Relation between vascular morphologic changes during stent implantation and the magnitude of in-stent neointimal hyperplasia

Intimal hyperplasia usually occurs after balloon overstretch injury or wire coil stimuli to coronary arteries. We examined whether the degree of vesse l wall stretch during coronary stent placement could predict the amount of in-scent neointimal hyperplasia after a 6-month follow-vp. Serial (preinter vention, postballooning, poststent implantation, and a follow-up after 6 mo nths) intravascular ultrasound (IVUS) was used to study 457 consecutive cro ss-sectional areas in 28 patients. IVUS imaging, using a motorized pullback system at 0.5 mm/s, allowed l-mm axial increment measurements of the total vascular, stent, and lumen cross-sectional areas. The mean total vascular area changed from 10.89 +/- 2.50 mm(2) before to 11.27 +/- 2.49 mm(2) after ballooning, to 12.80 +/- 2.59 mm(2) after stenting, and to 12.58 +/- 2.41 mm(2) at follow-up (p < 0.0001), The mean lumen area changed from 3.36 +/- 1.95 mm(2) before to 4.21 +/- 1.65 mm(2) after ballooning, to 5.16 +/- 1.09 mm(2) after stenting, and to 3.57 +/- 1.23 mm(2) at follow-up (p < 0.0001) . The mean stent area decreased from 5.25 +/- 1.17 mm(2) after stenting to 5.09 +/- 0.90 mm(2) at follow-up (p < 0.0001), Stepwise logistic regression analysis showed that Delta total vascular area (after stent implantation-b efore intervention) was a strong predictor of the amount of intimal hyperpl asia (r = 0.57, p < 0.0001). Vascular overstretch caused by the stenting pr ocedure promotes intimal hyperplasia in proportion to the degree of section al vascular stretch. (C) 2000 by Excerpta Medica, Inc.