Presentation
Unable to be woken or extubated following elective open aortic arch replacement. Heavy aortic atheroma burden noted on intraoperative transesophageal echocardiogram. Examination findings included: fluctuating GCS between 4-10, right gaze preference, intermittent apneic breathing, absent reflexes to painful stimulus in upper limbs, intact cough, gag and corneal reflexes.
Patient Data
There is no extra or intra-axial bleeding identified, no fluid collections or mass lesions.
The main findings are bilateral cerebellar and cerebral hypodense lesions in multiple vascular territories (both carotid and vertebrobasilar arteries). There is sulcal effacement and gyral swelling in the parietal lobes with loss of grey/white matter differentiation.
The possible sources of the patients clinical state are either multiple watershed hypoxic infarcts (associated with prolonged aortic cross-clamp time in theater) or multiple infarcts associated with embolization of aortic atheroma.
There are extensive sub-acute areas of infarction of both superior cerebral hemispheres (predominantly fronto-parietal region but also involving occipital lobes).
There is extensive cerebellar involvement and left para median pons.
There is extensive deep infarction involving both hippocampi, right thalamus, posterior limb of the left internal capsule, head of both caudate nuclei, right external capsule, a moderate sized ovoid focus in the splenium and a smaller focus in the body of the corpus callosum. These areas demonstrate diffusion restriction and increased T2 and FLAIR signal.
There is an area of cystic encephalomalacia in the right corona radiata compatible with an older area of infarction.
The SWI sequence shows extensive small foci of susceptibility artefact scattered throughout both the cerebral and cerebellar hemispheres and scattered foci within the brain stem. No significant abnormality of the intracranial MRA.
Case Discussion
This 70 year old previously well female presented with chest pain 2/12 prior whilst overseas. She was worked up and diagnosed with an aortic arch aneurysm and right coronary artery (RCA) stenosis.
She returned to her home country and proceeded to elective aortic arch replacement and coronary artery bypass graft of the RCA. Her past medical history was untreated hypertension. She was a non-smoker. Family history unknown.
Cardiopulmonary bypass time was 208 minutes and aortic cross-clamp time was 88 minutes. It was noted on the intraoperative trans-esophageal echocardiogram that the patient had atheroma burden in her aortic arch.
The patient was admitted to the ICU intubated and sedated. Sedation was switched off but neurological deficits were apparent within several hours (as mentioned above).
The initial non-contrast CT was taken day 1 post-operative and signs were suggestive of sub-acute cerebral,cerebellar and brainstem infarction.
MRI was able to be performed on day 5 post-operative once the pacing wires were removed. The key finding that confirms multiple embolic infarcts are the hypointense susceptibility vessel signs seen on SWI.
It is likely the patient had a "shower" of microemboli from her aortic atheroma burden at the time of vessel cannulation or cross-clamping during surgery.
Unfortunately, the patient was not a candidate for clot retrieval nor thrombolysis. She succumbed to this injury and died when cardiopulmonary supports were withdrawn.
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