View clinical trials related to Ischemia.
Filter by:A custom-made, 2D-perfusion digital subtraction angiography (PDSA) algorithm has been designed and implemented towards foot perfusion quantification following endovascular treatment of critical limb ischemia (CLI), in order to assist intra-procedural decision-making and enhance clinical outcomes.
This study is being conducted to provide access to and collect test data for an established nuclear medicine diagnostic imaging test called Positron Emission Tomography (PET), using a specific radioactive drug called Ammonia N-13 (Ammonia), referred to simply as an Ammonia PET scan, which is used to visualize the blood flow through the blood vessels and into the heart muscle in order to identify areas of restricted blood flow within the heart. The scanner used in this study may be a stand-alone PET scanner or a PET/CT scanner, which combines the PET scanner and a Computed Tomography (CT) scanner into a single device. Unless otherwise stated in this consent form, the term PET will be used to refer to both stand-alone PET and PET/CT scanners. While physicians have used the Ammonia PET test for many years to visualize (image) the blood flow into the heart muscle (perfusion), it is now possible to also measure the flow of blood into the heart muscle. Research studies have demonstrated clinical value in reviewing the measured blood flow values in addition to reviewing the perfusion images of blood flow into the heart muscle. Therefore, this study will establish a database of a large number of Ammonia PET measured blood flow values to serve as a future reference.
Digital Variance Angiography (DVA) is a new tool in medical imaging with proven image quality reserve. The previously observed quality reserve of Digital Variance Angiography (DVA) in lower extremity angiographies, allowed to lower radiation exposure by 70 % during DSA in lower extremity diagnostic angiographies with non-inferior image quality. The aim of this study is to apply this non-inferior image quality and use it for radiation exposure reduction in diagnostic lower limb angiography. The project would prospectively block-randomise (50:50) patients, who undergo elective diagnostic angiography into two groups: a comparator group examined by means of conventional DSA using a standard care protocol (Siemens Artis Zee, Extremities Care setting, 1.2 µGy/frame) (Group B) and a study group examined by means of DVA using a low-dose protocol (0.36 µGy/frame corresponding to 70% decrease of radiation dose) (Group A). During each procedure the investigators record radiation exposure (cumulative dosage, dose area product) and contrast media usage and procedural time then compare the results of the groups. Qualitative image review is done to compare conventional DSA and reduced radiation exposure DVA images after image acquisition. Our hypothesis is that with the previously proven non-inferior image quality, the investigators will be able to reduce radiation exposure of the participants and also staff members in everyday clinical practice.
Proprotein convertase subtilisin/kexin type 9 inhibitor monoclonal antibodies (anti-PCSK9) significantly reduce the serum LDL-C level, leading to a regression of the coronary epicardial plaque demonstrated by intracoronary ultrasonography (IVUS), as well as cardiovascular events (CV) in patients with atherosclerotic CV disease treated with statin. The impact of PCSK9 inhibition on coronary microcirculation has never been assessed. However, microvascular coronary dysfunction (CMVD) is a powerful prognostic marker, irrespective of conventional CV risk factors, but also of the severity of the epicardial coronary involvement detected during coronary angiography. The investigators hypothesized that anti-PCSK9 would decrease CMVD, measured by the microcirculatory resistance index (MRI) during coronary angioplasty (Percutaneous coronary intervention, PCI) in patients with myocardial ischemia proved in myocardial scintigraphy.
Uncertainty remains regarding the impact of enteric-coated (EC) aspirin as it relates to the reduction of CV risk. We hypothesize that EC formulation based on the previous report may blunt aspirin response as evidenced by reduced Thromboxane A2 (TXA 2) levels in diabetic patients.
The main purpose of this study will be to evaluate the prognostic value at 3 months of life of brain perfusion MRI determined by Arterial Spin Labeling technique in the first week of life of term newborns with hypoxic-ischemic encephalopathy requiring management in neonatal intensive care unit.
Effectively identifying and treating risk factors for ischemic stroke and transient ischemic attack (TIA) is important to patients, their family members, and healthcare systems. While obstructive sleep apnea (OSA) is a known risk factor for stroke and TIA that is present in more than 70% of stroke/TIA survivors, testing for OSA is infrequently performed for patients and within healthcare systems. The Addressing Sleep Apnea Post-Stroke/TIA (ASAP) study intends to improve rates of guideline-recommended OSA testing and treatment through local quality improvement initiatives (QI) conducted within and across 6 VA Medical Centers. ASAP will also determine the impact of these local QI initiatives on rates of OSA diagnosis, OSA treatment, recurrent vascular events, and hospital readmissions.
The purpose of this research study is to discover the functions of circulating white blood cells, called monocytes, and associated circulating substances in heart attack and ischemic stroke patients. Ischemic Strokes (clots) occur as a result of an obstruction within a blood vessel supplying blood to the brain. A type of monocyte carrying a surface marker called "P2X4" helps the immune system sense and respond to danger signals from the body such as heart muscle and brain tissue injuries. The researchers expect to learn more about how these monocyte cells react to heart and brain tissue injury, and how the cells may then produce proteins or other chemical substances which promote the healing of heart muscle after heart attack and brain tissue after an ischemic stroke.
Coronary artery disease (CAD) pathophysiology involves endothelium-dependent (e.g. nitric oxide, acetylcholine) and -independent (e.g. adenosine) vascular dilation impairment, which have been demonstrated at the level of small coronary arteries, medium sized peripheral arteries and subcutaneous microcirculation. Oxygen supplementation, which is frequently overused in clinical settings, seems harmful in acute coronary syndromes and increases microvascular resistance in myocardial and subcutaneous microcirculation through alteration of endothelium-dependent and -independent dilation by an oxidative mechanism. Whether endothelial dysfunction, that is well documented at the level of cardiac microcirculation in CAD patients, is also present at the level of subcutaneous microcirculation is unknown. Also, unknown is whether an acute oxidative stress can be used to probe myocardial microcirculatory dysfunction at the level of subcutaneous microcirculation, which is an easily accessible vascular bed for an in vivo assessment of endothelial-dependent and-independent function. Alterations in cutaneous vascular signalling are evident early in the disease processes. Thus, studying subcutaneous circulation in patients with cardiovascular risk factors could provide vascular information early in CAD processes. This study will test the following 4 hypotheses: 1. Endothelial dysfunction observed at the level of microvascular cardiac arteries is readily present at the level of subcutaneous microcirculation in a given CAD patient. 2. An acute oxidative stress such as hyperoxia can be used to test myocardial microcirculatory dysfunction at the level of the more easily accessible subcutaneous microcirculation. 3. Subcutaneous microcirculation of CAD patients has a lesser vasodilatory response to acetylcholine or sodium nipride than matched healthy subjects. In addition, CAD patients are more prone to dermal vasoconstriction in response to oxygen compared to healthy subjects. 4. Taken that oxygen is still too often given in excess in most clinical settings, the aim of this study is to rule out possible pitfalls in coronary pressure and resistance determinations in CAD patients receiving unnecessary oxygen supplementation.
Postoperative surveillance of local metabolism of the surgical reconstruction after esophagectomy by means of Microdialysis. Dialysate is collected continuously for seven postoperative Days. Results analysed in a blinded fashion and related to the clinical outcome. Primary endpoint: anastomotic leakage