The purpose of this study was to determine the prevalence of clinical syndromes and pathologic changes of myocardial ischemia due to obstructive intramural coronary amyloidosis among patients with primary amyloidosis and cardiac involvement.

Medical records and pathologic specimens were reviewed from 96 patients with primary amyloidosis and cardiac involvement at autopsy or after cardiac transplantation during a 20-year period. Medical records were reviewed for patient demographic and clinical characteristics, including evidence for syndromes of myocardial ischemia. Pathologic specimens were examined for obstructive intramural coronary amyloidosis and microscopic changes of myocardial ischemia.

Obstructive intramural coronary amyloidosis was present in 63 of 96 patients (66%). Microscopic changes of myocardial ischemia were more common in patients with obstructive intramural coronary amyloidosis (86%) than in those without (52%) (P <.001). In the 76 patients without coexistent severe epicardial coronary atherosclerosis, changes of myocardial ischemia were more common in those with obstructive intramural coronary amyloidosis (83%) than in those without (45%) (P <.001). In patients who had tissue available for review, none had obstruction of epicardial coronary arteries from amyloid. Syndromes of myocardial ischemia affected 16 patients (25%) with obstructive intramural coronary amyloidosis but only 2 patients (6%) without (P=.027). For 11% of the patients with obstructive intramural coronary amyloidosis, a syndrome of myocardial ischemia consisting of acute myocardial infarction or angina pectoris was the first manifestation of primary amyloidosis.

Most patients with primary systemic amyloidosis and cardiac involvement have obstructive intramural coronary amyloidosis and associated microscopic changes of myocardial ischemia. Syndromes of myocardial ischemia may occur in these patients.