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779 result(s) for "Microvessels - physiopathology"
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Assessment of the sublingual microcirculation with the GlycoCheck system: Reproducibility and examination conditions
The glycocalyx is an extracellular layer lining the lumen of the vascular endothelium, protecting the endothelium from shear stress and atherosclerosis and contributes to coagulation, immune response and microvascular perfusion. The GlycoCheck system estimates glycocalyx' thickness in vessels under the tongue from perfused boundary region (PBR) and microvascular perfusion (red blood cell (RBC) filling) via a camera and dedicated software. Evaluating reproducibility and influence of examination conditions on measurements with the GlycoCheck system. Open, randomised, controlled study including 42 healthy smokers investigating day-to-day, side-of-tongue, inter-investigator variance, intraclass-correlation (ICC) and influence of examination conditions at intervals from 0-180 minutes on PBR and RBC filling. Mean (SD) age was 24.9 (6.1) years, 52% were male. There was no significant intra- or inter-investigator variation for PBR or RBC filling nor for PBR for side-of-tongue. A small day-to-day variance was found for PBR (0.012μm, p = 0.007) and RBC filling (0.003%, p = 0.005) and side-of-tongue, RBC filling (0.025%, p = 0.009). ICC was modest but highly improved by increasing measurements. Small significant influence of cigarette smoking (from 40-180 minutes), high calorie meal intake and coffee consumption was found. The latter two peaking immediately and tapering off but remained significant up to 180 minutes, highest PBR changes for the three being 0.042μm (p<0.05), 0.183μm (p<0.001) and 0.160μm (p<0.05) respectively. Measurements with the GlycoCheck system have a moderate reproducibility, but highly increases with multiple measurements and a small day-to-day variability. Smoking, meal and coffee intake had effects up to 180 minutes, abstinence is recommended at least 180 minutes before GlycoCheck measurements. Future studies should standardise conditions during measurements.
Cardiac (82)Rb PET/CT for fast and non-invasive assessment of microvascular function and structure in asymptomatic patients with type 2 diabetes
Coronary flow reserve (CFR) and coronary artery calcium (CAC) represent functional and structural aspects of atherosclerosis. We examined the prevalence of reduced CFR and high CAC scores in three predefined groups of participants without known cardiovascular disease: (1) patients with type 2 diabetes and albuminuria; (2) patients with type 2 diabetes and normoalbuminuria; and (3) non-diabetic controls. In a cross-sectional design, cardiac (82)Rb positron emission tomography/computed tomography was conducted in 60 patients with type 2 diabetes who were free of overt cardiovascular disease and who were stratified by normoalbuminuria (<30 mg/24 h) (n = 30; age [mean ± SD] 60.9 ± 10.1 years) and albuminuria (≥ 30 mg/24 h) (n = 30; age 65.6 ± 4.8 years), and in 30 healthy, non-diabetic controls (age 59.8 ± 9.9 years). In controls, normoalbuminuric and albuminuric patients, CFR was 3.0 ± 0.8, 2.6 ± 0.8 and 2.0 ± 0.5, respectively. Reduced CFR (<2.5) was observed in 16.7%, 40.0% and 83.3% of participants, respectively, and median (interquartile range) CAC scores were 0 (0-81), 36 (1-325) and 370 (152-1,025), respectively (p for trend <0.01). After adjustment, the difference in CFR and CAC between albuminuric patients and controls remained significant (p ≤ 0.001). There were trends towards lower CFR and higher CAC scores in normoalbuminuric patients vs controls (p ≤ 0.023) and towards higher CAC scores in albuminuric vs normoalbuminuric patients (p = 0.026). In multivariate regression analysis, a higher urinary albumin excretion rate (UAER) tended to predict reduced CFR in the total population (p = 0.045). When the CAC score was added, there was also a trend (p = 0.032) towards an inverse association with reduced CFR. Type 2 diabetic patients who were free of overt cardiovascular disease had a high prevalence of coronary microvascular dysfunction, especially with concomitant albuminuria, suggesting a common microvascular impairment occurring in multiple microvascular beds. Prospective studies are needed to show the prognostic significance of this finding.
A New Approach to Non-Invasive Microcirculation Monitoring: Quantifying Capillary Refill Time Using Oximetric Pulse Waves
(1) Background: To develop a novel capillary refill time measurement system and evaluate its reliability and reproducibility. (2) Methods: Firstly, the utilization of electromagnetic pressure technology facilitates the automatic compression and instantaneous release of the finger. Secondly, the employment of pressure sensing technology and photoelectric volumetric pulse wave analysis technology enables the dynamic monitoring of blood flow in distal tissues. Thirdly, the subjects were recruited to compare the average measurement time and the number of measurements required for successful measurements. The satisfaction of doctors and patients with the instrument was investigated through the administration of questionnaires. Finally, 71 subjects were recruited and divided into two groups, A and B. Three doctors repeated the measurement of the right index fingers of the subjects. In Group A, the same measuring instrument was used, and the consistency of the measurements was evaluated using the intragroup correlation coefficient. In Group B, one doctor repeated the measurement of each subject three times using the same measuring instrument, and the reproducibility of the CRT was evaluated using the analysis of variance of the repeated measurement data. (3) Results: The development of the capillary refill time meter was successful, with an average measurement time of 18 s and a single measurement. This study found that doctor–patient satisfaction levels were 98.3% and 100%, respectively. The intraclass correlation coefficient was 0.995 in Group A, and the p-value was greater than 0.05 in Group B. (4) Conclusions: The non-invasive monitoring of microcirculation has been rendered both rapid and effective, thus paving the way for the further mechanization and standardization of this process. The CRT, when measured using the capillary refill time meter test machine, demonstrated consistent and reproducible results, both when assessed by different researchers and when evaluated across varying measurement sets.
In women with symptoms of cardiac ischemia, nonobstructive coronary arteries, and microvascular dysfunction, angiotensin-converting enzyme inhibition is associated with improved microvascular function: A double-blind randomized study from the National Heart, Lung and Blood Institute Women's Ischemia Syndrome Evaluation (WISE)
We investigated the role of the renin-angiotensin system in women with signs and symptoms of ischemia without obstructive coronary artery disease (CAD). Although microvascular dysfunction has been suggested to explain this syndrome and recently was found to predict adverse outcomes, the mechanisms and treatments remain unclear. In a substudy within the WISE, 78 women with microvascular dysfunction (coronary flow reserve [CFR] <3.0 following adenosine) and no obstructive CAD were randomly assigned to either an angiotensin-converting enzyme inhibition (ACE-I) with quinapril or a placebo treatment group. The primary efficacy parameter was CFR at 16 weeks adjusted for baseline characteristics and clinical site. The secondary response variable was freedom from angina symptoms assessed using the Seattle Angina Questionnaire. A total of 61 women completed the 16-week treatment period with repeat CFR measurements, and treatment was well tolerated. For the primary outcome, at 16 weeks, CFR improved more with ACE-I than placebo ( P < .02). For the secondary outcome of symptom improvement, ACE-I treatment ( P = .037) and CFR increase ( P = .008) both contributed. Microvascular function improves with ACE-I therapy in women with signs and symptoms of ischemia without obstructive CAD. This improvement is associated with reduction in angina. The beneficial response of the coronary microvasculature was limited to women with lower baseline CFR values, suggesting that the renin-angiotensin system may be more involved among women with more severe microvascular defects.
Impact of myocardial scar burden on microvascular resistance reserve in patients with coronary artery disease
Purpose The impact of myocardial scar on coronary microcirculation is not well understood. This study aims to evaluate the association between microvascular resistance reserve (MRR) and scar tissue. Methods In this post-hoc analysis of the PACIFIC 2 trial, symptomatic patients with prior myocardial infarction (MI) and/or percutaneous coronary intervention (PCI) underwent [ 15 O]H 2 O positron emission tomography (PET), cardiac magnetic resonance (CMR) imaging, and fractional flow reserve (FFR). MRR was assessed utilizing PET-derived coronary flow reserve and FFR measurements. Scar quantification was assessed by CMR late gadolinium enhancement (LGE). Vessel LGE burden was defined as the scar tissue proportion in each myocardial territory. Total LGE burden was defined as the proportion of overall scar. Results The study included 154 patients with 397 vessels with a mean MRR of 3.56 ± 1.24. Patients with any scar tissues (LGE > 0%) exhibited a lower MRR in every myocardial territory than those without scar tissues. After adjusting for cardiovascular risk factors, either vessel LGE burden (β =-0.013, P  = 0.006) or total LGE burden (β =-0.039, P  = 0.002) independently predicted a reduced MRR. Compared to myocardial territories without scar tissues (LGE burdens = 0%), MRR was significantly lower in myocardial territories with vessel LGE burden = 0% + total LGE burden > 0%, and in myocardial territories with both LGE burdens > 0%. Conclusion Scar burden was negatively associated with MRR in patients with prior MI and/or PCI. Our findings indicate that both the proportion of myocardial scar in the vascular territory and the overall myocardial scar affect the microcirculation of individual vascular territories. Clinical trial number Not applicable.
Rationale and design of the British Heart Foundation (BHF) Coronary Microvascular Function and CT Coronary Angiogram (CorCTCA) study
Microvascular and/or vasospastic anginas are relevant causes of ischemia with no obstructive coronary artery disease (INOCA) in patients after computed tomography coronary angiography (CTCA). Our research has 2 objectives. The first is to undertake a diagnostic study, and the second is to undertake a nested, clinical trial of stratified medicine. A prospective, multicenter, randomized, blinded, sham-controlled trial of stratified medicine (NCT03477890) will be performed. All-comers referred for clinically indicated CTCA for investigation of suspected coronary artery disease (CAD) will be screened in 3 regional centers. Following informed consent, eligible patients with angina symptoms are enrolled before CTCA and remain eligible if CTCA excludes obstructive CAD. Diagnostic study: Invasive coronary angiography involving an interventional diagnostic procedure (IDP) to assess for disease endotypes: (1) angina due to obstructive CAD (fractional flow reserve ≤0.80); (2) microvascular angina (coronary flow reserve <2.0 and/or index of microvascular resistance >25); (3) microvascular angina due to small vessel spasm (acetylcholine); (4) vasospastic angina due to epicardial coronary spasm (acetylcholine); and (5) noncoronary etiology (normal coronary function). The IDP involves direct invasive measurements using a diagnostic coronary guidewire followed by provocation testing with intracoronary acetylcholine. The primary outcome of the diagnostic study is the reclassification of the initial CTCA diagnosis based on the IDP. Stratified medicine trial: Participants are immediately randomized 1:1 in the catheter laboratory to therapy stratified by endotype (intervention group) or not (control group). The primary outcome of the trial is the mean within-subject change in Seattle Angina Questionnaire score at 6 months. Secondary outcomes include safety, feasibility, diagnostic utility (impact on diagnosis and certainty), and clinical utility (impact on treatment and investigations). Health status assessments include quality of life, illness perception, anxiety-depression score, treatment satisfaction, and physical activity. Participants who are not randomized will enter a follow-up registry. Health and economic outcomes in the longer term will be assessed using electronic patient record linkage. CorCTCA will prospectively characterize the prevalence of disease endotypes in INOCA and determine the clinical value of stratified medicine in this population. [Display omitted]
Citrulline Supplementation Improves Microvascular Function and Muscle Strength in Middle-Aged and Older Adults with Type 2 Diabetes
Background: Patients with type 2 diabetes (T2D) develop vascular complications due to arginine deficiency-induced microvascular endothelial dysfunction, which is related to the loss of muscle strength (MS) associated with aging. Thus, increased nitric oxide (NO)-mediated vasodilation may improve MS. We investigated the impact of the NO precursor citrulline on microvascular function (endothelial and muscle reactivity) and MS in T2D patients. Methods: Sixteen participants with T2D (53–72 years, nine females) were randomized to citrulline supplementation (CITS, 6 g/day) or placebo for 4 weeks prior to an 8-week washout period, followed by the opposite supplement for 4 weeks in a crossover trial. Endothelial function (log-transformed reactive hyperemia index, LnRHI), forearm muscle reactivity (near-infrared spectroscopy-derived tissue oxygen index (TOI) reperfusion indices), plasma arginine levels (ARG), and handgrip strength (HGSrel) and calf MS (CMSrel) adjusted for body weight were measured at baseline and 4 weeks for each condition. Results: CITS increased the LnRHI (∆0.11 ± 0.16 vs. ∆−0.08 ± 0.24, p < 0.05), TOI range (∆2.6 ± 3.3 vs. ∆−1.5 ± 4.8%, p < 0.01), TOI hyperemic response (∆1.2 ± 1.4 vs. ∆−0.6 ± 2.8%, p < 0.05), TOI 2 min area under the curve (∆154 ± 187 vs. ∆−41 ± 194%/s, p < 0.01), ARG (∆43 ± 28 vs. ∆1 ± 16μM/L, p < 0.001), CMS (∆1.5 ± 2.8 vs. ∆−0.3 ± 1.2 kg, p < 0.05), and CMSrel (∆0.02 ± 0.03 vs. ∆−0.01 ± 0.02 kg/kg, p < 0.01) compared to placebo. The improvements in LnRHI and CMSrel were correlated (r = 0.37, p < 0.05). Conclusions: This study showed that CITS improves microvascular endothelial function, muscle microvascular reactivity, and calf muscle strength in middle-aged and older patients with T2D.
Beneficial effect of a polyphenol-rich diet on cardiovascular risk: a randomised control trial
ObjectivesThere is previous epidemiological evidence that intake of polyphenol-rich foods has been associated with reduced cardiovascular disease risk. We aimed to investigate the effect of increasing dietary polyphenol intake on microvascular function in hypertensive participants.MethodsAll participants completed a 4-week run-in phase, consuming <2 portions of fruit and vegetables (F&V) daily and avoiding berries and dark chocolate. Subjects were then randomised to continue with the low-polyphenol diet for 8 weeks or to consume a high-polyphenol diet of six portions F&V (including one portion of berries/day and 50 g of dark chocolate). Endothelium-dependent (acetylcholine, ACh) and endothelium-independent (sodium nitroprusside) vasodilator responses were assessed by venous occlusion plethysmography. Compliance with the intervention was measured using food diaries and biochemical markers.ResultsFinal analysis of the primary endpoint was conducted on 92 participants. Between-group comparison of change in maximum % response to ACh revealed a significant improvement in the high-polyphenol group (p=0.02). There was a significantly larger increase in vitamin C, carotenoids and epicatechin in the high-polyphenol group (between-group difference p<0.001; p<0.001; p=0.008, respectively).ConclusionsThis study has shown that increasing the polyphenol content of the diet via consumption of F&V, berries and dark chocolate results in a significant improvement in an established marker of cardiovascular risk in hypertensive participants.Trial registration numberNCT01319786.
The endothelin receptor antagonist bosentan improves peripheral endothelial function in patients with type 2 diabetes mellitus and microalbuminuria: a randomised trial
Aims/hypothesis Endothelial dysfunction is important in the development of vascular complications in diabetes. Patients with type 2 diabetes have increased production of the vasoconstrictor and pro-inflammatory peptide, endothelin-1. Short-term intra-arterial administration of endothelin antagonists improves endothelium-dependent vasodilatation in patients with type 2 diabetes. We tested the hypothesis that oral administration of the dual endothelin receptor antagonist, bosentan, improves peripheral endothelial function in patients with type 2 diabetes and microalbuminuria. Methods This placebo-controlled and double-blind study was performed on 46 patients with type 2 diabetes and microalbuminuria (urine albumin/creatinine ratio >3 mg/mmol) at a medical university department. Patients were randomised to bosentan, 125 mg two times per day ( n  = 28), or placebo ( n  = 28) for 4 weeks. The computer-generated randomisation code was kept in sealed envelopes. Patients and people doing examinations or assessing outcomes were blinded. The primary endpoint was change in microvascular endothelium-dependent vasodilatation, based on change in digital reactive hyperaemia index. The secondary endpoint was change in brachial artery flow-mediated vasodilatation. Results Reactive hyperaemia index increased from 1.73 ± 0.43 (mean ± SD) at baseline to 2.08 ± 0.59 at follow-up ( p  < 0.05) in the bosentan group ( n  = 22), but did not change in the placebo group (1.84 ± 0.49 to 1.87 ± 0.47; n  = 24). The change in reactive hyperaemia index from baseline was greater in the bosentan group than in the placebo group ( p  < 0.05). Nitroglycerine-induced digital hyperaemia was not affected. Brachial artery flow-mediated vasodilatation and blood pressure did not change during treatment. Conclusions/interpretation Oral treatment of 4 weeks duration with the dual endothelin receptor antagonist, bosentan, improves peripheral endothelial function in patients with type 2 diabetes and microalbuminuria. Trial Registration: ClinicalTrial.gov NCT01357109; Karolinska Clinical Trial Registration Identifier CT20090017 (see www.kctr.se ) Funding: Research Council of Sweden, Swedish Heart and Lung Foundation, Novo Nordisk Foundation, Karolinska Institutet/Stockholm County Council Strategic Cardiovascular Programme, Gustav V and Queen Victoria Foundation, the Family Erling Persson Foundation, Actelion Pharmaceuticals and Actelion Research Award.
Effect of Encapsulated Purple Garlic Oil on Microvascular Function and the Components of Metabolic Syndrome: A Randomized Placebo-Controlled Study—The ENDOTALLIUM Study
Endothelial dysfunction (ED) is associated with progressive changes contributing to clinical complications related to macro- and microvascular diseases. Garlic (Allium sativum L.) and its organosulfur components have been related to beneficial cardiovascular effects and could improve endothelial function. The ENDOTALLIUM Study aimed to evaluate the effect of the regular consumption of encapsulated purple garlic oil on microvascular function, endothelial-related biomarkers, and the components of metabolic syndrome (MetS) in untreated subjects with cardiometabolic alterations. Fifty-two individuals with at least one MetS component were randomized (1:1) in a single-center, single-blind, placebo-controlled, parallel-group study. The participants received encapsulated purple garlic oil (n = 27) or placebo (n = 25) for five weeks. Skin microvascular peak flow during post-occlusive reactive hyperemia significantly increased in the purple garlic oil group compared to the placebo group (between-group difference [95%CI]: 15.4 [1.5 to 29.4] PU; p = 0.031). Likewise, hs-CRP levels decreased in the purple garlic group compared to the control group (−1.3 [−2.5 to −0.0] mg/L; p = 0.049). Furthermore, we observed a significant reduction in the mean number of MetS components in the purple garlic group after five weeks (1.7 ± 0.9 vs. 1.3 ± 1.1, p = 0.021). In summary, regular consumption of encapsulated purple garlic oil significantly improved microvascular function, subclinical inflammatory status, and the overall MetS profile in a population with cardiometabolic alterations.