Search results for "Circulation"
showing 10 items of 1137 documents
Blood flow and metabolic microenvironment of brain tumors
1994
Summarizing thesein vivo data in the context of brain tumor therapy, the following aspects are of particular importance: Low and heterogeneous tumor blood flow may — in addition to the limiting effects of the blood-brain barrier — result in compromised delivery of drugs from blood to the tissue. Low tumor pO2 reduces sensitivity to standard radiation and ‘O2-dependent’ anticancer drugs. Treatment efficacy may be further altered by changes of tumor pH. Particularly acidosis can decrease radiation sensitivity and modulate the cytotoxicity of anticancer drugs. In the following presentations, these aspects will be discussed regardingin vivo data obtained with positron emission tomography.
Computed tomography imaging needs for novel transcatheter tricuspid valve repair and replacement therapies
2020
Abstract Transcatheter tricuspid valve therapies are an emerging field in structural heart interventions due to the rising number of patients with severe tricuspid regurgitation and the high risk for surgical treatment. Computed tomography (CT) allows exact measurements of the annular plane, evaluation of adjacent structures, assessment of the access route, and can also be used to identify optimal fluoroscopic projection planes to enhance periprocedural imaging. This review provides an overview of current transcatheter tricuspid valve repair and replacement therapies and to what extent CT can support these interventions.
Neuroinflammatory mechanisms in ischemic stroke: Focus on cardioembolic stroke, background, and therapeutic approaches
2020
One of the most important causes of neurological morbidity and mortality in the world is ischemic stroke. It can be a result of multiple events such as embolism with a cardiac origin, occlusion of small vessels in the brain, and atherosclerosis affecting the cerebral circulation. Increasing evidence shows the intricate function played by the immune system in the pathophysiological variations that take place after cerebral ischemic injury. Following the ischemic cerebral harm, we can observe consequent neuroinflammation that causes additional damage provoking the death of the cells; on the other hand, it also plays a beneficial role in stimulating remedial action. Immune mediators are the or…
[Coronary microvascular dysfunction: past, present, and future of an evolving disease].
2017
Coronary atherosclerosis is the main cause of myocardial ischemia. Nevertheless 10-30% of patients with angina has angiographically normal coronary arteries. In the last 30 years, several studies showed that in these patients the symptoms can be caused by dysfunction of the coronary microcirculation. Coronary microvascular dysfunction (CMVD) occurring in patients affected by specific cardiac or systemic diseases may be due to mechanisms of the underlying disease. On the other hand, in several patients affected by angina with angiographically normal coronary arteries, there is no specific disease, and CMVD only is responsible for the clinical picture. This condition can be defined as leading…
Hemodynamic Parameters Change Earlier Than Tissue Oxygen Tension in Hemorrhage
2010
BACKGROUND: Untreated hypovolemia results in impaired outcome. This study tests our hypothesis whether general hemodynamic parameters detect acute blood loss earlier than monitoring parameters of regional tissue beds. MATERIALS AND METHODS: Eight pigs (23-25 kg) were anesthetized and mechanically ventilated. A pulmonary artery catheter and an arterial catheter were inserted. Tissue oxygen tension was measured with Clark-type electrodes in the jejunal and colonic wall, in the liver, and subcutaneously. Jejunal microcirculation was assessed by laser Doppler flowmetry (LDF). Intravascular volume was optimized using difference in pulse pressure (dPP) to keep dPP below 13%. Sixty minutes after p…
[Diagnosis of coronary microvascualar dysfunction in diabetic patients with cardiac syndrome X: comparison by current methods].
2013
The study population included 208 patients with chest pain and uninjured coronary arteries that we split into two populations: diabetics (72 patients) and non-diabetics (136 patients). We split patients with chest pain and uninjured coronary arteries that had a myocardial scintigraphy into two populations: patients with positive scintigraphy and negative. We calculated, on angiographic images of each patient, stored on suitable digital supports, Timi Frame Count (TFC), Myocardial Blush Grade (MBG) and Total Myocardial Blush Score (TMBS) using the protocol described by Gibson and Yusuf. On the basis of Yusuf's experience we imagined a new index: the Total Timi Frame Count as the sum of the t…
Relationship Between Carotid Atherosclerosis and Pulse Pressure with Renal Hemodynamics in Hypertensive Patients.
2015
BACKGROUND Structural atherosclerotic damage, arterial stiffness, pulse pressure (PP), and renal hemodynamics may interact and influence each other. Renal resistance index (RRI) appears as a good indicator of systemic vascular changes. The aim of our study was to assess the independent relationships of carotid intima-media thickness (cIMT), aortic pulse wave velocity (aPWV), and peripheral PP with RRI in hypertensives with various degrees of renal function. METHODS We enrolled 463 hypertensive patients (30-70 years) with normal renal function (group 0; n = 280) and with chronic kidney disease (groups I-V; n = 183). All subjects underwent ultrasonographic examination of intrarenal and caroti…
Early Vascular Aging in Normotensive Patients With Systemic Lupus Erythematosus
2015
Connective tissue diseases, like systemic lupus erythematosus (SLE), are associated with early and accelerated atherosclerosis. Recently, the concept of “early vascular aging” (EVA) has been more widely accepted. Aortic stiffness is one of the important markers of EVA. We evaluated EVA and subclinical atherosclerosis, by measuring aortic pulse wave velocity (aPWV) and carotid intima–media thickness (cIMT), in 50 normotensive patients with SLE (mean age: 39 ± 12 years). We compared these participants with 50 age- and sex-matched patients with essential hypertension (EH) and 20 healthy controls. Each participant underwent 24-hour ambulatory blood pressure monitoring (ABPM), aPWV, and cIMT me…
Radiation-induced vascular changes in the intracranial irradiation field in medulloblastoma survivors: An MRI study
2019
While survival times after treatment of medulloblastoma are increasing, little is known about radiochemotherapy (RCT)-induced cerebrovascular changes. High resolution vessel wall imaging (VWI) sequences are an emerging tool for the evaluation of cerebrovascular diseases. We performed VWI in medulloblastoma long-term survivors to screen for late sequelae of RCT.Twenty-two pediatric medulloblastoma survivors (mean age 25.8 years (10-53 years); 16.3 years (mean) post primary RCT (range 1-45 years)) underwent 2D VWI-MRI. Vessel wall thickening, contrast enhancement and luminal narrowing were analyzed. The findings were correlated with the patients' radiation protocols.Vessel wall changes were o…
Prediction of cardio- and cerebro-vascular events in patients with subclinical carotid atherosclerosis and low HDL-cholesterol.
2007
Low HDL-cholesterol concentrations are associated with increased cardiovascular risk and recent evidences suggest that HDL may aggravate the atherosclerotic process promoting inflammation: HDL are anti-inflammatory in the absence of inflammation but can become proinflammatory in the presence of atherosclerosis. Yet, no data is available on the cardiovascular outcome in subjects with low HDL-cholesterol and early stages of atherosclerosis. Therefore, we included in a prospective 5-year follow-up study 150 subjects with low HDL-cholesterol concentrations and subclinical carotid atherosclerosis, as assessed by carotid colour doppler, evaluating at baseline all the established traditional cardi…