This is a case of a 58-year-old female with a history of mitral regurgitation who had undergone mitral valve repair and was readmitted in cardiogenic shock with pericardial effusion, and then developed an anterior ST-elevation myocardial infarction. Coronary angiography revealed an embolus in the left main artery which was treated with rheolytic thrombectomy. This represents an uncommon cause of acute myocardial infarction.

       Case Presentation. A 58-year-old female was transferred from an outside hospital with

Figure 1

Saddle embolus in the left main coronary artery.

impending cardiogenic shock and pericardial effusion. She had a history of mitral regurgitation due to myxomatous degeneraton and had undergone complex mitral valve repair with quadrangular resection of the second segment of the posterior leaflet and ring annuloplasty 7 weeks prior to presentation. There was also a history of paroxysmal atrial fibrillation for which she was treated with warfarin prior to admission, as well as after surgery. She was taken emergently to the operating room for a pericardial window and placement of an intra-aortic balloon pump. Intra-operative transesophageal echocardiography showed left ventricular dilatation and severe global dysfunction, with an estimated ejection fraction of 10%. The mitral annuloplasty ring had normal motion, with mild mitral regurgitation. The postoperative electrocardiogram showed anterior ST-elevations, which prompted urgent cardiac catheterization. Coronary angiography revealed a large saddle embolus at the distal end of the left main coronary artery that completely occluded flow to the left circumflex artery (LCx) and nearly occluded the left anterior descending artery (LAD) (Figure 1). Rheolytic thrombectomy was performed in both the LAD and LCx arteries using the AngioJet^® rheolytic thrombectomy device (Possis Medical, Inc., Minneapolis, Minnesota). The proximal thrombus was successfully removed, but

Figure 2

Left coronary artery after thrombus aspiration.

stenting of the distal LAD was required to treat thrombus which had embolized. Final angiography revealed no significant disease in the distal left main artery, proximal LCx or the LAD (Figure 2). Postintervention, the patient remained in cardiogenic shock despite maximal medical support, and several days later, had a left ventricular assist device placed as a bridge to heart transplantation.

       Discussion. Coronary artery embolism is an uncommon cause of myocardial infarction. In an autopsy series of 1,050 patients with myocardial infarction, Prizel et al. found only 55 patients who had coronary embolisms.¹ Coronary embolism should be suspected in patients presenting with acute myocardial infarction with associated active endocarditis, atrial fibrillation, valvular prosthesis or rheumatic heart disease, left ventricular aneurysm, left atrial or ventricular clot, or during cardiac catheterization or cardiac surgery. This case describes the relatively rare occurrence² of a large embolism to the left main coronary artery treated with rheolytic thrombectomy.

1. Prizel KR, Hutchins GM, Bulkley BH. Coronary artery embolism and myocardial infarction. Ann Intern Med 1978;88:155–161.
2. Antman EM. Acute myocardial infarction. In: Braunwald E, Zipes DP, Libby P, (eds.). Heart Disease: A Textbook of Cardiovascular Medicine. 5th ed. Philadelphia: Saunders, 1997, pp. 1193–1194.