Recurrent Myocardial Infarction in a Patient With Paroxysmal Nocturnal Hemoglobinuria
A 47-year-old diabetic man on long-term warfarin anticoagulation was admitted for an acute lateral ST-elevation myocardial infarction (MI) and was immediately transferred to the catheterization laboratory for primary angioplasty. The angiogram revealed an extensive thrombus in the left main trunk (Figure 1). Thrombectomy using the X-sizer device was attempted in the left main trunk, the left anterior descending artery, and the circumflex arteries but was unsuccessful. The left anterior descending and circumflex arteries were finally stented (Figure 2).
The patient’s initial blood work showed hemolytic regenerative anemia (8.4 g/dL), thrombocytopenia (84×109/L) without schisocytes on the blood smear, and an international normalized ratio of 1.5. Antiphospholipid antibodies were negative. The patient had a history of portal vein thrombosis of unknown origin and described recurrent paroxysmal episodes of red or brownish urine (Figure 3). Immunologic testing revealed a 40% decrease of glycosylphosphatidylinositol-linked proteins CD55 and CD59 on erythrocytes and white cells, confirming the suspicion of paroxysmal nocturnal hemoglobinuria.
After angioplasty, the patient received prolonged subcutaneous enoxaparin injections (1 mg/kg twice per day) in addition to aspirin and clopidogrel. An angiogram 1 week later confirmed nearly complete regression of the clot and presence of normal coronary arteries downstream (Figure 4). Two weeks after discharge, the patient was urgently readmitted for recurrent MI. Coronary angiogram showed thrombus recurrence in the left main trunk extending into the left anterior descending and circumflex arteries (Figure 5). The platelet count was unchanged, and enoxaparin was replaced by intravenous danaparoid adjusted to the anti-Xa activity, with a final dose of 12 000 IU per 24 hours and an anti-Xa activity of 1.0 IU/mL. The coronary clot disappeared totally after 1 week of medical treatment (Figure 6). The patient was discharged on subcutaneous danaparoid twice per day (3750 IU×2 per 24 hours), aspirin 75 mg, and clopidogrel 75 mg. A new angiogram performed 4 months after stenting showed no thrombus and no restenosis.
The editor of Images in Cardiovascular Medicine is Hugh A. McAllister, Jr, MD, Chief, Department of Pathology, St Luke’s Episcopal Hospital and Texas Heart Institute, and Clinical Professor of Pathology, University of Texas Medical School and Baylor College of Medicine.
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