TABLE 2.

Potential Causes and Pathogenic Mechanisms underlying CAE.

Cause	Pathogenic mechanism of coronary ectasia
Atherosclerosis	Local mechanical stress from stenosis, enhanced inflammatory response-induced proteolysis of extracellular matrix proteins
Kawasaki disease	Autoimmunity, vasculitis
Genetic susceptibility	Specific HLA class II genotypes such as HLA-DR B1*13 are more detectable
Inflammatory disorders (vasculitis)/connective tissue disorders	Increased plasma levels of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin; imbalances in protein levels of matrix metalloproteinase and its tissue inhibitor
Coronary Fistula	Compensatory dilatation secondary to a high-flow state
Coronary anomalies	Compensatory dilatation secondary to (e.g., ALCAPA) myocardial ischemia
Infection	Direct pathogen invasion of arterial wall, immune complex deposition
Trauma/iatrogenic	Mechanical and shear wall stress, and non-healing dissections
Drug-related	Vasoconstriction/endothelial damage

HLA, human leukocyte antigen; ALCAPA, anomalous origin of the left coronary artery from the pulmonary artery.