THE MORPHOLOGY OF THE CAROTID-ARTERY AFTER UNCOMPLICATED ENDARTERECTOMY

Endarterectomy of the carotid sinus is one of the most frequent vascul ar operations. Until now, however, few details have been reported on t he characteristic features of the disobliteration site during uncompli cated postoperative progress. Full histological and morphometric inves tigation was performed on the bifurcation of the carotid artery of 23 autopsies with previous endarterectomy, in some cases on both sides. T he postoperative interval was of up to 10 years duration (early phase up to 6 months poftoperatively 15 x, late phase 14 x). The findings we re compared with surgical specimens of 9 restenoses. The reconstructio n of an inner layer (so-called neointima) and the smoothing of the mar ginal layers of the disobliteraton site takes place rapidly through th e proliferation of smooth muscle cells from the remaining portions of the media. The narrower this remaining portion of the media, the great er the width achieved by these ''neo-intima'' (p<0,05). There is occas ional formation of elastic lamellae, similar to an elastic internal la mina, close to the luminal surface. Furthermore, in some cases the rec onstruction of an intimal thickening (fibrous ridge) characteristic of the carotid bifurcation was observed at the entrance to the carotid s inus; this can be assessed as an indication that flow irregularities a pparently persist postoperatively at this location. In the late phase, intramural calcification and new sclerotic plaques usually occur; the se plaques closely resemble those of surgically removed restenoses. Th e distribution of plaques of this kind is largely congruent with the p attern of plaques in asymptomatically diseased carotid arteries, Thus, following endarterectomy in the carotid sinus, sclerotic plaques recu r even during an uncomplicated course subsequent to reparative process es; as with the natural history of sclerotic plaques at the carotid bi furcation, this recurrence seems to be largely determined by hemodynam ic factors.