Randomized Study Comparing the Edwards Self-ExpandIng Lifestent versus Angioplasty Alone In LEsions INvolving The SFA and/or Proximal Popliteal Artery - RESILIENT

Description:

Although the superiority of stents over percutaneous transluminal angioplasty (PTA) alone for the treatment of coronary artery disease is well established, their role in the treatment of symptomatic peripheral vascular disease, especially superficial femoral artery (SFA) lesions, remains controversial. Currently, only two stents (a nitinol coil stent and a stent graft) are US Food and Drug Administration approved for the treatment of SFA lesions. The current trial sought to compare the safety and efficacy of a new flexible nitinol stent for the treatment of obstructive lesions of the SFA and proximal popliteal artery (PA) in patients with intermittent claudication.

Hypothesis:

Predilation followed by stenting with a self-expanding nitinol stent would be superior to PTA alone in patients with SFA and proximal PA disease.

Study Design

  • Randomized
  • Parallel

Patients Enrolled: 206
Mean Follow Up: 1 year
Mean Patient Age: Mean age 68 years

Patient Populations:

  • Patients Enrolled: 206
  • Mean Follow Up: 1 year
  • Age ≥18-80 years; mean age 68 years
  • Rutherford category 1-3 symptoms of intermittent claudication
  • Candidates for stenting or PTA
  • De novo stenotic, occlusive, or restenotic lesions in the SFA (beyond 1 cm of the profunda femoris artery), proximal PA (about 3 cm above the intercondylar notch of the femur), or both
  • Have at least one patent infrapopliteal runoff vessel to the foot
  • Lesion length ≤150 mm
  • Reference vessel diameter between 4 and 6.5 mm

Exclusions:

  • Critical limb ischemia (Ruterford categories 4-6)
  • Steroid/antihistamine-resistant sensitivity to contrast media
    Known allergy to study medications or materials
  • Serum creatinine >2 mg/dl
  • Hepatic insufficiency
  • Previous bypass surgery of the target limb
  • Extensive peripheral vascular disease that precludes insertion of an introducer sheath
  • Aneurysmal disease in the vessel segment to be treated
  • Thrombus in the area to be treated that could not be resolved
  • Angiographic evidence of poor inflow that was inadequate to support vascular bypass
  • On dialysis or immunosuppressive therapy

Primary Endpoints:

  • TLR at 12 months

Secondary Endpoints:

  • Primary and secondary patency at 6 and 12 months using duplex ultrasound
  • Acute lesion and hemodynamic success
  • TLR at 6 months
  • Target vessel revascularization and clinical success at 6 and 12 months
  • Quality of life assessments

Drug/Procedures Used:

Patients randomized to the stent group received a self-expanding, nitinol stent after predilation (LifeStent Self-Expanding Stent; Bard Peripheral Vascular, Tempe, AZ). Stent sizes available for the study were the 6-mm and 7-mm diameters in 40-mm, 60-mm, and 80-mm lengths. Stent selection was based on the manufacturer’s recommendation that 4- to 5.5-mm vessels should be treated with a 6-mm stent and that 5.6- to 7-mm vessels should be treated with a 7-mm stent (visual estimate). Postdilation was left to the discretion of the investigator.

Principal Findings:

A total of 206 patients (234 lesions) were randomized in a 2:1 fashion, 134 to stents, and 72 to PTA alone. About 38% of the patients had diabetes, about 77% were smokers, and 55% had evidence of concomitant coronary artery disease. The majority of patients had Rutherford class II (moderate; 38%) or class III (severe; 56%) claudication symptoms. Mean target limb ankle brachial index was 0.72. About 13% of the patients had two lesions and about 18% of the lesions were total occlusions; lesions were located in the proximal SFA (14%), middle SFA (35%), distal SFA (48%), and proximal PA (3%). The majority (two thirds) of the lesions had none or mild calcification. The mean reference vessel diameter was 5.1 mm, with a minimal lumen diameter of 1.4 mm. The mean lesion length per patient was 70.5 mm in the stent group and 64.4 mm for the angioplasty group, with a mean stented length of 99.2 mm, and a mean of 1.6 stents per patient. Of the 72 patients in the angioplasty group, 40.3% underwent a secondary bailout stenting procedure because of an inadequate PTA result, either a flow-limiting dissection or residual stenosis after multiple balloon inflations.

Acute lesion success per patient was superior for the stent arm compared with the PTA arm (95.8% vs. 83.9%; p < 0.01). There were no deaths in either arm within 30 days of the procedure. The primary endpoint of freedom from target lesion revascularization (TLR) at 12 months was significantly higher in the stent arm compared with the PTA arm (87.3% vs. 45.1, p < 0.0001). Other endpoints at 12 months such as primary patency (81.3% vs. 36.7%, p < 0.0001) and clinical success (72.3% vs. 32.3%, p < 0.0001) were also superior in the stent arm. Similarly, freedom from TLR at 6 months was also superior in the stent arm (98.5% vs. 52.6%). The incidence of major adverse cardiac events (MACE; death, myocardial infarction, stroke, significant distal embolization, emergent surgical revascularization of target limb, thrombosis, and worsening Rutherford category) at 6 months (93.1% vs. 92.8%, p = 0.95) and 12 months (85.8% vs. 86.6%, p = 0.88) was similar between the two arms. Other than an improvement in claudication pain in the stent group at 12 months, other quality of life measures were similar between the two arms. A total of 9 (3.1%) fractures were noted in the stent arm at 12 months. However, none of these patients lost primary patency or experienced a revascularization procedure.

Interpretation:

The results of the RESILIENT trial indicate that stenting with a flexible nitinol stent is superior to PTA alone in the treatment of lesions in the SFA or proximal PA, or both, in patients with symptomatic claudication. Results from stenting of SFA lesions have been mixed, with one randomized clinical trial (Schillinger et al.) showing a similar benefit with a nitinol stent, and another randomized clinical trial (FAST) with another nitinol stent showing no difference compared with PTA. The major difference between the two prior trials was that the former trial included longer SFA lesions (about 96 mm), whereas the latter included shorter lesions (about 45 mm). The current trial had a mean lesion length which was intermediate between the two trials (about 68 mm). A per-protocol analysis also suggested that the maximum benefit with stenting was for longer lesions. Thus, shorter SFA lesions can probably be treated efficaciously with PTA alone, whereas longer lesions require stenting in addition to PTA.

References:

Laird JR, Katzen BT, Scheinert D, et al. Nitinol stent implantation versus balloon angioplasty for
lesions in the superficial femoral artery and proximal popliteal artery: Twelve-month results from the RESILIENT randomized trial. Circ Cardiovasc Interv 2010;3:267-276.

Presented by Dr. Barry T. Katzen, at TCT 2007, Washington, DC.

Clinical Topics: Invasive Cardiovascular Angiography and Intervention, Vascular Medicine, Interventions and Coronary Artery Disease, Interventions and Vascular Medicine

Keywords: Intermittent Claudication, Coronary Artery Disease, Myocardial Infarction, Stroke, Ankle Brachial Index, Femoral Artery, Constriction, Pathologic, Pain, Angioplasty, Peripheral Vascular Diseases, Stents, United States Food and Drug Administration, Quality of Life, Thrombosis, Research Personnel, Pharmaceutical Preparations, Popliteal Artery, Diabetes Mellitus


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