単純結紮術後16年目に，突然死した左冠動脈肺動脈異常起始症の1例

Anomalous Origin of Left Coronary Artery from Pulmonary Artery:A sudden death 16 years after simple ligation of aberrant left coronary artery

　比較的稀な，左冠動脈肺動脈異常起始症（ALCAPA）の外科治療は，特異的な冠循環など，病態生理の解明とともに，手術手技も変遷してきた。1960年Sabistonら^1）によってはじめて本症に対する単純結紮術の成功例が得られて以来，多くの手術治験例が報告されている。しかし，これら術式の術後15年以上を経過した，長期遠隔例についての検討は，いまだ少ない^2）。最近我々は，本症coronary steal期^3）の診断で，37歳時に異常起始の左冠動脈単純結紮術を受け，自覚症状ないまま16年間経過し，ジョギング中に突然死を来たした53歳男性例を経験した。本例はたまたまこの3カ月前に心臓核医学検査を中心に，非観血的検索を行なった例である。本例ば著者らの知り得た範囲では，単純結紮術後の最長遠隔例と思われ，自然歴と手術予後，剖検所見と合わせ，若干の考察を加え報告する。

The case of a 53 year-old man with anomalous origin of the left coronary artery from the pulmo-nary artery, who had undergone simple ligation of the aberrant vessel was reported. This patient was asymptomatic and doing well under normal life for 16 years after ligation, but he died suddenly while jogging. Three months before his death he was checked through non-invasive examinations in our hospital.

The cardiac size on roentgenogram of the chest remained almost the same as it was in the pre-operative, coronary steal stage. The tomoechocar-diogram disclosed the dilated right coronary artery and prolapsing mitral leaflets. Abnormalities which persisted on ECG at rest were recorded in the last examinations. On treadmill exercise test, ECG didn't show any ischemic changes and sporadic PVCs disappeared at a heart rate over 140 beats/ min. The thallium 201 emission computed tomogram at exercise revealed permanent perfusion defects at anteroapical and lateral regions of the left ventricle without redistribution pattern by supine ergometer.

Postmortem specimen showed the right coronary artery arising from the aorta and the anomalous left coronary artery from the pulmonary artery. Myocardial infarction was found at the anteroapical and lateral region of the left ventricle. The mitral leaflets degenerated with the fibrous thickness and prolapsing. The high risk of sudden death in asymptomatic adult patients with this anomaly had resulted in prompt surgical treatment in literatures. If it is true, the simple ligation method in our case assumed not to prevent the death of arrhythmia in the post-operative periods. Further studies of this anomaly are needed, in order to determine the benefits of the surgical procedures which influenced the differences between the natural history and post-operative prognosis of adult patients with this condition.