Acute elastic recoil of coronary stents immediately after their implantation

ABSTRACT

The objective of this study was to evaluate the acute elastic recoil of coronary stents immediately [10 minutes] after balloon deflation, because of the close relation of this elastic recoil and the late restenosis of coronary stents. Forty patients with isolated coronary lesion were studied immediately after stenting following successful coronary angioplasty. Coronary angiography before stenting showed mean reference diameter of 2.23 +/- 0.58 mm and mean minimal lesion diameter of 0.65 +/- 0.35 mm with mean percentage stenosis of 70.7 +/- 9%. On the other hand, mean diameter of stent during balloon inflation was 2.37 +/- 0.8 mm, while mean duration of inflation through the stent was 15.3 +/- 4 seconds and mean pressure used for stent deployment was 13.6 +/- 4 bars. The immediate post stent angiography showed satisfactory results in all patients with mean stent diameter, 10 minutes after deployment of 2.02 +/- 0.30 mm and mean percentage elastic [ER] of 11.6 +/- 2.36%. All angiographic measures were done with the help of computer-based cardiovascular angiography analysis system [Artrex Image Comm]. The mean ER was much less than that previously reported after pTCA in previous studies and also better than that reported for post stenting in stress trial [11.6% vs 17%]. On the other hand, different types of stents were used [XT stents 17, NIR stents 12 and Palmaz Schatz stents 11] and they did not show any difference in absolute ER among the three subgroups according to the selected stent [XT = 0.51 +/- 0.49 mm, NIR = 0.45 +/- 0.41 mm and PS = 0.56 +/- 0.53 mm]. Furthermore, in this study, pressure up to 18 bars was used for stent deployment [13.6 +/- 4 bars] and this technique optimized stent opposition to the vessel wall increased final stent diameter and reduced elastic recoil and hence late restenosis