Histopathologic Findings in Specimens Obtained by Directional Coronary Atherectomy: Comparison with de novo Lesions, Restenosis Lesions and Acute Coronary Syndromes Lesions

This study characterized histopathologic findings using specimens excised during directional coronary atherectomy (DCA) in patients with different ischemic syndromes.We reviewed the histopathologic findings in 61 coronary atherectomy specimens from 61 consecutive patients. Clinical subgroups were classified into three groups: primary lesions of stable angina (Group P, n=7), 29 restenosis lesions (Group R, n=29) and acute coronary syndromes (Group A, n=25). These patients were diagnosed according to AHA criteria on admission. Fragments retrieved were screened on light microscopy after Hematoxylin-eosin staining to evaluate for presence of calcification, thrombus, angiogenesis, stellate cell proliferation, cholesterin, hemosiderin, foam cells and inflammation cells. All specimens were reviewed by two independent observers, using the light microscope, who were unaware of the clinical data. Angiograms were suitable for quantitative analysis by a cardiac image analysis system (Cardio 500, Kontron Elektronik GmbH). Automated contour detection was performed by a geometric edge differentiation technique. Restenosis was defined as presence of stenosis≥50% at follow-up angiography.There were no significant differences among the three groups in terms of reference diameter, or minimal lumen diameter (MLD) after DCA. MLD and severity of stenosis before DCA tended to be less in the primary group than in the other two groups, although these differences were not significant. There were no significant differences among the three groups in the presence of calcification, cholesterin deposit, foam cells or inflammation cells. There were less thrombus in the group P than that in the other two groups. In group A, angiogenesis was detected more frequently (60%) than in the other two groups (group P=14%, group R=35%) and hemosiderin deposit also tended to be more frequent. Stellate cell proliferation tended to be more frequent in group R (72%) than in the other two groups (P=43%, A=52%).The presence of angiogenesis correlated with acute coronary syndromes and the presence of activated smooth-muscle cells correlated with restenosis after angioplasty.