Abstract: Objective The differences in the thickness of fibrous cap and the percentage of fatty core of the coronary atherosclerotic plaques between sudden coronary death(SCD) group and the control group were investigated.Methods Sixty-four autopsy cases were divided into SCD and control groups.Samples were taken from the most severely damaged portions of the coronary atherosclerotic plaques,sectioned,stained with HE,and examined by light microscopy for morphologic changes and structural alternations.Image analysis system was adopted to compare the thickness of fibrous cap and percentage of fatty core in the whole plaque between the two groups,and all data were analyzed and calculated with SPSS 11.5 statistic software.Results There were 15 grade III and 21 grade IV atherosclerotic cases found in the SCD group,while there were 16 and 12 found in the control group,respectively.Although no significant differences on the severity of atherosclerosis were found between the two groups(P>0.05),there were significant differences on the thickness of the fibrous cap and the percentage of fatty core found between the two groups(P<0.01).Conclusion Our study indicates that there are significant differences in the thickness of fibrous cap and the percentage of fatty core in atherosclerosis plaques between the SCD group and the control group.These observed differences may be helpful for morphological diagnosis of SCD.

Key words: sudden death, sudden coronary death, atherosclerosis plaque of coronary, pathologic morphology