The impact of high pressure vs low pressure stent implantation on intimal hyperplasia and follow-up lumen dimensions - Results of a randomized trial

Aims Histology and retrospective clinical studies have indicated that the a mount of neointimal hyperplasia is dependent on the arterial injury induced during stent implantation. This study analysed, prospectively, the impact of high vs low pressure stent implantation techniques using a second genera tion stent on intimal hyperplasia and follow-up lumen dimensions. Methods and Results Post-intervention and follow-up (mean[+/- SD] 5.5 +/- 1 .3 months) angiographic and intravascular ultrasound studies were performed on 120 MultiLink HP stents randomized to implantation at either low (8-10 atm) or high (16-20 atm) pressure. Intravascular ultrasound measurements of the external elastic membrane, stent, and lumen cross-sectional area were performed at 1 mm axial increments. Peri-stent plaque+media cross-sectional area (external elastic membrane-stent cross-sectional area, intimal hyperp lasia cross-sectional area (stent-lumen cross-sectional area at follow-up), intimal hyperplasia thickness and peri-stent tissue growth cross-sectional area (Delta persistent plaque+media cross-sectional area) were calculated. Intravascular ultrasound demonstrated a larger minimal lumen cross-section al area postintervention in the high pressure group (7.3 +/- 2.0 vs 6.2 +/- 1.8 mm(2), P <0.001, high vs low pressure a cup, group respectively). At f ollow-up, the mean intimal hyperplasia cross-sectional area (1.7 +/- 0.9 vs 1.5 +/- 0.8 mm(2), P=0.708), the mean intimal hyperplasia thickness (0.16 +/- 0.12 vs 0.16 +/- 0.12 mm, P=0.818) and peri-stent tissue proliferation cross-sectional area were not greater in the high pressure group. Thus, the minimal lumen cross-sectional area at follow-up continued to be greater (5 .5 +/-2.0 vs 4.7 +/-1.7 mm(2), P=0.038) in the high pressure group. Conclusions High pressure stent implantation results in greater stent expan sion even with the less rigid second generation Multi-Link stent. Larger lu men dimensions persist at follow-up, while intimal hyperplasia is not signi ficantly greater after high pressure implantation compared to the low press ure technique. (C) 2001 The European Society of Cardiology.