Prospective assessment of cholesterol embolization in patients with acute myocardial infarction treated with thrombolytic vs conservative therapy.

PURPOSE To determine whether subclinical cholesterol embolization is a frequent sequela of thrombolytic therapy. Case reports of catastrophic cholesterol embolization temporally associated with thrombolytic therapy in 19 patients have suggested a causal relationship. PATIENTS AND METHODS We prospectively followed 60 patients with acute myocardial infarction who underwent coronary bypass surgery within 1 month. Twenty-nine received thrombolytic therapy for myocardial infarction; 31 were treated conservatively. Two muscle biopsy specimens and one skin biopsy specimen were obtained from the vein harvest site at the time of bypass surgery. Paraffin block and frozen sections from each biopsy specimen were analyzed for evidence of cholesterol embolization. RESULTS Cholesterol emboli were found in biopsy specimens from 4 of 29 patients who had undergone thrombolytic therapy (14%) and in 3 of 31 patients who had not undergone thrombolytic therapy (10%, p = NS). Clinical evidence of cholesterol embolization occurred in one patient. Cholesterol emboli were distributed inhomogeneously; they were not observed in any skin biopsy specimen and were never present in more than one muscle biopsy specimen from each patient. CONCLUSIONS The prevalence of cholesterol embolization in patients with acute myocardial infarction treated with thrombolytic therapy is not significantly higher than in those treated without thrombolytic therapy. The cholesterol embolization seen in 12% of our patients was mostly subclinical and was probably spontaneous and/or catheterization induced. Isolated case reports of severe cholesterol embolization temporally associated with thrombolytic therapy do not represent a phenomenon that has widespread subclinical occurrence.