Negative contrastを用いた血管内超音波が有効であった急性心筋梗塞を合併した冠動脈拡張症の1例

Clinical Usefulness of Negative Contrast Intravenous Ultrasound in Coronary Artery Ectasia with Acute Myocardial Infarction：a case report

要旨　患者は63歳の急性心筋梗塞の男性で，冠動脈造影では3枝にびまん性の冠動脈の拡張が認められた．さらに，右冠動脈の末梢の2枝において完全閉塞が認められ，中間部には透亮像が認められた．右冠動脈の末梢2枝に対して血栓吸引療法を施行し，良好な再灌流が得られた．その後，右冠動脈に対して血管内超音波検査を行ったが，中枢部から遠位部にかけて動脈硬化様の低エコー輝度の病変部が認められたが，negative contrast法ではそれらが器質化した壁在血栓であり，一部が浮遊していることが判明した．3本のステントにより壁在血栓を血管壁に圧着した．warfarinおよびticlopidineによる内服治療を行ったが，6カ月後の冠動脈造影および血管内超音波では血栓は消失した．

Summary

　The patient was a 63-year-old man with acute myocardial infarction. Coronary angiography revealed diffuse coronary artery ectasia in three vessels and partial occlusion of two distal portions of the right coronary artery. Rupture of an atheromatous plaque was also suspected in the mid-portion of the right coronary artery. The thrombi from the distal portions of the right coronary artery were aspirated using an aspiration catheter and revascularization of the right coronary artery was obtained. Intravenous ultrasound revealed hypoechoic regions, probably arising from atheromatous plaques, at the proximal and mid-portions of the ectatic right coronary artery, but no evidence of plaque rupture. However, intravenous ultrasound using negative contrast revealed evidence of organized thrombi in the ectatic right coronary artery. Three stents were implanted in the ectatic right coronary artery, and the organized thrombis were put between the stents and the coronary artery intima in such a way as to compress the organized thrombi against the coronary intima. The patient was subsequently treated with warfarin and ticlopidine. Six months later, neither coronary angiography nor intravenous ultrasound revealed any evidence of thrombi in the ectatic right coronary artery.