Zilver PTX: Novel DES for Femoropopliteal Disease Encouraging at 2 Years

At 24 months, patients with symptomatic femoropopliteal artery disease continue to benefit from receiving a dedicated paclitaxel-eluting stent vs. balloon angioplasty with provisional stenting, whether with the same DES or its bare-metal equivalent. Updated findings from the Zilver trial were presented on January 17, 2011, at the 23rd Annual International Symposium on Endovascular Therapy meeting in Miami Beach, FL.

Twelve-month results from the study were previously released in September 2010 at the annual Transcatheter Cardiovascular Therapeutics symposium in Washington, DC.

For the multinational trial, researchers led by Michael D. Dake, MD, of the Stanford University School of Medicine (Stanford, CA), randomized 478 patients with symptomatic, above-the-knee femoropopliteal disease and Rutherford class ≥ 2 to treatment with the Zilver PTX stent (n = 241; Cook Medical, Bloomington, IN) or balloon angioplasty (n = 238). Among patients assigned to angioplasty, results were suboptimal in 120, and these patients underwent a second randomization to provisional stenting with a Zilver PTX (n = 61) or a bare-metal Zilver stent (n = 59). The two devices have identical platforms.

Zilver PTX is a self-expanding nitinol stent specifically designed for the superficial femoral artery. It has a polymer-free paclitaxel coating (dose 3 µg/mm2) on the abluminal side of the stent struts.

At 12 months, the primary safety endpoint of survival free of amputation, TLR, or worsening Rutherford score (by 2 classes or to class 5 or 6) was met by 90.4% of patients who received the Zilver PTX stent vs. 82.6% who underwent angioplasty (P < 0.01). In addition, the primary efficacy endpoint of patency on duplex ultrasonography or angiography, when available, was reached by a greater proportion of patients receiving the Zilver PTX than those who underwent angioplasty or provisional implantation of a BMS.

Patency, Safety Maintained

In the 278 patients with 24-month follow-up data, patency rates once again were higher among those treated with the Zilver PTX stent, whether they received the stent following the first or second round of randomization (table 1). Imaging results were not available for patients who received angioplasty alone, however.

Table 1. Patency Outcomes at 12 and 24 Months

 

First Randomization

Second Randomization

Zilver PTX

Angioplasty

P Value

Zilver PTX

BMS

P Value

At 12 Months
(n = 479)

83.1%

32.8%

< 0.01

89.9%

73.0%

0.01

At 24 Months
(n = 278)

74.8%

81.2%

62.7%

< 0.01


Event-free survival among those randomized to the Zilver PTX stent in the first round was 86.6% at 24 months. Most of the events that did occur were repeat revascularizations or worsening symptoms. There was also one amputation. None of the deaths that occurred were related to the study device or procedure.

“The 24-month results presented [at ISET 2011] indicate levels of integrity, safety, and durability that supersede many of the well-known limitations seen in current non-invasive treatments for the management of PAD,” reported Dr. Dake in a press release issued by Cook Medical.

Study Warrants Cautious Optimism

Hitinder S. Gurm, MD, of the University of Michigan (Ann Arbor, MI), told TCTMD in a telephone interview that the event-free survival rate of 86.6% is especially promising. “As someone who always struggles with the high event rates that we see in these patients, it would be nice to have a therapy that works better,” he said. “But I wish we had complete follow-up. That would have made the results more robust. . . . While I’m cautiously optimistic, I would like to see the entire study published.”

In a subsequent e-mail communication, Dr. Gurm indicated he would like to see a randomized trial comparing Zilver PTX and the bare-metal Lifestent (Bard Peripheral Vascular, Tempe, AZ). “Primary patency with the Lifestent was very high [~80%] in the Resilient trial, and it is hard to know if this was due to differences in study population or differences in stent design,” he said.

 


Source:
Dake MD, Ansel GM. Zilver PTX randomized trial of paclitaxel-eluting stents for femoropopliteal artery disease: Twenty-four month update. Presented at: International Symposium on Endovascular Therapy; January 17, 2011; Miami Beach, FL.

 

 

Related Story:

Zilver PTX: Novel DES for Femoropopliteal Disease Encouraging at 2 Years

At 24 months, patients with symptomatic femoropopliteal artery disease continue to benefit from receiving a dedicated paclitaxel eluting stent vs. balloon angioplasty with provisional stenting, whether with the same DES or its bare metal equivalent. Updated findings from the Zilver
Disclosures
  • The trial was sponsored by Cook Medical.
  • Dr. Gurm reports no relevant conflicts of interest.

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