Incidence and risk factors for neurological signs after attenuation of a single congenital portosystemic shunt in 50 cats

Abstract

Objective To determine the incidence, outcome, and risk factors for postattenuation neurological signs (PANS) in cats treated for single congenital portosystemic shunts (CPSS). Study design Retrospective cohort study. Animals Cats (n = 50) with a single CPSS. Methods Medical records of cats treated by surgical attenuation of a single CPSS between 2003 and 2017 were reviewed for signalment, surgical technique, preoperative management and postoperative clinical outcomes. Binary logistic regression was performed to investigate risk factors for occurrence of PANS and seizures. Results Congenital portosystemic shunts in 50 cats included 40 extrahepatic and 10 intrahepatic shunts. Postattenuation neurological signs were recorded in 31 (62%) cats and graded as 1 in 10 cats, 2 in nine cats, and 3 in 12 cats. Postattenuation neurological signs included seizures in 11 cats. Five of 31 cats with PANS did not survive to discharge. No association was detected between PANS or seizures and the type of CPSS (intrahepatic or extrahepatic), degree of attenuation, age, or the use of perioperative levetiracetam or hepatic encephalopathy immediately preoperatively. Osmolality at a median 24 hours postoperatively was lower in cats with PANS (P < .049, Wald 3.867, odds ratio [Exp(B)] 0.855, CI 0.732‐0.999). Conclusion Postattenuation neurological signs are common complications in cats treated for CPSS. Preoperative levetiracetam did not prevent the occurrence of PANS or seizures. The only risk factor for PANS detected was lower postoperative Osmolality in cats with PANS at 24 hours. Clinical significance Postattenuation neurological signs including seizures occur frequently in cats undergoing surgical attenuation of a CPSS. Preoperative levetiracetam did not protect against the development of PANS.

Surgical treatment and outcome of intrahepatic shunts in 12 cats

“…19 Numerous studies report PANS as the most common short-term complication in cats with a CPSS. 1,5,9,[20][21][22] It has been suggested that later published studies report a higher incidence of PANS in cats with CPSS due to a better understanding of this complication and the ability to detect milder abnormal neurological presentations such as tremors or behavioural changes. 1,9 Similar to previous studies, a majority of cats in our study were able to recover from PANS, with excellent long-term outcomes.…”

“…1,5,9,[20][21][22] It has been suggested that later published studies report a higher incidence of PANS in cats with CPSS due to a better understanding of this complication and the ability to detect milder abnormal neurological presentations such as tremors or behavioural changes. 1,9 Similar to previous studies, a majority of cats in our study were able to recover from PANS, with excellent long-term outcomes. 1,5,9,20 The occurrence of PANS after a second surgery was much lower (one cat), potentially due to the improvement in liver function following partial shunt attenuation.…”

“… † Categorised according to a four-point grading system for hepatic encephalopathy before initiation of medical management 9,10 …”

“…Neurological signs after surgery were categorised according to severity and the degree of medical intervention required to control clinical signs, as described in a previous study. 9 Antiepileptic drugs were administered to effect according to clinician preference, if neurological signs developed postoperatively. Short-term clinical outcome (<30 days after first surgery) for surviving cats was graded as good (resolution of clinical signs), moderate (improvement in clinical signs) or poor (no improvement in clinical signs or relapse).…”

Percutaneous transvenous coil embolization of an extrahepatic portosystemic shunt in a cat

“… 1 – 4 Reported complication rates associated with open surgery for EHPSS correction in cats range from 32% to 77%, with the majority being neurologic (eg, blindness, seizures and encephalopathy) in nature. 1 – 5 Postattenuation neurologic syndrome is the most common cause of mortality in cats undergoing EHPSS attenuation, with mortality rates as high as 22%. 2 , 3 , 5 Given the risk of complications and the technological advancements in surgery over the past few decades, interest in the transvenous embolization of portosystemic shunts has arisen in dogs and, more recently, in cats.…”