Endovascular stenting of juvenile vessels: consequence of surgical stent removal on vessel architecture.

Aims: To investigate the effect of stenting and later surgical removal on the architecture and therefore growth potential of juvenile vessels.

Methods And Results: Stents were implanted in the carotid artery and jugular vein of six 6-week-old lambs. Ten weeks later, stents were excised and the vessels closed without the use of patch material. After another 10 weeks, the vessel size (treated and untreated control side) was measured angiographically and the animals terminated for histology. All arteries were patent: treated arterial size was 9 +/- 1 mm compared with 11 +/- 1 mm on the control side (P = ns). Two veins were completely occluded and two severely stenosed; vessel size was smaller compared with the control side (8 +/- 8 vs. 14 +/- 5 mm; P = 0.02). Preserved vessel wall integrity was observed in both arteries and veins (except for local rupture of the internal elastic lamina with neointimal formation in two arteries leading to mild stenosis).

Conclusion: Vessel wall architecture remains well preserved after surgical removal of stents implanted in juvenile arteries and veins. However, stenting and subsequent surgical removal results in a high risk of venous thrombosis (probably due to the lower blood velocity, lower pressure, and the absence of pulsatility in venous vessels).