Prinzmetal angina or coronary spasm related to anaphylactoid reaction?

Prinzmetal’s angina is a challenging diagnostic of spontaneous brief episodes of chest pain. Anaphylactoid reactions to radiocontrast media are immediate hypersensitivity responses that can mediate coronary artery spasm. Herein, we report the case of a 61-year-old man who underwent a coronary angiography for angina. The right coronary artery (RCA) was first visualized as normal, but during the left coronary system injections, he developed ST segment elevation and cardiogenic shock. No iatrogenic dissection of the left coronary system, which was initially normal, was displayed, but surprisingly, a retrograde supply to the RCA was visualized. Thus, we re-catheterized the RCA, which indicated a total occlusion of its second segment. Nitrate injections completely relieved the spasm and the clinical condition of the patient normalized. The possible related mechanisms are also discussed.