Circ: Nitinol stents trump balloon angio for endo arteries
Stent implantation with a nitinol stent produced better angiographic results compared to balloon angioplasty for patients with obstructive lesions to the superficial femoral artery and proximal popliteal artery, according to study results published online May 18 in Circulation: Cardiovascular Interventions.

“Controversy still exists regarding the best endovascular treatment strategy for patients with symptomatic disease of the superficial femoral artery,” the authors wrote.

John R. Laird, MD, of the University of California Davis Health System in Davis, Calif., and colleagues compared results of primary stenting with balloon angioplasty in 206 patients at 24 U.S. centers.

The 206 patients with obstructive lesions of the superficial femoral artery, proximal popliteal artery and intermittent claudication were randomized at a 2:1 ratio and underwent either percutaneous transluminal angioplasty (PTA) or nitinol stent implantation (LifeStent Self-Expanding Stent; Bard Peripheral Vascular).

The RESILIENT (Randomized Study Comparing the Edwards Self-Expanding Lifestent versus Angioplasty Alone in LEsions INvolving the SFA and/or Proximal Popliteal Artery) trial, which took place between December 2004 and August 2006, placed 134 patients in the nitinol stent arm and 72 in the PTA arm.

Patients placed in the PTA arm were younger, more likely to have MI and had less severe claudication.

Primary endpoints were target lesion revascularization (TLR) rates 12 months post-procedure. The researchers examined target lesions angiographically to verify a stenosis or restenosis of greater or equal to 50 percent and a lesion length of 150 mm or less.

Mean lesion lengths for both cohorts were 71 mm in the stent group and 64 mm in the angioplasty group.

Prior to procedure, patients were placed on a minimum of 81 mg of aspirin and 75 mg of clopidogrel (Plavix, Bristol-Myers Squibb/Sanofi Aventis) and were advised to continue aspirin treatment for six weeks post-procedure and clopidogrel for 12 weeks.

Researchers used stent sizes of 6 mm and 7 mm diameters and lengths of 40 mm, 60 mm and 80 mm in the stent arm of the study.

During the study, they treated 234 lesions, and 14 percent of patients had two lesions treated within the same superficial femoral artery, popliteal artery or both. Additionally, a mean of 1.6 stents were placed in each patient--50 percent received one stent, 44 percent received two stents and 6 percent received three stents during procedure.

Forty percent of the patients in the angioplasty arm underwent secondary bailout stenting due to inadequate PTA results related to either flow-limiting dissection or residual stenosis.

Lesion treatment tended to be more successful in the stent group compared to the PTA group, 95.8 versus 83.9 percent, respectively. Acute hemodynamic success rates were also better in the stent group, 73 percent versus 56.9 percent.

After a six-month follow-up, results showed that TLR rates were better in the stent group compared to the PTA group, 98.5 versus 52.6 percent, respectively. These same rates after a 12-month follow-up were 87.3 versus 45.1 percent, respectively.

Clinical success was also better in the stent group compared with the angioplasty group at six months, 81.4 versus 30.9 percent.

Freedom from major adverse cardiovascular event (MACE) six months after follow-up was 93.1 percent for the stenting arm and 92.8 percent for the angioplasty arm.

“The RESILIENT study demonstrated that for moderate length lesions (up to 15 cm) in the superficial femoral artery and proximal popliteal artery, use of the LifeStent self-expanding nitinol stent provided superior outcomes compared with balloon angioplasty,” the authors wrote.

Additionally, the authors wrote that previously there have been concerns that nitinol stents have high stent-fracture rates; however, LifeStent fracture rates were 3.1 percent after a 12-month follow up.

“Primary treatment with a flexible self-expanding nitinol stent for moderate-length lesions in the superficial femoral artery and proximal popliteal artery was associated with better acute angiographic results and improved clinical outcomes compared with balloon angioplasty,” the authors concluded. “The rate of stent fracture was low, and stent fracture was not associated with any adverse clinical sequelae.”