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Journal of the American College of... Nov 2018Coronary microvascular disease (CMD) refers to the subset of disorders affecting the structure and function of the coronary microcirculation, is prevalent in patients... (Review)
Review
Coronary microvascular disease (CMD) refers to the subset of disorders affecting the structure and function of the coronary microcirculation, is prevalent in patients across a broad spectrum of cardiovascular risk factors, and is associated with an increased risk of adverse events. Contemporary evidence supports that most patients with CMD also have macrovessel atherosclerosis, which has important implications for their prognosis and management. In this state-of-the-art review, the authors summarize the pathophysiology of CMD, provide an update of diagnostic testing strategies, and classify CMD into phenotypes according to severity and coexistence with atherosclerosis. They examine emerging data highlighting the significance of CMD in specific populations, including obesity and insulin resistance, myocardial injury and heart failure with preserved ejection fraction, and nonobstructive and obstructive coronary artery disease. Finally, they discuss the role of CMD as a potential target for novel interventions beyond conventional approaches, representing a new frontier in cardiovascular disease reduction.
Topics: Coronary Artery Disease; Coronary Circulation; Fractional Flow Reserve, Myocardial; Humans; Microcirculation; Review Literature as Topic
PubMed: 30466521
DOI: 10.1016/j.jacc.2018.09.042 -
Circulation Journal : Official Journal... Aug 2022Ischemic heart disease (IHD) is commonly recognized as the consequence of coronary atherosclerosis and obstructive coronary artery disease (CAD). However, a significant...
Ischemic heart disease (IHD) is commonly recognized as the consequence of coronary atherosclerosis and obstructive coronary artery disease (CAD). However, a significant number of patients may present angina or myocardial infarction even in the absence of any significant coronary artery stenosis and impairment of the coronary microcirculation has been increasingly implicated as a relevant cause of IHD. The term "coronary microvascular dysfunction" (CMD) encompasses several pathogenic mechanisms resulting in functional and/or structural changes in the coronary microcirculation and determining angina and myocardial ischemia in patients with angina without obstructive CAD ("primary" microvascular angina), as well as in several other conditions, including obstructive CAD, cardiomyopathies, Takotsubo syndrome and heart failure, especially the phenotype with preserved ejection fraction. The pathogenesis of CMD is complex and involves the combination of functional and structural alterations leading to impaired coronary blood flow and resulting in myocardial ischemia. In the absence of therapies specifically targeting CMD, attention has been focused on the role of modifiable risk factors. Here, we provide updated evidence regarding the pathophysiological mechanisms underlying CMD, with a particular focus on the role of cardiovascular risk factors and comorbidities. Moreover, we discuss the specific pathogenic mechanisms of CMD across the different cardiovascular diseases, aiming to pave the way for further research and the development of novel strategies for a precision medicine approach.
Topics: Coronary Artery Disease; Coronary Circulation; Coronary Vessels; Humans; Microcirculation; Microvascular Angina; Myocardial Ischemia
PubMed: 34759123
DOI: 10.1253/circj.CJ-21-0848 -
Critical Care (London, England) May 2023The goal of hemodynamic resuscitation is to optimize the microcirculation of organs to meet their oxygen and metabolic needs. Clinicians are currently blind to what is... (Review)
Review
The goal of hemodynamic resuscitation is to optimize the microcirculation of organs to meet their oxygen and metabolic needs. Clinicians are currently blind to what is happening in the microcirculation of organs, which prevents them from achieving an additional degree of individualization of the hemodynamic resuscitation at tissue level. Indeed, clinicians never know whether optimization of the microcirculation and tissue oxygenation is actually achieved after macrovascular hemodynamic optimization. The challenge for the future is to have noninvasive, easy-to-use equipment that allows reliable assessment and immediate quantitative analysis of the microcirculation at the bedside. There are different methods for assessing the microcirculation at the bedside; all have strengths and challenges. The use of automated analysis and the future possibility of introducing artificial intelligence into analysis software could eliminate observer bias and provide guidance on microvascular-targeted treatment options. In addition, to gain caregiver confidence and support for the need to monitor the microcirculation, it is necessary to demonstrate that incorporating microcirculation analysis into the reasoning guiding hemodynamic resuscitation prevents organ dysfunction and improves the outcome of critically ill patients.
Topics: Critical Care; Microcirculation; Resuscitation; Hemodynamics; Artificial Intelligence
PubMed: 37193993
DOI: 10.1186/s13054-023-04474-x -
Critical Care (London, England) 2015This article presents a personal viewpoint of the shortcoming of conventional hemodynamic resuscitation procedures in achieving organ perfusion and tissue oxygenation...
This article presents a personal viewpoint of the shortcoming of conventional hemodynamic resuscitation procedures in achieving organ perfusion and tissue oxygenation following conditions of shock and cardiovascular compromise, and why it is important to monitor the microcirculation in such conditions. The article emphasizes that if resuscitation procedures are based on the correction of systemic variables, there must be coherence between the macrocirculation and microcirculation if systemic hemodynamic-driven resuscitation procedures are to be effective in correcting organ perfusion and oxygenation. However, in conditions of inflammation and infection, which often accompany states of shock, vascular regulation and compensatory mechanisms needed to sustain hemodynamic coherence are lost, and the regional circulation and microcirculation remain in shock. We identify four types of microcirculatory alterations underlying the loss of hemodynamic coherence: type 1, heterogeneous microcirculatory flow; type 2, reduced capillary density induced by hemodilution and anemia; type 3, microcirculatory flow reduction caused by vasoconstriction or tamponade; and type 4, tissue edema. These microcirculatory alterations can be observed at the bedside using direct visualization of the sublingual microcirculation with hand-held vital microscopes. Each of these alterations results in oxygen delivery limitation to the tissue cells despite the presence of normalized systemic hemodynamic variables. Based on these concepts, we propose how to optimize the volume of fluid to maximize the oxygen-carrying capacity of the microcirculation to transport oxygen to the tissues.
Topics: Capillaries; Hemodynamics; Humans; Microcirculation; Resuscitation; Shock; Vasoconstriction
PubMed: 26729241
DOI: 10.1186/cc14726 -
Critical Care (London, England) May 2018Adrenaline has been used in the treatment of cardiac arrest for many years. It increases the likelihood of return of spontaneous circulation (ROSC), but some studies... (Review)
Review
Adrenaline has been used in the treatment of cardiac arrest for many years. It increases the likelihood of return of spontaneous circulation (ROSC), but some studies have shown that it impairs cerebral microcirculatory flow. It is possible that better short-term survival comes at the cost of worse long-term outcomes. This narrative review summarises the rationale for using adrenaline, significant studies to date, and ongoing research.
Topics: Epinephrine; Humans; Microcirculation; Propensity Score; Resuscitation; Treatment Outcome
PubMed: 29843791
DOI: 10.1186/s13054-018-2058-1 -
Microcirculation (New York, N.Y. : 1994) Oct 2022
Topics: Microcirculation
PubMed: 36125801
DOI: 10.1111/micc.12785 -
Microcirculation (New York, N.Y. : 1994) Oct 2022Microcirculation facilitates the blood-tissue exchange of nutrients and regulates blood perfusion. It is, therefore, essential in maintaining tissue health. Aberrations... (Review)
Review
Microcirculation facilitates the blood-tissue exchange of nutrients and regulates blood perfusion. It is, therefore, essential in maintaining tissue health. Aberrations in microcirculation are potentially indicative of underlying cardiovascular and metabolic pathologies. Thus, quantitative information about it is of great clinical relevance. Photoacoustic imaging (PAI) is a capable technique that relies on the generation of imaging contrast via the absorption of light and can image at micron-scale resolution. PAI is especially desirable to map microvasculature as hemoglobin strongly absorbs light and can generate a photoacoustic signal. This paper reviews the current state of the art for imaging microvascular networks using photoacoustic imaging. We further describe how quantitative information about blood dynamics such as the total hemoglobin concentration, oxygen saturation, and blood flow rate is obtained using PAI. We also discuss its importance in understanding key pathophysiological processes in neurovascular, cardiovascular, ophthalmic, and cancer research fields. We then discuss the current challenges and limitations of PAI and the approaches that can help overcome these limitations. Finally, we provide the reader with an overview of future trends in the field of PAI for imaging microcirculation.
Topics: Microcirculation; Photoacoustic Techniques; Diagnostic Imaging; Microvessels; Hemoglobins
PubMed: 35793421
DOI: 10.1111/micc.12776 -
Animal Models and Experimental Medicine Aug 2023Pericytes are the main cellular components of tiny arteries and capillaries. Studies have found that pericytes can undergo morphological contraction or relaxation under... (Review)
Review
Pericytes are the main cellular components of tiny arteries and capillaries. Studies have found that pericytes can undergo morphological contraction or relaxation under stimulation by cytokines, thus affecting the contraction and relaxation of microvessels and playing an essential role in regulating vascular microcirculation. Moreover, due to the characteristics of stem cells, pericytes can differentiate into a variety of inflammatory cell phenotypes, which then affect the immune function. Additionally, pericytes can also participate in angiogenesis and wound healing by interacting with endothelial cells in vascular microcirculation disorders. Here we review the origin, biological phenotype and function of pericytes, and discuss the potential mechanisms of pericytes in vascular microcirculation disorders, especially in pulmonary hypertension, so as to provide a sound basis and direction for the prevention and treatment of vascular microcirculation diseases.
Topics: Pericytes; Microcirculation; Endothelial Cells; Capillaries; Biology
PubMed: 37317664
DOI: 10.1002/ame2.12334 -
American Journal of Physiology. Heart... Dec 2022Microvascular disease plays a critical role in systemic end-organ dysfunction, and treatment of microvascular pathologies may greatly reduce cardiovascular morbidity and... (Review)
Review
Microvascular disease plays a critical role in systemic end-organ dysfunction, and treatment of microvascular pathologies may greatly reduce cardiovascular morbidity and mortality. The Call for Papers collection: New Developments in Translational Microcirculatory Research highlights key advances in our understanding of the role of microvessels in the development of chronic diseases as well as therapeutic strategies to enhance microvascular function. This Mini Review provides a concise summary of these advances and draws from other relevant research to provide the most up-to-date information on the influence of cutaneous, cerebrovascular, coronary, and peripheral microcirculation on the pathophysiology of obesity, hypertension, cardiovascular aging, peripheral artery disease, and cognitive impairment. In addition to these disease- and location-dependent research articles, this Call for Papers includes state-of-the-art reviews on coronary endothelial function and assessment of microvascular health in different organ systems, with an additional focus on establishing rigor and new advances in clinical trial design. These articles, combined with original research evaluating cellular, exosomal, pharmaceutical, exercise, heat, and dietary interventional therapies, establish the groundwork for translating microcirculatory research from bench to bedside. Although numerous studies in this collection are focused on human microcirculation, most used robust preclinical models to probe mechanisms of pathophysiology and interventional benefits. Future work focused on translating these findings to humans are necessary for finding clinical strategies to prevent and treat microvascular dysfunction.
Topics: Humans; Microcirculation; Microvessels; Hypertension; Endothelium; Peripheral Vascular Diseases
PubMed: 36306213
DOI: 10.1152/ajpheart.00566.2022 -
Arquivos Brasileiros de Cardiologia Aug 2018
Topics: Cardiovascular Diseases; Humans; Microcirculation
PubMed: 30183978
DOI: 10.5935/abc.20180149