Restenosis Following Cryoplasty of the Superficial Femoral and Popliteal arteries and Saphenous Vein Grafts: a 36 Month Kaplan Meier Analysis of a Single Center Experience

Background: Long-term patency remains a significant hurdle in the minimally invasive treatment of arteriosclerosis in the superficial femoral (SFA) and popliteal arteries. CryoPlasty^® therapy (Boston Scientific Corp., Natick, MA) is a novel approach designed to significantly reduce injury, elastic recoil, neointimal hyperplasia, and constrictive remodeling. The technique combines the dilatation forces of percutaneous transluminal angioplasty with cold thermal energy applied to the plaque and vessel wall. We have previously reported a technical success rate of 96% and freedom from restenosis at one year of 82.2%. We report here the 43 month follow up of the original cohort of 47 lesions as well as 45 further lesions treated by cryoplasty.
Methods: From December 2003 through July 2007, 64 consecutive patients (71 procedures, 67 limbs, 92 lesions) were treated using CryoPlasty therapy by three surgeons. The method has been previously described and reported.
Results: The immediate technical success rate was 88% (81 of 92 lesions). Nine stents were required following unsuccessful cryoplasty (9.8%). Technical failures were related to dissection in 2, dissection with calcification in 3, failure to dilate due to arterial calcification in 3, and failure to dilate unrelated to calcification in 3 lesions. There were no unanticipated adverse events, specifically no: thrombus; acute occlusions; distal embolizations; aneurysms; or groin complications. Thirty six lesions have recurred. Freedom from restenosis was 64%, 53%, and 44% at 12, 24 and 36 months respectively. Target lesion revascularization following successful revascularization was 15%, 26% and 35% at 12, 24 and 36 months respectively. Cryoplasty of heavily calcified lesions, vein graft lesions and stenotic stents faired poorly. If these lesions are excluded from analysis immediate success would have been 94% (81/86) and freedom from stenosis would be 70%, 58% and 48% at 12, 24 and 36 months respectively.
Conclusions: Analysis of this longer-term data would suggest that our earlier smaller study provided an overly optimistic appraisal of the benefits of cryoplasty. If used indiscriminately, cryoplasty will probably offer no added benefit over standard balloon angioplasty. However if calcified lesions, stenotic vein grafts and restenotic stents are not treated cryoplasty may offer superior long-term freedom from restenosis.