Prevalence and factors associated with the aortic ring sign in out-of-hospital cardiac arrest patients undergoing extracorporeal cardiopulmonary resuscitation
T Watanabe, R Amisaki, M HatanoAbstract
Background
In extracorporeal cardiopulmonary resuscitation (ECPR) cases, whole-body CT is considered effective for evaluating complications associated with resuscitation and cannulation. Conventionally, aortic ring sign (ARS) on non-contrast CT has been reported as a characteristic finding of anaemia (!). However, ARS is frequently observed in post-resuscitation CT scans. Studies comparing post-mortem and clinical imaging have shown that a hyperattenuating aortic wall was detected in 100% of post-mortem CTs compared to only 2% of scans in living patients (2). In critical care setting, such as post resuscitation, mechanisms other than anaemia may contribute to the appearance of ARS. However, the prevalence and clinical significance of ARS specifically in post-resuscitation CT remain poorly understood.
Purpose
To investigate the prevalence and the factors associated with ARS in cases of out-of-hospital cardiac arrest (OHCA) undergoing ECPR.
Methods
We analysed 56 OHCA patients treated with ECPR at our institute between January 2015 and February 2026. A total of 52 patients who underwent non-contrast CT post-ECPR were enrolled. Data on patient backgrounds, CT findings (including ARS), and in-hospital outcomes were collected.
Results
ARS was detected in 36 patients (69.2%). The median haemoglobin level was 14.0 g/dL. ARS was observed significantly more frequently in older patients (67.5 vs 50.5 years, p<0.01), those with prior coronary artery disease (40.0% vs 0%, p=0.04), and those with an initial non-shockable rhythm (44.5% vs 6.2%, p=0.03). The use of the Impella device was associated with a lower incidence of ARS (5.6% vs 37.5%, p=0.01). In-hospital mortality was 86.1% in the ARS group compared to 62.5% in the non-ARS group (p=0.07). Notably, haemoglobin levels were not significantly related to the presence of ARS (13.80 g/dL vs 14.70 g/dL, p=0.274).
Conclusion
ARS on non-contrast CT is frequently observed in OHCA patients undergoing ECPR, even in the absence of anaemia.