Histopathological study on coronary arterial lesions of adult autopsy cases who had a history of Kawasaki disease (KD) in childhood or who had coronary artery aneurysms (CAANs) was performed to analyze the relationship between post-inflammatory arterial lesions and atherosclerosis.
Materials and Methods: Five autopsy cases who contracted KD at childhood and 11 autopsy cases who had giant CAANs at autopsy although a history of KD was not confirmed were included in this study. The age at death ranged from 18 to 57 years old. Forty-eight coronary artery (CA) branches from 16 autopsies were histologically examined focusing on the atherosclerosis which developed on the post-inflammatory lesions.
Results: CAANs occurred in 30 arteries among 48 CA branches. CAANs were classified into 2 types; dilated CAANs (22 branches) and recanalized CAANs (8 branches).
Dilated CAANs: The early atherosclerotic lesions, which corresponded to Type III or less of AHA classification, were seen in 16 CAs, and among them 6 branches had thrombotic luminal occlusion caused by the intimal erosion. On the other hand, the advanced atherosclerotic lesions corresponding to Type IV or more were observed in 6 of 22 branches and thrombotic occlusion of the lumen was observed in 5 of 6 CA branches. The cause of those thrombotic occlusion was estimated the rupture of atheroma.
Recanalized CAANs: All atherosclerotic lesions developed in the recanalized CAANs were classified to the early lesions. Thrombotic occlusion was seen in 1 of 8 branches.
Non-CAANs: There were 18 CAs with no aneurysm formation. The majority of Non-CAANs (16 of 18 branches) showed early atherosclerotic lesions (Type I or II), but 2 branches of 1 patient showed the advanced atherosclerotic lesion and the lumen was occluded by the fresh thrombus caused by intimal erosion.
Conclusion: This histological study targeted at the post-inflammatory CA lesions in adult suggests two things: 1) Though advanced atherosclerotic lesions were often observed in the dilated CAANs, the atherosclerosis in the recanalized CAANs and Non-CAANs was still in early stage. 2) The erosion of the intima plays an important role in a formation of the thrombotic occlusion in the post-inflammatory arterial lesions even in adulthood.