Active clinical trials for "Ischemia"

This is an open label single center phase II trial, evaluating the utility of 64 slice CT perfusion (CTP) in acute ischemic stroke (AIS) patients. The main aim is to determine which aspects of CTP imaging can aid in expanding the time window for thrombolysis with IV (rt-PA) in AIS patients up to 6 hours after symptom onset.

Acetylsalicylic acid (Aspirin, ASA) is the most widely prescribed drug used in primary and secondary prevention of cardiovascular disease. However, aspirin resistance has been described, mostly in cardiac patients and is an independent predictive factor for a poor survival. Two frequent conditions in patients with cardiovascular diseases, diabetes and hypercholesterolemia, are also considered as risk factors for aspirin resistance. Among patients with peripheral arterial disease, those with critical limb ischemia have the worst cardiovascular prognosis. At one year, 23% are dead, 25% have a major cardiovascular event and 25% have a major amputation (which can be combined). Aspirin resistance is poorly studied in these patients, and to our knowledge no study has been made to assess the prognosis value of aspirin resistance on cardiovascular outcomes in critical limb ischaemia patients. Hospitalized critical limb ischaemia patients will be tested for aspirin resistance using the bed-side point of care VerifyNow®, and will be followed during one year, including death, fatal and non-fatal acute coronary syndromes, cardiac decompensation, stroke, and major amputation.

This study is being done to determine if patients receiving (iNO) will have increased liver function and less damage from IR than patients who do not receive (iNO).

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 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.

Most patients presenting to the emergency department with chest discomfort have a nonischemic ECG and biomarkers of myocardial necrosis within normal limits. These patients are routinely admitted to hospital because of diagnostic uncertainty for occult MI or ischaemia. Acute myocardial ischemia is associated with acute mycardial dysfunction We tested a non-invasive plethysmographic arterial pressure change index of myocardial performance (dP/dt) that could be added to the diagnostic triage of ischaemia in the ER avoiding unnecessary admissions.

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 .

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.

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.