Acute changes in aortic wall mechanical properties after stent placement in rabbits

PURPOSE: To evaluate mechanical property changes after endovascular stent p lacement in small-diameter arteries, MATERIALS AND METHODS: Self-expanding stents (Wallstent) were placed in the infrarenal aorta of five New Zealand White rabbits via a surgical right fe moral approach. Blood pressure changes (Delta P) were monitored in the aort a. Blood flow velocity was measured with a 20-MHz, pulsed Doppler probe (n = 4) to calculate the pulsatility index. Aortic diameter (d(A)) sand diamet er changes (Delta d) were measured with a 20-MHz probe in echo-tracking mod e, Diameter compliance (Cd) and distensibility coefficient (DC) were calcul ated as Cd = 2 Delta d/Delta P and DC = 2 Delta d/Delta P/d(A). RESULTS: Aortic diameter increased from 3.360 +/- 0.4033 mm to 4.020 +/- 0. 3033 mm after stent placement at the stent level only. Compliance decreased from 77.644 +/- 24.306 mm kPa(-1) to 31.150 +/- 8.245 x 10(-3) mm kPa(-1) at the stent level, and was then significantly lower than upstream (98.500 +/- 53.196 mm kPa(-1)) and down-stream (59.047 +/- 13.833 mm kPa(-1)). Ther e was no significant change in pulsatility index. CONCLUSIONS: Endovascular stent placement produces a significant decrease i n arterial wall compliance of the rabbit abdominal aorta.