主要冠動脈２枝と側枝１枝がほぼ同時期に閉塞したと思われた急性心筋梗塞の１例

A Case of Acute Myocardial Infarction with Simultaneous Occlusion of Two Main Coronary Branches and One Side Branch

要旨

　急性心筋梗塞は多枝同時閉塞で発症することは稀である．今回われわれは主要冠動脈2枝と側枝1枝の完全～亜完全閉塞による急性心筋梗塞の1例を経験した．患者は52歳，男性．冠危険因子は高血圧，糖尿病および喫煙．不安定狭心症を経て，急性心筋梗塞を発症した．入院時の心電図では下壁・側壁誘導にST上昇を認めた．緊急冠動脈造影では右冠動脈＃3と左前下行枝＃10が完全閉塞で，左回旋枝＃13に造影遅延を伴う99％狭窄を認めた．右冠動脈＃3と左回旋枝＃13に対して冠動脈内血栓溶解療法後，経皮的冠動脈形成術を行い，再開通に成功した．左前下行枝＃10は経過観察とした．退院時の冠動脈造影では左前下行枝＃10は自然再開通していた．発症機序として，急性心筋梗塞発症時に生じる血液凝固能や血小板凝集能の亢進が考えられた．

Summary

　Acute myocardial infarction with simultaneous occlusion of combined coronary branches is rare. Recently we encountered a case of acute myocardial infarction due to simultaneous occlusion of the two main coronary branches and one side branch. The case was a 52 year-old man. He had hypertension and diabetes mellitus. Also he was a heavy smoker. He experienced unstable angina and subsequent acute myocardial infarction. Electrocardiogram on admission revealed ST-segment elevation in the inferior and lateral leads. Emergent coronary arteriography demonstrated total occlusions of the right coronary artery (RCA)-segment 3, the left anterior descending coronary artery(LAD)-segment 10 and subtotal occlusion of the left circumflex coronary artery (LCX)-segment 13. Intracoronary thrombolysis and rescue percutaneous transluminal coronry angioplasty to RCA-segment 3 and LCX-segment 13 was successful. However we refrained from treating LAD-segment 10. Coronry arteriography before discharge demonstrated recanalization of LAD-segment 10. We considered that the mechanism of simultaneous occlusion of combined coronary branches was activation of the coagulation system and platelets at the onset of acute myocardial infarction.