SIR: 'Rapid Lysis' Dissolves Severe DVT

SEATTLE, March 5 -- Combining thrombolytic medication with a clot removal device dissolves extensive deep vein thrombosis in a single session, according to a retrospective study.

The "rapid lysis" also improved quality of life and may shorten hospital stays compared with traditional therapy, said Mark J. Garcia, M.D., of the Christiana Health Care System in Wilmington, Del., and colleagues, of the Society of Interventional Radiology meeting here.

The study included 102 patients (62% male, mean age 47) treated for 118 cases of large-volume, symptomatic DVT that commonly ran the length of the leg and often even into the vena cava.

For treatment, the AngioJet Rheolytic device was guided with a catheter to the clot where it sprayed diluted tissue plasminogen activator (25 mg/1,000 mL or 10 mg/500 mL depending on the type of catheter or 10 U/1000 mL). Then the device sucked the clot into the catheter as it passed through during retraction.

The AngioJet device was approved by the FDA last November for clot removal from upper- and lower-extremity peripheral veins.

Standard blood thinners for DVT, which help prevent further growth of the clot, rarely lead to clot dissolution. Thrombolysis alone, which is highly effective in dissolving clots, may take two to four days to do so during which the patient is at increased risk of bleeding.

With the device-drug combination, the results were:

• 51% had complete clot removal (more than 90% increase in flow).
• 31% had substantial clot removal (50 to 90% flow increase).
• 11% had partial clot dissolution (less than 50% flow increase).
• 4.2% had minimal clot removal.

Among these, 43% of patients had treatment completed at the first session without further infusion of thrombolytic medication.

At one month, 47% had open veins without DVT. This had further increased to 78% by six months and to 83% at one year.

Among the quality-of-life symptoms related to the DVT sequela post-thrombotic syndrome, the findings were:

• 68% never experienced pain after the procedure.
• 67% never experienced swelling after the procedure.
• 78% never experienced heat or burning after the procedure.

Adverse events occurred in 12 patients including three patients with acute renal failure (two related to the procedure), five needed transfusion, two needed treatment for bradycardia needing treatment, and three cases of hemorrhage related to anticoagulation.

Dr. Garcia said that single session treatment can lead to decreased use of the intensive care unit, or none at all, reduce the risk of bleeding complications from tPA therapy, and shorten hospital stays overall.

The device used in the trial is just one of several moving toward faster DVT treatment, said Robert L. Vogelzang, M.D., of Northwestern Memorial Hospital in Chicago, who moderated a press conference during which the findings were discussed.

"Our goal has always been to develop a treatment that can remove the clot in a single step," he said. "We are getting to that."

He said the study reflects a larger shift to less invasive treatments.

"This is all about moving treatments from the old surgical methods to the new minimally invasive, image-guided methods," Dr. Vogelzang concluded.