Background: There are no known biomarkers to identify dogs at risk of developing seizures following surgical attenuation of congenital portosystemic shunts (CPS).
Objectives: To evaluate the association between perioperative electroencephalographic (EEG) findings and the development of post-attenuation seizures (PAS). Animals: 25 client-owned dogs with CPS.
Methods: Cohort study. Dogs undergoing CPS attenuation underwent ambulatory EEG prior to and following surgery. EEG background activity and presence of paroxysmal discharges were assessed qualitatively. Quantitative analysis of randomly selected epochs included evaluation of the mean dominant frequency (MDF), and relative power of delta, theta, alpha and beta frequency bands.
Results: Three dogs developed PAS. PAS occurred within 7 days in two dogs. These dogs had qualitative electroencephalographic abnormalities prior to attenuation and onset of neurological signs (paroxysmal discharges, persistent high amplitude theta background in both sleep and wakefulness, absence of sleep transients). Both dogs developed refractory seizures and progressive encephalopathy and were euthanized. One dog developed seizures at 35 days post-attenuation and survived >1 year. Qualitative preoperative EEG was normal for 22 dogs without PAS. Quantitative analysis was available for 16 dogs without PAS, with mean MDF ± SD was 10.5 ± 0.3 Hz. MDF of dogs with PAS fell outside the MDF range for non-PAS dogs (10.0-10.9 Hz).
Conclusions: Based on preliminary results, EEG could provide useful diagnostic biomarkers to identify high-risk dogs undergoing attenuation of CPS.
