Kounis syndrome manifesting as left main coronary aneurysm with late coronary stent thrombosis

Abstract Kounis syndrome (KS) is defined as the occurrence of an acute coronary syndrome (ACS) concomitantly with hypersensitivity reactions triggered by an allergenic event. Patients with Drug Eluting Stents (DES) implantation are prone to hypersensitivity reactions from five potential antigens namely metal stent, polymer coating, eluted drug and antiplatelets (aspirin, clopidogrel). Coronary aneurysms are seen in 1.25–3.9% of patients after stent implantation and have been detected as early as three days after drug-eluting, and as late as nine years after bare metal stent implantation and are usually associated with dangerous stent thrombosis. Here we report a case of 25 year old female presented with KS manifesting as Intra-stent left main coronary aneurysm with late stent thrombosis.