Cryoplasty of the venous anastomosis for prevention of intimal hyperplasia in a validated porcine arteriovenous graft model.

OBJECTIVES

Cryoplasty combines conventional angioplasty - percutaneous transluminal angioplasty (PTA) - with cold thermal energy. In this animal study, we investigated if preventive cryoplasty could reduce intimal hyperplasia (IH) at the venous anastomosis.

DESIGN

We investigated cryoplasty versus PTA of the venous anastomosis in a validated porcine, bilateral, arteriovenous graft model.

ANIMALS AND METHODS

In 12 pigs, 24 expanded polytetrafluoroethylene (ePTFE) grafts were bilaterally inserted between the common carotid artery and internal jugular vein. Directly after surgery, one venous anastomosis was treated with cryoplasty at -10 degrees C, the contralateral anastomosis with conventional PTA. At 4 weeks, graft flow was measured, quantitative angiography was performed and grafts with adjacent vessels were excised for histological analysis.

RESULTS

Due to a number of thromboses, data for paired analysis were available from eight pigs. Angiographic outflow vein diameter and graft blood flow were not different between treatment groups. Compared with the control group, IH at the venous anastomosis was reduced by 47% (P=0.21) and intima/media ratio was reduced by 45% (P=0.07) by cryoplasty. Effects were most profound in those animals that tended to develop most IH.

CONCLUSION

Our results suggest that preventive cryoplasty of the venous anastomosis might help to reduce IH in those cases that develop most profound IH.