Thrombogenesis, which involves the localized accumulation of blood elements on an injured vessel wall, can cause heart attacks and strokes. Although a thrombus is initially composed of platelets and fibrin that serve to limit bleeding, excessive thrombus growth can lead to thrombosis that obstructs blood vessels and hence can produce ischemia in vascular beds.
Current options for venous thrombectomy are limited. Of the two devices widely used currently, one has been recently withdrawn and the other (Angiojet™) is known to produce side effects such as hemoglobinuria, renal failure and pancreatitis in patients. Furthermore, the small catheter size is limiting its usefulness in extensive thrombosis; fluid overload is a concern as saline has to be injected to pulverize the clot drawn into the catheter.
In patients at risk of thrombosis, conventional drug treatments (such as aspirin, heparin, and warfarin, for example) are used to slow thrombus growth. However, such treatments have the risk of bleeding complications that can be serious and sometimes fatal. For patients that develop a thrombus, there are approaches known in the art for retrieval of the thrombus (such as catheters and balloons) as well as chemical approaches to dissolve the thrombus (such as tissue plasminogen activators or plasmin). The chemicals, however, are not localized to the thrombus and can circulate through the patient's blood and cause bleeding. Hence, there is a need for localization of thrombus dissolution either chemically or physically and its removal without affecting the rest of the cardiovascular system.