冠動脈瘤を合併した冠動脈狭窄に対しオフポンプ冠動脈バイパス術およびcovered stent留置術を二期的に施行した1例

Two-Stage Treatment of a Coronary Artery Stenosis with a Coronary Aneurysm using Off-Pump Coronary Artery Bypass Grafting and Implantation of a Covered Stent:A Case Report

要旨　症例は80歳，男性．主訴は労作時胸痛．冠動脈造影で，左前下行枝(#6〜7)に90%狭窄，回旋枝(#12)に75%狭窄，#6に囊状で径13.1mmの冠動脈瘤を認めた．瘤は左前下行枝近位部に存在し，安全に処置するには人工心肺使用心停止下での手術が好ましいと判断した．しかし，上行大動脈の性状が悪く，遮断の危険が高いため，まずオフポンプ冠動脈バイパス術を施行し，術後10日目に，polytetrafluoroethylene-covered stentを瘤開口部に留置した．留置後の造影で瘤は描出されず，良好な結果を得た．冠動脈瘤の自然経過は不明で，治療に関して明確な指針はない．破裂した場合は致死的状態となるため，個々の症例に応じた適切な治療時期，治療方針の検討が必要である．

　An 80-year-old man was admitted to our hospital for the evaluation of exertional chest pain. Coronary angiography revealed 90% stenosis in the proximal and middle segments of the left anterior descending artery(LAD), 75% stenosis in the obtuse marginal branch, and a saccular coronary artery aneurysm(CAA)in the proximal LAD. The diameter of the CAA was 13.1mm. Because the CAA was present in the proximal part of the LAD, we preferred to perform the operation under cardiac arrest to ensure safe surgical treatment of the CAA. However, aortic cross-clamping under cardiopulmonary bypass was considered a high-risk procedure because of the degree of atherosclerosis in the ascending aorta. Therefore, off-pump coronary artery bypass grafting was performed first, and on postoperative day 10, a polytetrafluoroethylene-covered stent was implanted in the LAD to seal the CAA inlet. The blood flow in the aneurysm was completely blocked, and we were able to obtain an excellent result. The natural history of a CAA remains unclear. Therefore, the management of patients with a CAA is still controversial. As CAA rupture may be fatal, the appropriate therapeutic time and method for each individual case should be carefully chosen.