Active clinical trials for "Ischemia"

The objectives of this study were to: (1) evaluate the natural history of non-arteritic anterior ischemic optic neuropathy (NAION); (2) estimate the population incidence of NAION; and (3) identify potential risk factors for NAION.

This study will use magnetic resonance imaging (MRI) to determine if silent strokes occur during angioplasty of the blood vessels in the neck or skull. Neck and skull angioplasties are relatively new procedures whose possible complications are still under investigation. Patients 18 years of age or older who are admitted to Suburban Hospital in Bethesda, Maryland, for angioplasty of one or more of the blood vessels in the neck or skull may participate in this study. Participants must be able to undergo a brain MRI. Within 24 hours before their angioplasty, patients will provide a medical history and have a physical examination and brain MRI. The physical examination and MRI will be repeated within 24 hours after the angioplasty. MRI is a diagnostic test that uses a magnetic field and radio waves to show structural and chemical changes in tissues. This technique is more sensitive than X-rays in detecting some changes that occur in diseases of the brain. For the procedure, the patient lies on a table that slides into a metal cylinder (the scanner). The confined space may produce anxiety in some patients, and patients can talk to the technician at all times during the procedure. Earplugs are provided to muffle loud knocking and pulsing noises that occur while the scanner is taking pictures. During the study, the contrast material gadolinium may be injected into an arm vein. Gadolinium "brightens" the pictures, producing better images of brain blood flow. Patients will be contacted by telephone 30 days after the procedure to follow how they are doing and learn whether any complications resulted from the angioplasty.

To examine the relationships among psychosocial factors and carotid atherosclerosis, myocardial ischemia, arrhythmias, and thrombosis.

The aim of the study is to evaluate the use of combined fluid attenuated inversion recovery (FLAIR) imaging and diffusion weighted imaging (DWI) as surrogate marker of lesion age within the first 6 hours of ischemic stroke in order to identify patients ≤ 3 or ≤ 4.5 hours of symptom onset in a large multicenter study hours of ischemic stroke. The investigators hypothesize that the pattern of a visible lesion on DWI together with a negative FLAIR ("DWI-FLAIR mismatch") will identify patients ≤ 3 hours of symptom onset with >80% specificity and positive predictive value.

In order to observe the influence of the Dengzhan Shengmai Capsule on the endpoint of patients with ischemic stroke, we hold the multi-centered prospective cohort study. From November 2007 to December 2009, 12000 subjects are included in 200 clinical research centers all over China. The subjects naturally formed two cohorts based on taking Dengzhan Shengmai capsule or not. The basic therapy included antiplatelet aggregation , stroke health education, management of blood pressure, blood lipid and blood glucose, etc. Then all of the subjects are visited on the 360th day after inclusion. The recurrence of stroke, cardiovascular events, and peripheral arterial events are observed.

The health and well being of patients with refractory angina will be assessed using validated questionnaires (SF-36 and Seattle Angina Questionnaire [SAQ]) at baseline and one year.

T-wave alternans is a test that looks at microvolt changes in the T-wave on a beat to beat basis. The presence or absence of such changes has been shown to predict or exclude future arrhythmic events. The mechanism of T-wave alternans is unclear, but may relate to calcium metabolism in the heart, and may be affected by conditions such as ischemia or heart failure. The purpose of this study is to determine whether T-wave alternans, as measured through the lead of an implantable defibrillator, is produced by acute ischemia induced by occlusion during percutaneous coronary interventions.

The purpose of the study is to verify the ability of the HyperQ signal to detect Dobutamine induced Ischemia. The gold standard for ischemia will be the results of Angiography if performed, or Echocardiographic imaging, which was performed during the test.

The lack of blood flow to the small intestine causes mesenteric ischemia. Using a Superconducting QUantum Interference Device (SQUID) which measures the magnetic field of the small intestine, we are hoping to identify abnormalities without surgical intervention.

The investigators propose to compare the proteomic analysis of umbilical venous blood from neonates with brain injury to gestational age matched noninjured controls. After delivery an umbilical arterial gas and a 10 ml umbilical venous sample are obtained, then the remainder of the cord blood is discarded. The investigators plan to use this cord blood that would otherwise be discarded to perform our proteomic analysis. The investigators will use up to 20 ml of cord blood per delivery. This will be a 5 year study during which time the investigators hope to analyze 450 infants at Johns Hopkins Hospital and Bayview Medical Center. The investigators will obtain an umbilical venous sample from infants born at < 34 weeks gestation. For infants born at > 34 weeks the investigators will obtain an umbilical venous sample for any infant suspected to be at risk for neurologic injury by having a diagnosis of chorioamnionitis during labor, nonreassuring fetal heart rate tracing at the time of delivery, or a 5 minute Apgar < 7. For the infants born at < 34 weeks the brain injured infants will be compared to gestational age matched controls without brain injury. For the infants born at > 34 weeks, each infant later confirmed to have neurologic morbidity will be compared to a gestational age matched noninjured control. The investigators hope to use proteomic analysis to determine if there are measurable differences in protein expression between the 2 groups.