ステントフラクチャーにより右冠動脈入口部から大動脈にステントの一部が逸脱したCypherTMステント再々狭窄の1例

A Case of Repeated Restenosis of CypherTM Stent Partially Dislocated from the Entrance of the Right Coronary Artery into the Aorta due to Stent Fracture

要旨　患者は62歳，女性．2005年3月に糖尿病性足壊疽で整形外科入院中に狭心症の疑いにて当科を紹介された．冠動脈造影検査にて＃1 90%狭窄を認め，＃1遠位部にTUNAMI^TM2.5×15mm，＃1近位部にCypher^TM2.5×18mmを留置した．4カ月後フォローアップでCypher^TMに99%狭窄，TUNAMI^TMに90%狭窄を認め，血管内超音波でCypher^TMは入口部から遠位側に3mmほどmigrationしており，そのためカバーされていない入口部に強い内膜増殖が認められた．続いて右冠動脈入口部から1ストラット出す形でCypher^TM3.0×28mmを留置した．2006年1月に狭心症発作が出現し救急受診した．＃1入口部に99%再々狭窄を認め，Cypher^TM内にフラクチャーを，また3ストラット大動脈へステント逸脱が確認された．バルーン拡張にて50%に改善するも同日胸痛と高度房室ブロックが出現し，バイパス手術のため転院．本症例の再狭窄にmigrationが，再々狭窄にフラクチャーが深く関与したと考えられた．

　The patient was a 62-year-old female in whom angina pectoris was suspected in March, 2005, during hospitalization in the orthopedic department for diabetic gangrene of the patient's leg, and she was referred to our department. Coronary angiography detected 90% stenosis of ＃1, and TUNAMI^TM(2.5×15mm) and Cypher^TM(2.5×18mm) were implanted in distal and proximal regions of ＃1, respectively. On follow-up after 4 months, the Cypher^TM and TUNAMI^TM stents were 90% and 99% occluded. Intravascular ultrasonography detected that the Cypher^TM stent had migrated for 3mm toward the distal side from the ostium, which had caused severe proliferation of the intima in the uncovered ostial region. Cypher^TM(3.0×28mm) was implanted at a site 1-strut out of the ostium of the right coronary artery. Anginal attack occurred in January, 2006, and the patient visited our hospital. The ＃1 ostium was 99% occluded, and the Cypher^TM stent was fractured and dislocated into the aorta for 3-struts. The occlusion was reduced to 50% by balloon dilatation, but chest pain and severe atrioventricular block occurred on the same day. The patient transferred to another hospital for bypass surgery. The migration and fracture may have been closely associated with the first and second restenosis, respectively.