Allergic myocardial infarction (type III Kounis syndrome) secondary to mushroom ingestion: An unusual cause of very late stent thrombosis of saphenous venous graft and refractory no-reflow phenomenon.

The clinical presentation of myocardial injury associated with allergy responses is known in the cardiology literature as Kounis syndrome or allergic angina/myocardial infarction. An allergic acute coronary syndrome (ACS) may be caused by systemic increase of allergy mediators, or by local stimulation activating heart tissue mast cells (precipitating coronary spasm or generating plaque rupture and coronary or stent thrombosis). Acute allergic/anaphylactic reactions may cause ACS by directly affecting the heart and atherosclerotic plaque, or by exacerbating underlying illness. We present a case of a 67-year-old, Indian male, who had coronary artery bypass surgery and percutaneous coronary intervention and developed very late stent thrombosis of the saphenous venous graft as a result of an allergic response to mushrooms. Learning objectives: •A prototypical patient with Kounis syndrome who experienced allergy symptoms and myocardial ischemia after being exposed to a probable allergenic stimulus.•A link between Type III Kounis syndrome and drug-eluting stent thrombosis has recently been hypothesized.•Mast cells are plentiful in cardiac tissue and may lead to coronary artery/stent thrombosis.