Treatment of acute vascular occlusions with intra-arterial urokinase

Article Abstract:

Treatment of vascular or graft occlusion (blockage) is aimed at both removal of the clot and correction of the underlying cause of the occlusion. This must be accomplished rapidly to avoid irreversible tissue damage. Treatment with thrombolytic (clot-dissolving) drugs, such as urokinase, not only dissolves the clot but improves the blood flow in the smaller vessels. There are complications with this method of treatment, including bleeding and dye-induced injury from multiple angiographic studies. Additionally, thrombolysis is an expensive procedure, both in terms of materials and staff time. A study of 57 patients was undertaken to determine the usefulness of urokinase in treating vascular occlusion; 71 occlusions were treated from 1985 to 1988. The average patient age was 60.5 years; 39 percent had diabetes and 51 percent had hypertension; 46 percent were current smokers. Urgent surgery had been planned for 49 patients (89 percent). Use of urokinase positively identified the cause of vascular occlusion in 52 percent of cases, and a possible cause was identified in another 23 percent. Total clot dissolution was achieved in 73 percent of cases (this success rate improved with experience, reaching 81 percent for cases treated from 1987 to 1988). After urokinase surgery, one-third of the surgical candidates eventually had an operation of lesser magnitude than originally planned. In 47 cases (66 percent), some additional therapy (surgery or angioplasty) was required. Of the 18 cases not needing additional treatment, nine re-occluded in an average of 25 days. A patent blood vessel is one that is not blocked and is functioning. The one-year patency rates for patients treated with urokinase and other treatment after initial thrombolytic success were 17 percent for vein grafts, 20 percent for artificial grafts, and 55 percent for arterial grafts. Despite these low patency rates, this procedure is still used for patients when there are limited treatment options. (Consumer Summary produced by Reliance Medical Information, Inc.)

Arterial occlusions, Arterial occlusive diseases, Urokinase

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Ultrasound-guided balloon angioplasty is a new technique for vascular surgeons

Article Abstract:

There are many new intravascular procedures that require exact placement of a device within the blood vessel. One such procedure is balloon angioplasty, a procedure in which a balloon-tipped catheter is threaded through an closed vessel to the point of obstruction by atherosclerotic plaque; the balloon tip is inflated and deflated several times to split the atheroma and flatten the plaque against the artery wall. Accurate placement of the tip requires exposing both patient and medical personal to X-rays and ionizing radiation; the patient is also exposed to the risk of injection of contrast dye. A new technique/device has been developed which uses duplex ultrasound to guide balloon angioplasty. Duplex ultrasound combines real-time ultrasound and pulse-gated Doppler study to provide excellent visualization of the blood flow within the peripheral vascular system. A report is presented of the initial use of this technique in dogs, and its accuracy is compared with that of angiography (X-ray examination of the blood vessels following injection of radio-opaque contrast dye). This new technique was tested in 10 dogs and was successful in all cases. The ultrasound findings accurately indicated catheter placement and predicted outcome; the accuracy of these findings was confirmed by arteriogram. The authors conclude that the new balloon angioplasty catheter can be positioned and manipulated accurately using only duplex ultrasound guidance. The new catheter device is currently being tested in clinical trials. This system eliminates the risks of X-rays and permits real-time monitoring during the procedure. (Consumer Summary produced by Reliance Medical Information, Inc.)

Innovations, Equipment and supplies, Blood vessels, Transluminal angioplasty, Balloon angioplasty, Duplex ultrasonography

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Pathogenesis, diagnosis and treatment of thrombosis

Article Abstract:

Common causes of death and illness are thrombosis and embolism. Thrombosis is an abnormal condition in which clotting elements and cell debris accumulate and attach to the interior wall of the vein. A major complication of thrombosis is thromboembolism, blockage of a blood vessel by a clot. Thrombosis and embolism may occur as a primary disease or as a secondary complication of another condition. Recently, a better understanding has been gained of the causes of thromboembolism, along with the role of platelets (clotting factors), endothelium (inner lining of the blood vessels), and the plasma proteins that regulate blood coagulation. Angiography remains the definitive technique for diagnosing thrombosis; however, duplex scanning has been shown to have a high degree of accuracy and may be the preferred diagnostic technique in the future. For the past 30 years, the major treatment for thrombosis has been administration heparin, which neutralizes thrombin (a clotting factor). Oral anticoagulants, such as coumarin, are also used. Newer thrombolytic agents, including streptokinase, urokinase, and tissue plasminogen activator, are being investigated. The use of these drugs is limited by the risk of systemic bleeding, and their role in treating thrombosis is still evolving. These thrombolytic agents can clear the small vessels of clots, reducing tissue injury due to ischemia (decreased blood supply to the tissue). Development of new drugs and techniques of delivery, as well as surgical removal of clots and anticoagulation, are expected to enhance the treatment of patients with thrombosis. (Consumer Summary produced by Reliance Medical Information, Inc.)

Diagnosis, Development and progression

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