Deep Vein Thrombosis
Scope of the Problem
Deep vein thrombosis (DVT) is a condition characterized by blood coagulation and thrombus formation in the deep veins of the leg. Without proper treatment to remove the thrombus, either with mechanical, lytic, or oral anti-coagulant therapy, thrombus can break off, or embolize, and travel to the lungs, leading to pulmonary embolism (PE) and the potential for sudden death. It is estimated that 300,000 to 600,000 people in the U.S. are affected by DVT each year, with more than 100,000 related deaths, 25% of which are sudden deaths [1]. The SARS-CoV-2 pandemic has exacerbated the occurrence rates of DVT, as well. Based on systemic duplex ultrasound studies, it has been found that between 25 and 84% of patients that are hospitalized due to a COVID-19 infection present with DVT [2].
The Open Vein Hypothesis
In the treatment of DVT, the open-vein hypothesis proposes that early and active removal of thrombus will improve deep venous flow, reduce venous reflux, and decrease the risk of post-thrombotic syndrome (PTS). However, the largest acute DVT trials to date have demonstrated the controversial result that binary progression to PTS is not inhibited by catheter-directed thrombolysis or thrombectomy (CDT).
The Inflammatory Hypothesis
Post-thrombotic syndrome is a chronic complication arising in 30-50% of patients after treatment of deep vein thrombosis within 6 months of therapy, regardless of whether patients have been treated with CDT or anticoagulation medicines alone. PTS arises from a complex interplay of multiple factors that ultimately result from venous blockage and valve dysfunction causing venous reflux. Inflammation is at the heart of these conditions, as it leads both to the original thrombotic event and then to fibrosis, thickening and hardening of the vein wall, which can entrap or harden the venous valves. Removing the thrombus does not relieve the inflammation, which is the potential reason that mechanically opening the vein only leads to immediate relief of symptoms but not long-term prevention of PTS.
Research
Preclinical research conducted by Mercator MedSystems has shown that the early signals of inflammation arising from DVT formation can be dramatically reduced with the localized, perivenous delivery of an anti-inflammatory corticosteroid, dexamethasone. The company has thus kicked off clinical trials to study the usefulness of the therapy in preventing the complications arising from DVT. Click here for more information on the DEXTERITY clinical trials.
