Prognostic factors for short-term survival of dogs that experience postattenuation seizures after surgical correction of single congenital extrahepatic portosystemic shunts: 93 cases (2005-2018).

Ronan A Mullins,Melanie Olive,Laura E Selmic,Davina M Anderson,Barbara M Kirby,Carlos Sanchez Villamil,J Brad Case,Herve Brissot,Kathryn M Pratschke,Anne Kummeling,Jean‐Philippe Billet Dr Vét,Donald A Yool,Robert N White,Ameet Singh,Cameron Broome,Michael S Tivers,Ines Gordo,Hilde Rooster,Kelley M Thieman Mankin

doi:10.1111/vsu.13422

Abstract

To identify prognostic factors for short-term survival of dogs that experience seizures within 7 days after surgical correction of single congenital extrahepatic portosystemic shunts (cEHPSS). Multi-institutional retrospective study. Ninety-three client-owned dogs. Medical records at 14 veterinary institutions were reviewed to identify dogs that underwent surgical attenuation of a single cEHPSS from January 1, 2005 through February 28, 2018 and experienced postattenuation seizures (PAS) within 7 days postoperatively. Logistic regression analysis was performed to identify factors associated with 1-month survival. Factors investigated included participating institution, signalment, shunt morphology, concurrent/historical conditions, presence of preoperative neurologic signs, presence of preoperative seizures, aspects of preoperative medical management, surgical details including method and degree of shunt attenuation, type of PAS (focal only or generalized ± focal), drugs administered as part of the treatment of PAS, and development of complications during treatment of PAS. Thirty (32.3%) dogs survived to 30 days. Seventy-six (81.7%) dogs experienced generalized PAS. Factors positively associated with short-term survival included having a history of preoperative seizures (P = .004) and development of focal PAS only (P = .0003). Most nonsurvivors were humanely euthanized because of uncontrolled or recurrent seizures. Dogs that experienced PAS that had a history of preoperative seizures and those that experienced focal PAS only had significantly improved short-term survival. The results of this study provide information that will help in the counseling of owners who seek treatment for PAS after surgical correction of cEHPSS. © 2020 The American College of Veterinary Surgeons.

Highlights

(focal only or generalized +/- focal), electrolyte, glucose and ammonia concentrations around time of post-attenuation seizures (PAS) occurrence; anti-seizure medication(s) administered as part of treatment of PAS; complications experienced during treatment of PAS; and whether the dog survived to one month
Details of 75 dogs are the subject of another report.REDACTED Details of 16 dogs have partially been reported previously.[17,18,20,21]
The main findings of this study are: (1) affected dogs that had a history of preoperative seizures and those that experienced focal PAS only had significantly increased odds of survival to 30 days, and (2) having received prophylactic treatment with LEV, treatment of PAS with propofol continuous rate infusion (CRI), and having undergone surgery/experienced PAS in the second half of the study period were not associated with improved short-term survival

Summary

Introduction

Development of post-attenuation seizures (PAS) is a well-recognized complication of surgical correction of portosystemic shunts in dogs,[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25] with often fatal consequences.[1,2,3,8,9,10,12,15,18,21,22]These seizures have an incidence of up to 4.7-8.1% in the recent literature,18,21,22,REDACTED and occur almost exclusively within five days postoperatively.[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25] The etiopathogenesis of PAS is not well understood. Development of post-attenuation seizures (PAS) is a well-recognized complication of surgical correction of portosystemic shunts in dogs,[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25] with often fatal consequences.[1,2,3,8,9,10,12,15,18,21,22]. Proposed theories include a decline in systemic concentrations of endogenous benzodiazepines/benzodiazepine-like substances, hypoglycemia, electrolyte derangements (hypocalcemia and hypokalemia), hypoxemia, exacerbation of hepatic encephalopathy, an unknown perioperative metabolic event, sudden correction of an adapted to altered metabolic state, systemic hypertension, concurrent brain disease, intraoperative hypotension, and prolonged surgical and anesthetic times.[2,3,9,10,21,23,26,26] ; none of these has been consistently identified in previous studies.[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25] For instance, PAS have been reported in the face of normal to only mildly elevated ammonia concentrations,[2,7,9,10,17,20,22] and normal glucose[7,8,9,10,17,20,21,23] and electrolyte concentrations.[17,20]

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Results

Conclusion