Microcirculation and biomarkers in patients with resistant or mild-to-moderate hypertension: a cross-sectional study

Evaluation of endothelial dysfunction in hypertensive children and adolescents

BACKGROUND

Atherosclerotic changes can be attributed to early endothelial damage in individuals with hypertension. We aimed to explore the relationship between endothelial dysfunction and hypertension in newly diagnosed children without end-organ damage, considering carotid intima-media thickness (CIMT), flow-mediated dilatation (FMD), and functional capillaroscopy parameters. We also analyzed the differences between dipper and non-dipper patients.

METHODS

In this cross-sectional study, 20 patients diagnosed with essential hypertension with no target organ damage, and 20 age and sex-matched healthy volunteers were enrolled. The patient group comprised newly diagnosed individuals not receiving antihypertensive treatment. Hypertensive patients were divided into two groups (dipper and non-dipper patients). The measurements of CIMT, brachial FMD, and functional capillaroscopy were performed before starting treatment.

RESULTS

Among the patients, 11 were boys, and 9 were girls, with a median age of 16.0 (2.13) years. Of 20 hypertensive patients, 10 were dipper and 10 were non-dipper. Significant differences were observed between the hypertensive patients and controls in terms of CIMT (p = 0.04), brachial artery FMD (p = 0.02), and functional capillary density (p < 0.001). Hypertensive patients exhibited increased CIMT, reduced brachial artery FMD, and lower capillary density. However, there were no differences between dippers and non-dippers regarding age, sex, height SDS, weight SDS, CIMT SDS, brachial artery FMD, and capillary density.

CONCLUSIONS

Understanding the vascular consequences associated with essential hypertension emphasizes the importance of early detection and management of hypertension. Herein, we have effectively highlighted significant endothelial changes through the analysis of three parameters in newly diagnosed children without apparent target organ damage.

The Relationship between TNF-a, IL-35, VEGF and Cutaneous Microvascular Dysfunction in Young Patients with Uncomplicated Type 1 Diabetes

The aim of this study was to analyze the relationship between immunological markers and the dysfunction of cutaneous microcirculation in young patients with type 1 diabetes. The study group consisted of 46 young patients with type 1 diabetes and no associated complications. Microvascular function was assessed with the use of nail fold capillaroscopy before and after implementing post-occlusive reactive hyperemia. This evaluation was then repeated after 12 months. Patients were divided into two subgroups according to their baseline median coverage (defined as the ratio of capillary surface area to surface area of the image area), which was established during the initial exam (coverageBASE). Additionally, the levels of several serum biomarkers, including VEGF, TNF-a and IL-35, were assessed at the time of the initial examination. HbA1c levels obtained at baseline and after a 12-month interval were also obtained. Mean HbA1c levels obtained during the first two years of the course of the disease were also analyzed. Patients with coverageBASE below 16.85% were found to have higher levels of VEGF and TNF-α, as well as higher levels of HbA1c during the first two years following diabetes diagnosis. Our results support the hypothesis that the development of diabetic complications is strongly influenced by metabolic memory and an imbalance of pro- and anti-inflammatory cytokines, regardless of achieving adequate glycemic control.

The nailfold dermoscopy findings of patients with atypical haemolytic uremic syndrome

INTRODUCTION

Hemolytic uremic syndrome (HUS) is a severe disease characterized by microangiopathic anemia, thrombocytopenia, and acute renal failure.

OBJECTIVES

Atypical HUS (aHUS) that results due to genetic disorders of the alternative complement pathway results in inflammation, endothelial damage, and kidney injury. Therefore, simple and non-invasive tests are needed to evaluate the activity of the disease by assessing the microvascular structure in aHUS.

METHODS

A dermoscope (×10) is an inexpensive and easily portable device used to visualize nailfold capillaries and has high clinical performance and interobserver reliability. In this study, the nailfold capillaries of patients with aHUS who were in remission under eculizumab treatment were examined, and the findings were compared to those of a healthy control group to evaluate disease characteristics.

RESULTS

All children with aHUS had decreased capillary densities even if they were in remission. This may be indicative of ongoing inflammation and microvascular damage in aHUS.

CONCLUSION

A dermoscopy can be used as a screening tool for disease activity in patients with aHUS.

Nailfold video-capillaroscopy in the study of cardiovascular disease: a systematic review

OBJECTIVES

Nailfold video-capillaroscopy (NVC) is an inexpensive method of assessing microcirculation. We reviewed the literature to assess whether changes to the nailfold capillaries exist in patients with cardiovascular disease (CVD).

METHODS

We searched PubMed, Scopus and Cochrane Library databases for original research articles relating to the use of noninvasive microvascular assessment in patients with CVD. Methodological quality was assessed with the 'Quality Assessment Tool for Observational Cohort and Cross-sectional Studies.' The results obtained from NVC were analysed qualitatively and compared with other forms of microvascular assessment.

RESULTS

In total 2759 articles were screened, of which 22 studies involving 562 patients (~40% women) with CVD were included. Mean age ranged between 3.7-68.4 years (cases) and 4.0-58.0 years (controls). Reduced capillary density and increased capillary dimensions were seen in patients with pulmonary arterial hypertension (PAH). Among patients with systemic sclerosis, advanced scleroderma patterns can be used to identify patients with or at risk of developing PAH. Functional nailfold changes precede structural changes in patients with hypertension. However, the studies were heterogeneous in the diagnosis of disease and the measurement of nailfold parameters. Most studies did not exclude conditions with altered nailfold features, and only one study performed a power calculation. Furthermore, abnormal nailfold findings are present in patients without systemic disease.

CONCLUSIONS

Structural and functional changes to the nailfold are a feature of established CVD and precede the development of PAH. However, heterogeneity in measurement and abnormal findings in healthy participants limit their use in the wider population.

Structural and functional state of various parts of skin microcirculation at an early stage of hypertension in working-age men

STUDY PURPOSE

To conduct a cross-sectional study on the structural and functional characteristics of various parts of skin microcirculation in working-age men with newly diagnosed hypertension (HTN).

MATERIALS AND METHODS

The study included 118 male participants (ages 30 to 60) who were not regularly taking any medicine, had no medical complaints, and subjectively considered themselves healthy at the time of study. All participants underwent a cross-sectional comprehensive medical examination. The following tests were performed: complete blood count, biochemical blood tests, video capillaroscopy (VCS), laser Doppler flowmetry (LDF) and photoplethysmography (PPG) on the left hand fingers, determination of flow-mediated vasodilation of the brachial artery, echocardiography, ultrasound of extracranial and femoral arteries, 24-h ambulatory blood pressure monitoring (ABPM). According to ABPM data, the participants were divided into two equal groups called a control group(CG) and a hypertension group(HG). There were 59 participants with normal BP in CG, and 59 participants with newly diagnosed HTN in HG.

RESULTS

Nailfold VCS of the ring finger revealed no significant differences between the groups at the level of exchange microvessels. According to LDF data, there was no decrease in tissue perfusion and signs of an increase in the activity of endothelial, neurogenic, and myogenic regulation of the tone of precapillary arterioles in the HTN group. According to PPG of the index finger, in contrast to CG, HTN participants had significantly higher values of the following parameters: normalized augmentation index (Alp75) - 3.8 % and - 5.25 % (p < 0.005), stiffness index (SI) - 7.6 m/s and 7.35 m/s (p < 0.05), reflection index (RI) - 36.5 % and 28.4 % (p < 0.005), respectively.

DISCUSSION

Working-age men in the early stage of HTN have neither capillary rarefaction nor an increase in the tone of skin precapillary arterioles. The largest contribution to peripheral vascular resistance in the onset of HTN is most likely made by large muscular arterioles, in which the neurogenic regulation of vascular tone predominates.

Lymphatic microcirculation profile in the progression of hypertension in spontaneously hypertensive rats

OBJECTIVE

The contractile behavior of collecting lymphatic vessels occurs in essential hypertension in response to homeostasis, suggesting a possible role for microcirculation. We aimed to clarify the nature of the lymphatic microcirculation profile in spontaneously hypertensive rats (SHRs) and normotensive controls.

METHODS

The vasomotion of collecting lymphatic vessels in eight- and thirteen-week-old SHRs and age-matched Wistar-Kyoto rats (WKYs, n = 4 per group) was visualized by intravital video and VasTrack. The lymphatic vasomotion profile (frequency and amplitude) and contractile parameters (contraction fraction and total contractility activity index) were compared. Plasma nitrite/nitrate levels were assessed by the Griess reaction, and plasma endothelin-1 was measured by enzyme-linked immunosorbent assay.

RESULTS

WKYs and SHRs differed in the vasomotion of collecting lymphatic vessels. Both eight- and thirteen-week-old WKYs revealed a high-amplitude pumping pattern, whereas a low-amplitude pattern was observed in SHRs. Moreover, compared with age-matched WKYs, SHRs exhibited deteriorated output and reflux capability and lost the ability to regulate collecting lymphatic vasomotion. Additionally, the chemistry complements the microcirculatory lymphatic profile as demonstrated by an increase in plasma nitrite, nitrate, and endothelin-1 in SHRs. ET-1 inhibitor meliorated the lymphatic contractile capability in SHRs partially through regulating frequency of lymphatic vasomotion.

CONCLUSIONS

We used an intravital lymphatic imaging system to observe that SHRs exhibit an impaired collecting lymphatic vasomotion profile and deteriorated contractility and reflux.

New Noninvasive Methods to Evaluate Microvascular Structure and Function

The structural and functional alterations of microvessels are detected because of physiological aging and in several cardiometabolic diseases, including hypertension, diabetes, and obesity. The small resistance arteries of these patients show an increase in the media or total wall thickness to internal lumen diameter ratio (MLR or WLR), often accompanied by endothelial dysfunction. For decades, micromyography has been considered as a gold standard method for evaluating microvascular structural alterations through the measurement of MLR or WLR of subcutaneous small vessels dissected from tissue biopsies. Micromyography is the most common and reliable method for assessing microcirculatory endothelial function ex vivo, while strain-gauge venous plethysmography is considered the reference technique for in vivo studies. Recently, several noninvasive methods have been proposed to extend the microvasculature evaluation to a broader range of patients and clinical settings. Scanning laser Doppler flowmetry and adaptive optics are increasingly used to estimate the WLR of retinal arterioles. Microvascular endothelial function may be evaluated in the retina by flicker light stimulus, in the finger by tonometric approaches, or in the cutaneous or sublingual tissues by laser Doppler flowmetry or intravital microscopy. The main limitation of these techniques is the lack of robust evidence on their prognostic value, which currently reduces their widespread use in daily clinical practice. Ongoing and future studies will overcome this issue, hopefully moving the noninvasive assessment of the microvascular function and structure from bench to bedside.

Parameters of cutaneous microvasculature in men of working age with newly diagnosed arterial hypertension

OBJECTIVE

To investigate structural and functional features of cutaneous microvasculature in men of working age with newly diagnosed arterial hypertension (AH).

MATERIALS AND METHODS

The study included 161 apparently healthy men from 30 to 60 years, who underwent a comprehensive examination of cardiovascular system "from the heart to the capillaries". Control group (CG) included 60 normotensive men. AH group included 101 men with elevated BP.

RESULTS

There is no rarefaction of the capillary bed and latent fluid retention in the interstitial space in the skin in men with AH. No data were obtained for increased endothelial, neurogenic and myogenic tone of resistive cutaneous precapillary arterioles in AH group, but a decrease in the perfusion efficiency of the endothelial and myogenic mechanisms of tissue perfusion modulation was noted.

CONCLUSION

Obtained results allow making the assumption that metabolic disorders at the level of capillaries that are of a systemic nature prevail in men with the onset of AH.

Evaluation of demodicosis, nailfold capillaroscopy, and oxidative stress in rosacea: a case-control study

Introduction

Inflammation, immune system disorders, Demodex infestation, neurovascular dysregulation and oxidative stress are thought to be contributory factors in the pathogenesis of rosacea.

Aim

To evaluate the presence of Demodex mites, the morphologic features of the nailfold capillaries, and the systemic oxidative stress status in patients with rosacea.

Material and methods

Thirty-one patients diagnosed with rosacea and 37 healthy age- and gender-matched subjects were included in this prospective case-control study. The presence of Demodex infestation, the findings of nailfold capillaroscopy (NFC), and the status of systemic oxidative stress measured by total oxidant capacity (TOC), total antioxidant capacity (TAC) and oxidative stress index (OSI) were evaluated.

Results

Demodex infestation rates were significantly higher in rosacea patients than in controls (p = 0.001). Increases in the diameters of the capillaries and the presence of avascular areas and crossing and abnormal structures were significantly more common in rosacea patients than in the healthy controls (p < 0.01, p = 0.016, p = 0.02, p < 0.001, respectively), and hairpin structures were significantly less common in rosacea patients than in the controls (p < 0.001). The presence of crossing capillaries was positively correlated with higher TOC levels (p = 0.05), while abnormal structures were found to be correlated with lower levels of TAC (p = 0.045).

Conclusions

Oxidative status and NFC may play diagnostic and prognostic roles in rosacea, which should be confirmed by studies with larger sample sizes.

Nailfold capillaroscopic changes of sleep apnea patients

BACKGROUND

Obstructive Sleep Apnea Syndrome (OSAS) have frequent association with comorbidities and this makes it an independent risk factor for cardiovascular disease. Not only endothelial dysfunction, but also arterial stiffening, increased inflammatory mediators, oxidative stress after hypoxemia that develops due to OSAS, cause vascular pathologies in all diameters of vessels. Nail bed capillaroscopy is a simple, noninvasive, useful method to examine microcirculation and evaluate nail bed capillary abnormalities in diseases that cause vascular damage. The aim of this study is to examine microvascular changes in the nail bed of OSAS patients by capillaroscopy.

METHODS

59 OSAS patients and 60 healthy cases (totally 119) were included. One single attended polysomnography was applied with Embla N7000 series (RemLogic Eastmed, Natus); and apnea-hypopnea index (AHI), oxygen de-saturation index >4% (ODI4%), minimum oxygen saturation (SaO2 Min.), total duration of oxygen desaturation, comorbidities, body mass index (BMI), smoking habit, sleep questionnaire applications were analyzed. Nailfold capillaroscopy was performed using a digital dermoscope (Molemax II, X30) and all images were evaluated for capillary density, capillary loop enlargement, capillary tortuosity, branching vessels, micro hemorrhages, avascular areas and splinter hemorrhages.

RESULTS

The prevalence rates of all capillaroscopy findings were significantly higher in the patient group (p < 0.05). There was an inverse and moderate relationship between AHI and mean saturation (p < 0.05). A statistically significant correlation was detected between the presence of hypertension (HT) and the severity of capillary tortuosity (CT) (p = 0.002), avascular area (AA) (p = 0.004), and periungual cyanosis (PUC) (p = 0.042); also between smoking habit and intensity of capillary dilatation, enlargement dilatation-enlarged giant capillaries (CELON) (p = 0.004), CT (p = 0.018) findings. Capillary distribution (CD), CELON, CT and AA findings were significantly higher in the group with low mean saturation (p < 0.05). DM was found to be significantly higher in individuals with high Epworth Sleep Scale (ESS) (p = 0.035).

CONCLUSION

In this study; 1) the nail bed capillaroscopy was used to examine vascular damage in OSAS, and 2) irregularities detected in the distal nail bed specific to a disease have been mentioned for the first time. It has been shown that endothelial damage is particularly related to the severity of hypoxia. HT and smoking history causes endothelial damage independent of the severity of the disease and hypoxia. Also, ESS may be more determinant in the screening of sleep disorders in diabetic patients.

Pancreatic Microcirculation Profiles in the Progression of Hypertension in Spontaneously Hypertensive Rats

BACKGROUND

Emerging evidence indicates that the pancreas serves as a major source of degrading protease activities and that uncontrolled proteolytic receptor cleavage occurs under hypertensive conditions, which leading to systemic dysfunction and end-organic damage. However, changes in pancreatic microcirculation profiles during the progression of hypertension remain unknown.

METHODS

Pancreatic microcirculatory blood distribution patterns and microvascular vasomotion of spontaneously hypertensive rats (SHRs) and normotensive control Wistar Kyoto rats at 5, 8, 13, and 18 weeks of age were determined. Wavelet transform analysis was performed to convert pancreatic microhemodynamic signals into time-frequency domains and construct 3-dimensional spectral scalograms. The amplitudes of characteristic oscillators including endothelial, neurogenic, myogenic, respiratory, and cardiac oscillators were compared among groups. Plasma nitrite/nitrate levels were measured using a Griess reaction. Additionally, endothelin-1, malondialdehyde, superoxide dismutase, and interleukin-6 levels were determined by enzyme-linked immunosorbent assay.

RESULTS

SHRs exhibited a reduced blood distribution pattern with progressively decreased average blood perfusion, amplitude, and frequency of microvascular vasomotion. Wavelet transform spectral analysis revealed significantly reduced amplitudes of endothelial oscillators from 8- to 18-week-old SHRs. Additionally, the blood microcirculatory chemistry complements explained the microhemodynamic profiles partially, as demonstrated by an increase in plasma nitrite/nitrate, endothelin-1, malondialdehyde, and interleukin-6 levels and a decreased superoxide dismutase level in SHRs.

CONCLUSIONS

Pancreatic microcirculation profiles are abnormal in the progression of hypertension in SHRs, including a disarranged blood distribution pattern, impaired microvascular vasomotion, and reduced amplitudes of endothelial oscillators.

Nailfold capillaroscopy : a comprehensive review on common findings and clinical usefulness in non-rheumatic disease

Nailfold video-capillaroscopy (NVC) is a useful diagnostic tool, used to early detect abnormalities in micro-circulation, providing a qualitative description of microvascular anomalies in Raynaud's phenomenon. NVC role in the diagnosis of Systemic Sclerosis is well known. In other rheumatic conditions such as connective tissue diseases, vasculitis, and arthritis, the NVC anomalies are often included in a scleroderma like pattern. The use of NVC in non-rheumatic diseases (NRD), with remarkable microvascular damage, as diabetes, is not standardized yet, although several research studies are carrying on. The aim of this article is to provide a resume of published results in order to lay the groundwork for the employment of NVC both in the diagnosis and follow up of microvascular complication in NRD. Furthermore, we mention NVC findings in pathologies without well recognize microvascular damages in their pathogenesis : micro-vessels abnormalities may suggest a different point of view. J. Med. Invest. 68 : 6-14, February, 2021.

Red blood cell folate and cardiovascular deaths among hypertensive adults, an 18-year follow-up of a national cohort

A shift towards high folate concentration has emerged following folate fortification. However, the association between folate and health outcomes beyond neural tube defects remains inconclusive. To assess the relationship between red blood cell (RBC) folate and the risk of cardiovascular death among hypertensive patients, we analyzed the data of 2,986 adults aged 19 or older with hypertension who participated in the National Health and Nutrition Examination Survey (1991-1994) as the baseline examination and were followed up through December 31, 2010. After 32,743 person-years of follow-up with an average of 11.7 (standard error = 0.03) years, 1192 deaths were recorded with 579 cardiovascular deaths. The median survival time was significantly shorter in adults in the high folate quartile than in patients in the low folate quartile: 11.97 vs. 13.85 years for heart diseases and 13.37 vs. 14.82 years for myocardial infarction deaths. The cardiovascular mortality was 13.04, 16.95, and 26.61/1,000 person-years for the groups with low, intermediate and high folate quartiles, respectively. After adjustment for age, sex and other factors, a J-shaped association emerged. The hazard ratios (HRs) of all cardiovascular deaths in patients with low, intermediate, and high folate quartiles were 1.09 (0.94, 1.27), 1.00 (reference), and 1.44 (1.31, 1.58), respectively. The corresponding HRs of acute myocardial infarction were 1.13 (0.86, 1.50), 1.00, and 2.13 (1.77, 2.57), respectively. The estimates remained significant after adjustment for BMI and medication use. Compared to moderate RBC folate levels, high folate levels were significantly associated with an increased risk of cardiovascular deaths, especially acute myocardial infarction.

Comparisons of skin microvascular changes in patients with primary aldosteronism and essential hypertension

The aim of our cross-sectional study was to evaluate skin microvascular alterations in patients with hypertension secondary to primary aldosteronism (PA) and in subjects with essential hypertension (EH). Skin microcirculation was detected by nailfold videocapillaroscopy (NVC) and laser Doppler perfusion imaging (LDPI), both noninvasive techniques for the evaluation of digital capillaroscopic damage and hand skin blood perfusion. From September 2018 to April 2019, we consecutively enrolled 80 patients, of whom 42 had PA and 38 had EH. A morphological and structural study of cutaneous microcirculation was carried out through NVC, while functional evaluation of the peripheral microcirculation was carried out with LDPI. Using LDPI indices, dermal perfusion gradients were calculated in various regions of interest at the level of the back of the hand (ROI1 and ROI2). No differences between the two groups in NVC parameters were found. In contrast, LDPI showed worse skin perfusion parameters in patients with PA compared with patients with EH (ROI1: 143.9 ± 29.9 pU vs 163.3 ± 35.2 pU, p = 0.01; perfusion gradient ROI1-ROI2: 62.4 ± 28.8 pU vs 79.3 ± 33.5 pU, p = 0.019). Furthermore, the ROI1-ROI2 (proximal-distal) perfusion gradient was negatively correlated with aldosterone plasma levels (r -0.269; p = 0.017). Multivariate analysis showed that aldosterone was significantly associated with the ROI1-ROI2 perfusion gradient (b -0.220; p = 0.044). Patients with PA showed altered skin perfusion and greater microvascular dysfunction compared with the EH group. Our results are consistent with the hypothesis that aldosterone may have a pathophysiological role in microvascular remodeling in patients with PA, with predominant functional dysfunction.

Analysis of Endothelin-1 Concentrations in Individuals with Periodontitis

Endothelin 1 (ET-1) has been shown to have a key role in homeostasis and function of endothelium and maybe fundamental in the relationship between coronary heart disease (CHD) and periodontitis. In this trial, we assessed the influence on serum and salivary ET-1 levels of gingival health, CHD, periodontitis, or a combination of periodontitis-CHD. Clinical and periodontal parameters, were collected from periodontitis patients (n = 34), CHD patients (n = 34), periodontitis + CHD patients (n = 34), and from healthy patients (n = 34) together with saliva and serum samples. The median concentrations of salivary and serum ET-1 were significantly higher in the CHD patients [serum: 1.4(1.1-1.6) pg/ml; saliva 1.2 (0.9-1.6) µmol/g, p < 0.01] and in the periodontitis + CHD patients [serum: 1.7 (1.2-21.8) pg/ml; salivary 1.4(1-1.6) µmol/g, p < 0.001] respect to periodontitis and control patients. Through a univariate regression analysis, c-reactive protein (CRP) and CHD (both p < 0.001) and periodontitis (p = 0.029) were statistically correlated with ET-1 in serum. The multivariate regression analysis demonstrated that only CRP was the statistically predictor of ET-1 in serum(p < 0.001). The multivariate regression analysis in saliva demonstrated that, regarding ET-1 levels the only predictor were CRP (p < 0.001) and total cholesterol (p = 0.042). The present study evidenced that subjects with CHD and periodontitis plus CHD had higher serum and salivary levels of ET-1 compared to subjects with periodontitis and healthy controls. Moreover, only CRP remained a major predictor of increased ET-1 concentrations in both serum and saliva.

Association of serum 25-hydroxyvitamin D levels with primary hypertension: a study from south India

Hypertension is a major risk factor for cardiovascular and cerebrovascular disease. Recent studies have identified an association between low vitamin D levels and hypertension. We investigated the association between vitamin D levels and hypertension in the general population. We recruited 400 hypertensive subjects and compared them with 400 age- and sex-matched normotensive subjects. This study was carried out at Yashoda Hospital, Hyderabad, India from January 2015 to December 2017. Both groups underwent risk factor evaluation, estimation of serum 25-hydroxyvitamin D levels, and C-reactive protein (CRP) and liver function tests. Out of the 400 hypertensive subjects, 164 (40.2%) had serum 25-hydroxyvitamin D deficiency, compared with 111 (27.7%) normotensive subjects (p = 0.0001). Deficiency of serum 25-hydroxyvitamin D in hypertensive subjects was significantly associated with CRP positivity, low levels of mean serum calcium, low levels of mean serum phosphorous, high levels of mean alkaline phosphatase (p < 0.0001), and abnormal alanine transaminase (ALT) (p = 0.0015) compared with the same parameters in the normotensive subjects. After adjustment in the multiple logistic regression analysis, serum 25-hydroxyvitamin D deficiency (odds: 1.78; 95% CI: 1.31-2.41), CRP positivity (odds: 1.48; 95% CI: 1.48-2.32) and abnormal ALT (odds: 1.2; 95% CI: 0.98-1.94) were significantly associated with hypertension. Serum 25-hydroxyvitamin D deficiency was significantly associated with hypertension.

Validation of a novel ultrasound Doppler monitoring device (earlybird) for detection of microvascular circulatory changes

OBJECTIVE

In this proof-of-concept study we aim to validate a novel ultrasound Doppler monitoring device for evaluating microcirculation (earlybird) against LDF and pulsed Doppler.

METHODS

In ten healthy subjects, we measured microcirculatory function at rest and during different autonomic tests (forced respiration, isometric exercise, Valsalva maneuver and cold pressor). Earlybird, LDF and pulsed Doppler were recorded simultaneously. We performed a ZNCC to determine correlation.

RESULTS

The curves for earlybird and LDF or pulsed Doppler correlates visually well. Overall median ZNCC 0.87 (interquartile range 0.77 -0.91) between the LDF and earlybird measurements, and 0.90 (0.82 - 0.95) for pulsed Doppler and earlybird. Median ZNCC for baseline and each provocation test for earlybird against LDF and pulsed Doppler were calculated; baseline: LDF 0.87 (0.73 - 0.97) pulsed Doppler 0.91 (0.81 - 0.94), forced respiration: LDF 0.87 (0.28 - 0.90) pulsed Doppler 0.90 (0.85 - 0.96), isometric exercise: LDF 0.82 (0.59 - 0.90) pulsed Doppler 0.87 (0.68 - 0.94), Valsalva maneuver: LDF 0.88 (0.82 - 0.91) pulsed Doppler 0.94 (0.92 - 0.97) and cold pressor: LDF 0.90 (0.85 - 0.95) pulsed Doppler 0.89 (0.65 - 0.94).

CONCLUSION

Earlybird records vasoconstrictions in healthy subjects as well as LDF and pulsed Doppler.