Report from SIR: Minimally invasive therapies break through in DVT

April 15, 2005

New thrombolysis techniques provide safer, more cost-effective alternatives for the treatment of deep vein thrombosis. By combining clot-busting drugs with nonsurgical, mechanically powered instruments, interventional radiologists gain the right tool for the right job, according to three studies presented at the Society of Interventional Radiology meeting in New Orleans.

New thrombolysis techniques provide safer, more cost-effective alternatives for the treatment of deep vein thrombosis. By combining clot-busting drugs with nonsurgical, mechanically powered instruments, interventional radiologists gain the right tool for the right job, according to three studies presented at the Society of Interventional Radiology meeting in New Orleans.

The new combination techniques make one-day, single-treatment sessions a reality, a significant treatment advance for DVT, said author Dr. Suresh Vedantham, an assistant professor of radiology and surgery at Washington University in St. Louis.

Using the Power Pulse Spray (PPS) technique, physicians inject a diluted thrombolytic at high pressure to break up blood clots. About 30 minutes later, they insert a specially designed catheter to deliver a saline infusion in powerful bursts, creating a vacuum that draws thrombi away through the catheter.

During applications of the Trellis infusion system, balloons inflate on two extremes of the device to isolate the treatment zone, preventing runaway clots and unwanted bleeding from infused lytic agents. A thin wire then whips the clot, chewing it into pieces that are removed through a catheter.

The Helix thrombectomy device works like a miniblender. A miniature impeller at the end of a catheter creates a vortex that macerates and vacuums the clot away. It can also be used in combination with thrombolytics.

In the PPS study, Dr. Jacob Cynamon and colleagues at Montefiore Medical Center in The Bronx enrolled 14 patients with acute iliofemoral DVT. All showed symptom improvement after the treatment, with complete clot removal in 71% of cases.

At Stanford University, Dr. Mahmood Razavi and colleagues assessed the technical success, bleeding complications, and cost for 66 patients with DVT treated with the Trellis system. Results were compared against catheter-directed thrombolysis (CDT) data reported in the National Venous Registry. Razavi found the Trellis system technically feasible, safer, and significantly more cost-effective compared with CDT.

Vedantham and colleagues at the Mallinckrodt Institute of Radiology compared a group of 11 patients who underwent conventional CDT (A) and a group of 25 patients who underwent Helix thrombectomy (B). They achieved overall complete or partial thrombolysis in 88% of limbs treated. The found, however, a significant variation of successful outcomes between groups: 71% for group A versus 94% for group B. Infusion times and doses were also significantly shorter in group B (p = 0.003 and p = 0.01, respectively). Fewer bleedings were observed in group B, but results were not statistically significant.

The techniques can potentially become the standard outpatient approach and could change the way DVT patients are treated, Vedantham said.

For more information from the Diagnostic Imaging archives:

Revolution storms along in thrombolytic agents

Coming soon: Planet of the PAs (a horror film)

CT dose techniques address PE, DVT

MRI gains favor for early, accurate DVT diagnosis