Active clinical trials for "Ischemia"

Patients with coronary artery disease are often prescribed drugs called statins because research has shown that, by lowering cholesterol, they reduce the risk of having a heart attack or other complications in the long-term. Experimental studies have suggested that statins may also have rapid anti-inflammatory, anti-oxidant and anti arrhythmic actions; however, whether these effects are of any benefit to patients remains to be proven. The purpose of STARR trial (Statin Therapy in Atrial Refractoriness and Reperfusion injury) is to evaluate whether a short course of a commonly used statin (atorvastatin, 80 mg once a day) decreases inflammation and stabilises electrical properties of the upper chamber of the heart in the post operative period of patients undergoing cardiac surgery on the heart-lung machine either for valve replacement and/or coronary artery bypass grafting. It will also examine whether this treatment can protect the heart from sustaining tissue damage when blood supply is restored after a period of ischaemia during the course of the surgery.In addition it will also explore the impact of this intervention on biology of the vessels used for bypass surgery and the fat tissue in the vicinity of the heart & blood vessels.

The aim of this clinical investigation is to determine the effect of intraoperative ventilation on cerebral oxygen saturation in patients undergoing arthroscopic shoulder surgery in the beach chair position (BCP)

Making a limb transiently ischemic induces ischemic tolerance in distant organs such as the heart. This study aims to evaluate the feasibility, safety and initial efficacy of using briefly repetitive bilateral limb ischemic preconditioning (BLIPC) to protect the brain in octogenarians with symptomatic intracranial arterial stenosis.

Cardiovascular disease (CVD) continues to be the major cause of morbidity and mortality in western countries. It has been shown that CVD events are known to be higher in the winter than in the summer. Low environmental temperatures may induce increased cardiovascular stress resulting in cold-induced hypertension (CIH), the leading risk factor for CVD events. Similar to whole-body cold exposure, the cold pressor test (CPT), an external local cold stimulus, has been used for evaluation of cardiovascular and hemodynamic reactivity to sympathetic stimulation. It has been shown that brachial blood pressure (BP), pressure pulse wave reflection, aortic BP, heart rate (HR), and arterial stiffness are increased during CPT. However, the physiologic mechanisms for the cardiovascular complications related to low temperatures are not completely clear. Isometric-handgrip (IHG) exercise has been used as a tool for assessing cardiovascular autonomic control by a maneuver defined as post-exercise muscle ischemia (PEMI). PEMI induces exercise pressor reflex (metaboreflex) by trapping metabolites in the previous active muscle at the cessation of exercise. During PEMI, the accumulation of contraction-derived metabolites induces sympathetic mediated vascular stimulation and an increased BP, whereas the HR fully recovers. This suggests that the fall in HR is evoked by an increase in parasympathetic activity which overpowers the sympathetic activation. Implication of IHG exercise followed by PEMI provides important clinical information because impaired autonomic and cardiovascular functions are associated with cardiovascular events. Recently, oral supplementation with the amino acid L-citrulline (L-cit) has been proposed as a possible adjunct treatment for hypertension and arterial stiffness. L-cit is known to enhance the bioavailability of L-arginine (L-arg), the endothelial substrate for nitric oxide (NO) production. Cold exposure might include a temperature-dependent inhibition of endothelial NO synthase (eNOS), the enzyme that produces NO from the amino acid L-arg and may trigger various types of CVD. It has been shown that L-cit supplementation has effectively attenuated the CIH response during cold pressor test. Thus, L-cit supplementation may be effective to reduce the cardiovascular responses associated with cold exposure and the exercise pressor reflex imposed by PEMI. Therefore, the proposed study is important for the following reasons: (1) the results of his study will add to our understanding regarding the cardiovascular and autonomic mechanisms associated with exercise and cold exposure; (2) the results of this study will contribute to the development of an adjunct therapy for the prevention of cardiovascular adverse events that are particularly increased during stress such as cold exposure and exercise.

This is an open-label, non-randomized, multi center, patient sponsored study of Adipose-Derived Stromal Cell (ASC) implantation via intramuscular injections in patients who have critical limb ischemia not amenable for revascularization. The intent of this clinical study is to answer the questions: 1) Is the proposed treatment safe and 2) Is treatment effective in improving the disease pathology of patients with diagnosed critical limb ischemia ASCs will be collected from the patient's adipose-derived tissue (body fat). Using local anesthesia, Liposuction will be performed to collect the adipose tissue specimen. The adipose tissue is then transferred to the laboratory for separation of the adipose tissue derived stem cells. In addition, peripheral blood will be collected for isolation of platelet rich plasma, which are then combined with the ASC's for intramuscular injection into the lower limb.

The purpose of the study is to assess the diagnostic performance of fully automated motion corrected (MC) first pass myocardial perfusion MRI, compared to the original non-corrected first pass myocardial perfusion images in a cohort of patients with suspected ischemic heart disease, using coronary angiography as the reference standard. It is expected that this improved comprehensive protocol for cardiac MRI be accurate at detecting significant coronary artery disease and may obviate the need for other more expensive and invasive diagnostic tests currently used.

The main purpose of this study is to determine whether intravenous glutamate infusion given in association with surgery for unstable coronary artery disease can protect the heart from myocardial injury, postoperative heart failure and death.

Not infrequently, a physician is faced with uncertainty regarding the ability of a patient to perform adequate exercise in the noninvasive evaluation of known or suspected coronary artery disease (CAD) by the use of radionuclide stress myocardial perfusion imaging. In selected patients, protocols that combine exercise (either low-level or symptom-limited) with vasodilator stress agents have been found to be safe and effective in both identification of the presence and severity of CAD as well as risk stratification for adverse cardiac outcome. However, currently utilized combined stress protocols have drawbacks. Further refinement of combined stress protocols would potentially lead to more appropriate stress protocol selection for patients while enhancing laboratory efficiency. The purpose of this prospective, randomized study will be to evaluate the relative merits of combining regadenoson with symptom-limited exercise in patients clinically-referred for vasodilator-exercise stress myocardial perfusion imaging for the assessment of known or suspected CAD. It is hypothesized that combining regadenoson with symptom-limited exercise is a safe and feasible stress testing modality which is non-inferior to that which combines symptom-limited exercise with dipyridamole.

STUDY QUESTIONS What is the real prevalence of platelet "resistance" to aspirin during the acute phase of stroke and after 3 months, and 1 year, as measured using different platelet function tests? Do all methods measure similar levels of resistance, or are some methods more sensitive than others? Does this resistance result in a worse clinical prognosis? Is this result independent of other variables? OBJECTIVES Hospital Phase (Acute Stroke) Determination, using various methods, of the prevalence of platelet hyperreactivity in patients treated with aspirin to treat ischemic stroke (acute phase) Comparison of different assessment methods and identification of the most accurate of these Identification of variables that correlate with platelet hyperreactivity Follow-up Phase Correlation between platelet hyperreactivity and important clinical outcomes at 12, 24, and 36 months Correlation between platelet hyperreactivity and death or dependency at hospital discharge, at 3, 12, 24, and 36 months (Modified Rankin Scale) Correlation between platelet hyperreactivity and recurrent stroke of any type Correlation between different methods for evaluating platelet functions and identification of the most accurate method Analysis of hyperreactivity over time THE STUDY The study will include 200 consecutive patients seen in the emergency department of a large, urban hospital (1500 inpatient beds) and diagnosed with stroke in the acute phase; these patients will be treated with aspirin for an undetermined period The investigators will not include patients who require full anticoagulation treatment, regardless of the cause Importantly, the analysis of primary and secondary outcomes will be carried out after blinding the examiner to the results of the platelet aggregation tests PLATELET TESTS Whole Blood Aggregometer, ChronoLog VerifyNow, Accumetrics PFA-100, Siemens Plateletworks, Helena Impact-R, Diamed Serum thromboxane B2

A highly desired result during carotid endarterectomy (CEA) is the ability to predict and warn the surgeon if the brain is at risk of damage during the period of time that the carotid artery is cross-clamped for surgical repair of the vessel narrowing. A number of approaches for cerebral monitoring have been developed, including EEG, cerebral oximetry, and measurement of arterial to jugular venous concentration differences of oxygen, glucose or lactate. This study will utilize and compare multiple monitoring approaches for detecting when and if the brain is at risk of injury during CEA. As such, this robust approach to monitoring may permit a more prompt intervention to prevent or limit damage should cerebral ischemia occur. In this study we will compare a processed EEG monitor -- the EEGo, which uses nonlinear analysis to a bispectral (BIS) index monitor, and to the FORE-SIGHT cerebral oximeter to assess the ability of each to identify cerebral ischemia should it occur with carotid artery cross-clamping during CEA. These monitors will be correlated with arterial to jugular venous lactate concentration difference, which has recently been shown to be a sensitive indicator of hemispheric ischemia during CEA.