LAUSR

A 39-year-old woman was placed under femoro-axillary venoarterial extra-corporeal membrane oxygenation (VA-ECMO) (tip positions: right subclavian artery/inferior vena cava, subhepatic veins level) for graft dysfunction after cardiac transplantation. Eleven days later, a cervicocephalic computed tomography angiography (CTA) with contrast injection through a left subclavian central venous catheter was performed, while VA-ECMO flow rate was 3.1 L/min. There was no opacification of the right internal carotid and right middle cerebral artery (MCA) (Fig. 1a, c), despite present blood flow assessed by Doppler ultrasonography in internal carotids and MCA. The patient did not present any neurological deficit. Due to improving cardiac function, VA-ECMO was removed 24 h later. A subsequent CTA showed normal opacification of the right carotid territory, confirming the initial misestimation of cerebral perfusion (Fig. 1b, d). Lower ECMO pump flow and intrinsic cardiac output resulted in differential opacifications of the carotid arteries: right-sided perfusion from ECMO-injected, non-contrasted blood originating from the inferior vena cava and left-sided cardiac-contrasted blood from the superior vena cava. These phenomena depend on arterial and venous cannula location, ECMO pump flow and site of contrast bolus injection. Intensivists and radiologists should be aware of these potential pitfalls of CTA head imaging in VA-ECMO patients.