Republished: Paradoxical cerebral air embolism causing large vessel occlusion treated with endovascular aspiration

Iatrogenic stroke caused by cerebral air embolism and acute reperfusion therapy using hyperbaric oxygen

Objective:

Air embolisms are mostly iatrogenic and a rare yet dreaded complication following percutaneous procedures. Intravascular entrapment of air can result in occlusion of end arteries and subsequent tissue ischemia and infarction. Cerebrovascular occlusions caused by air embolisms are time-sensitive and an uncommon cause of ischemic stroke, warranting an alternative acute management and reperfusion strategy.

Methods:

During a CT-guided lung biopsy, the patient developed left-sided paresis and sensory deficits prior to loss of consciousness. CT revealed air in the aorta, both ophthalmic arteries and vessels in the right parietal region. The patient was swiftly air-lifted to the nearest hyperbaric oxygen chamber for an alternate emergency reperfusion therapy. The following eight days the patient received hyperbaric oxygen therapy and gradually improved. Nine days after symptom onset he was discharged with a minor left facial palsy.

Conclusions

Cerebrovascular occlusions are critical events regardless of etiology. Air embolism is rare but potentially catastrophic and can occur during both percutaneous procedures and surgeries. Vigilance and knowledge of this potential complication are needed to rapidly provide beneficial treatment. That is, high flow oxygen and correct positioning pending hyperbaric oxygen therapy.

Intra-aneurysmal air after flow diversion treatment in intracranial aneurysms: incidence, characteristics and clinical significance

OBJECTIVE

To describe the rate and characteristics of air bubble retention (ABR) within cerebral aneurysms treated by flow diversion.

METHODS

Procedural flat detector CT (FDCT) studies were scrutinized for the presence of air bubbles (density < - 200 HU) in patients treated by flow diversion. Patients with intrasaccular treatment or previous clipping were excluded. Clinical outcomes, procedural angiograms, aneurysm characteristics and imaging features of air within the aneurysm were evaluated.

RESULTS

Bubbles were noted in 17.1% of 105 aneurysms in 85 FDCTs. Aneurysms with ABR were significantly larger (mean diameter: 18.9 versus 7.5 mm, P < 0.0001). There was a trend for the use of multiple devices during the treatment of these aneurysms (72.2% vs 49.4%, P = 0.071). All of the bubbles were located rostrally in the aneurysm sac and were smaller than 6 mm (mean diameter: 2.1 ± 1.3 mm). None of the patients had post-procedural neurological deterioration. The air had spontaneously disappeared on follow-up CT images (available in 12 patients) obtained at a mean follow-up duration of 48 h.

CONCLUSIONS

ABR is not infrequent in cerebral flow diversion procedures. It is a clinically silent and self-limited technical complication. We propose air entrapment or filtration through the flow diverter as causative factors.