心停止を来した原発性冠動脈解離の1例

A Case of Primary Coronary Artery Dissection Complicated by Cardiac Arrest

　症例は62歳，男性，後下壁心筋梗塞を発症し心原性ショックより心停止となったが，蘇生に成功した．発症6時間で冠動脈造影を施行したところ，右冠動脈中節部に偏心性狭窄と冠動脈内血栓，その末梢の造影遅延を認めた．冠動脈内血栓溶解療法後に同部に陰影欠損を残したが，右冠動脈の完全再疎通が得られたため血管形成術は追加しなかった．第42病日の再造影では右冠動脈中節部に線状陰影欠損と偽腔による真腔の圧排を認め，原発性冠動脈解離と診断した．諸検査より血行再建の適応外としたが，内科的治療により患者は約2年を経過した現在も元気で生存中である．原発性冠動脈解離は急性心筋梗塞，突然死の原因になりうるが，心停止に至った例を救命し得た報告はきわめて稀である．診断には冠動脈造影が有用であるが，心筋梗塞急性期に冠動脈内血栓により解離が明らかでない場合があり，注意が必要である．

A 62 year old man had a postero inferior myocardial infarction with cardiogenic shock followed by cardiac arrest from which he was successfully resuscitated. Coronary angiographic studies at 6 hours after infarc-tion showed a significant eccentric narrowing and an intracoronary thrombus in the mid-portion of the right coronary artery (RCA), with slow distal flow. After intracoronary thrombolysis, a residual tilling defect was shown in the lesion. However, complete perfusion of the RCA was achieved, so coronary angioplasty was not performed. Repeat angiographic studies 42 days later showed a radiolucent line separating the true and false lumen of the vessel and the compression of the true lumen by the false lumen in the mid RCA, and a diagno-sis of primary coronary artery dissection was made. Many examinations showed that coronary revascular-ization was not indicated for the coronary dissection. Under medical treatment, the patient is now alive and well 2 years after infarction.

Primary coronary artery dissection may lead to acute myocardial infarction or sudden death, but cases in which a patient has survived an acute myocardial infarction complicated by cardiac arrest are quite rare. Angiographically several findings are diagnostic for primary coronary artery dissection, but our case in point demonstrates that a coronary dissection is not always indicative of an intracoronary thrombus, espe-cially in the acute phase of a myocardial infarction.