EVISTA-DVT Shows Superior Results for Stents Compared to Balloons

May 6, 2011—The Society for Cardiovascular Angiography and Interventions (SCAI) announced that Mohsen Sharifi, MD, presented results from the EVISTA-DVT (Endovenous Infra-Inguinal Stenting and Angioplasty in Deep Vein Thrombosis) trial at the SCAI 2011 scientific sessions in Baltimore, Maryland. EVISTA-DVT compared the safety and effectiveness of stenting versus balloon angioplasty for treatment of venous stenosis in patients with deep vein thrombosis (DVT).

SCAI stated that the EVISTA-DVT investigators focused on patients with blocked veins who had been treated with thrombolysis and found stenting was more effective than balloons alone at restoring and maintaining blood flow through the thigh veins. The trial included 141 patients who had initial clot-dissolving drug therapy, but continued to have blockage of their vein. Patients were randomly assigned to further treatment with stenting (71 patients) or balloon venoplasty alone (70 patients) to open up the blocked vein. Every 6 months researchers checked blood flow through the leg veins using ultrasound. During a follow-up that averaged 35 months, three patients (4%) in the stent group and seven patients (10%) in the balloon venoplasty group redeveloped DVT. The patency of the treated vein was higher in the stent group versus the control group.

According to the investigators, percutaneous endovenous intervention has been shown to be an effective tool in the treatment of acute proximal DVT and the sequelas associated with it. Endovenous stenting is part of therapeutic armamentarium, but data are lacking on the outcome of stents placed in the femoropopliteal veins. The study, therefore, was conducted to assess the efficacy and safety of stenting in the femoropopliteal veins in the setting of DVT and compare it with balloon venoplasty in a randomized fashion.

As detailed by Dr. Mohsin, patients with high-grade residual stenosis > 70% after percutaneous endovenous intervention were randomized to receive stenting (stent group = 71 patients) or balloon venoplasty alone (control group = 70 patients). The mean follow-up was 35 months. All patients underwent venous duplex scanning every 6 months or sooner if symptomatic. Those with suspicion of redevelopment of DVT underwent repeat venography with intravascular ultrasound evaluation.

There were six patients of the stent group and 15 patients of the control group who underwent venography and intravascular ultrasound for presumed DVT. DVT was found in three (4%) and seven (10%) patients, respectively. DVT was asymptomatic in most patients in the stenting group and mildly symptomatic in the control group. The mechanism of stent thrombosis was thrombus extension and external compression due to venosclerosis. There was no neointimal proliferation as the cause of stent stenosis. There were no stent fractures, extrusion, or perforation.

The EVISTA-DVT investigators found that the natural history of stenting in the venous circulation is fundamentally different than that seen in the arterial system. They noted that stent thrombosis occurs in 4% of cases and is not due to neointimal proliferation, it does not occur independently, and is usually an extension of DVT in the adjacent venous segments with high-grade stenosis. External compression is an important factor in preventing full stent expansion, which is seen in extensive venosclerosis. Stenting is superior to balloon venoplasty alone, the investigators concluded.