Active clinical trials for "Ischemia"

The study seeks to determine the accuracy of using anatomic and physiologic information measurable by computed tomography features of stenosis, plaque, fractional flow reserve-CT and to compare this measure to stress testing for the detection of myocardial ischemia against the gold standard of cardiac catheterization with fractional flow reserve. The hypothesis of this proposal is that integrating anatomic plaque features with physiologic fractional flow reserve-CT will optimize identification of coronary lesions that are ischemia-causing by computed tomography .

This study will compare two ways of treatment for acute ischemic stroke: an endovascular treatment (EVT), defined as intraarterial thrombolysis and/or mechanical thrombectomy as a first choice treatment versus intravenous thrombolytic therapy (IVT) only or followed by EVT in patients with acute ischemic stroke due to a main brain artery occlusion within 4.5 hours after onset. Patients treated with IVT only or with IVT followed by EVT will be analyzed separately.

Treatment of acute ischemic stroke (AIS) is aimed at salvaging viable but ischemic brain by opening the occluded artery and restoring anterograde perfusion as quickly as possible. Time saved while making critical decisions correctly is vital in AIS management. Conventional angiography is invasive, resource intensive and not feasible as a fast diagnostic tool. Perfusion CT and MRI are both susceptible to patient motion, need trained personnel to process and take at least 10-30 min to acquire and interpret. The investigators have developed a new imaging tool, multi-phase CT Angiography (CTA), which generates multiple time resolved images of backfilling arteries beyond a blocked artery filled by collaterals. Investigators seek to determine: i) if patients with AIS will have a differential clinical response to early recanalization based on collateral status assessed on multi-phase CTA, ii) if the extent to which collateral assessment on multi-phase CTA resembles perfusion CT in predicting which patients will have good clinical outcome with early recanalization, iii) Identify determinants of variability in native collateral status in patients with acute ischemic stroke. Investigators hypothesize that patients with good and intermediate collaterals on multi-phase CTA achieve good clinical outcome with early recanalization (within 4 hours of baseline imaging); patients with poor collaterals do not do well even with early recanalization. Prove-IT is a prospective multi-center hospital-based cohort study of 500 consecutive patients with acute ischemic stroke presenting within 12 hours of stroke symptom onset with evidence of intracranial occlusion on routine CTA over 3 years. Calgary and seven other comprehensive stroke centers will recruit patients into this study. Primary outcome is defined as a National Institute of Health Stroke Scale (NIHSS) score of 0 to 2 at 24 hours or an 8-point drop in NIHSS score from baseline to 24 hours. Secondary outcomes are a) 90-day modified Rankin Score (mRS) 0-2 or equal to the pre-stroke mRS; b) percent neurologic improvement comparing NIHSS at baseline to 24 hours; c) 90-day NIHSS score 0-2; d) infarct volume on 24 hour imaging and e) parenchymal intracerebral hemorrhage type 1 and 2 (ECASS II criteria) at 24 hrs. Prove-IT looks to establish the ideal imaging selection tool for intra-arterial (IA) and thrombolysis decisions in the setting of AIS which is widely available, and can quickly and reliably detect salvageable brain.

Specific cardiovascular diseases, such as stroke and heart attack, have been shown to vary by ethnic group. However, less is known about differences between ethnic groups and a wider range of cardiovascular diseases. This study will examine differences between ethnic groups (White, Black, South Asian and Mixed/Other) and first lifetime presentation of twelve different cardiovascular diseases. This information may help to predict the onset of cardiovascular diseases and inform disease prevention strategies. The hypothesis is that different ethnic groups have differing associations with the range of cardiovascular diseases studied.

The aim of the study is to assess presence of myocardial ischemia by contrast stress echocardiography in patients with symptomatic non-obstructive coronary artery disease (CAD) by CT-coronary angiography, and the clinical, vascular, biochemical and genetic markers of myocardial ischemia in such patients.

The purpose of this registry is to assess clinical outcomes, and different factors that may affect these clinical outcomes such as systems of care, associated with the use of Covidien market-released neurothrombectomy devices intended to restore blood flow in patients experiencing acute ischemic stroke due to large intracranial vessel occlusion.

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 purpose of this research project is to test the diagnostic accuracy (i.e., sensitivity, specificity, positive and negative predictive value, and receiver operator curve area under the curve) of cardiac computed tomography (CT) perfusion as compared to the best non-invasive test of blood flow -- cardiac positron emission transmission (PET) perfusion imaging. The primary outcome of the study is to determine the CT perfusion technique with the highest overall diagnostic accuracy measured by the highest area under the receiver operator curve. The investigators will test 4 different CT perfusion techniques. (A) Qualitative, visual inspection of the contrast-enhanced CT images (B) Enhanced voxel distribution analysis (C) Rate of myocardial contrast enhancement analysis (D) Quantitative heart blood flow using a distributed 2-region analysis A second aim is to reduce the radiation dose needed to maintain CT perfusion diagnostic accuracy. Using the CT perfusion data, the investigators will model the minimal number of cardiac cycle radiation exposures needed to keep the diagnostic accuracy similar to the full data set. A third aim is to test the incremental diagnostic accuracy of CT angiography plus CT perfusion to identify regions of low blood flow as compared to PET perfusion alone.

The goal in this research is to develop better ways to detect and treat the damage caused by bleeding in the brain.

The purpose of this study is to study the demographic,laboratory,endoscopic, and outcomes of ischemic colitis patient presented with severe lower gastrointestinal bleeding compared to other diagnoses.