Drug-Eluting Stent Below The Knee - DES-BTK

Description:

Conventionally, infrapopliteal disease is treated with angioplasty alone, and sometimes with bare-metal stents (BMS). The DES-BTK trial sought to compare outcomes after sirolimus-eluting stenting (SES) versus BMS in patients with either intermittent claudication or critical limb ischemia (CLI) who had a de novo lesion up to 5 cm in length in an infrapopliteal artery.

Hypothesis:

SES would be superior to BMS in patients with either intermittent claudication or CLI, who had a de novo lesion up to 5 cm in length in an infrapopliteal artery.

Study Design

  • Blinded
  • Parallel
  • Randomized

Patient Populations:

  • Single de novo lesion in infrapopliteal arterial circulation
  • Lesion length <5 cm

    Number of enrollees: 161
    Duration of follow-up: 1 year
    Mean patient age: 73 years
    Percentage female: 33%

Primary Endpoints:

  • Primary patency at 1 year, defined as freedom from in-stent restenosis (≥50%) detected with angiography or if appropriate with duplex US

Secondary Endpoints:

  • 6-month primary patency rate
  • Secondary patency rates
  • TLR rates
  • Changes in Rutherford-Becker classification
  • ABI
  • Composite endpoint of TLR, major and minor amputation, MI, and death

Drug/Procedures Used:

Patients were randomized in a 1:1 fashion to either a polymer-free SES (Yukon stent) or a placebo-coated BMS.

Concomitant Medications:

  • Aspirin 100 mg daily for life
  • Clopidogrel 600 mg 24 hours prior to the procedure, and then 75 mg daily for 6 months

Principal Findings:

A total of 161 patients were randomized, 82 to SES and 79 to BMS. Baseline characteristics were fairly similar between the 2 arms. About 28% had diabetes mellitus, and 35% had co-existing renal insufficiency. Target lesion was anterior tibial artery in 25%, tibioperoneal trunk in 40%, and posterior tibial in 16% of the patients.

At baseline, Rutherford-Becker class 3 symptoms were noted in 42%, class 4 in 6%, and class 5 in 41% of the patients, with a median class of 3 in this patient population. CLI was noted in 48% of the patients, with baseline ABIs of 0.47 and 0.49 in the SES and BMS arms, respectively. The mean reference vessel diameter was 3 mm, with a mean lesion length of 30 mm, and a mean preintervention diameter stenosis of 88%. About 30% of the patients received more than one stent. Procedural success was noted in all patients.

The primary endpoint of primary patency at 1 year was significantly higher in the SES arm, as compared with the BMS arm (80.6% vs. 55.6%, p = 0.003). Secondary patency (91.9% vs. 71.4%, p = 0.005) was also higher, while ABI at the end of 1 year was numerically higher, but statistically nonsignificant in the SES arm (0.75 vs. 0.47, p = 0.1). Event-free survival for the composite endpoint of target lesion revascularization (TLR), major and minor amputation, myocardial infarction (MI), and death was similar over the duration of follow-up (p = 0.2).

At 6 months, there was no difference in the number of patients who experienced a ≥1 class improvement in Becker-Rutherford classification symptoms (76.5% vs. 65.7%, p > 0.05), although this was significantly higher in the SES arm at 1 year (83.9% vs. 61.9%, p < 0.05).

Interpretation:

The results of the DES-BTK trial indicate that implantation of a polymer-free SES (Yukon stent) for infrapopliteal peripheral vascular disease results in significant improvements in primary and secondary patency, as compared with BMS, with a greater number of patients noting at least one grade improvement in claudication symptoms, as assessed by the Rutherford-Becker classification. Event-free survival was, however, similar between the SES and BMS arms. Similar results had been noted earlier in the PaRADISE trial comparing DES-treated patients to historical controls.

If confirmed by other trials, a change in practice patterns in the treatment of infrapopliteal lesions, especially if focal and short, may be necessary, since they are currently mostly treated with angioplasty alone. Moreover, since these are essentially modified coronary stents, the optimal duration of dual antiplatelet therapy will need to be defined.

References:

Presented by Dr. Thomas Zeller at the Transcatheter Cardiovascular Therapeutics Meeting (TCT 2010), Washington, DC, September 24, 2010.

Clinical Topics: Invasive Cardiovascular Angiography and Intervention, Vascular Medicine, Atherosclerotic Disease (CAD/PAD), Interventions and Vascular Medicine

Keywords: Intermittent Claudication, Myocardial Infarction, Follow-Up Studies, Sirolimus, Constriction, Pathologic, Angioplasty, Peripheral Vascular Diseases, Stents, Renal Insufficiency, Metals, Tibial Arteries, Diabetes Mellitus


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