Non-atherosclerotic Occlusion

This occlusion in an epicardial coronary artery occurred in a young woman positive for lupus anticoagulant. Note total occlusion by an organized thrombus.

Higher magnification reveals fibrosis and recanalization in the occluding thrombus.

The list of non-atherosclerotic causes of myocardial ischemia resulting from coronary artery luminal insufficiency is a lengthy one. Most such conditions are rare but cannot be easily dismissed. On the short list are 1) Congenital anomalies including anomalous coronary artery origins and myocardial bridging 2) Thromboemboli whether naturally occurring as in use of oral contraceptives, tumor emboli, calcium emboli, vegetations or iatrogenic as following cardiac surgery, cardiac catheterization, angioplasty, or prostheses. Paradoxical emboli from leg veins can occur. 3) Coronary artery dissection whether originating in coronary artery or extending into the coronary artery from aorta. 4) Spasm. 5) Trauma, penetrating or non-penetrating. 6) Arteritis including Takayasu, polyarteritis, SLE, Kawasaki, syphilis, other infections, Buerger’s disease, giant cell arteritis. 7) Metabolic disorders including Hunter’s, Hurler’s, homocystinuria, Fabry disease, amyloidosis. 8) Intimal proliferation whether due to irradiation, cardiac transplant, fibromuscular hyperplasia, ostial cannulation, angioplasty, infantile arterial calcification, cocaine. 9) External compression from aortic aneurysm, tumor metastases, or muscle bridging. 10) Thrombosis without atherosclerosis in conditions such as polycythemia, thrombocytosis, sickle cell anemia, or hypercoagulable states. 11) Substance use with cocaine or amphetamines. 12) Small vessel coronary artery disease as seen in hypertrophic cardiomyopathy, amyloidosis, cardiac transplant, neuromuscular diseases, diabetes mellitus.