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Circulation. Cardiovascular Imaging Oct 2021The status of the systemic right ventricular coronary microcirculation in hypoplastic left heart syndrome (HLHS) is largely unknown. It is presumed that the systemic...
BACKGROUND
The status of the systemic right ventricular coronary microcirculation in hypoplastic left heart syndrome (HLHS) is largely unknown. It is presumed that the systemic right ventricle's coronary microcirculation exhibits unique pathophysiological characteristics of HLHS in Fontan circulation. The present study sought to quantify myocardial blood flow by cardiac magnetic resonance imaging and evaluate the determinants of microvascular coronary dysfunction and myocardial ischemia in HLHS.
METHODS
One hundred nineteen HLHS patients (median age, 4.80 years) and 34 healthy volunteers (median age, 5.50 years) underwent follow-up cardiac magnetic resonance imaging ≈1.8 years after total cavopulmonary connection. Right ventricle volumes and function, myocardial perfusion, diffuse fibrosis, and late gadolinium enhancement were assessed in 4 anatomic HLHS subtypes. Myocardial blood flow (MBF) was quantified at rest and during adenosine-induced hyperemia. Coronary conductance was estimated from MBF at rest and catheter-based measurements of mean aortic pressure (n=99).
RESULTS
Hyperemic MBF in the systemic ventricle was lower in HLHS compared with controls (1.89±0.57 versus 2.70±0.84 mL/g per min; <0.001), while MBF at rest normalized by the rate-pressure product, was similar (1.25±0.36 versus 1.19±0.33; =0.446). Independent risk factors for a reduced hyperemic MBF were an HLHS subtype with mitral stenosis and aortic atresia (=0.017), late gadolinium enhancement (=0.042), right ventricular diastolic dysfunction (=0.005), and increasing age at total cavopulmonary connection (=0.022). The coronary conductance correlated negatively with systemic blood oxygen saturation (r, -0.29; =0.02). The frequency of late gadolinium enhancement increased with age at total cavopulmonary connection (=0.014).
CONCLUSIONS
The coronary microcirculation of the systemic ventricle in young HLHS patients shows significant differences compared with controls. These hypothesis-generating findings on HLHS-specific risk factors for microvascular dysfunction suggest a potential benefit from early relief of frank cyanosis by total cavopulmonary connection.
Topics: Child; Child, Preschool; Coronary Circulation; Echocardiography, Doppler; Female; Follow-Up Studies; Humans; Hypoplastic Left Heart Syndrome; Magnetic Resonance Imaging, Cine; Male; Microcirculation; Myocardial Ischemia; Myocardial Perfusion Imaging; Oxygen Saturation; Prospective Studies
PubMed: 34610753
DOI: 10.1161/CIRCIMAGING.121.012468 -
Indian Journal of Ophthalmology Oct 2023To evaluate retinal and choroidal alterations in eyes with inactive ocular sarcoidosis and to compare the findings with healthy controls.
PURPOSE
To evaluate retinal and choroidal alterations in eyes with inactive ocular sarcoidosis and to compare the findings with healthy controls.
METHODS
This cross-sectional study included 11 patients with inactive ocular sarcoidosis (study group) and 11 healthy individuals (control group). Retinal and choroidal vascular differences were evaluated using optical coherence tomography angiography (OCTA) and enhanced depth imaging-optical coherence tomography (EDI-OCT).
RESULTS
A total of 21 eyes of ocular sarcoidosis patients without active inflammation and 22 eyes of healthy controls were analyzed. The mean whole-image deep capillary plexus vessel density was significantly lower in the study group than in the control group (P = 0.03). The acircularity index values were significantly higher, and the foveal density-300 values were significantly lower in the study group than in the control group (P = 0.01, both). The flow areas of the choriocapillaris at 1-, 2-, and 3-mm radius areas were also significantly lower in the study group (all P < 0.01). The mean choroidal thickness (CT) was significantly lower in all regions between nasal and temporal at 3000 μm in the study group (all P < 0.05). The choroidal vascularity index (CVI) values were also significantly lower in the study group (P < 0.01).
CONCLUSION
Ocular sarcoidosis was associated with a reduction in CT and the CVI with a decrease in retinal vessel density and choriocapillary flow parameters. The combination of OCTA and EDI-OCT imaging may be useful in monitoring ocular sarcoidosis eyes to detect alterations in the retinal and choroidal layers.
Topics: Humans; Microcirculation; Cross-Sectional Studies; Retina; Choroid; Sarcoidosis; Endophthalmitis
PubMed: 37787237
DOI: 10.4103/IJO.IJO_3262_22 -
Chinese Medical Journal Jan 2022Fluid resuscitation is an essential intervention in critically ill patients, and its ultimate goal is to restore tissue perfusion. Critical illnesses are often... (Review)
Review
Fluid resuscitation is an essential intervention in critically ill patients, and its ultimate goal is to restore tissue perfusion. Critical illnesses are often accompanied by glycocalyx degradation caused by inflammatory reactions, hypoperfusion, shock, and so forth, leading to disturbed microcirculatory perfusion and organ dysfunction. Therefore, maintaining or even restoring the glycocalyx integrity may be of high priority in the therapeutic strategy. Like drugs, however, different resuscitation fluids may have beneficial or harmful effects on the integrity of the glycocalyx. The purpose of this article is to review the effects of different resuscitation fluids on the glycocalyx. Many animal studies have shown that normal saline might be associated with glycocalyx degradation, but clinical studies have not confirmed this finding. Hydroxyethyl starch (HES), rather than other synthetic colloids, may restore the glycocalyx. However, the use of HES also leads to serious adverse events such as acute kidney injury and bleeding tendencies. Some studies have suggested that albumin may restore the glycocalyx, whereas others have suggested that balanced crystalloids might aggravate glycocalyx degradation. Notably, most studies did not correct the effects of the infusion rate or fluid volume; therefore, the results of using balanced crystalloids remain unclear. Moreover, mainly animal studies have suggested that plasma may protect and restore glycocalyx integrity, and this still requires confirmation by high-quality clinical studies.
Topics: Animals; Colloids; Crystalloid Solutions; Fluid Therapy; Glycocalyx; Humans; Hydroxyethyl Starch Derivatives; Isotonic Solutions; Microcirculation; Resuscitation
PubMed: 34985018
DOI: 10.1097/CM9.0000000000001869 -
American Journal of Physiology.... Mar 2020Reactive hyperemia is a well-established technique for noninvasive assessment of peripheral microvascular function and a predictor of all-cause and cardiovascular... (Review)
Review
Reactive hyperemia is a well-established technique for noninvasive assessment of peripheral microvascular function and a predictor of all-cause and cardiovascular morbidity and mortality. In its simplest form, reactive hyperemia represents the magnitude of limb reperfusion following a brief period of ischemia induced by arterial occlusion. Over the past two decades, investigators have employed a variety of methods, including brachial artery velocity by Doppler ultrasound, tissue reperfusion by near-infrared spectroscopy, limb distension by venous occlusion plethysmography, and peripheral artery tonometry, to measure reactive hyperemia. Regardless of the technique used to measure reactive hyperemia, blunted reactive hyperemia is believed to reflect impaired microvascular function. With the advent of several technological advancements, together with an increased interest in the microcirculation, reactive hyperemia is becoming more common as a research tool and is widely used across multiple disciplines. With this in mind, we sought to review the various methodologies commonly used to assess reactive hyperemia and current mechanistic pathways believed to contribute to reactive hyperemia and reflect on several methodological considerations.
Topics: Blood Flow Velocity; Brachial Artery; Humans; Hyperemia; Ischemia; Microcirculation; Vasodilation
PubMed: 32022580
DOI: 10.1152/ajpregu.00339.2019 -
Journal of Thrombosis and Haemostasis :... Sep 2023Microvascular dysfunction is a growing determinant of sex differences in coronary heart disease (CHD). Dysregulation of the coagulation system is involved in CHD...
BACKGROUND
Microvascular dysfunction is a growing determinant of sex differences in coronary heart disease (CHD). Dysregulation of the coagulation system is involved in CHD pathogenesis and can be induced by endothelial glycocalyx (EG) perturbation. However, little is known about the link between EG function and coagulation parameters in population-based studies on sex specificity.
OBJECTIVES
We sought to examine the sex differences in the relationship between EG function and coagulation parameters in a middle-aged Dutch population.
METHODS
Using baseline measurements of 771 participants from the Netherlands Epidemiology of Obesity study (age, 56 years [IQR, 51-61 years]; 53% women; body mass index, 27.9 kg/m [IQR, 25.1-30.9 kg/m]), associations between glycocalyx-related perfused boundary region (PBR) derived using sidestream dark-field imaging and coagulation parameters (factor [F]VIII/IX/XI; thrombin generation parameters; and fibrinogen) were investigated using linear regression analyses, adjusting for possible confounders (including C-reactive protein, leptin, and glycoprotein acetyls), followed by sex-stratified analyses.
RESULTS
There was a sex difference in the associations between PBR and coagulation parameters. Particularly in women, 1-SD PBR (both total and feed vessel, indicating poorer glycocalyx status) was associated with higher FIX activity ([1.8%; 95% CI, 0.3%-3.3%] and [2.0%; 95% CI, 0.5%-3.4%], respectively) and plasma fibrinogen levels ([5.1 mg/dL; 95% CI, 0.4-9.9 mg/dL] and [5.8 mg/dL; 95% CI, 1.1-10.6 mg/dL], respectively). Furthermore, 1-SD PBR was associated with higher FVIII activity (3.5%; 95% CI, 0.4%-6.5%) and plasma fibrinogen levels (5.3 mg/dL; 95% CI, 0.6-10.0 mg/dL).
CONCLUSION
We revealed a sex-specific association between microcirculatory health and procoagulant status, which suggests that microvascular health be considered during early development of CHD in women.
Topics: Middle Aged; Humans; Male; Female; Netherlands; Microcirculation; Obesity; Blood Coagulation; Fibrinogen; Coronary Disease
PubMed: 37301258
DOI: 10.1016/j.jtha.2023.06.001 -
Microcirculation (New York, N.Y. : 1994) Oct 2022Monitoring microcirculation and visualizing microvasculature are critical for providing diagnosis to medical professionals and guiding clinical interventions. Ultrasound...
OBJECTIVE
Monitoring microcirculation and visualizing microvasculature are critical for providing diagnosis to medical professionals and guiding clinical interventions. Ultrasound provides a medium for monitoring and visualization; however, there are challenges due to the complex microscale geometry of the vasculature and difficulties associated with quantifying perfusion. Here, we studied established and state-of-the-art ultrasonic modalities (using six probes) to compare their detection of slow flow in small microvasculature.
METHODS
Five ultrasonic modalities were studied: grayscale, color Doppler, power Doppler, superb microvascular imaging (SMI), and microflow imaging (MFI), using six linear probes across two ultrasound scanners. Image readability was blindly scored by radiologists and quantified for evaluation. Vasculature visualization was investigated both in vitro (resolution and flow characterization) and in vivo (fingertip microvasculature detection).
RESULTS
Superb Microvascular Imaging (SMI) and Micro Flow Imaging (MFI) modalities provided superior images when compared with conventional ultrasound imaging modalities both in vitro and in vivo. The choice of probe played a significant difference in detectability. The slowest flow detected (in the lab) was 0.1885 ml/s and small microvasculature of the fingertip were visualized.
CONCLUSIONS
Our data demonstrated that SMI and MFI used with vascular probes operating at higher frequencies provided resolutions acceptable for microvasculature visualization, paving the path for future development of ultrasound devices for microcirculation monitoring.
Topics: Microcirculation; Ultrasonography; Microvessels; Ultrasonography, Doppler
PubMed: 35611457
DOI: 10.1111/micc.12770 -
GeroScience Dec 2019Aging of the microcirculatory network plays a central role in the pathogenesis of a wide range of age-related diseases, from heart failure to Alzheimer's disease. In the... (Review)
Review
Aging of the microcirculatory network plays a central role in the pathogenesis of a wide range of age-related diseases, from heart failure to Alzheimer's disease. In the eye, changes in the choroid and choroidal microcirculation (choriocapillaris) also occur with age, and these changes can play a critical role in the pathogenesis of age-related macular degeneration (AMD). In order to develop novel treatments for amelioration of choriocapillaris aging and prevention of AMD, it is essential to understand the cellular and functional changes that occur in the choroid and choriocapillaris during aging. In this review, recent advances in in vivo analysis of choroidal structure and function in AMD patients and patients at risk for AMD are discussed. The pathophysiological roles of fundamental cellular and molecular mechanisms of aging including oxidative stress, mitochondrial dysfunction, and impaired resistance to molecular stressors in the choriocapillaris are also considered in terms of their contribution to the pathogenesis of AMD. The pathogenic roles of cardiovascular risk factors that exacerbate microvascular aging processes, such as smoking, hypertension, and obesity as they relate to AMD and choroid and choriocapillaris changes in patients with these cardiovascular risk factors, are also discussed. Finally, future directions and opportunities to develop novel interventions to prevent/delay AMD by targeting fundamental cellular and molecular aging processes are presented.
Topics: Aging; Choroid; Disease Progression; Humans; Microcirculation; Regional Blood Flow; Retinal Vessels; Wet Macular Degeneration
PubMed: 31797238
DOI: 10.1007/s11357-019-00138-3 -
Neurourology and Urodynamics Jan 2020Oxygen plays a crucial role in wound healing after prolapse surgery. Trauma to the vaginal vasculature might limit the delivery of oxygen to the surgical wound, which...
AIMS
Oxygen plays a crucial role in wound healing after prolapse surgery. Trauma to the vaginal vasculature might limit the delivery of oxygen to the surgical wound, which may negatively affect wound healing and regeneration of connective tissue. This possibly increases the future risk of recurrence. We aimed to determine the effects of vaginal prolapse surgery on the microcirculation of the vaginal wall.
METHODS
We evaluated the vaginal microcirculation in healthy participants without known vascular disease undergoing anterior and/or posterior colporrhaphy. We used incident dark-field imaging for in vivo assessment before and after (1 day, 2 weeks, and 6 weeks) surgery. We studied perfusion (microvascular flow index [MFI]), angioarchitecture (morphology/layout of microvessels) and capillary density.
RESULTS
Ten women were included. Interindividual differences were observed 1 day postoperatively with regard to perfusion and angioarchitecture. Microvascular flow at the surgical site was absent or significantly reduced in some participants, whereas normal microvascular flow was observed in others (MFI range 0-3). Perfusion and angioarchitecture had been restored in all participants after 6 weeks (MFI range 2-3), regardless of the extent of vascular trauma 1 day postoperatively.
CONCLUSIONS
The difference in the extent of vascular trauma between women undergoing seemingly identical surgical procedures suggests that some individuals are more susceptible to vascular trauma than others. Delivery of oxygen to the wound and subsequent wound healing may be compromised in these cases, which could be related to the development of anatomical recurrence. Future studies should investigate whether there is a relationship between the vaginal microvasculature and the recurrence of prolapse.
Topics: Aged; Female; Gynecologic Surgical Procedures; Humans; Microcirculation; Microvessels; Middle Aged; Pelvic Organ Prolapse; Recurrence; Surgical Mesh; Vagina
PubMed: 31691336
DOI: 10.1002/nau.24203 -
JACC. Cardiovascular Interventions Feb 2023Microvascular resistance reserve (MRR) is a new index to assess coronary microvascular (dys)function, which can be easily measured invasively using continuous...
BACKGROUND
Microvascular resistance reserve (MRR) is a new index to assess coronary microvascular (dys)function, which can be easily measured invasively using continuous thermodilution. In contrast to coronary flow reserve (CFR), MRR is independent of epicardial coronary disease and hemodynamic variations. Its measurement is accurate, reproducible, and operator independent.
OBJECTIVES
The aim of this study was to establish the range of normal values for MRR and to determine an optimal cutoff point.
METHODS
In this exploratory study in 214 patients with angina and no obstructive coronary artery disease, after excluding significant epicardial disease, all physiological parameters, such as fractional flow reserve, index of microvascular resistance, CFR, absolute blood flow, absolute microvascular resistance, and MRR, were measured. On the basis of concordant positive or concordant negative results of index of microvascular resistance and CFR, subgroups of patients were defined with high probability of either normal (n = 122) or abnormal (n = 24) microcirculatory function, and MRR was studied in these groups.
RESULTS
Mean MRR in the "normal" group was 3.4 compared with a mean MRR of 1.9 in the "abnormal" group; these values were significantly different between the groups. MRR >2.7 ruled out coronary microvascular dysfunction (CMD) with a certainty of 96%, whereas MRR <2.1 indicated the presence of CMD with a similar high certainty of 96%.
CONCLUSIONS
MRR is a suitable index to distinguish the presence or absence of CMD in patients with angina and no obstructive coronary artery disease. The present data indicate that an MRR of 2.7 virtually excludes the presence of CMD, while an MRR value <2.1 confirms its presence.
Topics: Humans; Coronary Artery Disease; Fractional Flow Reserve, Myocardial; Microcirculation; Treatment Outcome; Myocardial Ischemia; Angina Pectoris
PubMed: 36858668
DOI: 10.1016/j.jcin.2022.12.012 -
American Journal of Physiology. Heart... Jul 2022Hyperspectral imaging (HSI) provides a fast, reliable, and noninvasive way for the study of vascular microcirculation in animal models. Rapid hyperspectral imaging of...
Hyperspectral imaging (HSI) provides a fast, reliable, and noninvasive way for the study of vascular microcirculation in animal models. Rapid hyperspectral imaging of large portions of the microcirculatory preparation is critical for understanding the function and regulation of vascular microcirculatory networks. This report presents the application of an off-the-shelf benchtop HSI linear scanning system to acquire larger field-of-view images of microcirculatory preparations. The HSI line detector was displaced perpendicular to the scanning direction to map larger areas, with a rate of displacement determined by the scanning rate and the exposure time. Analysis of the collected image was used to assess dynamic changes in the microcirculation. The system records dynamic changes in microvascular hemoglobin oxygen (HbO) saturation and vascular morphology during hypoxia and reoxygenation and has similar acquisition speeds to commonly referenced spectral-scanning HSI systems. In addition, the HbO saturations collected via HSI closely correlate with those collected by phosphorescence quenching microscopy. The reported system enables dynamic functional imaging of the microcirculation for broad experimental and clinical applications. This study presents a novel bench setup and algorithm to measure intravascular hemoglobin oxygen saturation in microcirculation. Wide-field hyperspectral imaging allows for rapid quantification of intravascular changes in hemoglobin saturation. The method described in this manuscript can expand the understanding of oxygen delivery to tissues in vivo.
Topics: Animals; Hemoglobins; Hypoxia; Microcirculation; Microscopy; Oxygen
PubMed: 35522555
DOI: 10.1152/ajpheart.00624.2021