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The European Respiratory Journal Jun 2022Pulmonary arterial hypertension (PAH) is a rare dyspnoea-fatigue syndrome caused by a progressive increase in pulmonary vascular resistance and eventual right... (Review)
Review
Pulmonary arterial hypertension (PAH) is a rare dyspnoea-fatigue syndrome caused by a progressive increase in pulmonary vascular resistance and eventual right ventricular (RV) failure. In spite of extensive pulmonary vascular remodelling, lung function in PAH is generally well preserved, with hyperventilation and increased physiological dead space, but minimal changes in lung mechanics and only mild to moderate hypoxaemia and hypocapnia. Hypoxaemia is mainly caused by a low mixed venous oxygen tension from a decreased cardiac output. Hypocapnia is mainly caused by an increased chemosensitivity. Exercise limitation in PAH is cardiovascular rather than ventilatory or muscular. The extent of pulmonary vascular disease in PAH is defined by multipoint pulmonary vascular pressure-flow relationships with a correction for haematocrit. Pulsatile pulmonary vascular pressure-flow relationships in PAH allow for the assessment of RV hydraulic load. This analysis is possible either in the frequency domain or in the time domain. The RV in PAH adapts to increased afterload by an increased contractility to preserve its coupling to the pulmonary circulation. When this homeometric mechanism is exhausted, the RV dilates to preserve flow output by an additional heterometric mechanism. Right heart failure is then diagnosed by imaging of increased right heart dimensions and clinical systemic congestion signs and symptoms. The coupling of the RV to the pulmonary circulation is assessed by the ratio of end-systolic to arterial elastances, but these measurements are difficult. Simplified estimates of RV-pulmonary artery coupling can be obtained by magnetic resonance or echocardiographic imaging of ejection fraction.
Topics: Familial Primary Pulmonary Hypertension; Heart Failure; Humans; Hypertension, Pulmonary; Hypocapnia; Hypoxia; Pulmonary Arterial Hypertension; Pulmonary Artery; Ventricular Dysfunction, Right; Ventricular Function, Right
PubMed: 34737219
DOI: 10.1183/13993003.02334-2021 -
The British Journal of Radiology Jan 2022Dual-energy CT (DECT) imaging is a technique that extends the capabilities of CT beyond that of established densitometric evaluations. CT pulmonary angiography (CTPA)... (Review)
Review
Dual-energy CT (DECT) imaging is a technique that extends the capabilities of CT beyond that of established densitometric evaluations. CT pulmonary angiography (CTPA) performed with dual-energy technique benefits from both the availability of low kVp CT data and also the concurrent ability to quantify iodine enhancement in the lung parenchyma. Parenchymal enhancement, presented as pulmonary perfused blood volume maps, may be considered as a surrogate of pulmonary perfusion. These distinct capabilities have led to new opportunities in the evaluation of pulmonary vascular diseases. Dual-energy CTPA offers the potential for improvements in pulmonary emboli detection, diagnostic confidence, and most notably severity stratification. Furthermore, the appreciated insights of pulmonary vascular physiology conferred by DECT have resulted in increased use for the assessment of pulmonary hypertension, with particular utility in the subset of patients with chronic thromboembolic pulmonary hypertension. With the increasing availability of dual energy-capable CT systems, dual energy CTPA is becoming a standard-of-care protocol for CTPA acquisition in acute PE. Furthermore, qualitative and quantitative pulmonary vascular DECT data heralds promise for the technique as a "one-stop shop" for diagnosis and surveillance assessment in patients with pulmonary hypertension. This review explores the current application, clinical value, and limitations of DECT imaging in acute and chronic pulmonary vascular conditions. It should be noted that certain manufacturers and investigators prefer alternative terms, such as spectral or multi-energy CT imaging. In this review, the term dual energy is utilised, although readers can consider these terms synonymous for purposes of the principles explained.
Topics: Computed Tomography Angiography; Humans; Hypertension, Pulmonary; Lung Diseases; Pulmonary Circulation; Pulmonary Embolism; Vascular Diseases
PubMed: 34538091
DOI: 10.1259/bjr.20210699 -
Acta Bio-medica : Atenei Parmensis Nov 2021The Fontan operation has been the final palliation for patients born with congenital heart defects with a functional single ventricle for more than 4 decades. The... (Review)
Review
The Fontan operation has been the final palliation for patients born with congenital heart defects with a functional single ventricle for more than 4 decades. The "normal" Fontan physiology is characterized by the loss of the sub-pulmonary ventricle with consequent elevated pressure in the caval system, non-pulsatile blood flow in the pulmonary circulation and at least mild reduction of the systemic output. When successful, this procedure is associated with a range of benefits including improved arterial saturation and abolishment of chronic volume overload, allowing a fairly normal life to the majority of patients through early adulthood. As we enter the 5th decade of caring for patients palliated with the Fontan procedure, it is evident that adult survivors face significant morbidity due to multiorgan dysfunction, early mortality and need for heart transplantation. Several late complications may occur: ventricular dysfunction, arrhythmia, cyanosis, exercise intolerance, elevated pulmonary vascular resistance, protein-losing enteropathy, plastic bronchitis, hepatic and renal complications. The mechanism of late Fontan failure is multifactorial and not completely understood, it depends on interactions between the ventricle, the pulmonary vascular bed, the venous and lymphatic compartments. Conclusions: the aim of this review is to describe the pathophysiology of Fontan circulation and the clinical and hemodynamic characteristics of early and late failing Fontan survivors, their association with morbidity and mortality, and the strategies for their management.
Topics: Adult; Fontan Procedure; Heart Defects, Congenital; Heart Failure; Humans; Postoperative Complications; Protein-Losing Enteropathies; Ventricular Dysfunction
PubMed: 34738582
DOI: 10.23750/abm.v92i5.10893 -
International Journal of Nanomedicine 2023Exosomes are small extracellular vesicles, ranging in size from 30-150nm, which can be derived from various types of cells. In recent years, mammalian-derived exosomes... (Review)
Review
Exosomes are small extracellular vesicles, ranging in size from 30-150nm, which can be derived from various types of cells. In recent years, mammalian-derived exosomes have been extensively studied and found to play a crucial role in regulating intercellular communication, thereby influencing the development and progression of numerous diseases. Traditional Chinese medicine has employed plant-based remedies for thousands of years, and an increasing body of evidence suggests that plant-derived exosome-like nanovesicles (PELNs) share similarities with mammalian-derived exosomes in terms of their structure and function. In this review, we provide an overview of recent advances in the study of PELNs and their potential implications for human health. Specifically, we summarize the roles of PELNs in respiratory, digestive, circulatory, and other diseases. Furthermore, we have extensively investigated the potential shortcomings and challenges in current research regarding the mechanism of action, safety, administration routes, isolation and extraction methods, characterization and identification techniques, as well as drug-loading capabilities. Based on these considerations, we propose recommendations for future research directions. Overall, our review highlights the potential of PELNs as a promising area of research, with broad implications for the treatment of human diseases. We anticipate continued interest in this area and hope that our summary of recent findings will stimulate further exploration into the implications of PELNs for human health.
Topics: Humans; Animals; Exosomes; Extracellular Vesicles; Cell Communication; Medicine, Chinese Traditional; Pulmonary Circulation; Mammals
PubMed: 37693885
DOI: 10.2147/IJN.S420748 -
International Journal of Hematology Jan 2021The pathology of coronavirus disease 2019 (COVID-19) is exacerbated by the progression of thrombosis, and disseminated intravascular coagulation (DIC), and cytokine... (Review)
Review
The pathology of coronavirus disease 2019 (COVID-19) is exacerbated by the progression of thrombosis, and disseminated intravascular coagulation (DIC), and cytokine storms. The most frequently reported coagulation/fibrinolytic abnormality in COVID-19 is the increase in D-dimer, and its relationship with prognosis has been discussed. However, limits exist to the utility of evaluation by D-dimer alone. In addition, since the coagulation/fibrinolytic condition sometimes fluctuates within a short period of time, regular examinations in recognition of the significance of the examination are desirable. The pathophysiology of disseminated intravascular coagulation (DIC) associated with COVID-19 is very different from that of septic DIC, and both thrombotic and hemorrhagic pathologies should be noted. COVID-19 thrombosis includes macro- and microthrombosis, with diagnosis of the latter depending on markers of coagulation and fibrinolysis. Treatment of COVID-19 is classified into antiviral treatment, cytokine storm treatment, and thrombosis treatment. Rather than providing uniform treatment, the treatment method most suitable for the severity and stage should be selected. Combination therapy with heparin and nafamostat is expected to develop in the future. Fibrinolytic therapy and adsorption therapy require further study.
Topics: Adult; Anticoagulants; Benzamidines; Blood Coagulation Disorders; Blood Coagulation Tests; COVID-19; Cytokine Release Syndrome; Disseminated Intravascular Coagulation; Female; Fibrin Fibrinogen Degradation Products; Fibrinolysis; Guanidines; Humans; Lymphopenia; Male; Middle Aged; Pandemics; Prognosis; Pulmonary Circulation; SARS-CoV-2; Survivors; Thrombocytopenia; Thrombophilia; COVID-19 Drug Treatment
PubMed: 33161508
DOI: 10.1007/s12185-020-03029-y