Purpose To determine the frequency and predictors of post-procedural diffusion-weighted-imaging (DWI) abnormalities in patients with cerebral aneurysms treated with the Pipeline Embolization Device (PED).

Methods Two interventional neuroradiologists reviewed post-procedural MRI examinations performed in patients with cerebral aneurysms treated with the PED at our institution to determine the number of DWI abnormalities present in the vascular territory of the treated aneurysm. Baseline patient and aneurysm characteristics and procedural variables were recorded.

Results Twenty-two patients were included, 15 female (68%) and 7 male (32%), mean age 53.2 years (25–79 years). Mean aneurysm size 11.2 mm (2.5–22 mm), mean neck size 6.5 mm (1.6–17 mm), 5 aneurysms were fusiform (22.7%). Mean pre-procedure P2Y12 reaction units (PRU) value was 164.9 (81–275). PEDs were deployed in the internal carotid artery (ICA) in 16 patients (72.8%), middle cerebral artery in 3 patients (13.6%) and vertebral artery in 3 patients (13.6%). Mean procedure time was 86 min (median 75 min, range 39–189 min). Mean number of PEDs deployed was 1.2. At the time of post-procedural MRI, 4 patients exhibited focal neurological deficits (18%, mean 3.5 days post-procedure) and 18 were asymptomatic (82%, all on post-operative day [POD] 1). At least 1 DWI abnormality was observed in 17 patients (77%), including all 4 symptomatic (100%) and 13 asymptomatic patients (72%). Mean number of DWI abnormalities was 12.5 (median 4, range 0–70), with a trend towards a higher number in symptomatic patients (mean 26.8, range 5–70) than in asymptomatic patients (mean 9.3, range 0–48, p-value 0.1). Eleven patients had a high DWI burden, defined as ≥5 DWI abnormalities (50%). Predictors of a high DWI burden were fusiform aneurysm morphology (100%, p-value 0.035), female sex (67%, p-value 0.06), and procedure time >90 min (70%, p-value 0.09).

Conclusion We observed a high rate of asymptomatic ipsilateral DWI abnormalities after PED procedures (72%). The combination of a high DWI burden and P2Y12-receptor over-inhibition post-procedure may play an important role in the aetiology of delayed ipsilateral ICHs encountered after PED procedures.

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Abstract O-005 Figure 1

Female patient undergoing urgent treatment of fusiform right ICA aneurysm on ticagrelor, procedure time 93 min, with high asymptomatic DWI burden (n = 48) and an asymptomatic ipsilateral intracerebral haemorrhage (ICH) identified in routine MRI on POD 1 (PRU 49 at time of asymptomatic ICH). On POD 4, after administration of 75 mg clopidogrel doses on POD 2 and 3, the patient developed severe headache, hemiparesis and hemianopsia with marked ICH enlargement and further P2Y12-receptor over-inhibition (PRU 8)

Disclosures J. Delgado Almandoz: 2; C; Covidien/ev3. Y. Kadkhodayan: 2; C; Covidien/ev3. J. Fease: None. J. Scholz: None. A. Blem: None. K. Tran: None. B. Crandall: 2; C; Covidien/ev3.