Contrast-Induced Type II Kounis Syndrome Complicated by a Cardiac Arrest Successfully Managed With Extracorporeal Membrane Oxygenation (ECMO): A Case Report.

Kounis syndrome (KS) is a rare allergic-mediated acute coronary syndrome (ACS) characterized by coronary vasospasm, plaque rupture, or thrombosis. It is typically triggered by allergens such as medications, contrast agents, or environmental factors. We report the case of a 58-year-old man with hypertension who developed Type II KS after iodinated contrast administration for coronary evaluation. Shortly after contrast exposure, he experienced sudden hypotension, chest pain, and loss of consciousness, followed by cardiac arrest despite prompt resuscitation. Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) and an intra-aortic balloon pump (IABP) were initiated for refractory hemodynamic instability. Coronary computed tomography angiography (CCTA) demonstrated atherosclerosis with 80% stenosis of the proximal left anterior descending artery (LAD), which, in the clinical context of contrast exposure and systemic allergic manifestations, supported the diagnosis of Type II KS. Over the following days, cardiac biomarkers declined, and ECMO was successfully weaned. Follow-up imaging confirmed adequate coronary perfusion without the need for percutaneous coronary intervention (PCI). The patient was discharged without neurological deficits at the three-month follow-up. This case underscores the importance of early recognition of KS, especially in patients with underlying coronary artery disease, and highlights the potential role of ECMO as rescue support in hemodynamically unstable presentations.