Advances in Pharmacomechanical Thrombolysis

In an interview in the February issue of Vascular Disease Management, Dr. Mark Garcia discusses pharmacomechanical techniques to remove both new and old venous thrombus more rapidly and effectively than conventional techniques. This has the potential to reduce risk, cost, and length of hospitalization for patients with venous thrombosis who are presently being treated by thrombolysis. Perhaps more importantly, it has the potential to change the treatment paradigm from simple anticoagulation to more aggressive clot removal to lessen risk of postphlebitic syndrome in patients presenting with acute deep venous thrombosis. Dr. Garcia also comments on the role of pharmacomechanical thrombolysis in treating patients with symptomatic chronic deep venous thrombosis, with encouraging results for symptomatic improvement and long-term patency.

Deep venous thrombosis (DVT) is common, with estimates of up to 900,000 people affected each year in the United States alone. Estimates of death secondary to pulmonary emboli (PE) range from 60,000 to 100,000 per year. About one-third of patients with DVT or PE will have recurrence within 10 years. Up to 50% of patients who experience proximal DVT will develop postphlebitic syndrome. Between 5% and 8% of the US population have genetic defects that increase risk of thrombosis.

Despite these facts, aggressive treatment of deep venous thrombotic events is uncommon. While there has been a trend toward more aggressive therapy of acute DVT, treatment of chronic DVT is uncommon. Fear of bleeding complications with lytic therapy (particularly intracranial bleeding) and suboptimal initial results with mechanical thrombectomy devices are some of the reasons that more aggressive therapy is not routinely utilized. Mechanical thrombectomy coupled with lytic therapy can potentially lessen the bleeding risk and hospitalization time. In this interview Dr. Garcia specifically discusses two techniques to improve clot removal. 

One of the techniques (utilized in relatively acute thrombus) is the use of the AngioJet device (Boston Scientific) with local delivery of lytic therapy. The entire device is delivered via a hockey-stick guiding catheter to direct the jet toward the vessel wall, allowing more complete thrombus removal, particularly in larger veins. The other technique that he describes (utilized in chronic thrombus) is balloon angioplasty followed by ultrasound-facilitated delivery of lytic therapy to achieve more rapid thrombus dissolution in chronic thrombus that has resulted in postphlebitic syndrome. He cites data showing dramatic symptomatic improvement and excellent long-term venous patency in this group. In addition to the points noted by Dr. Garcia, early aggressive intervention has the potential to identify and treat central venous occlusive syndromes such as May-Thurner syndrome.

Optimizing the therapy of DVT is a goal that every physician should strive to achieve. This problem is common, is associated with substantial morbidity and mortality, and represents a major cost in health care. More studies and new algorithms are needed to guide appropriate therapy.