Aortic Dissection Mimicry Under Extracorporeal Membrane Oxygenation (ECMO) After Cardiac Arrest: A Case Report of Emergency Imaging Dilemmas.

Background and Clinical Significance: Peripheral veno-arterial extracorporeal membrane oxygenation (VA-ECMO) substantially alters aortic flow dynamics, generating catastrophic false-positive pathology on standard imaging. We report a case of ECMO-induced artifacts mimicking a Stanford type A aortic dissection (TAAD), which led to an unnecessary exploratory sternotomy. Case Presentation: A 67-year-old man underwent extracorporeal cardiopulmonary resuscitation (ECPR) for a shockable out-of-hospital cardiac arrest. Post-resuscitation chest computed tomography angiography (CTA) and preoperative transesophageal echocardiography (TEE) demonstrated a prominent flap-like structure in the ascending aorta, prompting emergency sternotomy. Intraoperative exploration revealed no intimal tear. Subsequent evaluation confirmed an acute anterior myocardial infarction, managed with coronary intervention. Following a dismal neurological prognosis due to hypoxic encephalopathy, VA-ECMO was palliatively withdrawn on day 9, and the patient expired on day 19. The interaction between retrograde ECMO flow and varying levels of intrinsic cardiac function dictates the topology of flow disturbances. Absent native flow creates contrast layering within the aortic root, whereas preserved native flow creates a volatile downstream watershed zone. Based on these distinct phenotypes, we propose a novel conceptual framework for tailor-made imaging strategies titrated to native flow strength-such as temporary ECMO flow reduction for preserved native output, or circuit contrast injections for profound cardiac depression.

Conclusions

ECMO-related artifacts present substantial diagnostic pitfalls. Clinicians should adopt a context-aware approach, integrating multi-modality imaging with hemodynamic status to implement individualized, physiologically guided imaging protocols.