Track topics on Twitter Track topics that are important to you
This study will test the effectiveness of low-dose recombinant tissue plasminogen activator (rtPA, or alteplase) in dissolving blood clots in deep leg veins. rtPA is given to patients with heart attacks to dissolve blood clots in blocked coronary arteries. Blood clots that develop in the deep leg veins can cause pain and swelling and may break loose and lodge in the lungs. Current Routine treatments use anticoagulants (blood thinners) such as heparin, or rtPA to dissolve the clots to stop the clots from enlarging. In an earlier study we showed that rtPA could be used to actually dissolve the clots. This study will determine whether lower doses of rtPA can effectively dissolve clots with fewer bleeding complications than the current previous higher-dose regimen.
Patients 18 years of age and older who have blood clots in a deep vein of the pelvis or leg may be eligible for this study if they have had symptoms for 14 days or less and if they have never had clots in their deep veins before.
Participants are admitted to hospital for 3 to 5 days. On the first treatment day, the patient has a venogram to show the location of the clots. The radiologist injects an x-ray contrast material into a small vein in the foot and watches the dye by x-ray as it moves up the leg, revealing the clot(s). A catheter (plastic tube) is then inserted into a vein either behind the knee, in the groin, or in the neck, and advanced until it reaches the clots. When the catheter is in place, rtPA is injected while the radiologist watches the vein under the x-ray image. The amount of rtPa needed will depends on the size of the clot. Up to five venograms may be done if the clot requires the maximum four rtPA treatments allowed in this study. During the treatments, patients receive standard doses of heparin, given continuously by vein, and Coumadin, another blood thinner, taken by mouth. Patients continue taking Coumadin for 6 months.
Blood samples are drawn shortly before the first dose of rtPa and at five time points afterward to measure the rtPa in the circulation and other factors that indicate whether the rtPa is affecting clotting ability. Blood also is drawn at least once a day to monitor heparin levels.
To evaluate the impact of treatment on the function of the leg, patients are evaluated in the Rehabilitation Medicine Department before receiving rtPA and again at the end of the hospitalization. Patients are also fitted for a compression stocking for the leg, which should be worn to reduce the chance of swelling.
Deep venous thrombosis (DVT) of the lower extremities is routinely treated with anticoagulants, which typically yield a satisfactory result, at least in the short term. However, DVT often causes permanent vein damage that leads to late complications. There is evidence that this may be prevented, and therefore long-term sequellae avoided, if the thrombi are dissolved quickly with thrombolytic agents. In a previous protocol we developed a method using intra-clot injections of alteplase (recombinant tissue plasminogen activator, rtPA) for the treatment of lower extremity DVT. Although the treatment was usually successful and complications were uncommon, we think the regimen can be made safer and perhaps even more effective by using a substantially lower dose of alteplase. The current protocol is a pilot study to test this hypothesis. Up to 25 patients with first-time DVT symptomatic for less than or equal to 14 days will be accepted from referring physicians both within and outside the NIH. They will be treated with less than or equal to 10 mg alteplase per day for up to four days. The protocol is designed so that if the low-dose regimen is unsuccessful, the patient will subsequently receive the higher-dose regimen that has previously been shown to be effective. The patients will be anticoagulated for approximately 6 months and re-evaluated after approximately 6 weeks and approximately 6 months with venography and/or duplex sonography.
Endpoint Classification: Safety/Efficacy Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Treatment
Alteplase (Activase, Genentech)
National Institutes of Health Clinical Center, 9000 Rockville Pike
Active, not recruiting
National Institutes of Health Clinical Center (CC)
Published on BioPortfolio: 2014-08-27T03:54:25-0400
The purpose of this study is to determine if the use of adjunctive Pharmacomechanical Catheter Directed Thrombolysis, which includes the intrathrombus administration of rt-PA--Activase (Al...
The purpose of this study is to determine if the use of adjunctive catheter-directed thrombolysis (CDT), which includes the intrathrombus administration of rt-PA (Activase/Alteplase), can ...
Stroke is the third leading cause of death in the United States, responsible for 158,488 deaths in 1998 (American Heart Association). Nationwide, each year, an estimated 600,000 to 750,000...
We are investigating a new way of administering alteplase to remove clots from hemodialysis catheters. Currently, alteplase is left to dwell inside the catheter between dialysis treatment...
Epidemiological studies have shown a 2-3 fold increased long-term risk of arterial cardiovascular disease after venous thrombosis, most predominant in the first year following initial veno...
Epidural venous thrombosis is a rare clinical entity with a characteristic constellation of findings in contrast-enhanced MRI, which should be considered in the differential diagnosis in the case of c...
Venous malformations (VMs) are ubiquitous, low-flow vascular anomalies known to be occasionally painful due to thrombotic episodes within the lesion. The prevalence of superficial or deep vein thrombo...
Cancer is an established risk factor for leg vein thrombosis and pulmonary embolism. Controlled studies assessing the risk of cerebral venous thrombosis (CVT) in patients with cancer have not been per...
The association between lower-extremity venous thrombosis and cancer is well-established. However, the extent to which upper-extremity deep venous thrombosis (U-DVT) is a marker of cancer and a progno...
The association between impaired kidney function and venous thrombosis has been previously reported but supportive data are still sparse. We here wish to strengthen this association by investigating, ...
Embolism or thrombosis involving blood vessels which supply intracranial structures. Emboli may originate from extracranial or intracranial sources. Thrombosis may occur in arterial or venous structures.
Formation or presence of a blood clot (THROMBUS) in the CRANIAL SINUSES, large endothelium-lined venous channels situated within the SKULL. Intracranial sinuses, also called cranial venous sinuses, include the superior sagittal, cavernous, lateral, petrous sinuses, and many others. Cranial sinus thrombosis can lead to severe HEADACHE; SEIZURE; and other neurological defects.
Impaired venous blood flow or venous return (venous stasis), usually caused by inadequate venous valves. Venous insufficiency often occurs in the legs, and is associated with EDEMA and sometimes with VENOUS STASIS ULCERS at the ankle.
A platelet-specific protein which is released when platelets aggregate. Elevated plasma levels have been reported after deep venous thrombosis, pre-eclampsia, myocardial infarction with mural thrombosis, and myeloproliferative disorders. Measurement of beta-thromboglobulin in biological fluids by radioimmunoassay is used for the diagnosis and assessment of progress of thromboembolic disorders.
The formation or presence of a blood clot (THROMBUS) within a vein.
Cardiology is a specialty of internal medicine. Cardiac electrophysiology : Study of the electrical properties and conduction diseases of the heart. Echocardiography : The use of ultrasound to study the mechanical function/physics of the h...
Pain is defined by the International Association for the Study of Pain as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage”. Some illnesses can be excruci...