Coronary artery restenosis after atherectomy is primarily due to negative remodeling

The primary cause of restenosis following directional coronary atherectomy (DCA) remains obscure. "Negative remodeling," a decrease in vessel area, is believed to be more causative than is increase in plaque area. The DCA tec hnique used in these patients, designed tai facilitate the removal of plaqu e, should allow a more precise evaluation of the relative roles of these tw o mechanisms. Twenty-five patients underwent DCA. In 17, complete angiograp hic and intravascular ultrasound (IVUS) images were obtained before and aft er DCA and at follow-up (6 to 9 months), Internal elastic lamina (IEL), lum en, and plaque areas were calculated at preatherectomy, postatherectomy, an d follow-up. Postathlerectomy, the mean IEL area increased by 32% and the m ean plaque area decreased by 51%, resulting in a significant mean increase in lumen area, 500%, At follow-up when compared to postatherectomy, the cha nge in IEL area was variable; however, the mean did not change significantl y (p = 0.58). Plaque area change, when standardized for initial vessel size , was small (mean increase 2.8 +/- 3.5%), The mean lumen area did not decre ase significantly at follow-up (p = 0.43), A highly significant correlation (r = 0.96) was noted between IEL area change and lumen area at follow-up. In contrast, the correlation between plaque area change and lumen area chan ge over the same period was much less significant (r = 0.64), These data in dicate that decrease in IEL area primarily is responsible for restenosis. ( C) 1999 by Excerpta Medica, Inc.