Xpert-BTK study hails dedicated stent for below-the-knee


According to the 24-month results from the Xpert-BTK Study, the Xpert nitinol self-expanding below-the-knee (BTK) stent (Abbott Vascular) is an efficient tool for the treatment of BTK lesions. However, angioplasty (PTA) for treatment of BTK-lesions should be the first approach, and only in case of failure or suboptimal outcomes followed by bail-out stenting with dedicated BTK stents (e.g. balloon-expandable or self-expanding), explained Dr Marc Bosiers, Belgium, in his presentation at CIRSE 2008.

The study was a prospective, multi-centre, non-randomised clinical trial which aimed to assess the safety and performance of the 4F Self Expanding Xpert for the treatment of infrapopliteal lesions in patients with chronic critical limb ischaemia (CLI). Patients with stenotic (>50%) or occlusive BTK arteries were recruited, with a lesion length of <10cm. A maximum of two lesions in one or more BTK vessels was an essential part of the inclusion criteria, along with patients presenting with symptomatic critical limb ischaemia (Rutherford 4–6), and patients with one stenosed and patent artery were also included on the pre-condition that the stenosed artery supplies the wounded area.

Patients excluded were those with lesion lengths that required more than two stent implants, more than two infrapopliteal lesions in the same limb, previously implanted stent(s) or angioplasty (PTA) at the same lesion site, and inflow-limiting arterial lesions that were left untreated.

The study showed that at two years, primary patency was achieved in 54.4% and limb salve in 90.8% of patients (n=94: 46.8% were diabetic). Two-year survival was 71.9%. Stratifying the outcomes for lesion location (proximal vs. distal),  there was no significant difference in primary patency (56.8% vs. 52.3%, respectively). However, limb salvage was significantly better for patients treated with proximal compared to distal BTK-lesions (95.1% vs. 81.1%, respectively).

The study initially ran for 12 months, then was extended for another 12 months. In the 12-month initial report (May 2005 – December 2005), 51 CLI patients were enrolled and the primary endpoint was one-year angiographic patency, as well as absence of >50% stenosis on QVA (Quantative Vessel Analysis). The 24-month extension (May 2005 – Nov 2007) study involved 94 CLI patients, and the primary endpoint was two-year duplex patency and absence of >50% stenosis. Secondary endpoint was two-year limb salvage rate.

In his concluding remarks, Bosiers said, “The Xpert stent is an efficient tool for the treatment of below-the-knee lesions. Limb salvage rates are better for proximal compared to distal lesions.”