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)

Abstract

Objective: To identify prognostic factors for short-term survival of dogs that experienced seizures within seven days following surgical correction of single congenital extrahepatic portosystemic shunts (cEHPSS).Study Design: Multi-institutional retrospective study. Sample Population: Ninety-three client-owned dogs. Methods: Medical records at 14 veterinary institutions were reviewed to identify dogs that underwent surgical attenuation of a single cEHPSS from January 1 st 2005 through February 28 th 2018 and experienced post-attenuation seizures (PAS) within seven days postoperatively. Logistic regression analysis was performed to identify factors associated with one 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. Results: 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=0.004) and development of focal PAS only (p=0.0003).The majority of non-survivors were humanely euthanized due to uncontrolled or recurrent seizures.Conclusions: Dogs that experienced PAS that had a history of preoperative seizures and those that experienced focal PAS only had significantly improved short-term survival. Clinical Significance:The results of this study will help in the counseling of owners who seek treatment for PAS following surgical correction of cEHPSS.

Feasibility of thoracoscopic attenuation of the azygos vein as a model for portoazygos shunts: A canine cadaveric study

“…Thus, surgeons may experience more challenges related to the small body size of dogs with PA shunts compared with those encountered in this cadaveric study. Nonetheless, the median body weight of cadavers in this study (7.7 kg) was similar to the median body weights reported in other studies of dogs with CEPSS (range, 4.5‐6.5 kg) 7,21‐23 . In our study, the only modifications required to faclititate device placement in smaller cadavers consisted of removing the cannulas and using the 5‐mm right‐angle forceps to place the ameroid key.…”

“…Nonetheless, the median body weight of cadavers in this study (7.7 kg) was similar to the median body weights reported in other studies of dogs with CEPSS (range, 4.5-6.5 kg). 7,[21][22][23] In our study, the only modifications required to faclititate device placement in smaller cadavers consisted of removing the cannulas and using the 5-mm right-angle forceps to place the ameroid key. With the exception of the 10-mm right-angle forceps and the 12-mm endoscopic clip applicator, 5-mm instruments were used to isolate the azygos vein and place the attenuation devices.…”

Postattenuation neurologic signs after surgical attenuation of congenital portosystemic shunts in dogs: A review

“…13,48 Absence of preoperative neurologic signs/HE (prior to medical management or immediately preoperatively) does not exclude the possibility of PANS. 39,41,47 In a study that included 93 dogs affected by PAS, 47 approximately 25% of affected dogs did not have preoperative neurologic signs and only 17.2% had preoperative seizures. In another retrospective study, 23 only 1 of 7 dogs with PAS had preoperative seizures, while in 3 small case series 4,16,32 and a case report, 17 no dog with generalized PAS had a history of preoperative seizures.…”

“…Most published reports include only dogs affected by PAS, 1,2,4,[6][7][8][9]12,16,17,[23][24][25][26][27][29][30][31][32][33][34][35][37][38][39][40]42,[45][46][47][48][49] but others include dogs that manifest any form of PANS. 5,10,11,[13][14][15][18][19][20][21][22]28,36,41,43,44,50 Within the latter reports, 5,10,11,…”

“…PANS are reported after attenuation of portocaval, portophrenic, and portoazygos shunt submorphologies. 10,13,46,47 One retrospective study identified a trend toward dogs with portoazygos shunts being at greater risk of PANS than dogs with portocaval shunts. 13 Dogs with portoazygos shunts tend to be older at diagnosis than dogs with portocaval shunts and it is possible that their older age is responsible for increased risk of PANS in such dogs rather than the shunt submorphology.…”