極めて稀なLipton R-I型単冠動脈の1例

A Case of Lipton R-I Type of Single Coronary Artery:a very rare anomaly

　患者は74歳，男性．60歳から高血圧，軽度大動脈弁閉鎖不全で通院中．1997年6月18日に動悸，胸部不快感を主訴に入院した．頻脈性心房細動，肺うっ血を認め，心エコーで左室前壁の壁運動が低下していた．血清酵素は正常であった．ループ利尿薬，ジギタリスにて心不全は改善し洞調律に戻った．9日後の冠動脈造影では，右Valsalva洞から起始した右冠動脈が通常どおり走行し後下行枝を出した後も左房室間溝を上行して後側壁枝を出し，更に心基部前面で円錐枝と吻合して前下行枝となっていた．左Valsalva洞から起始する冠動脈はなかった．これは単冠動脈症の中でもLipton R-I型に相当する極めて稀な型である．左室造影で前壁運動は改善していた．本例は胸痛や運動負荷心電図でのST-T変化を認めないため内科的に加療している．入院時に低下していた左室前壁運動がその後改善したことは同部位の冠予備能低下を示唆する．

A 74-year-old man was admitted to our hospitalbecause of palpitation and chest discomfort in June1997. He had a 14-year history of hypertension and mildaortic regurgitaion. Mild congestion was showen onchest X-ray film and CTR was 62%. The electrocardio-gram revealed atrial fibrillation at a rate of 150 beats/min and no ST deviation. Reduced anterior wall motionof the left ventricle was observed by ecocardiography.The blood gas analysis showed hypoxia. Creatine kinaselevel was normal. He was succesfully treated for conges-tive heart failure with loop diuretic, oxgenation anddigitalis, and his sinus rhythm was normalized. On theninth hospital day cardiac catheterization was perfor-med. Wall motion of the left ventricle was normal. Itwas found that there was no left coronary artery fromthe left sinus of Valsalva. The right coronary arteryfollowed the course of a normal right coronary artery,with the posterior descending artery branching off in thenormal fashion, then continued in the left atrioventri-cular groove, giving off posteriolateral left ventricularbranches, receiving a conus branch, and developing intoa left anterior descending artery. This indicated LiptonR-I type of single coronary artery. This anomaly seemsto be quite rare. Because of the absence of chest painand ST-T change in exercise stress testing, we havetreated this case with medication. The anterior wallmovement of the left ventricle which had been inducedduring hospitalization and indicated a decrease in coro-nary reserve was shown to have improved.