Surgical Attenuation Research Articles

Outcome of 21 dogs treated for the portocaval subtype of extrahepatic portosystemic shunts.

To assess outcomes of dogs with side-to-side portocaval extrahepatic portosystemic shunts (PC-EHPSS) and poor portal perfusion to the liver treated with medical management alone (MM) or surgical attenuation (SA). Multi-institutional retrospective study. A total of 21 dogs with PC-EHPSS (14/21 MM and 7/21 SA). Medical records were reviewed, and data was collected on dogs <12 kg with PC-EHPSS treated with MM or SA between June 2008 to June 2021. Signalment, clinical signs, postoperative complications, bloodwork values, long-term clinical outcome, survival, and owner reported quality of life were recorded. Of 21 dogs included, 10 were mixed breeds and 14 were females. Median age at time of presenting clinical signs was 163 days. At final follow-up examination (median 1119 days), all SA and 6/14 MM dogs were alive, with a median survival time of 2138 days following treatment onset. In surviving MM dogs, outcome was fair in 3/6 and poor in 3/6. In SA dogs with long-term follow-up, outcome was fair in 5/6, and poor in 1/6. A greater proportion of SA dogs had improved bloodwork parameter values at final follow-up examination, and the mean relative change in final bloodwork values was higher when compared to MM dogs. These findings demonstrate that SA has improved clinical outcomes to MM for PC-EHPSS; however, SA clinical outcomes appear worse than those previously reported for other EHPSS. This information may have implications for expected outcomes in other EHPSS subtypes associated with severely diminished portal perfusion.

Hepatic Gene Expression of Angiogenic and Regeneration Markers in Cats with Congenital Portosystemic Shunts (CPSS).

Congenital portosystemic shunts (CPSS) are vascular anomalies resulting in liver hypoplasia and hepatic insufficiency. Cats with CPSS typically show signs of hepatic encephalopathy associated with increased ammonia, inflammatory cytokines, and oxidative stress. Surgical attenuation of the CPSS results in improved liver function, resolution of clinical signs, and increased portal blood flow. Hepatic gene expression has not previously been investigated in cats with CPSS. Here, we compared the hepatic expression of genes involved in the urea cycle (CPS1, NAGS), angiogenesis (VEGFR2, NPPA, NPR1, NPPC, NPR2, HIF1a), liver regeneration (SERPINB1, HGF, TGFβ), and metabolism (FGF21) from a small series of cats (n = 18) with CPSS to that of control cats (n = 10). The expression of TGFβ, VEGFR2, HGF, FGF21, and CPS1 was significantly elevated in liver biopsies from cats with CPSS. Cats that could only tolerate partial closure of their CPSS had increased hepatic expression of SERPINB1, HIF1a, and NPR2 compared with those that could tolerate complete ligation. Furthermore, there were no significant correlations between gene expression and pre-operative plasma ammonia concentrations in cats with CPSS. The changes in hepatic gene expression in cats with CPSS are in direct contrast to those seen in dogs with CPSS, suggesting alternative mechanisms may be involved in mediating hepatic changes in cats with CPSS.

Clinical outcomes for 20 cats with congenital extrahepatic portosystemic shunts treated with ameroid constrictor ring attenuation (2002-2020).

To report the clinical perioperative, short-term, and long-term outcomes for cats undergoing ameroid ring constrictor (ARC) attenuation of a congenital extrahepatic portosystemic shunt (EHPSS). Retrospective case series from a single veterinary teaching hospital (2002-2020). Twenty client-owned cats with EHPSS. Data collected from medical records included signalment, history, physical examination, clinicopathologic testing, medications, diagnostic imaging, intraoperative findings, perioperative complications, and postoperative clinical outcomes. Long-term clinical outcome was obtained from a standardized owner interview or medical records. Perioperative complications were reported in five cats out of 20, including blindness (two cats), ascites (one cat), head pressing (one cat), and seizures and death (one cat). Short-term clinical outcome was excellent in 14/18 cats, good in 2/18 cats, and poor in 2/18 cats that were available for follow up, and long term clinical outcome was excellent in 15/18, good in 1/18 cats, and poor in 2/18 cats that were available for follow up. Long-term clinical outcome was good or excellent in 16/18 of cats available for follow up. Perioperative complications were reported in five cats. Surgical attenuation of EHPSS with an ARC can result in resolution of clinical signs and biochemical abnormalities in the majority of cats. The perioperative complication rate for feline patients with EHPSS attenuated with an ARC was lower than reported historically. Seizures may persist in the long term despite normal bile acid stimulation test results, complete blood count, and biochemistry analysis.

Regional cerebral blood flow in dogs with congenital extrahepatic portosystemic shunts before surgery and six months after successful closure

Previous studies both in humans and dogs with chronic liver diseases have shown that regional cerebral brain flow (rCBF) is altered. The current study aimed to assess abnormalities in rCBF in dogs with congenital extrahepatic portosystemic shunts (cEHPSS), both at diagnosis and after successful surgical attenuation. Furthermore, the influence of age at diagnosis, severity of hepatic encephalopathy (HE) and type of cEHPSS on rCBF were explored as a base for future research.Single photon emission computed tomography (SPECT) with 99mtechnetium-hexamethylpropylene amine oxime tracer was performed before surgical attenuation and six months postoperatively.Twenty-four dogs with cEHPSS had SPECT at time of diagnosis and 13 dogs with a confirmed closed cEHPSS had a second SPECT six months postoperatively. At diagnosis, dogs with cEHPSS had an altered rCBF distribution compared to healthy dogs. This altered rCBF distribution seemed to be most apparent in dogs ≥ one year and in dogs with overt HE at diagnosis. Six months postoperatively, only the rCBF distribution in the subcortical region decreased compared to pre-operatively.In conclusion, all dogs with cEHPSS had altered rCBF which did not seem to normalize completely six months after successful surgical attenuation. Dogs diagnosed at an older age seemed to have more distinct abnormalities in rCBF compared to younger dogs.

Outcomes in dogs with congenital extrahepatic portosystemic shunts treated with surgical ligation or medical management.

The objective of this study was to evaluate differences in outcomes in dogs treated for extrahepatic portosystemic shunts (EHPSS) by either complete suture ligation, partial suture ligation or medical management. This wasa retrospective, single institutional study. Dogs (n = 152) with EHPSS treated with suture ligation (n = 62), surgery with no ligation (n = 2), or medical management (n = 88). Medical records were reviewed for data on signalment, treatment variables, complications, and outcome. Kaplan-Meier plots were generated to assess survival across groups. Cox's proportional hazard models were used to assess the relationship between survival times and multiple predictor variables. For outcomes of interest, backwards, stepwise regression was performed (p < 0.05). Complete suture ligation was possible in 46/64 (71.9%) of dogs where surgical attenuation was attempted. One dog was euthanized following partial suture ligation due to suspected portal hypertension. Dogs with complete suture ligation of the EHPSS had a significantly longer median survival time (MST) compared to the medical management group (MST not reached vs. 1730 days [p < 0.001]). Complete resolution of clinical signs (without the need for further medical treatment or dietary changes) was achieved in 16/20 (80.0%) dogs with complete suture ligation and 4/10 (40.0%) dogs with partial suture ligation of their EHPSS. Suture ligation (complete or partial) for the treatment of EHPSS, where clinically possible, yielded the best clinical outcome and increased longevity compared to medical management in this study. While medical management for the treatment of EHPSS in dogs is a valid treatment option, better clinical outcomes are achieved with surgical intervention.

Congenital Portosystemic Shunts in Dogs and Cats: Treatment, Complications and Prognosis.

Congenital portosystemic shunts (CPSS) are a common vascular anomaly of the liver in dogs and cats. Clinical signs of CPSS are non-specific and may wax and wane, while laboratory findings can raise the clinical suspicion for CPSS, but they are also not specific. Definitive diagnosis will be established by evaluation of liver function tests and diagnostic imaging. The aim of this article is to review the management, both medical and surgical, complications, and prognosis of CPSS in dogs and cats. Attenuation of the CPSS is the treatment of choice and may be performed by open surgical intervention using ameroid ring constrictors, thin film banding, and partial or complete suture ligation or by percutaneous transvenous coil embolization. There is no strong evidence to recommend one surgical technique over another. Medical treatment strategies include administration of non-absorbable disaccharides (i.e., lactulose), antibiotics, and dietary changes, and are indicated for pre-surgical stabilization or when surgical intervention is not feasible. After CPSS attenuation, short- and long-term post-surgical complications may be seen, such as post-operative seizures and recurrence of clinical signs, respectively. Prognosis after surgical attenuation of CPSS is generally favorable for dogs and fair for cats.

Opioid‐free anaesthesia for surgical attenuation of a congenital extrahepatic portosystemic shunt in a dog

AbstractAnimals with impaired hepatic metabolism may experience reduced effect from some anaesthetic drugs and are more prone to developing unwanted side effects. Due to reduced blood flow to the liver, it is important to carefully select anaesthetic drugs in patients with extrahepatic shunt. We present the case in which a dog was submitted for surgical attenuation of congenital extrahepatic portosystemic shunt through placement of an ameroid constrictor. A multimodal regimen was designed in order to provide an opioid‐free anaesthesia, relying on analgesia through a locoregional quadratus lumborum block with bupivacaine. Dexmedetomidine was administered intramuscularly as pre‐anaesthetic medication, propofol was used for the induction and anaesthesia was maintained with isoflurane. The present case describes the first case in which an extrahepatic portosystemic shunt was surgically treated using an opioid‐free anaesthesia in a dog.

Prediction of outcome after ligation or thin film banding of extrahepatic shunts, based on plasma albumin concentration and hematologic expression of 8 target genes in 85 dogs.

In dogs with a congenital extrahepatic portosystemic shunt (EHPSS), outcome after surgical attenuation is difficult to predict. Develop a minimally invasive test to predict outcome after surgical EHPSS attenuation and establish risk factors for postattenuation seizures (PAS). Eighty-five client-owned dogs referred for surgical attenuation of a single EHPSS. mRNA expression of 8 genes was measured in preoperatively collected venous blood samples. Outcome was determined at a median of 92 days (range, 26-208) postoperatively by evaluating clinical performance, blood test results and abdominal ultrasonography. Multivariable logistic regression was used to construct models predicting clinical and complete recovery. The associations between putative predictors and PAS were studied using univariable analyses. Five of 85 dogs developed PAS. Risk factors were age, white blood cell (WBC) count and expression of hepatocyte growth factor activator and LysM and putative peptidoglycan-binding domain-containing protein 2. Clinical recovery was observed in 72 of 85 dogs and complete recovery in 51 of 80 dogs (median follow-up, 92 days). The model predicting clinical recovery included albumin, WBC count, and methionine adenosyltransferase 2 alpha (MAT2α) expression, whereas the model predicting complete recovery included albumin, and connective tissue growth factor precursor and MAT2α expression. The areas under the receiver operating characteristic curves were 0.886 (95% confidence interval [CI]: 0.783, 0.990) and 0.794 (95% CI: 0.686, 0.902), respectively. Two models were constructed for predicting outcome after EHPSS attenuation using venous blood samples. The model predicting clinical recovery showed the best diagnostic properties. Clinical application requires further validation.

Postattenuation neurologic signs after surgical correction of congenital portosystemic shunts in cats: A narrative review.

Development of postattenuation neurological signs (PANS) is a potentially severe complication after surgical attenuation of congenital portosystemic shunts in cats. This review summarizes findings of 15 publications that report occurrence of PANS in cats. PANS includes seizures but also milder neurologic signs such as blindness, ataxia, abnormal behavior, tremors, and twitching. Incidence of PANS and specifically postattenuation seizures in studies including a minimum of five cats ranges from 14.3% to 62.0% and 0% to 32.0%, respectively. Etiology of PANS in cats is unknown, however, several hypotheses have been proposed including central nervous system disease/derangement, perioperative hypoglycemia and electrolyte disturbances, and postoperative portal hypertension. A number of possible risk factors have been identified including lower grades of intraoperative postocclusion mesenteric portovenography and osmolality at 24 h postoperatively. Evidence for use of prophylactic antiepileptics such as levetiracetam to prevent or reduce incidence of PANS in cats is limited and does not support their use. Because the cause is unknown, treatment is aimed at controlling neurologic signs, preventing progression to more severe signs, and providing general supportive care. Prospective studies comparing the efficacy of different antiepileptics for treatment of PANS in cats are required. Prognosis for recovery is variable and dependent on severity of neurologic signs. For cats surviving to discharge, long-term survival is possible but persistence or recurrence of neurologic signs in the long-term is not uncommon.

Attenuation of right gastrocaval extrahepatic shunt with cellophane band in a dog: Case report

Congenital extrahepatic portosystemic shunt is a vascular anomaly that consists in the communication between the portal and systemic circulation, causing substances normally metabolized and excreted by the liver to be diverted directly to the systemic circulation and triggering changes in neurological, gastrointestinal and urinary systems. Diagnosis is through imaging tests, such as ultrasound and computed tomography. For patient stabilization, initial clinical treatment is highly indicated, especially for those who manifest signs of hepatic encephalopathy, and the definitive treatment is gradual surgical attenuation. Currently, the most indicated techniques for shunt occlusion are the ameroid constrictor ring and the cellophane band, which have good long-term results. The prognosis of patients undergoing the surgical procedure varies according to the general condition of the patient at the time of diagnosis and the complications that may occur in the trans and postoperative periods, such as portal hypertension, seizures, hypoglycemia and failure to close the shunt. This report aims to describe a case of surgical attenuation of a right extrahepatic gastrocaval shunt using the cellophane band technique. The canine patient, pug, aged eight months, was treated at the Veterinary Hospital of the Federal University of Paraná, presenting neurological clinical signs and a previous diagnosis of portosystemic shunt. To determine the origin of the anomalous vessel and optimize surgical planning, computed angiotomography was indicated. Clinical treatment was instituted and, after 15 days, surgical attenuation of the shunt was performed using the cellophane band fixed with titanium clips. The patient showed signs of portal hypertension, ascites and postoperative hypoglycemia, which were treated during hospitalization. After 15 days of hospital discharge, the patient returned to the Veterinary Hospital with good general condition, absence of ascites and neurological signs and no significant changes were observed in laboratory tests, demonstrating the effectiveness of the chosen surgical technique.

Shear wave elastography measurements in dogs treated surgically for congenital extrahepatic portosystemic shunts.

Assessing the postoperative surgical success of congenital extrahepatic portosystemic shunt (EHPSS) attenuation can be challenging and involve invasive imaging methods. Elastography is an ultrasound technique that allows qualitative and quantitative estimation of tissue stiffness and has extensively been used in people with liver disease. In recent years, increased interest in this technique has developed in veterinary medicine due to its non-invasive nature, availability, and low cost. The objective of this study was to compare liver stiffness values between dogs with closed EHPSS and those with multiple acquired portosystemic shunts (MAPSS) after gradual surgical attenuation and to assess whether shear wave elastography could be used to determine EHPSS closure. As a secondary objective, measurements obtained from both intercostal and subxiphoidal views were compared. Mean values for the average, median, and maximum two-dimensional shear wave velocities (2D SWV) for the closed EHPSS were 2.88 +/−0.11 m/s; 2.83 +/−0.11 m/s; and 3.75 +/−0.16 m/s, respectively. In the MAPSS dogs, mean values for the average, median, and maximum 2D SWV were 2.77 +/– 0.17 m/s; 2.71 +/– 0.17 m/s; and 3.66 +/−0.24 m/s, respectively. No significant differences in 2D SWV were present between dogs with closed EHPSS and those with MAPSS (P = 0.33; P = 0.33; P = 0.42, respectively). When assessing potential differences between intercostal and subxiphoidal 2D SWV measurements, no effect was observed for the average and median 2D SWV (P = 0.06; P = 0.07, respectively). Yet, a significant difference was identified for the maximum 2D SWV between intercostal 4.00 +/−0.20 m/s and subxiphoidal 3.41 +/−0.17 m/s measurements (P = 0.02). The relevance of this finding is uncertain as many other studies about liver elastography only report mean and not maximum values.

Surgical treatment and outcome of intrahepatic shunts in 12 cats.

The objective of this case series was to describe the presentation, surgical treatment and outcome of a congenital intrahepatic portosystemic shunt (IHPSS) in 12 cats. A retrospective case series of cats undergoing surgical treatment for an IHPSS was undertaken. Signalment, clinical signs, imaging, surgical treatment, complications and short-term outcome (<30 days) were obtained using medical records. Long-term outcome (>1 year after first surgery) was obtained, where possible, using a health-related quality of life owner questionnaire. Seven cats were diagnosed with a left divisional shunt, three with a central divisional shunt and two with a right divisional shunt using intraoperative mesenteric portovenography. Three cats tolerated complete acute suture attenuation, eight cats underwent partial suture attenuation, four of which received complete suture ligation at a second surgery, and one cat underwent partial attenuation with a thin film band. Six cats (50%) developed post-attenuation neurological signs (PANS) after first surgery and two cats (17%) died or were euthanased due to severe PANS. Long-term outcome was available for eight cats (67%), with a median follow-up time of 1743 days (range 364-2228), and was described as excellent in five cats (63%), fair in two cats (25%) and poor in one cat (12%). Few papers exist that describe the presentation, intraoperative imaging, treatment and outcome of IHPSSs in cats. This is the first to describe surgical attenuation with a thin film band in a cat with an IHPSS. This case series reports excellent long-term outcomes in a majority of surgically treated cats with IHPSS.

Total lipid concentration of hairs increases after successful attenuation of extrahepatic portosystemic shunts in dogs.

Skin and coat quality can reflect nutritional deficiencies in humans and dogs with liver diseases. Determine skin and coat quality based on a scoring protocol and skin biopsies in dogs with an extrahepatic portosystemic shunt (EHPSS), and determine total lipid concentrations in hairs of dogs at time of surgery and 3 months after successful shunt closure. Ten client-owned dogs that underwent successful gradual attenuation of EHPSS, as defined by transsplenic portal scintigraphy, were included. A prospective cohort study was performed. All dogs underwent gradual attenuation of the EHPSS. Skin and coat scoring was performed at diagnosis, surgery, and 1 and 3 months postoperatively. Hair was plucked from the lumbar region for total lipid analysis and an 8 mm punch skin biopsy was taken at time of surgery and 3 months postoperatively, when the dogs underwent transsplenic portal scintigraphy to determine EHPSS closure. No significant differences were observed in skin and coat scoring over time. Total lipid concentrations of hairs increased significantly from surgery to 3 months postoperatively [30 μg/mg hair (13-56 μg/mg hair) to 47 μg/mg hair (25-63 μg/mg hair); p= 0.005]. Skin biopsies showed the presence of significantly more scales 3 months postoperatively (p= 0.018). A significant increase in total lipid concentrations in hairs suggests that successful surgical attenuation of EHPSS improves either intestinal absorption of lipids, fat metabolism in the liver, or a combination of both.

Dogs ≥ five years of age at the time of congenital extrahepatic portosystemic shunt diagnosis have better long-term outcomes with surgical attenuation than with medical management alone.

To determine the outcome in dogs diagnosed with congenital extrahepatic portosystemic shunts (EHPSS) at ≥ 5 years of age treated with medical management only (M) or with surgical attenuation (S). The hypothesis was that dogs undergoing surgical attenuation would have a longer survival time than dogs undergoing medical management only. 351 dogs definitively diagnosed with EHPSS at ≥ 5 years of age. Medical records from 2009 to 2019 at 16 veterinary teaching hospitals were evaluated. Data collected included signalment, clinical signs at diagnosis, clinicopathologic data, surgical and medical treatments, shunt morphology, clinical signs and medical treatments at 6 to 12 months after diagnosis, and survival time. 351 dogs (M, 119 [33.9%]; S, 232 [66.1%]) were included in the study. Survival time was longer with surgery than medical management (hazard ratio, 4.2; M, 3.4 years; S, 10.9 years). Continued clinical signs at 6 to 12 months after diagnosis were more common with medical management (M, 40% [33/88]; S, 14% [21/155]). Continued medical treatments at 6 to 12 months after diagnosis were more common in the medical management group (M, 78% [69/88]; S, 34% [53/155]). Perioperative mortality rate was 7.3%. Dogs diagnosed at ≥ 5 years of age with EHPSS have significantly better survival times and fewer clinical signs with surgical attenuation, compared with medical management. Older dogs have similar surgical mortality rates to dogs of all ages after surgical EHPSS attenuation.

Does surgical or medical management of extrahepatic portosystemic shunts in dogs carry a better prognosis for the resolution and reduction of neurological dysfunction?

PICO question&#x0D; In dogs with congenital extrahepatic portosystemic shunts that are treated with surgical attenuation what is the persistency, frequency, severity and outcome of neurological signs when compared to dogs that are treated medically?&#x0D; &#x0D; Clinical bottom line&#x0D; Category of research question&#x0D; Prognosis&#x0D; The number and type of study designs reviewed&#x0D; Ten papers were critically reviewed&#x0D; Strength of evidence&#x0D; Weak&#x0D; Outcomes reported&#x0D; For short-term success, owners reported an overall decrease in neurological signs associated with neurological dysfunction and an increase in quality of life after the initiation of either medical management or surgical management. Surgical management has a weak association with higher mortality or severe neurological signs in the immediate postoperative period&#x0D; Conclusion&#x0D; It is challenging to make a direct comparison between medical and surgical management but, overall, both strategies seemed to decrease neurological signs in the short term. There was a lack of evidence and available data about the efficacy of each for long-term control of neurological signs&#x0D; &#x0D; How to apply this evidence in practice&#x0D; The application of evidence into practice should take into account multiple factors, not limited to: individual clinical expertise, patient’s circumstances and owners’ values, country, location or clinic where you work, the individual case in front of you, the availability of therapies and resources.&#x0D; Knowledge Summaries are a resource to help reinforce or inform decision making. They do not override the responsibility or judgement of the practitioner to do what is best for the animal in their care.&#x0D; &#x0D;

Persistent hypercobalaminemia three months after successful gradual attenuation of extrahepatic shunts in dogs: a prospective cohort study

BackgroundDeficiencies in vitamin A and D and disorders in the vitamin B complex are often present in people with chronic liver diseases. So far, the serum concentrations of these vitamins have not yet been studied in dogs with congenital extrahepatic portosystemic shunts (EHPSS), who also have some degree of liver dysfunction. The objective was to assess serum vitamin concentrations in dogs with EHPSS from diagnosis to complete closure. A prospective cohort study was performed using ten client-owned dogs with EHPSS, closed after gradual surgical attenuation. Serum concentrations of vitamin A, 25-hydroxyvitamin D, folic acid, cobalamin and methylmalonic acid (MMA) were measured at diagnosis prior to institution of medical therapy, prior to surgery, and three months after gradual attenuation and complete closure of the EHPSS.ResultsAt diagnosis, median serum concentrations of vitamin A, 25-hydroxyvitamin D and folic acid were 18.2 μg/dL (8.8 - 79.5 μg/dL), 51.8 ng/mL (19.4 - 109.0 ng/mL), and 8.1 μg/L (5.2 - 14.5 μg/L), respectively, which increased significantly postoperatively (88.3 μg/dL (51.6 - 182.2 μg/dL, P=0.005), 89.6 ng/mL (49.3 - >150.0 ng/mL, P =0.005), and 14.8 μg/L (11.5 - 17.7 μg/L, P <0.001), respectively). Median serum cobalamin concentrations were 735.5 ng/L (470 - 1388 ng/L) at diagnosis and did not significantly decrease postoperatively (P =0.122). Both at diagnosis and three months postoperatively 7/10 dogs had hypercobalaminemia.ConclusionsSerum concentrations of vitamin A, 25-hydroxyvitamin D and folic acid significantly increase after surgical attenuation. Nevertheless, persistent hypercobalaminemia is suggestive of ongoing liver dysfunction, despite successful surgery.

Assessment of stress response attenuation with caudal morphine using a surrogate marker during pediatric cardiac surgery.

Background:Measurement of biomarkers representing sympathetic tone and the surgical stress response are helpful for objective comparison of anesthetic protocols.Aims:The primary aim was to compare changes in chromogranin A levels following pump pediatric cardiac surgery between children who received bolus caudal morphine and those who received a conventional intravenous narcotic-based anesthesia regime. The secondary objectives were to compare hemodynamic responses to skin incision and the magnitude of the rise in blood sugar values between the groups.Settings and Design:A prospective observational study at a tertiary cardiac center.Measurements and Methods:Sixty pediatric cardiac surgical patients were randomized to Group I [n = 30] to receive intravenous narcotic-based anesthesia and Group II [n = 30] to receive single-shot caudal morphine. Baseline and postoperative chromogranin A levels, the hemodynamic response to skin incision, changes in blood sugar levels, and the total intravenous narcotic dose administered were recorded for each participant.Statistical Analysis:Pearson's Chi-squared test was used for comparison of categorized variables, and Mann–Whitney test was used for the analysis of continuous data.Results:Changes in chromogranin A levels and blood sugar levels were comparable in both groups. Group II received a lower narcotic dosage (P ≤ 0.001), and the response to skin incision as reflected by systolic pressure rise was less (P = 0.006).Conclusions:Surgical stress response attenuation was similar to caudal morphine as compared with intravenous narcotic-based anesthesia techniques as reflected by a similar increase in chromogranin A levels.

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

The development of postattenuation neurologic signs (PANS) is a poorly understood and potentially devastating complication after surgical attenuation of congenital portosystemic shunts in dogs. Postattenuation neurologic signs include seizures but also more subtle neurologic signs such as depression, behavioral changes, tremors, and twitching. They most commonly occur within 7 days postoperatively and are typically unrelated to hyperammonemia, hypoglycemia, or electrolyte disturbances. This narrative review summarizes the findings of 50 publications from 1988-2020 that report occurrence of PANS. While most published reports included only dogs affected by postattenuation seizures (PAS), others included dogs with any form of PANS. Overall, PANS (including PAS) affected 1.6%-27.3% of dogs, whereas incidence of PAS ranged from 0%-18.2%. The etiology of PANS remains unknown; however, several theories have been proposed. Risk factors include preoperative hepatic encephalopathy, increasing age, and possibly certain breeds and extrahepatic shunt morphology. There is increasing evidence that prophylactic antiepileptic drugs do not prevent PANS. Treatment is centered around controlling neurologic signs with antiepileptic drugs and providing supportive intensive care. The 30-day survival rate in studies that included a minimum of four dogs affected by PANS was 0%-100% (median, 50.0%) and 0%-75.0% (median, 37.5%) for those with PAS. Mortality associated with PANS was typically related to occurrence of generalized seizure activity. Prognostic factors positively associated with short-term survival included having a history of preoperative seizures and development of focal seizures only. If affected dogs survived to discharge, survival for several years was possible, and the majority of neurologic signs manifested as part of the phenomenon of PANS appeared to resolve.

Plasma amino acid profiles in dogs with closed extrahepatic portosystemic shunts are only partially improved 3 months after successful gradual attenuation.

BackgroundDogs with portosystemic shunts have an altered blood amino acid profile, with an abnormal branched‐chained amino acid (BCAA)‐to‐aromatic amino acid (AAA) ratio being the most common abnormality. Different liver diseases have distinctive amino acid profiles.ObjectivesDetermine the changes in plasma amino acid profiles in dogs with extrahepatic portosystemic shunts (EHPSS) from diagnosis to complete closure.AnimalsTen client‐owned dogs with EHPSS closed after surgical attenuation.MethodsProspective cohort study. Medical treatment was instituted in dogs diagnosed with EHPSS. At least 4 weeks later, gradual surgical attenuation was performed. Three months postoperatively, EHPSS closure was confirmed by transsplenic portal scintigraphy. Clinical signs were scored and blood was taken before institution of medical treatment, at time of surgery, and 3 months postoperatively. At the end of the study, the plasma amino acid profiles were analyzed in batch.ResultsThe median BCAA‐to‐AAA ratio was extremely low (0.6) at time of diagnosis and remained low (0.5) at time of surgery, despite the fact that median neurological score significantly improved from 22 to 2 after starting medical treatment (P = .04). Three months after surgical attenuation, a significantly higher BCAA‐to‐AAA ratio (1.5) was observed (P < .001).Conclusions and Clinical ImportanceMedical treatment does not improve the BCAA‐to‐AAA ratio in dogs with EHPSS, despite substantial clinical improvement. Although the ratio significantly increased after EHPSS closure, it was still indicative of moderate to severe hepatic dysfunction in all dogs.

Serum hyaluronic acid, a marker for improved liver perfusion after gradual surgical attenuation of extrahepatic portosystemic shunt closure in dogs

Current liver function tests used in dogs do not consistently normalise after successful surgical attenuation of portosystemic shunts (PSS). Serum hyaluronic acid (sHA) concentrations in dogs with PSS are reported to be higher at diagnosis than in healthy dogs. The objective of this study was to assess sHA as a marker of liver perfusion by measuring sHA concentrations in dogs before and after gradual surgical attenuation of extrahepatic (EH)PSS and by determining whether sHA concentrations could differentiate closed EHPSS from persistent shunting. Specificity of sHA was assessed by comparing sHA concentrations in dogs with EHPSS to those in dogs with other liver diseases.Twenty dogs with EHPSS had sHA concentrations measured at diagnosis, 1, 3, and 6 months postoperatively. In addition, sHA concentrations were determined in 10 dogs with other liver diseases. At EHPSS diagnosis, median sHA concentration was 335.6 ng/mL (43.0−790.7 ng/mL). All dogs had a significant decrease in sHA concentrations from 1 month postoperatively onwards (P < 0.05), regardless of surgical outcome. At all postoperative follow-up visits, there was a significant difference between the median sHA concentration in dogs with closed EHPSS vs. those with persistent shunting (P < 0.05). Median sHA concentration in dogs with other liver diseases was 89.8 ng/mL (22.9−160.0 ng/mL), which was significantly lower than dogs with EHPSS at diagnosis (P < 0.001). In conclusion, sHA is a promising non-invasive biomarker that can help to determine liver perfusion after surgical attenuation of EHPSS. In addition, sHA could potentially be used to differentiate dogs with EHPSS from dogs with other liver diseases.