Deposition of amyloid proteins in the epicardial coronary arteries of 58 patients with primary systemic amyloidosis

Introduction: We sought to determine the distribution and the effect of amyloid on epicardial coronary arteries in patients with primary cardiac amyloidosis. Methods: We reviewed pathologic specimens taken after autopsy or cardiac transplantation from 58 patients with primary cardiac amyloidosis. Patients were seen from 1981 to 2000. Multiple sections of epicardial coronary arteries (left anterior descending artery, left circumflex artery, and right coronary artery) were examined to determine the degree of amyloid deposition in the intima, media, adventitia, and vasa vasorum (vasa vasorum are nutrient arteries for the coronary arteries themselves). Results: In 56 of 58 patients (97%), amyloid was present in epicardial coronary arteries. Amyloid was identified in all artery layers (intima, media, and adventitia), and more patients had amyloid in the adventitia. However, amyloid did not cause intraluminal obstruction of epicardial coronary arteries in any patient. The vasa vasorum had considerable deposits and, in many patients, were obstructed by amyloid. Patients with obstruction of the vasa vasorum were significantly more likely to have obstructive intramural coronary amyloidosis than patients without vasa vasorum obstruction (P=.002). Conclusions: The epicardial coronary arteries of patients with primary cardiac amyloidosis had extensive amyloid deposition. This deposition, however, did not lead to obstruction of epicardial coronary arteries and therefore did not contribute to ischemic syndromes observed in these patients. Obstruction of the vasa vasorum was associated with obstructive intramural coronary amyloidosis.