Peripheral Endothelial Function Research Articles

Imaging Assessment of Endothelial Function: An Index of Cardiovascular Health.

Endothelial dysfunction is a key early mechanism in a variety of cardiovascular diseases and can be observed in larger conduit arteries as well as smaller resistance vessels (microvascular dysfunction). The presence of endothelial dysfunction is a strong prognosticator for cardiovascular events and mortality, and assessment of endothelial function can aid in selecting therapies and testing their response. While the gold standard method of measuring coronary endothelial function remains invasive angiography, several non-invasive imaging techniques have emerged for investigating both coronary and peripheral endothelial function. In this review, we will explore and summarize the current invasive and non-invasive modalities available for endothelial function assessment for clinical and research use, and discuss the strengths, limitations and future applications of each technique.

Microvascular dysfunction and neurovascular uncoupling are exacerbated in peripheral artery disease, increasing the risk of cognitive decline in older adults.

Peripheral artery disease (PAD) is a vascular pathology with high prevalence among the aging population. PAD is associated with decreased cognitive performance, but the underlying mechanisms remain obscure. Normal brain function critically depends on an adequate adjustment of cerebral blood supply to match the needs of active brain regions via neurovascular coupling (NVC). NVC responses depend on healthy microvascular endothelial function. PAD is associated with significant endothelial dysfunction in peripheral arteries, but its effect on NVC responses has not been investigated. This study was designed to test the hypothesis that NVC and peripheral microvascular endothelial function are impaired in PAD. We enrolled 11 symptomatic patients with PAD and 11 age- and sex-matched controls. Participants were evaluated for cognitive performance using the Cambridge Neuropsychological Test Automated Battery and functional near-infrared spectroscopy to assess NVC responses during the cognitive n-back task. Peripheral microvascular endothelial function was evaluated using laser speckle contrast imaging. We found that cognitive performance was compromised in patients with PAD, evidenced by reduced visual memory, short-term memory, and sustained attention. We found that NVC responses and peripheral microvascular endothelial function were significantly impaired in patients with PAD. A positive correlation was observed between microvascular endothelial function, NVC responses, and cognitive performance in the study participants. Our findings support the concept that microvascular endothelial dysfunction and neurovascular uncoupling contribute to the genesis of cognitive impairment in older PAD patients with claudication. Longitudinal studies are warranted to test whether the targeted improvement of NVC responses can prevent or delay the onset of PAD-associated cognitive decline.NEW & NOTEWORTHY Peripheral artery disease (PAD) was associated with significantly decreased cognitive performance, impaired neurovascular coupling (NVC) responses in the prefrontal cortex (PFC), left and right dorsolateral prefrontal cortices (LDLPFC and RDLPFC), and impaired peripheral microvascular endothelial function. A positive correlation between microvascular endothelial function, NVC responses, and cognitive performance may suggest that PAD-related cognitive decrement is mechanistically linked, at least in part, to generalized microvascular endothelial dysfunction and subsequent impairment of NVC responses.

Endothelial dysfunction and altered endothelial biomarkers in patients with post-COVID-19 syndrome and chronic fatigue syndrome (ME/CFS)

BackgroundFatigue, exertion intolerance and post-exertional malaise are among the most frequent symptoms of Post-COVID Syndrome (PCS), with a subset of patients fulfilling criteria for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). As SARS-CoV-2 infects endothelial cells, causing endotheliitis and damaging the endothelium, we investigated endothelial dysfunction (ED) and endothelial biomarkers in patients with PCS.MethodsWe studied the endothelial function in 30 PCS patients with persistent fatigue and exertion intolerance as well as in 15 age- and sex matched seronegative healthy controls (HCs). 14 patients fulfilled the diagnostic criteria for ME/CFS. The other patients were considered to have PCS. Peripheral endothelial function was assessed by the reactive hyperaemia index (RHI) using peripheral arterial tonometry (PAT) in patients and HCs. In a larger cohort of patients and HCs, including post-COVID reconvalescents (PCHCs), Endothelin-1 (ET-1), Angiopoietin-2 (Ang-2), Endocan (ESM-1), IL-8, Angiotensin-Converting Enzyme (ACE) and ACE2 were analysed as endothelial biomarkers.ResultsFive of the 14 post-COVID ME/CFS patients and five of the 16 PCS patients showed ED defined by a diminished RHI (< 1.67), but none of HCs exhibited this finding. A paradoxical positive correlation of RHI with age, blood pressure and BMI was found in PCS but not ME/CFS patients. The ET-1 concentration was significantly elevated in both ME/CFS and PCS patients compared to HCs and PCHCs. The serum Ang-2 concentration was lower in both PCS patients and PCHCs compared to HCs.ConclusionA subset of PCS patients display evidence for ED shown by a diminished RHI and altered endothelial biomarkers. Different associations of the RHI with clinical parameters as well as varying biomarker profiles may suggest distinct pathomechanisms among patient subgroups.

The effects of exercise training in the cold on cerebral blood flow and cerebrovascular function in young healthy individuals.

Exercise elicits acute increases in cerebral blood flow velocity (CBFv) and provokes long-term beneficial effects on CBFv, thereby reducing cerebrovascular risk. Acute exposure to a cold stimulus also increases CBFv. We compared the impact of exercise training in cold and thermoneutral environments on CFBv, cerebrovascular function and peripheral endothelial function. Twenty-one (16 males, 22±5years) individuals were randomly allocated to either a cold (5°C) or thermoneutral (15°C) exercise intervention. Exercise consisted of 50-min cycling at 70% heart rate max, three times per week for eight weeks. Transcranial Doppler was used to determine pre and post intervention CBFv, dynamic cerebral autoregulation (dCA) and cerebrovascular reactivity (CVRCO2). Conduit endothelial function, microvascular function and cardiorespiratory fitness were also assessed. Cardiorespiratory fitness improved (2.91ml.min.kg-1, 95%CI 0.49, 5.3; P=0.02), regardless of exercise setting. Neither intervention had an impact on CBFv, CVRCO2, FMD or microvascular function (P>0.05). There was a significant interaction between time and condition for dCA normalised gain with evidence of a decrease by 0.192%cm.s-1.%mmHg-1 (95%CI -0.318, -0.065) following training in the cold and increase (0.129%cm.s-1.%mmHg-1, 95%CI 0.011, 0.248) following training in the thermoneutral environment (P=0.001). This was also evident for dCA phase with evidence of an increase by 0.072rad (95%CI -0.007, 0.152) following training in the cold and decrease by 0.065 (95%CI -0.144, 0.014) radians following training in the thermoneutral environment (P=0.02). Both training interventions improved fitness but CBFv, CVRCO2 and peripheral endothelial function were unaltered. Exercise training in the cold improved dCA whereas thermoneutral negated dCA.

Endothelial and microvascular function in liver cirrhosis: an old concept that needs re-evaluation?

Liver cirrhosis is characterized by significant circulatory dysregulation, related to an imbalance among several vasodilating agents, mainly nitric oxide. In contrast to portal vein and macrovascular hemodynamic alterations, which have been rather well described, the peripheral microcirculatory and endothelial structure and function in this population are less well studied. Endothelial dysfunction is characterized by an imbalance between endothelium-derived relaxing and contracting factors. A number of methods have been used to assess endothelial and microvascular function in human studies. Venous occlusion plethysmography was used for many years as the gold standard for evaluating endothelial function, but flow-mediated dilatation (FMD) of the forearm is currently the most frequently used method. In patients with cirrhosis, the few existing studies have mainly used FMD, but the relevant results are largely contradictory. In recent years, several noninvasive and easily applicable methods, such as near-infrared spectroscopy, laser speckle contrast imaging, peripheral arterial tonometry, optical coherence tomography and nailfold video-capillaroscopy, have been increasingly used to assess peripheral microvascular function and have demonstrated a number of advantages. In this review, we present functional methods to evaluate peripheral microvascular and endothelial function, and we discuss the existing evidence on circulatory dysfunction in patients with liver cirrhosis.

63 Peripheral endothelial function in patients affected by pulmonary hypertension. Relationship between endothelial function, haemodynamic parameters, and therapy response

Abstract Aims Pulmonary hypertension (PH) is defined as a mean pulmonary arterial pressure (mPAP) of 25 mmHg or greater at rest, confirmed by right heart catheterization (RHC). The World Health Organization has classified PH into five clinical subgroups. Pulmonary arterial hypertension (PAH) (group 1) is characterized by loss and obstructive remodelling of the pulmonary vascular bed. These patients are characterized haemodynamically by the presence of precapillary PH, defined as an mPAP of 25 mm Hg or greater, pulmonary artery wedge pressure (PAWP) of 15 mm Hg or less, and pulmonary vascular resistance (PVR) of three Wood units (WU) or greater. Pulmonary hypertension due to left-sided heart disease (LHD) (PH-LHD) (group 2) occurs in HF. Patients with PH-LHD usually have isolated postcapillary PH (PAWP &amp;gt;15 mm Hg and PVR &amp;lt;3 WU), although some of them have combined postcapillary and precapillary PH (PAWP &amp;gt;15 mm Hg and PVR ≥3 WU). PH due to chronic lung disease (CLD) (PH-CLD) and/or hypoxia (group 3) can occur in many lung diseases. These patients have precapillary PH. Chronic thromboembolic PH (CTEPH) (group 4) is characterized by obstruction of the pulmonary vasculature by organized thromboembolic material and vascular remodelling, resulting from prior pulmonary embolism. Patients with unclear and/or multifactorial mechanisms are listed as group 5. Specific pulmonary vasodilators are approved only in PAH patients. While research was predominantly focused on pulmonary vasculature, little is known about the peripheral endothelial damage in different vascular beds in PH patients. To evaluate the relationship between the peripheral endothelial function and the haemodynamic parameters, in order to provide a non-invasive method for the indirect evaluation of mean pulmonary pressure and vascular resistance, to predict if the PH is a precapillary or postcapillary, to select more accurately the patients who should undergo RHC. Moreover, we investigate if there is a possible correlation between endothelial dysfunction and response to specific PH therapies. Methods and results Patients with suspected PH, based on symptoms, medical history, and clinics will undergo physical examination, ECG, echocardiography, and RHC. In all patients, endothelial function was assessed by FMD. Medical history, heart rate, systolic blood pressure, body mass index, WHO functional class, and medications were recorded. All patients underwent blood analysis, erythrocyte sedimentation rate (ERS), high sensitivity C-reactive protein (CRP), and NT-proBNP levels were assayed. Increased peripheral endothelial dysfunction in patients with precapillary PH, with a linear correlation between endothelium dysfunction and increased PVR at the right catheterization. To differentiate pre and post capillary PH forms by cut-off values of the FMD. The degree of endothelial dysfunction could be a marker of therapy response. Sequential combination therapy in the pre-capillary PH forms could be the one with a worst endothelial response than up-front combination therapy.

Characterization of Cardiac, Vascular, and Metabolic Changes in Young Childhood Cancer Survivors.

Background: Childhood cancer survivors (CCS) are at an increased risk for cardiovascular diseases (CVD). It was the primary aim of this study to determine different measures of cardiac, carotid, lipid, and apolipoprotein status in young adult CCS and in healthy controls.Methods: Cardiac and common carotid artery (CCA) structure and function were measured by ultrasonography. Lipids and apolipoproteins were measured in the blood. Peripheral arterial endothelial vasomotor function was assessed by measuring digital reactive hyperemia index (PAT-RHI) using the Endo-PAT 2000.Results: Fifty-three CCS (20–30 years, 35 men) and 53 sex-matched controls were studied. The CCS cohort was divided by the median dose of anthracyclines into a low anthracycline dose (LAD) group (50–197 mg/m2, n = 26) and a high anthracycline dose (HAD) group (200–486 mg/m2, n = 27). Carotid distensibility index (DI) and endothelial function determined by PAT-RHI were both lower in the CCS groups compared with controls (p < 0.05 and p = 0.02). There was no difference in carotid intima media thickness. Atherogenic apolipoprotein-B (Apo-B) and the ratio between Apo-B and Apoliprotein-A1 (Apo-A1) were higher in the HAD group compared with controls (p < 0.01). Apo-B/Apo-A1-ratio was over reference limit in 29.6% of the HAD group, in 15.4% of LAD group, and in 7.5% of controls (p = 0.03). Measured lipid markers (low density lipoprotein and total cholesterol and triglycerides) were higher in both CCS groups compared with controls (p < 0.05). Systolic and diastolic function were measurably decreased in the HAD group, as evidenced by lower EF (p < 0.001) and lower é-wave (p < 0.005) compared with controls. CCA DI correlated with Apo-B/Apo-A1-ratio and Apo-A1. Follow-up time after treatment correlated with decreased left ventricular ejection fraction (p = 0.001).Conclusion: Young asymptomatic CCS exhibit cardiac, vascular, lipid, and apolipoprotein changes that could account for increased risk for CVD later in life. These findings emphasize the importance of cardiometabolic monitoring even in young CCS.

Coronary microvascular function in patients with angina with no obstructive coronary artery disease-What factors affect it clinically or angiographically?

Abstract Background In the clinical setting, we have often experienced patients with angina with no obstructive coronary artery disease (ANOCA), and it has been proposed that the presence of coronary microvascular dysfunction (CMD) play a pivotal role in the pathogenesis of ANOCA. Thus, it is important to assess coronary microvascular function (CMF). However, it has not been clarified what clinical factors or lesion characteristics on coronary angiography (CAG) affect CMF. Thus, we investigated the relationship between CMF and clinical factors or lesion characteristics on CAG in patients with ANOCA. Methods Thirty-four patients with chest pain, who underwent CAG, spasm provocation test (SPT) and CMF test, were enrolled. We excluded patients who had moderate coronary stenosis (% stenosis &amp;gt;30%). In the SPT with acetylcholine for left coronary artery and right coronary artery (RCA), the coronary spasm was defined as &amp;gt;90% narrowing of coronary artery on CAG accompanied with chest symptoms and/or ST-T changes on ECG during SPT, and coronary microvascular spasm (MVS) was defined as ≤90% narrowing of coronary artery on CAG with accompanied with chest pain and ST-T changes during SPT. In each coronary artery, the presences of atherosclerosis (20%≤%stenosis≤30%), focal spasm (spasm occurred within one segment of AHA classification), diffuse spasm (spasm occurred over two segments of AHA classification) and MVS, were checked. In the CMF test with a pressure-wire during adenosine triphosphate infusion, the index of microvascular resistance (IMR) was measured. IMR values were obtained in 34 of the left anterior descending coronary artery (LAD) and 12 in RCA. In each patient, conventional coronary risk factors, blood chemical parameters, peripheral endothelial function such as flow-mediated dilation (FMD) of brachial artery and left ventricular mass index (LVMI) were checked. Results In 34 patients, clinical factors including blood chemical parameters, FMD and LVMI, except for smoking status did not affect IMR values on LAD. Only the smoking status was associated with IMR values as follows: median IMR values were 44, 22 and 25 in current smokers (n=5), past smokers (n=8) and never smokers (n=21, p=0.03), respectively. In 46 coronary arteries, the presence of atherosclerosis, the type of the coronary spasm, such as focal and diffuse spasm and MVS, did not affect the IMR values, however, it was significantly higher in the RCA (median 38) than that in the LAD (median 26, p=0.02). Conclusion These results suggest that smoking status affected CMF in patients with ANOCA, suggesting the possibility of improvement of CMF by stop smoking in such patients. In addition, in the assessment of CMF, it may be important to take into account which coronary artery being evaluated. Funding Acknowledgement Type of funding sources: None.

Impact of Peripheral Microvascular Endothelial Dysfunction on White Matter Hyperintensity

BackgroundWhite matter hyperintensity (WMH), characterized by hyperintensities on T2‐weighted fluid‐attenuated inversion recovery brain magnetic resonance imaging, has been linked to an increased risk of ischemic stroke (IS). Endothelial dysfunction is an indicator of vascular dysfunction, predicting the risk of IS. This study aimed to investigate the association between endothelial dysfunction and regional WMH, and its impact on future risk of IS.Methods and ResultsWe enrolled 219 patients (mean age, 53.1±14.1 years; 34.7% men) who underwent peripheral endothelial function assessment using reactive hyperemia peripheral arterial tonometry and brain magnetic resonance imaging without any history of IS. Volumetric WMH segmentation was automatically extrapolated using a validated automated digital tool. Total and juxtacortical WMH volume/intracranial volume (%) increased with aging and became more prominent in patients aged >50 years (n=131) than those aged ≤50 years (n=88) (total WMH: ≤50 years, Pearson r=0.24, P=0.03; >50 years, Pearson r=0.62, P<0.0001; juxtacortical WMH: ≤50 years, Pearson r=0.09, P=0.40; >50 years, Pearson r=0.55, P<0.0001). Reactive hyperemia peripheral arterial tonometry index was negatively associated with total and juxtacortical WMH volume/intracranial volume (%) in patients aged >50 years after adjustment for other covariates (reactive hyperemia peripheral arterial tonometry index, standardized β coefficient −0.17, P=0.04). Juxtacortical WMH volume/intracranial volume (%) was associated with an increased risk of IS during median follow‐up of 6.5 years (hazard ratio, 1.47; 95% CI, 1.05–1.92; P=0.03).ConclusionsPeripheral endothelial dysfunction is associated with an increased volume of juxtacortical WMH in patients aged >50 years, which is a potential marker to predict future risk of IS.

Peripheral microvascular dysfunction is associated with plaque progression and adverse long-term outcomes in heart transplant patients.

AimsCardiac allograft vasculopathy (CAV) is the major cause of increased morbidity and mortality after heart transplantation. Peripheral endothelial dysfunction (PED) is associated with early atherosclerosis and future risk of major adverse cardiovascular events (MACE) in non‐heart transplant population. We aimed to investigate the association of PED with future MACE, and plaque progression assessed by intravascular ultrasound (IVUS) after heart transplantation.Methods and resultsWe included 66 transplant patients who underwent serial IVUS surveillance for CAV and baseline assessment of peripheral endothelial function using reactive hyperaemia peripheral arterial tonometry. PED was defined as reactive hyperaemia index < 2. The primary endpoint of the study was to investigate the association of PED with CAV progression assessed by intravascular ultrasound (IVUS). CAV progression was assessed as the change (Δ) in plaque volume divided by segment length, and Δ plaque index (plaque volume/vessel volume), adjusted for the time between IVUS measurements (median 3.0 [2.2, 3.1] years). The secondary endpoint was to investigate the association between PED and future MACE, which was defined as any incident of revascularization, heart failure hospitalization, stroke, myocardial infarction, re‐transplantation, and death. Patients with PED (n = 27) had more yearly plaque progression (0.50 ± 0.66 vs. 0.15 ± 0.50 mm3/mm/year, P = 0.02) and a higher Δ plaque index (2.41 ± 2.53% vs. 0.69 ± 2.22%, P = 0.01). Patients with PED were more likely to experience MACE during a median follow‐up of 8.2 years (interquartile range [7.6, 8.4]), after adjustment for potential cofounders such as age, high‐density lipoprotein cholesterol levels, total rejection score, baseline International Society for Heart & Lung Transplantation CAV grade, and indication of transplantation. (hazard ratio 2.15, 95% confidence interval [1.09, 4.23], P = 0.03).ConclusionsPeripheral endothelial dysfunction is associated with increased plaque progression and adverse long‐term cardiovascular outcomes in transplant patients. PED assessment might be a useful clinical tool for risk stratification after heart transplantation.

Impact of glycemic variability on coronary and peripheral endothelial dysfunction in patients with coronary artery disease

Background: Previous studies have reported that glucose variability leads to endothelial dysfunction and progression of coronary atherosclerosis. However, few studies have directly evaluated the relation between glucose variability and coronary endothelial function in patients with coronary artery disease (CAD).Methods: A total of 38 patients with chronic CAD and a history of coronary drug-eluting stent implantation were enroled. Coronary endothelial function was evaluated by measuring the coronary vasoreactivity using quantitative coronary angiography in the segment distal to implanted stent in response to intracoronary acetylcholine (ACh) infusion (10−7 mol/l). Peripheral endothelial function was also assessed with reactive hyperemia index (RHI). The mean amplitude of glycemic excursion (MAGE) was calculated as a primary metric of glucose variability using a flash glucose monitoring system.Results: Of 38 patients, 17 (45%) had diabetes mellitus. The mean levels of glycated hemoglobin, MAGE, and RHI were 6.3 ± 0.8%, 71.4 ± 29.8 mg/dl, and 1.85 ± 0.63. In the distal segment to coronary stent, lumen diameter was constricted by 0.6 ± 7.3% in response to intracoronary ACh infusion compared to that at baseline. While peripheral endothelial function assessed with RHI was not significantly associated with MAGE (r = −0.16, p = 0.35), coronary endothelial function was correlated with MAGE (r = −0.38, p = 0.02).Conclusion: Greater glucose variability was significantly associated with coronary rather than peripheral endothelial dysfunction in patients with CAD, suggesting an impact of glucose variability on coronary atherosclerosis.

Endothelial impairment evaluation by peripheral arterial tonometry in pediatric endocrinopathies: A narrative review.

Endothelial dysfunction (ED) is characterized by an imbalance between vasodilator and vasoconstriction agents. Several pathological conditions clinically diagnosed in childhood and adolescence are characterized by ED and increased risk for early development of microangiopathic and macroangiopathic impairment, in particular type 1 diabetes mellitus (T1DM), T2DM, obesity, metabolic syndromeand pituitary dysfunction associated to various endocrinopathies. More recently insulin resistance following chemotherapy or radiotherapy for tumors, bone marrow transplantation for hematological malignancies (i.e., cancer survivors), or immunosuppressive treatment for solid organ transplantation has been observed. Assessment of ED by means of non-invasive techniques is the gold standard for early ED detection before clinical manifestation. It is aimed to recognize patients at risk and to avoid the development and progression of more serious illnesses. Reactive hyperemia-peripheral artery tonometry is a noninvasive technique to assess peripheral endothelial function by measuring modifications in digital pulse volume during reactive hyperemia, and represents a non-invasive, reproducible and operator-independent tool able to detect precocious ED. This narrative review aimed to provide an overview of the most important papers regarding ED detection by EndoPat 2000 in children and adolescents with different endocrine diseases. A comprehensive search of English language articles was performed in the MEDLINE database without using other search filters except the publication interval between 2005 and 2020.

High-but not moderate-intensity exercise acutely attenuates hypercapnia-induced vasodilation of the internal carotid artery in young men.

Exercise-induced increases in shear rate (SR) across different exercise intensities may differentially affect hypercapnia-induced vasodilation of the internal carotid artery (ICA), a potential index of cerebrovascular function. We aimed to elucidate the effects of exercise intensity on ICA SR during exercise and post-exercise hypercapnia-induced vasodilation of the ICA in young men. Twelve healthy men completed 30min of cycling at moderate [MIE; 65 ± 5% of age-predicted maximal heart rate (HRmax)] and high (HIE; 85 ± 5% HRmax) intensities. Hypercapnia-induced vasodilation was induced by 3min of hypercapnia (target end-tidal partial pressure of CO2 + 10mmHg) and was assessed at pre-exercise, 5min and 60min after exercise. Doppler ultrasound was used to measure ICA diameter and blood velocity during exercise and hypercapnia tests. SR was not altered during either exercise (interaction and main effects of time; both P > 0.05). ICA conductance decreased during HIE from resting values (5.1 ± 1.3 to 3.2 ± 1.0mL·min-1·mmHg-1; P < 0.01) but not during MIE (5.0 ± 1.3 to 4.0 ± 0.8mL·min-1·mmHg-1; P = 0.11). Consequently, hypercapnia-induced vasodilation declined immediately after HIE (6.9 ± 1.7% to 4.0 ± 1.4%; P < 0.01), but not after MIE (7.2 ± 2.1% to 7.3 ± 1.8%; P > 0.05). Sixty minutes after exercise, hypercapnia-induced vasodilation returned to baseline values in both trials (MIE 8.0 ± 3.1%; HIE 6.4 ± 2.9%; both P > 0.05). The present study showed blunted hypercapnia-induced vasodilation of the ICA immediately after high-intensity exercise, but not a moderate-intensity exercise in young men. Given that the acute response is partly linked to the adaptive response in the peripheral endothelial function, the effects of aerobic training on cerebrovascular health may vary depending on exercise intensity.

Cerebrovascular reactivity is related to peripheral endothelial function among healthy postmenopausal women but not midlife and older men

Background Age is the primary risk factor for cardiovascular diseases (CVD), cognitive decline, Alzheimer's disease and related dementias. Young women are at a lower risk for the above-mentioned diseases compared to age-matched men; however, their risk becomes greater than men after menopause. Age-related declines in peripheral and cerebral vascular function are thought to play a role in the increased risk for CVD and related chronic conditions. It is often assumed that changes in peripheral vascular function are directly indicative of changes in cerebrovascular function. However, in young, healthy adults, there does not appear to be an association between peripheral and cerebral vascular function. There is still limited evidence for whether peripheral vascular function is indicative of cerebrovascular function in postmenopausal (PM) women and midlife and older (ML/O) men. Purpose To determine the relation between cerebrovascular reactivity (CVR; an index of cerebrovascular function) and vascular endothelial function (brachial artery flow-mediated dilation [FMDBA]) in PM women and ML/O men and to determine if cerebrovascular function is associated with cognitive function in these groups. Methods CVR, FMDBA, and cognitive function were assessed in 17 PM women (67±6 years) and 26 men (66±7 years). Middle cerebral artery velocity (MCAv; cm/s) using a 2-MHz transcranial Doppler probe and end-tidal CO2 (etCO2; mmHg) were measured during 5 minutes of normocapnia and 5 minutes of hypercapnia (5% CO2). CVR was calculated as ΔMCAv/ΔetCO2. FMDBA was determined with the forearm cuff method and data expressed as Δ% from baseline diameter. The NIH Toolbox Cognition Battery of tests was used to assess global cognitive function, as well as specific cognitive domains. Results CVR was correlated with FMDBA (r=0.33, p=0.02) in PM women but was not correlated with FMDBA in ML/O men (r<0.01, p=0.85). There was a significant difference in this relation between sexes (p=0.04). Stepwise linear regression identified CVR and body mass index (BMI), but not age, blood pressures, LDL and HDL cholesterol, triglycerides or glucose, as significantly related to FMD­BA in PM women; correcting for BMI strengthened the relation between CVR and FMDBA in PM women (r=0.62, p<0.01). In contrast, only plasma LDL cholesterol and triglycerides were significantly related to FMD­BA in ML/O men. There were no relations between CVR and cognitive function in PM women (all p>0.05). In men there was a significant positive relation between CVR and the picture vocabulary test measure of language (r=0.56, p<0.01), but no other measures of cognitive function (all p>0.05). Conclusions These findings suggest cerebrovascular function is associated with peripheral vascular endothelial function in PM women, but not ML/O men, while cerebrovascular function has no to minimal relation to cognitive function in these groups. Controlling for BMI increased the strength of the relation between CVR and FMD­BA in PM women, indicating that body composition may be an important factor influencing cerebrovascular function in these women.

Relationship between peripheral arterial reactive hyperemia and the index of myocardial resistance in patients undergoing invasive coronary angiography

BackgroundCoronary microvascular dysfunction is a powerful prognostic factor in patients with coronary artery disease. We investigated the role of reactive digital hyperemia peripheral arterial tonometry (RH-PAT) as a non-invasive tool to identify patients with impaired coronary microvasculature. MethodsPatients undergoing elective coronary angiography were consecutively assessed for peripheral microvascular endothelial function before coronary angiography: both the Reactive Hyperemic Index (RHI) and the Framingham reactive hyperemic index (Endoscore) were measured. During coronary angiography, the Index of microvascular resistance (IMR) was measured in all patients, and an IMR value > 25 identified patients with coronary microvascular impairment. ResultsA total of 47 patients with chronic coronary syndromes candidate to coronary angiography were included. Those with coronary microvascular impairment (n = 18 [38%]) presented with significantly lower RHI (1.68 ± 0.38 vs. 1.94 ± 0.93, p = 0.04) and Endoscore 0.50 ± 0.23 vs. 0.64 ± 0.23, p = 0.04) values as compared with patients with preserved coronary microvasculature. A significant relationship was observed between IMR with both RHI (r = 0.35, p = 0.02) and Endoscore (r = 0.34, p = 0.02). At the multivariable analysis, RHI and Endoscore were the only independent predictors of an IMR > 25. ConclusionsOur study demonstrates that digital reactive hyperemia indexes are lower in patients with high IMR values, suggesting a role for RH-PAT as non-invasive tool for identifying patients with coronary microvascular impairment.

Can exercise training enhance the repeated remote ischaemic preconditioning stimulus on peripheral and cerebrovascular function in high-risk individuals?

BackgroundRepeated exposure to remote ischaemic preconditioning (rIPC; short bouts of non-lethal ischaemia) enhances peripheral vascular function within 1 week; whereas, longer periods of rIPC (~ 1 year) may improve cerebral perfusion. Increasing the ‘dose’ of rIPC may lead to superior effects. Given the similarities between exercise and rIPC, we examined whether adding exercise to the rIPC stimulus leads to greater adaptation in systemic vascular function.MethodsNineteen individuals with increased risk for cardiovascular disease (CVD) were randomly allocated to either 8 weeks of rIPC (n = 9) or 8 weeks of rIPC + exercise (rIPC + Ex) (n = 10). rIPC was applied three times per week in both conditions, and exercise consisted of 50 min (70% heart rate max) of cycling 3 times per week. Peripheral endothelial function was assessed using flow-mediated dilation (FMD) before and after ischaemia–reperfusion (IR). Cerebrovascular function was assessed by dynamic cerebral autoregulation (dCA) and cerebrovascular reactivity (CVR), and cardio-respiratory fitness (VO2peak) using a maximal aerobic capacity test.ResultsFMD% increased by 1.6% (95% CI, 0.4, 2.8) following rIPC + Ex and by 0.3% (− 1.1, 1.5) in the only rIPC but this did not reach statistical significance (P = 0.65). Neither intervention evoked a change in dCA or in CVR (P > 0.05). VO2peak increased by 2.8 ml/kg/min (1.7, 3.9) following the rIPC + Ex and by 0.1 ml/kg/min (− 1.0, 1.4) following the rIPC only intervention (P = 0.69).ConclusionCombining exercise with rIPC across an 8-week intervention does not lead to superior effects in cerebrovascular and peripheral vascular function compared to a repeated rIPC intervention in individuals at risk of CVD.

Parasympathetic modulation withdrawal improves functional capacity in pulmonary arterial hypertension

In 15 pulmonary arterial hypertension patients, the relation of functional capacity to their peripheral endothelial function and sympathaovagal modulation was studied by carrying out brachial artery ultrasound and electrocardiogram spectral analysis, respectively. The functional capacity was assessed by cardiopulmonary exercise testing and six-minute walking test. The sympathovagal modulation was correlated with the predicted peak oxygen consumption (peak VO2 %; r = 0.692, P < 0.05), peak O2 pulse (mL/beat; r = 0.661, P < 0.05), VE, minute ventilation, VCO2 carbon dioxide production (VE/VCO2 slope; r=-0.806, P < 0.01) and distance walked predicted (%6MWT; r = 0.694, P < 0.05). Moreover, there were negative correlations between parasympathetic modulation with peak VO2 (r = 0.755, P < 0.01), peak VO2% (r=-0.727, P < 0.01) and peak O2 pulse (r = 0.615, P < 0.05), %6MWT (r=-0.834, P < 0.01). Collectively these correlations indicate that parasympathetic withdrawal is crucial for improving functional capacity. This conclusion is supported by both positive and negative correlations of parasympathetic modulation with the functional capacity parameters. The sympathetic modulation predominance, although increases the cardiovascular risk, is probably crucial to facilitate the bronchodilation and the oxygen uptake.

High-intensity interval training vs. hydrochlorothiazide on blood pressure, cardiovascular health and cognition: Protocol of a non-inferiority trial

BackgroundWhile the number of people with hypertension (HBP) continues to increase, the therapeutic target for optimal blood pressure (BP) has been revised to a lower level. Studies have suggested that High-Intensity Interval Training (HIIT) could be as efficient as BP-lowering drugs, but no study has compared their efficacy in a randomized trial. The aim of this protocol is to determine if HIIT is as efficient as Hydrochlorothiazide (HCTZ) in lowering 24 h ambulatory BP in prehypertensive older adults. Moreover, the secondary aim is to determine if HIIT is associated with greater cardiovascular and cognitive benefits than HCTZ. MethodsThis study is an interventional, single-center, non-inferiority trial, with two randomized parallel groups of prehypertensive participants aged 60 years or more. One group will be prescribed daily doses of 12.5 mg of HCTZ for 12 weeks, and the other group will follow thrice-weekly HIIT for 12 weeks. Each group will be composed of 30 participants. The primary outcome is 24 h ambulatory BP. Secondary outcomes are scores on neuropsychological assessments, balance and gait performances, maximal oxygen uptake, peripheral endothelial function, and arterial stiffness. Non-inferiority tests will be performed on the primary outcome, and secondary outcomes will be compared using independent t-tests. ConclusionThis study will determine if HIIT is at least as efficient as HCTZ in lowering BP in prehypertensive older adults. This study will also determine if HIIT provides greater benefits in terms of cardiovascular and cognitive status (NCT04103411).

Vascular Aging Detected by Peripheral Endothelial Dysfunction Is Associated With ECG-Derived Physiological Aging.

BackgroundAn artificial intelligence algorithm that detects age using the 12‐lead ECG has been suggested to signal “physiologic age.” This study aimed to investigate the association of peripheral microvascular endothelial function (PMEF) as an index of vascular aging, with accelerated physiologic aging gauged by ECG‐derived artificial intelligence–estimated age.Methods and ResultsThis study included 531 patients who underwent ECG and a noninvasive PMEF assessment using reactive hyperemia peripheral arterial tonometry. Abnormal PMEF was defined as reactive hyperemia peripheral arterial tonometry index ≤2.0. Accelerated or delayed physiologic aging was calculated by the Δ age (ECG‐derived artificial intelligence–estimated age minus chronological age), and the association between Δ age and PMEF as well as its impact on composite major adverse cardiovascular events were investigated. Δ age was higher in patients with abnormal PMEF than in patients with normal PMEF (2.3±7.8 versus 0.5±7.7 years; P=0.01). Reactive hyperemia peripheral arterial tonometry index was negatively associated with Δ age after adjustment for cardiovascular risk factors (standardized β coefficient, –0.08; P=0.048). The highest quartile of Δ age was associated with an increased risk of major adverse cardiovascular events compared with the first quartile of Δ age in patients with abnormal PMEF, even after adjustment for cardiovascular risk factors (hazard ratio, 4.72; 95% CI, 1.24–17.91; P=0.02).ConclusionsVascular aging detected by endothelial function is associated with accelerated physiologic aging, as assessed by the artificial intelligence–ECG Δ age. Patients with endothelial dysfunction and the highest quartile of accelerated physiologic aging have a marked increase in risk for cardiovascular events.

Brachial Artery Flow-Mediated Vasodilation is Related to the Coronary Index of Microcirculatory Resistance in Non-ST Elevation Acute Coronary Syndrome

While peripheral endothelial function has been demonstrated to be correlated with epicardial coronary endothelial function, its relationship with measures of coronary microvascular dysfunction (CMD) in non-ST acute coronary syndrome (NSTEACS) is less clear.