A 63-year-old man without coronary risk factors was admitted to our hospital for investigation of increasing chest discomfort. Acute myocardial infarction (AMI) of the inferior-posterior wall was suspected. Emergency coronary angiography revealed that thrombus occluded the left circumflex coronary artery and the distal diagonal branch (Fig. 1). Percutaneous coronary intervention with a thrombectomy catheter enabled continuous sequential aspiration of white intracoronary material from the culprit lesions. The postinterventional course was uneventful; however, on the 5th hospital day, histopathologic examination of the aspirated materials revealed both platelet thrombus and myxomatous tissue (Fig. 2). Furthermore, transesophageal echocardiography revealed a gelatinous mass in the left atrium. On the basis of these findings, we diagnosed AMI due to coronary embolization from a left atrial myxoma; then we placed the patient under cardiopulmonary bypass and uneventfully excised the gelatinous tumor, which displayed a friable surface (Fig. 3).
Fig. 1 Emergency coronary angiography upon hospital admission shows the thrombotic occlusions of the left circumflex coronary artery and the diagonal branch (arrows).
Fig. 2 Microscopic findings of a particle that was aspirated by the thrombectomy catheter show both A) myxomatous tissue (4 × 3 mm) and B) platelet thrombus (2 × 2 mm) (H & E, orig. ×1.25).
Fig. 3 Macroscopic examination of the excised mass reveals a gelatinous tumor with a friable surface (dimensions, 20 × 25 × 10 mm; weight, 4.8 g).
Comment
Although disruption of atherosclerotic plaque and consequent intracoronary thrombus formation are widely accepted as the main pathophysiologic cause of AMI,1 coronary embolization with complicating atrial fibrillation is one of the less common causes. Such embolization induced by cardiac myxoma is rare2,3 but should be considered in young-to-middle-aged patients who present with signs of AMI in the absence of coronary risk factors.
Footnotes
Address for reprints: Naoki Konagai, MD, Tokyo Vascular Clinic, Shinjuku Kokusai Building Shinkan 601-2, 6-6-3 Nishishinjuku, Shinjuku-ku, Tokyo 160-0023, Japan
E-mail: konagai@tvclinic.jp
References
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