Results presented by Dr Martin Schillinger, Vienna, Austria, at the recent SITE meeting in Barcelona, Spain, demonstrate that primary stenting with the Absolute nitinol stent (Guidant) seems to improve primary patency rates at six months compared to balloon angioplasty with optional stenting. The ABSOLUTE Study is the first randomised controlled trial comparing percutaneous transluminal arterial angioplasty (PTA) plus selective stenting, which is the currently recommended approach for superficial femoral artery treatment vs. primary superficial femoral artery stenting with nitinol stents.
Previous randomised controlled trials comparing PTA vs. stainless steel stents in the superficial femoral artery demonstrated high rates of recurrences and no beneficial effect of stenting in the intermediate term. Therefore, superficial femoral artery stenting was restricted to bail-out procedures in patients with significant residual stenosis after plain balloon angioplasty.
Recent studies have indicated that the use of nitinol stent technology seemed to improve the durability of superficial femoral artery stents with six-month patency rates ranging around 80%. These promising results led the Angiology and Interventional Radiology Departments in Vienna University to initiate a randomised controlled trial comparing primary PTA (plus selective stenting in case of PTA failure) vs. primary stenting with nitinol stents for treatment of superficial femoral artery obstructions.
Study entry criteria included symptomatic peripheral artery disease with severe intermittent claudication (Fontaine stage IIb), or critical limb ischaemia in patients with stenosis or occlusions originating in the superficial femoral artery classified as the Trans Atlantic Society's Consensus (TASC) B, C or D lesions. The primary study endpoint was the occurrence of restenosis after endovascular treatment measured by CT-angiography or conventional Digital Subtraction Angiography at six months. Secondary endpoints were clinical and hemodynamic outcomes. Analysis will be performed according to intention to treat.
Preliminary results indicate that primary superficial femoral artery stenting with this new nitinol stent may yield superior results to PTA plus selective stenting. Primary technical success rates were 68% after PTA and 100% after primary stenting, respectively. In all 17 patients with primary PTA failure (32%), secondary stenting was successfully performed as a bail-out procedure. Six months restenosis rates were 43.5% in the plus selective stenting vs. 23.5% in the primary stenting group.
Baseline demographic data, clinical characteristics and interventional data were not significantly different between patients undergoing PTA plus selective stenting (n=53) compared to patients with primary stent implantation (n=51). Median lesion length was 8cm (IQR 4 to 12) in the PTA group and 8cm (IQR 6 to 15) in the primary stent group (p=ns).
However, Schillinger said that larger randomised controlled trials are needed to confirm a clinical benefit.
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