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Differences in histopathologic findings in restenotic lesions after directional coronary atherectomy or balloon
1Second Department of Internal Medicine, Hiroshima University School of Medicine, Japan. kono@mcai.med.hiroshima-u.ac.jp
Insights
Restenotic lesions after directional coronary atherectomy (DCA) show significantly higher smooth muscle cell proliferation compared to primary lesions or those after balloon angioplasty (PTCA). Fewer foam cells are observed in restenotic lesions following either procedure than in primary lesions.
Area of Science:
- Cardiovascular Pathology
- Interventional Cardiology
- Histopathology
Background:
- Directional coronary atherectomy (DCA) and percutaneous transluminal coronary angioplasty (PTCA) are methods for dilating stenotic coronary vessels.
- The morphological differences in restenotic lesions following DCA versus PTCA are not well understood.
Purpose of the Study:
- To investigate and compare the histopathologic characteristics of restenotic lesions after DCA and PTCA.
- To identify potential differences in cellular composition and proliferation between primary and restenotic lesions.
Main Methods:
- Coronary atherectomy specimens from 37 patients with stable angina were analyzed.
- Patients were grouped into restenotic after DCA (n=8), restenotic after PTCA (n=14), and primary lesions (n=15).
- Immunohistochemistry was used to assess smooth muscle cells, endothelial cells, foam cells, and cell proliferation (Ki-67).
Main Results:
- Restenotic lesions after DCA exhibited significantly higher stellate smooth muscle cell (S-SMC) content (87%) compared to primary (40%) and PTCA restenotic lesions (43%).
- Foam cell prevalence was higher in primary lesions (67%) than in DCA (25%) or PTCA restenotic lesions (36%).
- No significant differences were found in thrombus, calcification, or neovascularization among the groups.
Conclusions:
- Smooth muscle cell proliferation appears to play a key role in the development of restenosis after DCA.
- Restenotic lesions after both DCA and PTCA contain fewer foam cells compared to primary lesions.
Background:
Directional coronary atherectomy (DCA) and balloon angioplasty (percutaneous transluminal coronary angioplasty, PTCA) differ in their method of dilating stenotic vessels. It is not known whether there is any morphologic difference between restenotic lesions that occur after DCA and those occurring after PTCA.
Methods:
To evaluate histopathologic differences between restenotic lesions after DCA or PTCA, we reviewed coronary atherectomy specimens excised from 37 patients with stable angina. Patients were classified into three groups: those with restenotic lesions after DCA (n = 8), those with restenotic lesions after PTCA (n = 14), and those with primary lesions (n = 15). Specimens were analyzed immunohistochemically using monoclonal antibodies specific for smooth muscle cells (HHF35), endothelial cells (CD31), macrophage-derived foam cells (CD6B) and cell replication activity (Ki-67). In seven patients undergoing repeat DCA, de novo plaques and restenotic plaques were compared.
Results:
Stellate smooth muscle cell (S-SMC) content in restenotic lesions after DCA (87%) was significantly greater than that in primary lesions (40%; P = 0.032) and that in restenotic lesions after PTCA (43%; P = 0.045). Foam cells tended to be more prevalent in primary lesions (67%) than in restenotic lesions after DCA (25%; P = 0.062) or after PTCA (36%; P = 0.10). Restenotic lesions after DCA had more S-SMC proliferation and fewer foam cells than did primary lesions. There were no differences in the presence of thrombus, calcification, cholesterin, hemosiderin, the percentage of HHF35-positive cells or Ki-67-positive cells, or neovascularization among the three groups.
Conclusions:
Smooth muscle cell proliferation may have an important role in the development of restenosis after DCA. Fewer foam cells are present in restenotic lesions after DCA or PTCA than are present in primary lesions.