Background. Restenosis is an important issue after classic and endovascular revascularization of atherosclerotic carotid arteries. Pathogenesis of this phenomenon remains unclear and unsolved. The aim of this study was to evaluate the histopathological and immunohistochemical features of atherosclerotic plaques retrieved at carotid endatrerectomy in patients who developed restenosis at ultrasound follow-up.
Material and methods. One hundred thirty patients operated because of atherosclerotic carotid artery stenosis were evaluated. On the base of postoperative ultrasound examinations 52 patients were qualified for this study. Atherosclerotic plaques were investigated histopathologically and with immunohistochemical methods with monoclonal and polyclonal antibodies (DAKO) to define the phenotype of inflammatory, smooth muscle and endothelial cells as well as fibrinogen deposits and HLADPQR antigens.
Results. By means of the ultrasonography, in a period of 6–18 months following the surgery, patients were classified into two, significantly different groups: group I with an evident restenosis and group II without restenosis nor intimal hyperplasia. Advanced and fibrocellular atherosclerotic plaques with thrombosis, intraplaque haemorrhages, fibrous cap rupture, intimal hyperplasia, necrosis, calcium and cholesterol deposits were found more often in patients of group I. Moreover, the percentage of vascular smooth muscle cells (SMA+) and fibrinogen (Fbg+) deposits was significantly higher in this group (p < 0.005). Atherosclerotic plaques from group II patients were more frequently fibrosclerotic and were rich in macrophages (Mac 387+) (p = 0.007). Inflammatory infiltrates consisting mainly of lymphocytes T (CD3+, OPD 4+) and mast cells (mast cells tryptase +), limfocytes T (CD8+), limfocytes B ( CD20+) were more frequent in group I.
Conclusion. Although classic risk factors of atherosclerosis do not play a role in the development of restenosis, histological and immunohistochemical (SMA, Fbg, Mac 387) studies of primary atherosclerotic plaques may be useful to selected the patients at risk of carotid postendartrectomy restenosis.