2019 年 83 巻 4 号 p. 837-
A 72-year-old woman was referred for examination of exertional angina. Exercise stress test indicated broad redistribution of thallium-201 uptake (Figure B) associated with ST-segment depression on electrocardiogram (Figure A), but coronary angiography showed no stenotic lesions (Figure C). The patient continued to have angina despite maximum pharmacotherapy under a possible diagnosis of coronary artery spasm or microvascular angina. The patient died because of progressive heart failure at 14 months after the first visit.
Although exercise stress testing showed (A) significant ST changes on electrocardiogram (Left, at rest; Right, during exercise) and (B) positive single-photon emission computed tomography thallium-201 scintigram in the inferior left ventricle (Left, at rest; Right, 3 h after exercise), (C) coronary angiogram showed no significant stenotic lesions (Upper, right coronary artery; Lower, left coronary artery). (D) In the autopsied heart, amyloid fibrils stained with direct fast scarlet (DFS) were observed in the walls of the intramural small coronary arteries, particularly (E) in the myocardium (scale bar, 1 mm). Coronary amyloid deposition was more dominant in the (*E-2) subendocardium than in the (**E-1) subepicardium. (E-4) Some small arteries in the subendocardium were occluded with these deposits, which covered the elastic lamina (Elastin van Gieson staining), whereas (E-3) the subepicardial artery was spared, with an intact elastic lamina (E1–4 scale bars, 100 μm). (F-1,2) Massive amyloid deposition was seen in the myocardial interstitium besides intramural arterial wall (scale bars, 200 μm). (G) Immunohistochemical staining showed IgG λ-light-chain expression in the DFS-positive area (scale bar, 400 μm).
At autopsy (Figure D), dilation of both cardiac ventricles suggesting cardiac failure was observed macroscopically. Histopathology was characterized by AL and lambda-type amyloid fibril deposits predominantly in the intramural coronary arteries (Figure G) and partly in the myocardial interstitium (Figure F). Figure E shows the unequal distribution of amyloid deposition in the vascular walls: scant deposits in the subepicardial coronary arteries and deposit-filled cavities in the occluded subendocardial coronary arteries.1
Although heart failure due to hypertrophied and restrictive myocardium is the most common cardiac manifestation, angina symptoms may precede the onset of heart failure in some patients with primary amyloidosis.2 Clinicians must consider amyloidosis as a differential diagnosis when evaluating patients with angina pectoris with no angiographically apparent lesions.
The authors declare no conflict of interest.
