Drug-coated peripheral stents hold promise as a safe and effective therapy for the treatment of occluded leg arteries, according to two-year results of the Zilver PTX trial presented at the 23rd annual International Symposium on Endovascular Therapy (ISET) in Miami Beach, Fla.
The multicenter, prospective, randomized Zilver PTX trial included 479 patients treated at 55 institutions in the U.S., Japan and Germany with 241 patients randomized to the Zilver PTX (paclitaxel-coated stent) group and 238 to the percutaneous transluminal angioplasty (PTA) group. Demographics and lesion characteristics (e.g., lesion length 66 mm and 63 mm, respectively) were similar for the groups.
Michael D. Dake, MD, from the department of cardiovascular surgery at Stanford University School of Medicine in Stanford, Calif., and colleagues randomized symptomatic patients with superficial femoral artery (SFA) denovo lesions or non-in-stent restenosis to PTA or Zilver PTX stent (Cook Medical) placement. PTA patients experiencing acute failure (e.g., at least 30 percent residual stenosis) underwent secondary randomization to provisional stenting with Zilver bare-metal stents (BMS) or Zilver PTX. Follow-up included event-free survival and primary patency by duplex ultrasound core laboratory analysis (peak systolic velocity ratio less than two).
The one-year study results met the 12-month primary endpoint goals showing non-inferior EFS (90.4 vs. 82.6 percent) and superior primary patency (83.1 vs. 32.8 percent) for the Zilver PTX compared to PTA. The randomized comparison of provisional stenting with Zilver PTX versus Zilver BMS also showed significant paclitaxel coating benefit, with 12-month patency rates of 89.9 percent and 73 percent, respectively.
The researchers collected new two-year data, which were presented Jan. 17 at ISET, on 278 patients—with approximately 50 percent getting the Zilver PTX, 25 percent getting angioplasty alone, 12.5 percent getting angioplasty plus provisional BMS, and 12.5 percent getting angioplasty plus provisional Zilver PTX stent.
After two years, 74.8 percent of arteries remained open in patients who received the drug-coated stents. There was no imaging of the angioplasty-only group after the first year, at which point only 32.8 percent had arteries that remained open.
After two years, event-free survival was 86.6 percent for Zilver PTX patients. Events that did occur primarily involved the need to undergo another procedure to open the original blockage, worsening symptoms of PAD and one amputation. No patient deaths were related to the study device or procedure.
In the provisional stenting group at two years, 81.2 percent of arteries treated with drug-coated stents remained opened versus 62.7 percent of those treated with bare-metal stents.
“There’s evidence of a significant drug effect even at two years, with a much higher rate of the arteries remaining open than with angioplasty alone or with bare metal stents,” said principal investigator Dake. “We have not had long-term problems with late thrombosis or aneurysm, which also suggests the results are safe and durable.”