REMODELING OF IN-STENT NEOINTIMA, WHICH BECAME THINNER AND TRANSPARENT OVER 3 YEARS - SERIAL ANGIOGRAPHIC AND ANGIOSCOPIC FOLLOW-UP

Background-Recently, it has been reported that the luminal diameter sh ows phasic changes after stenting: the progression of luminal narrowin g followed by its regression. To elucidate the mechanisms involved in the phasic changes in luminal diameter after stenting, we examined the changes in neointimal thickness and the appearance of neointima by a series of angiographic and angioscopic observations for 3 years after stent implantation. Methods and Results-In 12 patients who received a Wiktor coronary stent, serial angiographic and angioscopic examination s were performed immediately, 2 to 4 weeks, 3 months, 6 months, and 3 years after the stenting without repetition of angioplasty, Neointimal thickness was determined by angiography as the difference between ste nt and luminal diameters. The angioscopic appearance of neointima over the stent was classified as transparent or nontransparent according t o the visibility of the majority of the stent. Neointimal thickness in creased significantly at 3 months (0.75+/-0.32 mm) without further cha nges at 6 months (0.74+/-0.32 mm). Thereafter, however, it decreased s ignificantly over 3 years (0.51+/-0.26 mm). The angioscopic appearance was classified as transparent in 8 patients (100%) immediately after stenting, 6 patients (100%) at 2 to 4 weeks, 2 patients (17%) at 3 mon ths, 2 patients (20%) at 6 months, and 7 patients (58%) at 3 years. Co nclusions-The neointima became thick and nontransparent until 6 months and then became thin and transparent by 3 years. We conclude that neo intimal remodeling exists after stenting and plays a major role in the alteration of coronary luminal diameter after stenting.