Combined approach boosts deep vein thrombosis cure

Anecdotal evidence suggests that combining catheter-directed thrombolysis with a mechanical thrombectomy device might be more successful than either procedure alone in treating deep vein thrombosis. The results of the first study to compare the procedures support the combined technique as the most cost-effective approach.

Researchers from Johns Hopkins University found that percutaneous catheter-directed thrombolysis with rheolytic percutaneous mechanical thrombectomy was as effective as thrombolysis alone. But the combined approach was significantly faster, required lower lytic agent doses, and resulted in lower costs. The mean cost for catheter-directed thrombolysis alone was $10,127 compared with $5128 for combined thrombolysis/thrombectomy (J Vasc Interv Radiol 2006;17:1099-1104).

The retrospective study, led by Dr. Hyun S. Kim, a radiologist at JHU, involved 26 limbs in 23 consecutive patients treated with catheter-directed thrombolysis with urokinase. The team also reviewed 19 limbs in 14 patients who underwent catheter-directed thrombolysis plus percutaneous mechanical thrombectomy with the AngioJet system (Possis Medical, Minneapolis).

Disappointing results from percutaneous mechanical thrombectomy have prevented many interventional radiologists from using it as a stand-alone therapy for DVT. But the device has been useful in practice as an adjunct to catheter-directed thrombolysis because of its ability to speed up lysis. Whether that use makes a difference clinically and economically has been a lingering question, according to Dr. Mahmood Razavi, director of the Center for Clinical Trials at the St. Joseph Vascular Institute in Orange, CA.

"This study suggests that there may be an economic advantage," Razavi said.

But the study's limitations demand careful interpretation of its conclusions, he said. The absence of a predefined end-point for therapy precludes accurate comparisons. The retrospective nature of the study introduces a number of biases, including the exclusive use of urokinase and one mechanical thrombectomy device.

The mean duration of catheter-directed thrombolysis, at 56 hours in the study, is too long and is no longer the protocol in most labs. Today catheter-directed thrombolysis takes considerably less time. A meaningful change in practice patterns will require more rigorous study design and outcomes data, Razavi said.

Such studies are already under way. Dr. Suresh Vedantham, an assistant professor of radiology and surgery at Washington University's Mallinckrodt Institute of Radiology in St. Louis, is leading a multidisciplinary group in the development of a prospective randomized study of pharmacomechanical DVT therapy. Vedantham recently submitted a grant application to the National Institutes of Health for the Acute Venous Thrombosis: Thrombus Removal with Adjunctive Catheter-Directed Thrombolysis (ATTRACT) trial. A response is expected by year's end, he said.