Active clinical trials for "Thrombosis"

More than 2 million patients in North America are treated with warfarin - a "blood thinner" - to prevent blood clots in arteries or veins. The treatment has to be monitored with a blood test and the dose changed accordingly every 1-4 weeks. One third of the patients have very stable results and hardly ever have to change the dose. The investigators wish to show that the level of control of the treatment with warfarin in these very stable patients is not worse with 12-weekly testing. A pilot study the investigators performed indicated that 12-weekly testing would be safe but this has to be confirmed in a large study. One third of patients taking warfarin have not had any changes in the dose for the past 6 months or longer. These patients will be asked about participation in the study. They will be randomized to testing and dosing every 4 or 12 weeks. Each patient is in the study until it ends, which will be minimum 1 year and can be up to about 4 years. The study is designed to show that 12-weekly testing does not significantly increase the risk for major bleeding or blood clots. The results would be important for a large number of patients. An increase of the interval between blood tests from 4 to 12 weeks would reduce the burden for these patients on life-long treatment considerably.

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

The objective of this clinical study was to demonstrate the performance of the Vasculaire Compression System to increase femoral venous peak velocity (PFV) in healthy subjects. This study was a single-arm, open label, prospective, single-center clinical study.

This study is to assess if DU176b is effective in prevention of blood clots following hip replacement surgery. The duration is 7-10 days of treatment and 30 and 60 day follow-up visits.

Morbidly obese individuals are at high risk for potentially life threatening blood clots around the time of abdominal surgical procedures. Fondaparinux sodium (Arixtra) is an FDA- approved medication used in the prevention of deep venous thrombosis (DVT) at the time of orthopedic or abdominal surgery, as well as for the treatment of DVT and pulmonary embolism (PE). As with many medications, therapeutic dosages have not been fully investigated for the morbidly obese population. Our goal is to study the therapeutic blood levels, after 2 different dosages of the medication are given to morbidly obese volunteers. We will recruit 21 morbidly obese (Body Mass Index (BMI) > 35) individuals who are in the evaluation process for bariatric surgery. They will be divided into 7 groups: 3 participants with BMI 35 - 39.9, 3 with a BMI of 40 - 49.9, 3 with a BMI of 50 - 59.9, 3 with a BMI > 60, 3 with a weight of 100 - 149 KG, 3 with a weight of 150 - 199 KG and 3 with a weight of 200 - 249 KG. Participants will be administered two different doses of the medication with a 2-week interval in between, then blood will be drawn in various intervals throughout the next 48 hours to see which dose provides the best therapeutic levels. Participants will be monitored closely for any side effects or complications.

The purpose of this study is to learn whether apixaban can prevent the blood clots in the leg (deep vein thrombosis) and lung (pulmonary embolism) that sometimes occur after hip replacement surgery and to learn how apixaban compares with enoxaparin in preventing these clots. The safety of apixaban will also be studied

It has been demonstrated that implantation of inferior vena cava filter was safe and effective in the prevention or reduction of fatal pulmonary thromboembolism in numerous clinical researches. When acute deep venous thrombosis need transcatheter thrombolysis, transfemoral Günther Tulip Filter implantation could avoid catheter across the Günther Tulip Filter. Although incidence of significant filter tilting (>10°) is not high (13%-16%), severe tilting of the Günther Tulip Filter may be associated with difficulty or sometimes impossibility of retrieval. It has been reported that a simple technique of keeping tension of the delivery system may prevent significant tilting of the transjugular Günther Tulip Filter in an in-vitro study. But no clinical study of prevention transfemoral Günther Tulip Filter from tilting has been reported. The investigators conducted a randomized, controlled study to test whether the introducer curving technique is useful to decrease the extent of tilting of transfemoral Günther Tulip Filter.

The primary objective of this study is to establish a cut off level of platelet inhibition that separates patients with or without previous stent occlusion with acute clinical onset while on aspirin and clopidogrel treatment within 6 months after coronary stenting for coronary artery disease.

Currently, patients with suspected deep vein thrombosis (DVT) of the lower extremities receive the ultrasound investigation of their deep vein system, either by limited ultrasonography (ultrasonography confined to the proximal veins, repeating the test after one week in patients with positive D-dimer) or by extended ultrasonography (ultrasonography extented to the entire deep vein system of the legs). No study has directly compared the two strategies to assess their accuracy and safety. We plan to compare the accuracy and safety of the two strategies in a prospective randomized study addressing more than 2000 consecutive outpatients presenting with the clinical suspicion of DVT.

The VITRO (Vitamins and Thrombosis) study investigated the effect of homocysteine lowering by daily supplementation of B-vitamins on the risk reduction of deep-vein thrombosis and pulmonary embolism. Patients between 20 to 80 years old with a first objectively confirmed proximal deep-vein thrombosis or pulmonary embolism in the absence of major risk factors and a homocysteine concentration above the 75th percentile of a reference group were asked to participate (hyperhomocysteinemic group). A similar study was conducted in a random sample of patients with a homocysteine below the 75th percentile of the reference group (normohomocysteinemic group). After informed consent patients were randomized to daily multivitamin supplementation (5 mg folic acid, 50 mg pyridoxine and 0.4 mg cyanocobalamin) or placebo and were followed for 2.5 years. End-points were objectively diagnosed recurrent deep-vein thrombosis or pulmonary embolism.