Acute coronary syndrome secondary to allergic coronary vasospasm (Kounis Syndrome): a case series, follow-up and literature review.

Kounis syndrome (KS) is the concurrence of acute coronary syndrome associated with mast-cell and platelet activation in the setting of hypersensitivity and allergic or anaphylactic insults. Many drugs and environmental exposures had been reported as inducers, but various inducers and the mechanism of KS remained unknown till now. The widely used traditional Chinese medicine (TCM) as a potential sensitizer were scarcely reported to induce allergic vasospasm due to the ignorance of the linkage between traditional medicine allergy and vasospasm.

We described 5 rare cases of KS including unreported triggers of TCM and abortion, reported the treatment strategy and 1~4 years' follow-up results, and tried to probe into the etiology of KS. Case 1 and case 2 for the first time reported acute ST-segment elevation myocardial infarction (STEMI) caused by Chinese herbs related allergic coronary vasospasm. Case 3 reported recurrent angina following allergen contact and wheezing, indicating the internal linkage of coronary vasospasm and allergic asthma. Case 4 described a childbearing-age woman suffered refractory ischemic chest pain due to coronary vasospasm in a special period of post-abortion, the attacks suddenly disappeared when her menopause recovered. Case 5 described an isolated episode of allergic coronary vasospasm under exposure of smoking and stress, which was successfully prevented by avoiding the exposures.

Kounis syndrome is not rare but rarely recognized and under-diagnosed. It is necessary to recognize KS and various inducers, especially for the patients suffering refractory vasospastic cardiac attacks concentrating in special periods. Blood test of eosinophil might contribute to diagnose KS and anti-allergic agents might be helpful for controlling KS attacks.