Cryoplasty versus angioplasty in the treatment of arterial restenosis in an experimental model of atherosclerosis in rabbits.

Cryoplasty may reduce the incidence of post-angioplasty restenosis in peripheral atherosclerotic arteries. Our study is looking to investigate the mid-term effects (4 weeks) of an FDA-approved cryoplasty catheter (PolarCath(®), Boston Scientific) compared to a conventional angioplasty catheter using a hypercholesterolemic rabbit model of arterial restenosis based on diet plus vessel injury. Thirty-six normolipidemic, 3-month old male New Zealand White rabbits were used. Balloon angioplasty was performed on left external iliac arteries on day 1. Animals were fed with a hypercholesterolemic diet for 60 days. On day 120, three groups of animals were established: conventional PTA (percutaneous transluminal angioplasty) was applied on the PTA group; the CRY group was treated with the PolarCath(®) cryoplasty system and no treatment was given to a control (CTR) group. A broad variety of atheromatous lesions were observed 30 days after treatment, presenting significant differences between groups. Most of the complicated lesions were found in the CRY group, while advanced and early lesions were more often appreciated in the CTR and PTA groups, respectively. The histomorphometric evaluation of the arteries showed significant differences between the CRY group and the other two groups, with the highest percentage of IEM (internal elastic membrane) injury, vascular stenosis and ratio intima/media being registered on animals treated with cryoplasty. Intravascular cryotherapy induces complicated lesions in arterial walls 30 days after treatment in a hypercholesterolemic rabbit model based on diet plus vessel injury. Cryoplasty leads to the production of severe fibrosis and mineralisation and stenosis compared to a conventional angioplasty.