Focal wall overstretching after high-pressure coronary stent implantation does not influence restenosis

To determine if vessel wall overstretching during coronary stenting is asso ciated with a higher restenosis rate, the intravascular ultrasound morpholo gical evaluation was performed following ultrasound criteria. A total of 46 8 lesions with successful coronary Palmaz-Schatz stenting guided by intrava scular ultrasound were classified into the no overstretching group (n = 295 ) and the overstretching group (n = 147). There were 26 lesions not classif iable due to the poststent morphology, Balloon-to-vessel ratio was 1.12 +/- 0.17 in the no focal overstretching group and 1.20 +/- 0.20 in the overstr etching group (P < 0.0002). Follow-up angiogram was performed in 77% of no focal overstretching group and in 75% of the focal overstretching group. Th e restenosis rate of the no focal overstretching group was 19.8% and 20.9% in the focal overstretching group, respectively (P = 0.65). Focal overstret ching was more frequent following balloon oversizing. No increase in resten osis rate, found in focal overstretched stented lesions, leads us to the hy pothesis of a regulation of smooth-muscle-cell proliferation activated by t he normalization of blood flow and of shear stress, when stent implantation succeeds in optimally improving the lumen. (C) 1999 Wiley-Liss, Inc.