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Trends in Endocrinology and Metabolism:... Mar 2020Chest pain with non-obstructive coronary artery disease (NOCAD) occurs more frequently in women than in men and is mainly related to coronary microvascular disease... (Review)
Review
Chest pain with non-obstructive coronary artery disease (NOCAD) occurs more frequently in women than in men and is mainly related to coronary microvascular disease (CMD). The majority of CMD patients are postmenopausal women, suggesting a role for lack of estrogens in the development and progression of CMD. Patients are often discharged without a clear treatment plan due to the limited understanding of etiology and diagnostic parameters of CMD and have significantly higher rates of future cardiovascular events. Thus, there is a need for a better understanding of the underlying biology, and CMD-specific diagnostic tests and therapies. In this article, we reviewed recent studies on CMD, estrogen action in coronary microvasculature, and diagnosis and treatment options for CMD in postmenopausal women.
Topics: Coronary Artery Disease; Estrogens; Female; Humans; Male; Microcirculation; Postmenopause; Receptors, Estrogen; Sex Characteristics; Signal Transduction
PubMed: 31787492
DOI: 10.1016/j.tem.2019.11.001 -
Microcirculation (New York, N.Y. : 1994) Apr 2021
Topics: Microcirculation
PubMed: 33629399
DOI: 10.1111/micc.12688 -
Journal of Cerebral Blood Flow and... Oct 2023Temporal lobe epilepsy (TLE) is increasingly associated with blood-brain barrier dysfunction and microvascular alterations, yet the pathophysiological link is missing....
Temporal lobe epilepsy (TLE) is increasingly associated with blood-brain barrier dysfunction and microvascular alterations, yet the pathophysiological link is missing. An important barrier function is exerted by the glycocalyx, a gel-like layer coating the endothelium. To explore such associations, we used intraoperative videomicroscopy to quantify glycocalyx and microcirculation properties of the neocortex and hippocampus of 15 patients undergoing resective brain surgery as treatment for drug-resistant TLE, and 15 non-epileptic controls. Fluorescent lectin staining of neocortex and hippocampal tissue was used for blood vessel surface area quantification. Neocortical perfused boundary region, the thickness of the glycocalyx' impaired layer, was higher in patients (2.64 ± 0.52 µm) compared to controls (1.31 ± 0.29 µm), 0.01, indicative of reduced glycocalyx integrity in patients. Moreover, erythrocyte flow velocity analysis revealed an impaired ability of TLE patients to (de-)recruit capillaries in response to changing metabolic demands ( = 0.75, 0.01), indicating failure of neurovascular coupling mechanisms. Blood vessel quantification comparison between intraoperative measurements and resected tissue showed strong correlation ( = 0.94, 0.01). This is the first report on assessment of glycocalyx and microcirculation properties in TLE patients, confirming the pivotal role of cerebrovascular changes. Further assessment of the cerebral microcirculation in relation to epileptogenesis might open avenues for new therapeutic targets for drug-resistant epilepsy.
Topics: Humans; Epilepsy, Temporal Lobe; Glycocalyx; Microcirculation; Blood-Brain Barrier; Capillaries
PubMed: 37231664
DOI: 10.1177/0271678X231179413 -
Current Opinion in Pediatrics Jun 2024This review summarizes current literature about the relationships between macro and microcirculation and their practical clinical implications in children with septic... (Review)
Review
PURPOSE OF REVIEW
This review summarizes current literature about the relationships between macro and microcirculation and their practical clinical implications in children with septic shock.
RECENT FINDINGS
Current evidence from experimental and clinical observational studies in children and adults with septic shock reveals that the response to treatment and resuscitation is widely variable. Furthermore, there is a loss of hemodynamic coherence, as resuscitation-induced improvement in macrocirculation (systemic hemodynamic parameters) does not necessarily result in a parallel improvement in the microcirculation. Therefore, patient-tailored monitoring is essential in order to adjust treatment requirements during resuscitation in septic shock. Optimal monitoring must integrate macrocirculation (heart rate, blood pressure, cardiac output, and ultrasound images), microcirculation (videomicroscopy parameters and capillary refill time) and cellular metabolism (lactic acid, central venous blood oxygen saturation, and difference of central venous to arterial carbon dioxide partial pressure).
SUMMARY
There is a dire need for high-quality studies to assess the relationships between macrocirculation, microcirculation and tissue metabolism in children with septic shock. The development of reliable and readily available microcirculation and tissue perfusion biomarkers (other than lactic acid) is also necessary to improve monitoring and treatment adjustment in such patients.
Topics: Humans; Microcirculation; Shock, Septic; Resuscitation; Child; Hemodynamics
PubMed: 38446225
DOI: 10.1097/MOP.0000000000001345 -
Anesthesia and Analgesia Sep 2021
Topics: Humans; Microcirculation; Shock, Septic
PubMed: 34403395
DOI: 10.1213/ANE.0000000000005630 -
Clinical Hemorheology and... 2015Adequate monitoring of patients on intensive care units is of highest priority to provide optimal treatment and to detect patients at risk. Within recent years the... (Review)
Review
Adequate monitoring of patients on intensive care units is of highest priority to provide optimal treatment and to detect patients at risk. Within recent years the microcirculation became more and more attention due to its central importance for the outcome of patients. Microcirculatory disorders may include capillary flow disturbances as well as changes in the density of perfused vessels. In the clinical setting, the most often used parameter to detect alterations in the microcirculation is serum lactate. Since this parameter is characterized by major limitations, other strategies including non-invasive methods to quantify microvascular perfusion have been developed. A successful surveillance of the microcirculation in the individual patient may guide diagnostic and treatment strategies in order to optimize organ perfusion and oxygenation, subsequently leading to an individualized therapy. Intravital microscopy has been used to stratify patients at risk and to predict patients' outcome. The aim of this review is to evaluate clinical correlates of microcirculatory disorders as well as giving an overview of newer diagnostic devices that may directly or indirectly evaluate the microcirculation and are available for use in critically ill patients.
Topics: Critical Illness; Humans; Microcirculation; Monitoring, Physiologic; Shock, Cardiogenic
PubMed: 26410873
DOI: 10.3233/CH-151994 -
European Heart Journal. Cardiovascular... Jan 2015Coronary microvascular dysfunction (CMD) has been increasingly recognized as an important cardiac condition that can cause signs and symptoms of myocardial ischaemia in... (Review)
Review
Coronary microvascular dysfunction (CMD) has been increasingly recognized as an important cardiac condition that can cause signs and symptoms of myocardial ischaemia in various clinical settings. The dysfunction is located on the level of the coronary microcirculation with a vessel diameter of <500 µm and can be characterized by structural as well as functional vascular alterations. The underlying mechanisms are diverse, frequently overlapping and still incompletely understood. A common and often underdiagnosed clinical manifestation of CMD is in patients who have angina symptoms yet no obstructive epicardial coronary artery disease nor myocardial disease. There are still very few data regarding the effectiveness of pharmacological treatments for CMD. The current ESC guidelines on the management of stable coronary artery disease suggest using aspirin and statins as well as β-blockers and/or calcium-channel blockers for the treatment of CMD. This review gives an overview of the currently available pharmacological concepts for the treatment of coronary microvascular dysfunction in patients without epicardial coronary artery disease and without myocardial disease.
Topics: Cardiovascular Agents; Coronary Circulation; Humans; Microcirculation; Microvascular Angina; Treatment Outcome
PubMed: 27533969
DOI: 10.1093/ehjcvp/pvu020 -
Medical Hypotheses Jun 2018Microcirculation is a network of perfused capillaries that connects macrocirculation with the cells. Although research has provided insight into microcirculatory blood...
Microcirculation is a network of perfused capillaries that connects macrocirculation with the cells. Although research has provided insight into microcirculatory blood flow, our knowledge remains limited. In this article, we propose a new role of microcirculation in physiological and shock states. In healthy individuals, microcirculation maintains cellular homeostasis via preconditioning. When blood volume decreases, the ensuing microcirculatory changes result in heterogeneity of perfusion and tissue oxygenation. Initially, this is partly compensated by the preserved autoregulation and the increase in the metabolism rate of cells, but at later stages, the loss of autoregulation activates the cascade of intracellular hypothermia.
Topics: Blood Volume; Body Temperature; Hemodynamics; Homeostasis; Humans; Hypothermia; Intracellular Space; Ischemic Preconditioning; Microcirculation; Models, Cardiovascular; Shock, Hemorrhagic
PubMed: 29685204
DOI: 10.1016/j.mehy.2018.03.006 -
Current Opinion in Critical Care Aug 2015In shock states, optimizing intravascular volume is crucial to promote an adequate oxygen delivery to the tissues. Our current practice in fluid management pivots on the... (Review)
Review
PURPOSE OF REVIEW
In shock states, optimizing intravascular volume is crucial to promote an adequate oxygen delivery to the tissues. Our current practice in fluid management pivots on the Frank-Starling law of the heart, and the effects of fluids are measured according to the induced changes on stroke volume. The purpose of this review is to evaluate the boundaries of current macrohemodynamic approach to fluid administration, and to introduce the microcirculatory integration as a fundamental part of tissue perfusion monitoring.
RECENT FINDINGS
Macrocirculatory changes induced by volume expansion are not always coupled to proportional changes in microcirculatory perfusion. Loss of hemodynamic coherence limits the value of guiding fluid therapy according to macrohemodynamics, and highlights the importance of evaluating the ultimate target of volume administration, the microcirculation.
SUMMARY
Current approach to intravascular volume optimization is made from a macrohemodynamic perspective. However, several situations wherein macrocirculatory and microcirculatory coherence is lost have been described. Future clinical trials should explore the usefulness of integrating the microcirculatory evaluation in fluid optimization.
Topics: Critical Care; Fluid Therapy; Hemodynamics; Humans; Hypovolemia; Microcirculation; Shock
PubMed: 26103148
DOI: 10.1097/MCC.0000000000000220 -
Acta Anaesthesiologica Scandinavica Aug 2020The Revised (or "Extended") Starling principle is based on highly controlled laboratory-based frog and rodent experiments and remains a hypothesis awaiting clinical... (Review)
Review
The Revised (or "Extended") Starling principle is based on highly controlled laboratory-based frog and rodent experiments and remains a hypothesis awaiting clinical validation. A key point is that the endothelial glycocalyx layer moves the oncotic gradient from being between the plasma and the interstitium to between the plasma and a virtually protein-free space between the glycocalyx and the endothelial cell membrane, which dramatically changes the prerequisites for fluid absorption from tissue to plasma. However, many experimental and clinical observations in humans agree poorly with the new microcirculatory proposals. The most troubling aspect of the explanation regarding the role of the glycocalyx in the Revised Starling principle is the effective reabsorption of fluid by skeletal muscle when the capillary filtration pressure is acutely reduced. Other issues include the plasma volume effects of hypertonic saline, iso-oncotic and hyper-oncotic albumin, fluid distribution during cardio-pulmonary bypass, and the virtually identical capillary leakage of plasma and albumin despite marked inflammation found in our fluid therapy studies. The Revised Starling principle deals mainly with steady-state conditions, but the circulatory system is highly dynamic. Second to second vasomotion is always operational and must be considered to understand what we observe in humans.
Topics: Capillary Permeability; Endothelium, Vascular; Fluid Therapy; Glycocalyx; Humans; Microcirculation; Reproducibility of Results
PubMed: 32270471
DOI: 10.1111/aas.13593