive hyperemia) is known as vascular reactivity (VR).

OBJECTIVE

Post ischemic beat to beat VR characterization was performed based on PAT measurements.

METHODS

Systolic Blood Pressure (SBP) and Augmentation index (AIx) variations were modeled, as a response to flow stimulus.

RESULTS

Obtained R2 values were around 70% for VR while, to a lesser degree, AIx fit was about 50% Conclusion: Beat to Beat VR was described in terms of SBP and AIx behavior. Further studies are needed to determine the clinical usefulness of the proposed indicators.

Beyond type 2 diabetes, obesity and hypertension: an axis including sleep apnea, left ventricular hypertrophy, endothelial dysfunction, and aortic stiffness among Mexican Americans in Starr County, Texas

BACKGROUND

There is an increasing appreciation for a series of less traditional risk factors that should not be ignored when considering type 2 diabetes, obesity, hypertension, and cardiovascular disease. These include aortic stiffness, cardiac structure, impaired endothelial function and obstructive sleep apnea. They are associated to varying degrees with each disease categorization and with each other. It is not clear whether they represent additional complications, concomitants or antecedents of disease. Starr County, Texas, with its predominantly Mexican American population has been shown previously to bear a disproportionate burden of the major disease categories, but little is known about the distribution of these less traditional factors.

METHODS

Type 2 diabetes, obesity and hypertension frequencies were determined through a systematic survey of Starr County conducted from 2002 to 2006. Individuals from this examination and an enriched set with type 2 diabetes were re-examined from 2010 to 2014 including assessment of cardiac structure, sleep apnea, endothelial function and aortic stiffness. Individual and combined frequencies of these inter-related (i.e., axis) conditions were estimated and associations evaluated.

RESULTS

Household screening of 5230 individuals aged 20 years and above followed by direct physical assessment of 1610 identified 23.7 % of men and 26.7 % of women with type 2 diabetes, 46.2 and 49.5 % of men and women, respectively with obesity and 32.1 and 32.4 % with hypertension. Evaluation of pulse wave velocity, left ventricular mass, endothelial function and sleep apnea identified 22.3, 12.7, 48.6 and 45.2 % of men as having "at risk" values for each condition, respectively. Corresponding numbers in women were 16.0, 17.9, 23.6 and 28.8 %. Cumulatively, 88 % of the population has one or more of these while 50 % have three or more.

CONCLUSIONS

The full axis of conditions is high among Mexican Americans in Starr County, Texas. Individual and joint patterns suggest a genesis well before overt disease. Whether they are all mediated by common underlying factors or whether there exist multiple mechanisms remains to be seen.

Endothelial Dysfunction After ST-segment Elevation Myocardial Infarction and Long-term Outcome: A Study With Reactive Hyperemia Peripheral Artery Tonometry

INTRODUCTION AND OBJECTIVES

Long-term data on the relationship between endothelial dysfunction after ST-segment elevation myocardial infarction and future adverse clinical events are scarce. The aim of this study was to noninvasively assess whether endothelial dysfunction 4 weeks to 6 weeks after primary percutaneous coronary intervention for acute ST-segment elevation myocardial infarction predicts future clinical events.

METHODS

This prospective cohort study was performed in 70 patients of the RESPONSE randomized trial, who underwent noninvasive assessment of endothelial function 4 weeks to 6 weeks after primary percutaneous coronary intervention. Endothelial function was measured by the reactive hyperemia peripheral artery tonometry method; an index<1.67 identified endothelial dysfunction.

RESULTS

The reactive hyperemia peripheral artery tonometry index measured on average 1.90±0.58. A total of 35 (50%) patients had endothelial dysfunction and 35 (50%) patients had normal endothelial function. Periprocedural "complications" (eg, cardiogenic shock, total atrioventricular block) were more common in patients with endothelial dysfunction than in those without (25.7% vs 2.9%; P<.01). During 4.0±1.7 years of follow-up, 20 (28.6%) patients had major adverse cardiovascular events: events occurred in 9 (25.7%) patients with endothelial dysfunction and in 11 (31.5%) patients with normal endothelial function (P=.52). There was an association between the prevalence of diabetes mellitus at baseline and the occurrence of major adverse cardiovascular events during follow-up (univariate analysis: hazard ratio=2.8; 95% confidence interval, 1.0-7.8; P<.05), and even in multivariate analyses the risk appeared to be increased, although not significantly (multivariate analysis: hazard ratio=2.5; 95% confidence interval, 0.8-7.5).

CONCLUSIONS

In this series of patients who survived an ST-segment elevation myocardial infarction, endothelial dysfunction, as assessed by reactive hyperemia peripheral artery tonometry 4 weeks to 6 weeks after myocardial infarction, did not predict future clinical events during a mean follow-up of 4 years.

Noninvasive effects measurements for air pollution human studies: methods, analysis, and implications

Human exposure studies, compared with cell and animal models, are heavily relied upon to study the associations between health effects in humans and air pollutant inhalation. Human studies vary in exposure methodology, with some work conducted in controlled settings, whereas other studies are conducted in ambient environments. Human studies can also vary in the health metrics explored, as there exists a myriad of health effect end points commonly measured. In this review, we compiled mini reviews of the most commonly used noninvasive health effect end points that are suitable for panel studies of air pollution, broken into cardiovascular end points, respiratory end points, and biomarkers of effect from biological specimens. Pertinent information regarding each health end point and the suggested methods for mobile collection in the field are assessed. In addition, the clinical implications for each health end point are summarized, along with the factors identified that can modify each measurement. Finally, the important research findings regarding each health end point and air pollutant exposures were reviewed. It appeared that most of the adverse health effects end points explored were found to positively correlate with pollutant levels, although differences in study design, pollutants measured, and study population were found to influence the magnitude of these effects. Thus, this review is intended to act as a guide for researchers interested in conducting human exposure studies of air pollutants while in the field, although there can be a wider application for using these end points in many epidemiological study designs.

A systematic review of vascular and endothelial function: effects of fruit, vegetable and potassium intake

AIM

To review the relationships between: 1) Potassium and endothelial function; 2) Fruits and vegetables and endothelial function; 3) Potassium and other measures of vascular function; 4) Fruits and vegetables and other measures of vascular function.

DATA SYNTHESIS

An electronic search for intervention trials investigating the effect of potassium, fruits and vegetables on vascular function was performed in MEDLINE, EMBASE and the Cochrane Library. Potassium appears to improve endothelial function with a dose of >40 mmol/d, however the mechanisms for this effect remain unclear. Potassium may improve measures of vascular function however this effect may be dependent on the effect of potassium on blood pressure. The effect of fruit and vegetables on endothelial function independent of confounding variables is less clear. Increased fruit and vegetable intake may improve vascular function only in high risk populations.

CONCLUSION

Increasing dietary potassium appears to improve vascular function but the effect of increasing fruit and vegetable intake per se on vascular function is less clear.

Endothelial function in migraine with aura - a systematic review

BACKGROUND

An increased risk of ischemic stroke is repeatedly reported in young subjects with migraine with aura (MA). Such may be caused by changes in endothelial function. The present review evaluates current evidence on endothelial function in MA patients.

METHODS

A systematic search of electronic databases (Medline, Embase, Cochrane library) was performed, and a search in associated reference lists of identified studies was done.

RESULTS

In total, 27 studies met inclusion criteria for this review. Six studies assessed endothelial function by flow-mediated dilation; four reported no differences compared with healthy subjects, one study reported an increase and one study a decrease in migraineurs. Peripheral arterial tonometry was applied in one study where no changes were detected between groups. Likewise, applying venous occlusion plethysmography elicited comparable responses. Arterial function was investigated in six studies; increased augmentation index and decreased arterial distensibility were reported in migraineurs, whereas findings regarding pulse wave velocity were dissimilar. However, when investigating levels of endothelial progenitor cells, two studies reported reduced levels in migraineurs, and several studies on endothelial markers in the areas of inflammation, oxidative stress, and coagulation found increased endothelial activation in migraineurs, particularly in MA. One study, assessing cerebral endothelial function using transcranial Doppler sonography, reported lower cerebrovascular reactivity to L-arginine in the posterior cerebral arteries in migraineurs.

CONCLUSION

Endothelial dysfunction appears not to be of importance in MA patients. However, the studies were few with a wide variety of techniques applied in small groups of patients. Endothelial biomarkers were increased in patients indicating a possible subtle change in the endothelium. Further investigations on larger groups of patients combining testing of endothelial dysfunction as well as biomarkers are warranted to identify whether or not endothelial changes may play a role in the increased risk of stroke in young MA patients.

Cardiovascular and lung function in relation to outdoor and indoor exposure to fine and ultrafine particulate matter in middle-aged subjects

This cross-sectional study investigated the relationship between exposure to airborne indoor and outdoor particulate matter (PM) and cardiovascular and respiratory health in a population-based sample of 58 residences in Copenhagen, Denmark. Over a 2-day period indoor particle number concentrations (PNC, 10-300 nm) and PM2.5 (aerodynamic diameter<2.5 μm) were monitored for each of the residences in the living room, and outdoor PNC (10-280 nm), PM2.5 and PM10 (aerodynamic diameter<10 μm) were monitored at an urban background station in Copenhagen. In the morning, after the 2-day monitoring period, we measured microvascular function (MVF) and lung function and collected blood samples for biomarkers related to inflammation, in 78 middle-aged residents. Bacteria, endotoxin and fungi were analyzed in material from electrostatic dust fall collectors placed in the residences for 4 weeks. Data were analyzed using linear regression with the generalized estimating equation approach. Statistically significant associations were found between indoor PNC, dominated by indoor use of candles, and lower lung function, the prediabetic marker HbA1c and systemic inflammatory markers observed as changes in leukocyte differential count and expression of adhesion markers on monocytes, whereas C-reactive protein was significantly associated with indoor PM2.5. The presence of indoor endotoxin was associated with lower lung function and expression of adhesion markers on monocytes. An inverse association between outdoor PNC and MVF was also statistically significant. The study suggests that PNC in the outdoor environment may be associated with decreased MVF, while PNC, mainly driven by candle burning, and bioaerosols in the indoor environment may have a negative effect on lung function and markers of systemic inflammation and diabetes.

Effect of acute hypobaric hypoxia on the endothelial glycocalyx and digital reactive hyperemia in humans

Introduction: Hypoxia is associated with increased capillary permeability. This study tested whether acute hypobaric hypoxia involves degradation of the endothelial glycocalyx.

Methods: We exposed 12 subjects to acute hypobaric hypoxia (equivalent to 4500 m for 2–4 h) and measured venous blood concentrations of biomarkers reflecting endothelial and glycocalyx degradation (catecholamines, syndecan-1, soluble CD40 ligand, protein C, soluble thrombomodulin, tissue-type plasminogen activators, histone-complexed DNA fragments, and nitrite/nitrate). Endothelial function was assessed by the hyperemic response to brachial artery occlusion by peripheral arterial tonometry.

Results: Compared with normoxic baseline levels, hypoxia increased concentrations of syndecan-1 from 22 (95% confidence interval: 17–27) to 25 (19–30) ng/ml (p < 0.02) and protein C from 76 (70–83)% to 81 (74–88)% (p < 0.02). Nitrite/nitrate decreased from 23 (18–27) μM at baseline to 19 (14–24) μM and 18 (14–21) μM in hypoxia and recovery, respectively (p < 0.05). Other biomarkers remained unchanged. The post-occlusion/pre-occlusion ratio (reactive hyperemia index, RHI) decreased from 1.80 (1.52–2.07) in normoxia to 1.62 (1.28–1.96) after 2–4 h of hypobaric hypoxia and thereafter increased to 2.43 (1.99–2.86) during normoxic recovery (p < 0.01).

Conclusions: The increase in syndecan-1 and protein C suggests that acute hypobaric hypoxia produces a minor degree of glycocalyx degradation and overall cellular damage. After hypoxia RHI rebounded to higher than baseline levels suggesting improved endothelial functionality.

Non-invasive endothelial function testing and the risk of adverse outcomes: a systematic review and meta-analysis

OBJECTIVES

We performed a systematic review and meta-analysis to understand the role of flow-mediated dilatation (FMD) of the brachial artery (BA) and peripheral arterial tonometry (PAT) in predicting adverse events, including cardiovascular (CV) events and all-cause mortality.

BACKGROUND

FMD of the BA and PAT are non-invasive measures of endothelial function. Impairment of endothelial function is associated with increased CV events. While FMD is the more widely used and studied technique, PAT offers several advantages. The purpose of this systematic review and meta-analysis is to determine whether brachial FMD and PAT are independent risk factors for future CV events and mortality.

METHODS

Multiple electronic databases were searched for articles relating FMD or PAT to CV events. Data were extracted on study characteristics, study quality, and study outcomes. Relative risks (RRs) from individual studies were combined and a pooled multivariate RR was calculated.

RESULTS

Thirty-six studies for FMD were included in the systematic review, of which 32 studies consisting of 15, 191 individuals were meta-analysed. The pooled RR of CV events and all-cause mortality per 1% increase in brachial FMD, adjusting for potential confounders, was 0.90 (0.88-0.92). In contrast, only three studies evaluated the prognostic value of PAT for CV events, and the pooled RR per 0.1 increase in reactive hyperaemia index was 0.85 (0.78-0.93).

CONCLUSION

Brachial FMD and PAT are independent predictors of CV events and all-cause mortality. Further research to evaluate the prognostic utility of PAT is necessary to compare it with FMD as a non-invasive endothelial function test in clinical practice.

An indoor air filtration study in homes of elderly: cardiovascular and respiratory effects of exposure to particulate matter

BACKGROUND

Exposure to particulate air pollution increases respiratory and cardiovascular morbidity and mortality, especially in elderly, possibly through inflammation and vascular dysfunction.

METHODS

We examined potential beneficial effects of indoor air filtration in the homes of elderly, including people taking vasoactive drugs.Forty-eight nonsmoking subjects (51 to 81 years) in 27 homes were included in this randomized, double-blind, crossover intervention study with consecutive two-week periods with or without the inclusion of a high-efficiency particle air filter in re-circulating custom built units in their living room and bedroom. We measured blood pressure, microvascular and lung function and collected blood samples for hematological, inflammation, monocyte surface and lung cell damage markers before and at day 2, 7 and 14 during each exposure scenario.

RESULTS

The particle filters reduced the median concentration of PM2.5 from approximately 8 to 4 μg/m3 and the particle number concentration from 7669 to 5352 particles/cm3. No statistically significant effects of filtration as category were observed on microvascular and lung function or the biomarkers of systemic inflammation among all subjects, or in the subgroups taking (n = 11) or not taking vasoactive drugs (n = 37). However, the filtration efficacy was variable and microvascular function was within 2 days significantly increased with the actual PM2.5 decrease in the bedroom, especially among 25 subjects not taking any drugs.

CONCLUSION

Substantial exposure contrasts in the bedroom and no confounding by drugs appear required for improved microvascular function by air filtration, whereas no other beneficial effect was found in this elderly population.

Long-term evaluation of endothelial function in Kawasaki disease patients

BACKGROUND

Kawasaki disease is an acute systemic vasculitis. Cardiac complications are frequent and include endothelial dysfunction in patients with coronary anomalies. So far, the presence of endothelial dysfunction in patients with no coronary lesions has not been demonstrated. Peripheral arterial tonometry (Endo-PAT) measures the microvascular function in response to local ischaemia and has been validated in adult population, but its use in children is scarce. Aim To evaluate endothelial dysfunction in children as a long-term complication after Kawasaki disease using Endo-PAT.

METHODS

We evaluated two groups of subjects: (1) Kawasaki disease patients over 11 years of age, diagnosed for >5 years, with no coronary lesions, or any other risk factors for cardiovascular disease; (2) control group of individuals without cardiovascular risk factors. Patients and controls were clinically accessed. Endo-PAT was performed to determine reactive hyperaemia index and augmentation index.

RESULTS

A total of 35 individuals (21 males, age 21 ± 6 years) were evaluated (group 1: 19; controls: 16). Kawasaki disease patients presented significant lower reactive hyperaemia index (1.68 ± 0.49 versus 2.31 ± 0.53; p = 0.001). Augmentation index was similar in both groups (-10 ± 7 versus -11 ± 5; p > 0.005). Most patients with Kawasaki disease disclosed endothelial dysfunction (68%) compared with only 12% in controls.

CONCLUSIONS

Endo-PAT is feasible and reproducible in the child population. Endothelial dysfunction is a frequent long-term complication in patients after Kawasaki disease with normal appearing coronary arteries. However, these results need validation in a larger population.

Endothelial dysfunction in patients with type 2 diabetes post acute coronary syndrome

This single visit study examined whether endothelial function, in addition to cardiovascular (CV) risk factors and plasma microparticle content, was normalised in 15 patients with type 2 diabetes + acute coronary syndrome (ACS) (6 weeks-6 months post cardiac event) undergoing standard clinical care compared to 16 sex- and age-matched healthy controls.

RESULTS

While total and low-density lipoprotein (LDL) cholesterol levels were well controlled in the patients with type 2 diabetes + ACS, residual CV risk profiles such as increased body mass index (BMI), systolic blood pressure, glucose levels and triglycerides and lower high-density lipoprotein (HDL) levels were still apparent. Endothelium-dependent responses to acetylcholine (ACh) were significantly lower in type 2 diabetes + ACS patients compared to controls. Correspondingly, the reactive hyperaemic index (RHI) was lower in the patient cohort. Endothelial microparticle (EMP) levels (CD31(+), CD41(-)) were 40% lower in the patient cohort. Simultaneous analysis of platelet microparticle (PMP) levels (CD41(+)) showed no difference between cohorts.

CONCLUSIONS

Patients with type 2 diabetes suffering from recent ACS exhibit residual CV risk factors despite being on standard clinical care. In addition, these patients continue to present with endothelial dysfunction despite having lower levels of EMPs.

Endothelial Dysfunction and Arterial Stiffness in Ischemic Stroke

Background and Purpose—

Sleep-disordered breathing (SDB) represents a risk factor for cardiovascular morbidity after a cerebral ischemic event (acute ischemic event, ischemic stroke, or transient ischemic attack). In the present study, endothelial function and arterial stiffness were analyzed in patients who experienced a postacute ischemic event with relation to SDB, sleep disruption, and nocturnal oxygenation parameters.

Methods—

SDB was assessed by full polysomnography in patients with acute ischemic event 3 months after the admission at our stroke unit. Moderate-severe SDB was defined according to the apnea-hypopnea index as apnea-hypopnea index ≥20. Endothelial function and arterial stiffness were assessed by peripheral arterial tonometry using Endo-PAT 2000.

Results—

Thirty-seven patients were included. The augmentation index was significantly different between patients with apnea-hypopnea index <20 and apnea-hypopnea index ≥20 (22.4±15.6% versus 34.6±21.6%; P =0.042), whereas reactive hyperemia index level was not (2.02±0.65 versus 2.31±0.61; P =0.127). Patients with apnea-hypopnea index ≥20 showed an increased risk for arterial stiffness (odds ratio, 5.98 [95% CI, 1.11–41.72]) even when controlling for age, sex, body mass index, hypertension, and diabetes mellitus. The augmentation index was correlated with the arousal index ( P =0.010) and with mean O 2 saturation ( P =0.043).

Conclusions—

Poststroke patients with moderate-severe SDB were more prone to have increased arterial stiffness, although we did not find significant differences in endothelial function. Arterial stiffness also correlated with sleep disruption (arousal index) and mean O 2 saturation.

Systemic vascular function is associated with muscular power in older adults

Age-associated loss of muscular strength and muscular power is a critical determinant of loss of physical function and progression to disability in older adults. In this study, we examined the association of systemic vascular function and measures of muscle strength and power in older adults. Measures of vascular endothelial function included brachial artery flow-mediated dilation (FMD) and the pulse wave amplitude reactive hyperemia index (PWA-RHI). Augmentation index (AIx) was taken as a measure of systemic vascular function related to arterial stiffness and wave reflection. Measures of muscular strength included one repetition maximum (1RM) for a bilateral leg press. Peak muscular power was measured during 5 repetitions performed as fast as possible for bilateral leg press at 40% 1RM. Muscular power was associated with brachial FMD (r = 0.43, P < 0.05), PWA-RHI (r = 0.42, P < 0.05), and AIx (r = -0.54, P < 0.05). Muscular strength was not associated with any measure of vascular function. In conclusion, systemic vascular function is associated with lower-limb muscular power but not muscular strength in older adults. Whether loss of muscular power with aging contributes to systemic vascular deconditioning or vascular dysfunction contributes to decrements in muscular power remains to be determined.

Relationship of flow-mediated arterial dilation and exercise capacity in older patients with heart failure and preserved ejection fraction

BACKGROUND

Older heart failure patients with preserved ejection fraction (HFpEF) have severely reduced exercise capacity and quality of life. Both brachial artery flow-mediated dilation (FMD) and peak exercise oxygen uptake (peak VO(2)) decline with normal aging. However, uncertainty remains regarding whether FMD is reduced beyond the degree associated with normal aging and if this contributes to reduced peak VO(2) in elderly HFpEF patients.

METHODS

Sixty-six older (70 ± 7 years) HFpEF patients and 47 healthy participants (16 young, 25 ± 3 years, and 31 older, 70 ± 6 years) were studied. Brachial artery diameter was measured before and after cuff occlusion using high-resolution ultrasound. Peak VO(2) was measured using expired gas analysis during upright cycle exercise.

RESULTS

Peak VO(2) was severely reduced in older HFpEF patients compared with age-matched healthy participants (15.2 ± 0.5 vs 19.6 ± 0.6 mL/kg/min, p < .0001), and in both groups, peak VO(2) was reduced compared with young healthy controls (28.5 ± 0.8 mL/kg/min; both p < .0001). Compared with healthy young participants, brachial artery FMD (healthy young, 6.13% ± 0.53%) was significantly reduced in healthy older participants (4.0 ± 0.38; p < .0002) and in HFpEF patients (3.64% ± 0.28%; p < .0001). However, FMD was not different in HFpEF patients compared with healthy older participants (p = .86). Although brachial artery FMD was modestly related to peak VO(2) in univariate analyses (r = .19; p = .048), it was not related in multivariate analyses that accounted for age, gender, and body size.

CONCLUSION

These results suggest that endothelial dysfunction may not be a significant independent contributor to the severely reduced exercise capacity in elderly HFpEF patients.

Controlled human wood smoke exposure: oxidative stress, inflammation and microvascular function

BACKGROUND

Exposure to wood smoke is associated with respiratory symptoms, whereas knowledge on systemic effects is limited. We investigated effects on systemic inflammation, oxidative stress and microvascular function (MVF) after controlled wood smoke exposure.

METHODS

In a randomised, double-blinded, cross-over study 20 non-smoking atopic subjects were exposed at rest to 14, 220, or 354 μg/m3 of particles from a well-burning modern wood stove for 3 h in a climate controlled chamber with 2 week intervals. We investigated the level of oxidatively damaged DNA, inflammatory markers and adhesion molecules before and 0, 6 and 20 h after exposure. Six h after exposure we measured MVF non-invasively by digital peripheral artery tonometry following arm ischemia.

RESULTS

The MVF score was unaltered after inhalation of clean air (1.58 ± 0.07; mean ± SEM), low (1.51 ± 0.07) or high (1.61 ± 0.09) concentrations of wood smoke particles in atopic subjects, whereas unexposed non-atopic subjects had higher score (1.91 ± 0.09). The level of oxidatively damaged DNA, mRNA of ITGAL, CCL2, TNF, IL6, IL8, HMOX1, and OGG1 and surface marker molecules ICAM1, ITGAL and L-selectin in peripheral blood mononuclear cells were not affected by inhalation of wood smoke particles.

CONCLUSIONS

Exposure to wood smoke had no effect on markers of oxidative stress, DNA damage, cell adhesion, cytokines or MVF in atopic subjects.

Endothelial function and circulating biomarkers are disturbed in women and children after preeclampsia

Preeclampsia is a long-term cardiovascular risk factor for the mother and possibly the offspring. Preeclampsia and cardiovascular diseases share common pathophysiological features, including endothelial dysfunction. We explored whether endothelial function, measured noninvasively, as well as circulating biomarkers reflecting lipid metabolism, angiogenesis, and inflammation, differed in paired mothers and offspring 5 to 8 years after delivery. Twenty-six mother and child pairs after pregnancies complicated by preeclampsia were compared with 17 mother and child pairs after uncomplicated pregnancies. In addition, we assessed whether concentrations of maternal circulating biomarkers at delivery predicted findings 5 to 8 years postpartum. We also included an assessment of early onset preeclampsia and specifically addressed the effects of small for gestational age. Endothelial function was significantly reduced in both mothers and children after preeclampsia when combined with a small-for-gestational-age infant compared with mothers and children after pregnancies without a small-for-gestational-age infant (mothers: P<0.001; children: P<0.05). Postpartum maternal soluble fms-like tyrosine kinase 1 (P=0.05) and high-sensitivity C-reactive protein (P=0.02) were elevated in the preeclampsia group compared with controls. High concentrations of these maternal biomarkers both at delivery and 5 to 8 years postpartum were also more frequent in preeclampsia compared with controls (P<0.05). The novelty of our study is the parallel finding of reduced endothelial function in mother and child pairs 5 to 8 years after small-for-gestational-age preeclamptic pregnancies, accompanied by increased inflammatory and antiangiogenic maternal biomarkers. This finding supports the concept of transgenerational risk of cardiovascular disease after preeclampsia.

Effects of lower extremity revascularization on the endothelial functions measured with noninvasive brachial artery flow-mediated dilatation

BACKGROUND

Endothelial function is best measured with the noninvasive brachial artery flow-mediated dilatation (FMD) method. Peripheral arterial diseases and systemic cardiovascular diseases have FMD-lowering effect. The effects of lower extremity ischemia are associated with muscle inflammation and claudication, which may further lead to arterial stress. Our aim in this study was to investigate the effects of peripheral arterial revascularization on the endothelial functions through noninvasive brachial artery FMD.

METHODS

Between January 2007 and February 2008, 54 patients diagnosed with lower extremity arterial disease undergoing revascularization were included in the study. Endothelial function is measured preoperatively and at the fourth week postoperatively using the brachial artery FMD method. Blood samples were collected at the same intervals for the measurement of interleukin-6, leukocyte count, tumor necrosis factor-alpha, and nitric oxide values.

RESULTS

Femoropopliteal bypass grafting was performed in all patients with a synthetic graft. The mean ankle-brachial index in the preoperative period was 0.29 ± 0.083, and after the operation, dorsalis pedis and/or posterior tibial artery became palpable in all patients. The nitric oxide, interleukin-6, high-sensitivity C-reactive protein, and tumor necrosis factor-alpha levels decreased significantly after 4 weeks postoperatively as compared with the preoperative levels (p < 0.05). Postoperative Doppler ultrasonography FMD of brachial artery increased from preoperative value of 9.2 ± 2.1 to 16.2 ± 4.5 (p < 0.01) at postoperative week 4.

CONCLUSIONS

Systemic inflammation and muscle ischemia lead to reduced endothelial functions. After successful lower extremity revascularization, endothelial functions improve dramatically, which may be easily detected with the noninvasive brachial artery FMD method.

The prevalence of endothelial dysfunction in patients with and without coronary artery disease

BACKGROUND

Endothelial dysfunction (ED) is frequently present in patients presenting with acute or stable coronary artery disease (CAD), but it is also found in patients presenting with chest pain without angiographic coronary lesions.

HYPOTHESIS

We hypothesized that even in patients without CAD, the presence of cardiovascular (CV) risk factors will correlate with the presence of ED.

METHODS

Our study included a total of 341 consecutive patients referred for coronary angiography. We used pulse wave analysis with a finger plethysmograph (peripheral arterial tonometry) to determine endothelial function. Hyperemia ratio was calculated as the ratio of the postischemic hyperemia response relative to baseline measurement.

RESULTS

The hyperemia ratio was significantly higher in patients without CAD (2.02 ± 0.52) compared with patients with chronic CAD (1.81 ± 0.44, P = 0.001) or acute CAD (1.74 ± 0.49, P < 0.001). Prevalence of ED was 33%, 46%, and 58%, respectively. In multivariate analysis, the presence of CAD, diabetes, and cigarette smoking, and the total number of CV risk factors, were strong predictors of ED. In 67% of the patients without CAD but with ≥3 CV risk factors, ED was present.

CONCLUSIONS

Prevalence of ED in patients with chest pain depends on the presence of CAD and CV risk factors. Patients without CAD but with ≥3 risk factors frequently presented with ED. Such patients may be at increased risk for future CV events and may profit from intensified therapy to control CV risk factors.

Endothelial function as a functional expression of cardiovascular risk factors

Traditional cardiovascular risk (CV) factors based on the Framingham study have been used to estimate the risk of CV events and determine target cholesterol levels for primary prevention. Recently published systematic reviews have, however, demonstrated that the Framingham risk score is limited in certain cohorts and requires adjustment. Indeed, traditional CV risk factors fail to predict the development of coronary heart disease in 25-50% of cases. This underscores the complex interplay between traditional CV risk factors, genetic predisposition and other atheroprotective factors present in individuals of different populations in predicting CV events. Endothelial dysfunction, a functional expression of the inherent atherosclerotic risk representing an integrated index of both the overall CV risk-factor burden and the sum of all vasculoprotective factors in an individual, may serve as the missing link between CV risk factors and atherosclerotic disease. Endothelial function measurements may aid in future prediction of CV events and help identify high-risk patients for targeted therapy as well as provide a primary therapeutic end point for clinical follow-up of these patients. Recently introduced reactive hyperemia peripheral arterial tonometry is emerging as a promising tool in endothelial function measurement and CV risk stratification.

A plethora of angiopoietin-2 effects during clinical sepsis

The interesting study by Davis and colleagues in the current issue of Critical Care expands on the increasingly recognized role of angiopoietins in human sepsis but raises a number of questions, which are discussed in this commentary. The authors describe an association between elevated angiopoietin (ang)-2 levels and impaired vascular reactivity, measured by the partly nitric oxide-dependent finger hyperemic response to forearm vascular occlusion, in patients with sepsis. This suggests that the ang-1/2-Tie2 system is involved in a number of pathophysiologic, phenotypic and perhaps prognostic alterations in human sepsis, on top of the effect on pulmonary endothelial barrier function. The novel inflammatory route may be a target for future therapeutic studies in human sepsis and acute lung injury, including those with activated protein C.