Kounis Syndrome Presenting as Very Late Stent Thrombosis in an Everolimus-Eluting Stent Following Wasp Stings
A 56-year old man was referred by an emergency physician to our hospital with an impression of ST-segment elevation myocardial infarction (STEMI). The patient was stung on the arm, neck and head several times by wasps while working on his field about 7 hours prior to admission. He had a mild allergic reaction involving local pain and urticarial swelling immediately after the incident without signs of anaphylaxis or shock. Just a few minutes after being stung, he started complaining of chest pain and called the emergency service. His blood pressure was 120/80 mm Hg, pulse rate was 90 beats per minute and electrocardiogram revealed ST-segment elevation with Q wave formation in the anterior leads and reciprocal ST-segment depression in the inferior leads (). His troponin T level was elevated to 1.86 ng/mL. After being given intravenous dexamethasone and antihistamine, he was promptly transferred to our catheterization laboratory. He had undergone an everolimus-eluting 3.5×15 mm stent placement (Promus®, Boston Scientific, MN, USA) in the mid-left anterior descending (LAD) artery for stable angina 3 years prior in our hospital. Clopidogrel (75 mg/d) was withdrawn 24 months after stent implantation, while aspirin (100 mg/d) had been continued until that day. Coronary angiography demonstrated a thrombosis in the previous stent in the LAD artery, completely occluding the vessel (). The remaining vessels showed insignificant stenosis. The lesion was crossed with a Runthrough® NS guidewire (Terumo) and sequential inflations using Nimbus PICO® (BARD) 1.25×12 mm, followed by 2.0×12 mm balloons to disperse the thrombus. Next, thrombus aspiration with a thrombus aspiration catheter (Thrombuster II®, Kaneka Corp., Japan) was performed. Abciximab infusion was started, of which half of the initial bolus was given directly into the left coronary system. However, Thrombolysis in Myocardial Infarction flow 3 was not established despite these measures. In the end, an everolimus-eluting 3.5×15 mm stent (Promus Element™, Boston Scientific, MN, USA) was deployed with an excellent angiographic result (). We did not measure serum tryptase and histamine levels with a half life of 90 minutes and of less than 30 minutes respectively because 7 hours had passed after the onset of symptoms. He was discharged from the hospital 6 days after the index procedure with dual anti-platelet therapy (DAPT). The patient is currently doing well and is being followed up in the outpatient department.