Endovascular cryotherapy accentuates the accumulation of the fibrillar collagen types I and III after percutaneous transluminal angioplasty in pigs.
OBJECTIVE
To investigate the effect of endovascular cryotherapy (Cryo) on the density of collagen types I (CI) and III (CIII), which are involved in the dynamic modulation of extracellular matrix (ECM) after percutaneous transluminal angioplasty (PTA).


METHODS
Twenty-one juvenile farm swine and 10 miniswine underwent PTA of the femoral arteries with and without Cryo (-50 degrees C for 2 minutes). Quantitative angiography, histomorphometry, and quantification of CI and CIII were performed at 1 week (n=7), 1 month (n=7), 3 months (n=7), and 6 months (n=10).


RESULTS
PTA decreased the minimal luminal diameter (MLD) (range 3.48+/-0.18 to 4.2+/-0.39 mm) compared to baseline values (range 3.67+/-0.15 to 4.59+/-0.23 mm), but the application of Cryo maintained the MLDs at preprocedural levels (range 3.88+/-0.31 to 4.58+/-0.21 mm). At the time of sacrifice, the MLDs were similar in PTA and Cryo-treated arteries, but the external elastic lamina was significantly greater after Cryo application (range 10.17+/-0.54 to 14.34+/-0.76 mm2) than after PTA (range 8.69+/-0.70 to 11.77+/-0.73 mm2, p<0.05). Cryo did not alter the luminal area or prevent neointimal growth. A time-dependent increase of both CI and CIII was observed as early as 1 week after PTA, peaking at 3 months, and declining thereafter. Cryo accentuated this increase at all time points.


CONCLUSIONS
The application of Cryo accentuates the accumulation of CI and CIII in PTA-treated femoral arteries. This effect may be of clinical relevance in the stabilization of peripheral atherosclerotic plaque.
Dorval
Jean-François
JF
Research Center and Department of Medicine, Montreal Heart Institute, Montreal, Quebec, Canada.
Geoffroy
Pascale
P
Sirois
Martin G
MG
Tanguay
Jean-François
JF
D000800:Angioplasty, Balloon / Q000379:methods*; D000818:Animals; D024042:Collagen Type I / Q000378:metabolism*; D024061:Collagen Type III / Q000378:metabolism*; D017679:Cryotherapy; D005263:Femoral Artery / Q000033:anatomy & histology / Q000378:metabolism; D013552:Swine; D013997:Time Factors
D024042:Collagen Type I; D024061:Collagen Type III