Long-term outcome after surgical ameroid ring constrictor placement for treatment of single extrahepatic portosystemic shunts in dogs

Evaluation of the Blood Neutrophil-to-Lymphocyte Ratio (NLR) as a Diagnostic and Prognostic Biomarker in Dogs with Portosystemic Shunt

The neutrophil-to-lymphocyte ratio (NLR) can help in assessing inflammatory diseases, sepsis, and chronic hepatic conditions in humans. Dogs with congenital portosystemic shunts (PSSs) have signs of generalized inflammation, and the clinical signs can overlap with other conditions, including hypoadrenocorticism (HOC). Thus, the potential diagnostic and prognostic value of leukocyte ratios as surrogate markers was assessed in a retrospective case-control study including 106 dogs diagnosed with PSSs. The disease control groups were dogs with parenchymal hepatopathy (PH; n = 22) or HOC (n = 31). In the PSS dogs, the blood NLRs were associated with the severity of systemic inflammation but not with the shunt type, hepatoencephalopathy, systemic infection, or hypoglycemia. The baseline NLRs did not differ between the three disease groups, between medically and surgically treated PSS dogs, or between those with successful PSS ligation and dogs experiencing peri-/post-surgical complications. However, dogs requiring two consecutive surgical interventions had significantly higher NLRs, and an NLR of <2.53 distinguished dogs with successful shunt ligation in one surgery from those requiring two consecutive surgeries for PSS closure. The blood NLR might be a useful clinicopathologic variable in PSS, but its value in helping differentiate PSS from HOC cases appears low. Integrating the NLR into a diagnostic algorithm may allow for a prediction of the number of surgical interventions required.

Diagnosis and treatment of a congenital portosystemic shunt in a ferret (Mustela putorius furo)

A 3-year-old female neutered ferret presented with progressive weight loss was diagnosed with portosystemic shunting based on increased fasting bile acids, rectal ammonia tolerance testing and advanced imaging. Ammonia reference values were determined in 16 healthy ferrets. A congenital extrahepatic spleno-caval shunt was visualised with ultrasonography and CT angiography of the abdomen. Complete surgical shunt closure by suture ligation was performed, without clinical improvement after surgery. Euthanasia was elected 4 months postoperatively because the clinical condition deteriorated. This is a case report of advanced diagnostics and surgical treatment of a congenital extrahepatic portosystemic shunt in a ferret, demonstrating rectal ammonia tolerance testing and imaging as feasible techniques for the diagnosis.

Percutaneous shunt vessel embolisation with Amplatzer vascular plugs II and IV in the treatment of dogs with splenophrenic shunts: four cases (2019-2022)

OBJECTIVES

To describe the treatment of four dogs with splenophrenic shunts using percutaneous shunting vessel embolisation with Amplatzer vascular plugs II and IV and provide information on their clinical outcomes.

MATERIALS AND METHODS

Dogs with splenophrenic shunts treated at a veterinary hospital from January 2019 to December 2022 were identified through a medical record search.

RESULTS

Six dogs with splenophrenic shunts were identified. Two dogs were excluded because they were treated with laparoscopic surgery. Four underwent percutaneous shunting vessel embolization with Amplatzer vascular plugs and were included in the case series. A sheath was placed in the left external jugular vein and a balloon catheter was advanced to the shunting vessel under fluoroscopy. Portal vein pressure was confirmed to be within an acceptable range during temporary balloon occlusion. Based on preoperative CT angiography and intraoperative contrast examination, Amplatzer vascular plugs II were selected for two dogs and IV were selected for two dogs. Under fluoroscopy, the plug was deployed into the shunting vessel, and angiography confirmed occlusion. In all cases, the increase in portal pressure after temporary occlusion was within the acceptable range, and complete occlusion of blood flow was possible with a single plug. There were no major procedure-related complications. No dogs developed post-ligation seizures or signs of portal hypertension. In addition, improvements in ammonia values were observed in all cases.

CLINICAL SIGNIFICANCE

Percutaneous splenophrenic shunt embolisation using Amplatzer vascular plugs II and IV is technically feasible in dogs, and assessed by intra-procedure angiography, a single plug completely obstructed blood flow in all dogs. Based on the literature search, this is the first report describing Amplatzer vascular plugs for the treatment of splenophrenic shunts.

Prospective Study Comparing Outcome following Complete Polypropylene Suture Ligation versus Partial Thin Film Band Attenuation of Congenital Portosystemic Shunts in Dogs

The main objective was to conduct a prospective study reporting the outcome for dogs with an extrahepatic congenital portosystemic shunt (CPSS) treated with a 'complete ligation where possible' philosophy. The second aim was to compare the outcomes following complete (C) polypropylene suture ligation versus partial thin film band (TFB) attenuation of a CPSS in dogs. Dogs that could not tolerate acute complete shunt ligation at surgery received partial shunt attenuation with TFB. Peri-operative complications, mortality, follow-up imaging findings, pre- and post-operative bile acid stimulation test results and details of any revision surgery performed were recorded. A follow-up health-related quality of life questionnaire enabled the calculation of a postoperative clinical shunt score, a quality of life score, and determined if any dogs were still on a hepatic diet and/or other medical management at a minimum of 6 months after surgery. Of the 110 dogs enrolled, 57 received complete ligation and 53 received partial TFB attenuation. Peri-operative mortality, the occurrence of post-attenuation neurological complications, the occurrence of multiple acquired shunts, the postoperative clinical shunt score and quality of life score were not significantly different between the two groups. Dogs in the C group were older, heavier and demonstrated a greater number of shunt classifications where the entry into the systemic circulation was the phrenic vein or azygous vein. Dogs in the TFB group had a greater number of unchanged bile acid concentrations after surgery, were more likely to remain on the hepatic diet and/or medical management after surgery and underwent a greater number of revision surgeries. There was variability in the precision of both ultrasound and computed tomographic angiography follow-up imaging compared to intra-operative mesenteric portovenography findings at revision surgery. Overall, dogs with an extrahepatic portosystemic shunt receiving either complete acute shunt ligation or partial TFB shunt attenuation are expected to have an excellent long-term clinical outcome and there is no reason to suggest that a dog able to tolerate complete acute shunt closure should be denied the benefit of this.

Portovenography Findings Following Partial Polypropylene Versus Thin Film Band Attenuation of a Single Congenital Extrahepatic Portosystemic Shunt: A Prospective Randomized Study in Dogs

The objective was to conduct a prospective, randomized study to compare mesenteric portovenogram findings following partial polypropylene suture versus thin film band extrahepatic portosystemic shunt attenuation in dogs. Dogs with extrahepatic portosystemic shunts that could not tolerate complete acute shunt closure received a partial attenuation with either a polypropylene suture or synthetic polymer thin film band. At a routine second surgery three months after shunt patency, missed shunt branches and/or development of multiple acquired shunts were assessed using intra-operative mesenteric portovenography. Twenty-four dogs were enrolled, 12 received partial polypropylene suture ligation, and 12 received partial thin film band shunt attenuation. Intra-operative mesenteric portovenography three months later demonstrated that nine dogs (75%) in the thin film band group had achieved complete shunt closure versus two dogs (16.7%) in the polypropylene suture group, which was significantly different (p = 0.004). No dogs in the polypropylene suture group and two dogs (16.7%) in the thin film band group developed multiple acquired shunts. This is the first study directly comparing follow-up intra-operative mesenteric portovenography imaging findings between two methods of partial portosystemic shunt attenuation in dogs. The study provides accurate information on the rates of complete anatomical shunt closure and development of multiple acquired shunts following partial shunt attenuation with either synthetic polymer thin film band or polypropylene suture.

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.

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

BACKGROUND

In dogs with a congenital extrahepatic portosystemic shunt (EHPSS), outcome after surgical attenuation is difficult to predict.

OBJECTIVES

Develop a minimally invasive test to predict outcome after surgical EHPSS attenuation and establish risk factors for postattenuation seizures (PAS).

ANIMALS

Eighty-five client-owned dogs referred for surgical attenuation of a single EHPSS.

METHODS

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.

RESULTS

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.

CONCLUSIONS AND CLINICAL IMPORTANCE

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.

Laparoscopic attenuation of a congenital extrahepatic portosystemic shunt in a dog—a thin-film banding for splenophrenic shunt: A case report

A 6-year-old castrated male Shih-Tzu dog weighing 6. 5 kg presented with chief complaints of pollakiuria and urine dribbling. He had a history of urolithiasis for 3 years, which was confirmed by the presence of ammonium urate in the urinary stone analysis, performed 2 years prior to the presentation. Blood examination showed high values of fasting ammonia, post-prandial bile acid, and low blood urea nitrogen. Microhepatica and urolithiasis were identified on plain radiography and ultrasonography. A computed tomography angiography demonstrated a shunting vessel, diameter up to 9.6 mm, originated from the splenic vein, and linked with the phrenic vein. A surgical attenuation with a thin-film banding was performed under laparoscopic visualization. Left triangular ligament was incised, and one stay suture was placed to the stomach to expose the vessel. The shunting vessel was dissected before it entered the diaphragm, and a thin-film band was applied around the vessel. The patient recovered uneventfully without post-attenuation neurologic signs. Portal vein diameter increased with time, and complete closure of the shunting vessel was identified on computed tomography angiography performed at 14 months after attenuation. The patient was doing well for 31 months after surgery without protein restriction. This is a report of laparoscopic attenuation for splenophrenic type of canine congenital extrahepatic portosystemic shunt with a favorable outcome using thin-film banding.

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.

Evaluation of different blood tests in dogs with extrahepatic portosystemic shunts to assess shunt closure after surgical treatment

OBJECTIVE

To determine the sensitivity and specificity of different individual and combined blood tests to assess extrahepatic portosystemic shunt (EHPSS) closure after gradual attenuation of EHPSS in dogs.

STUDY DESIGN

Clinical prospective study.

ANIMALS

Twenty client-owned dogs with EHPSS.

METHODS

Fasting ammonia (FA), preprandial, postprandial, and paired serum bile acids (SBA), the lidocaine/monoethylglycylxylidide (L/MEGX) test, and serum hyaluronic acid (SHA) were performed at diagnosis, and 1, 3, and 6 months postoperatively. Transsplenic portal scintigraphy was performed to determine EHPSS closure 3 months postoperatively. Their sensitivity and specificity in determining shunt closure postoperatively were calculated.

RESULTS

When assessing a single blood parameter, FA had the highest specificity (100%), whereas SHA and MEGX measured 15 min after lidocaine administration (T15) had the highest sensitivity (96.9% and 96.2%, respectively) for determining shunt closure postoperatively. The most promising blood test combinations were SHA (sensitivity 96.9%, specificity 81.8%), combined with the L/MEGX test (MEGX at T15: sensitivity 100%, specificity 72.4%) or the L/MEGX test (MEGX at T15) combined with either FA (sensitivity 100%, specificity 82.8%) or postprandial SBA (sensitivity 100%, specificity 81.5%).

CONCLUSION

Both SHA and the L/MEGX test were sensitive tests for determining shunt closure after gradual attenuation of EHPSS. Test performances could even be improved by combining these tests with each other or with traditional tests such as FA or postprandial SBA.

CLINICAL SIGNIFICANCE

Although SHA and the L/MEGX test are sensitive blood tests for determining EHPSS closure, especially when combined with traditional blood tests, imaging is still needed to confirm EHPSS closure.

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

OBJECTIVE

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.

ANIMALS

351 dogs definitively diagnosed with EHPSS at ≥ 5 years of age.

PROCEDURES

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.

RESULTS

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%.

CLINICAL RELEVANCE

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.

Protein C and comparative biochemical changes in dogs treated with percutaneous transvenous coil embolization of congenital intrahepatic portosystemic shunts

OBJECTIVE

To evaluate protein C (PC) activity after intrahepatic portosystemic shunt (IHPSS) percutaneous transvenous coil embolization (PTCE) in dogs; to identify if PC is associated with clinical status after intervention, and to compare PC with standard biochemical values.

STUDY DESIGN

Retrospective case series.

ANIMALS

Forty-seven client-owned dogs with IHPSS undergoing PTCE.

METHODS

Records were reviewed for preoperative and postoperative PC, hematocrit (HCT), mean corpuscular volume (MCV), albumin (ALB), and blood urea nitrogen (BUN). Ultimate clinical status was classified as excellent, fair, or poor, based on ongoing medical management and the presence of clinical signs. Intrahepatic portosystemic shunt was considered to be completely or incompletely occluded intraoperatively based on angiography.

RESULTS

Postoperative PC activity increased in 37/47 (78.7%) dogs with a mean increase of 38.7% ± 2.1%. Ultimate postoperative clinical status was excellent in 16/43 (37.2%), fair in 19/43 (44.2%), and poor in 8/43 dogs (18.6%). No association was detected between preoperative PC (46.8% ± 1.8%) and ultimate clinical status but mean postoperative PC (75.7% ± 1.4%), HCT, MCV, ALB, and BUN were higher in dogs with excellent clinical status. Postoperative PC activity was higher when shunts were completely occluded (96.3% ± 10.9%), which was a finding associated with excellent status.

CONCLUSION

Postoperative, but not preoperative, PC activity was higher in dogs with better ultimate clinical status. Similar trends were noted in standard hematological and biochemical values. Complete occlusion of shunts was associated with a higher postoperative PC and superior ultimate clinical status.

CLINICAL SIGNIFICANCE

Postoperative PC may provide valuable information about the success of PTCE for IHPSS as it relates to the ultimate status and the need for additional procedures.

Clinical and laboratory outcome after surgical treatment of single congenital extrahepatic portosystemic shunt using ameroid constrictor in 25 dogs

The objective of the study was to evaluate the clinical and laboratory outcome after the surgical treatment of a single congenital extrahepatic portosystemic shunt using an ameroid constrictor. Patient medical records were reviewed in retrospect. Data on the signalment, clinical signs, preoperative bile acid stimulation test and ammonia concentration were recorded. The surgical treatment success rate was evaluated by mortality in the perioperative and short-term postoperative period and by the long-term clinical outcome. Bile acid stimulation test and ammonia concentration were also analysed 2–3 days, 4–6 weeks, and 6–8 weeks postoperatively. No patient died in the selected periods. The long-term clinical outcome was excellent in 15 out of 20 patients, good in 3 out of 20 patients and poor in 2 out of 20 patients. Preprandial bile acid concentration was elevated in 96.00%, postprandial bile acid concentration in 100.00% and ammonia concentration in 80.95% of patients preoperatively. A significant decrease was found in postprandial bile acid and ammonia 2–3 days postoperatively and in preprandial bile acid 4–6 weeks postoperatively. A significant decrease in liver function parameters in days post operation indicates a rapid restoration of hepatic function. The surgical treatment of a single extrahepatic portosystemic shunt using an ameroid constrictor is a successful method of treatment for this type of portosystemic shunt, with as much as 75.00% of the patients having an excellent long-term clinical outcome.

Liver function tests in dogs with congenital portosystemic shunts and their potential to determine persistent shunting after surgical attenuation

Portosystemic shunts (PSS) are congenital or acquired vascular anomalies that cause blood to bypass the liver. Liver function tests, such as fasting ammonia, ammonia tolerance test, and (paired) serum bile acids, are reliable for the diagnosis of PSS in dogs. Surgical attenuation is a common treatment for congenital PSS. Following surgical attenuation, it is useful to evaluate shunt closure. In this critical review, the ability of liver function tests to determine the presence and degree of residual shunting following surgical attenuation of canine PSS is discussed. Despite the availability of several liver function tests, a single rapid, simple, cost-effective, sensitive and specific test to evaluate surgical attenuation of PSS is not available.

Long-term clinical outcomes of dogs with single congenital extrahepatic portosystemic shunts attenuated with thin film banding or ameroid ring constrictors

OBJECTIVE

To compare long-term clinical outcomes of dogs with single congenital extrahepatic portosystemic shunts (CEHPSS) treated with thin film banding (TFB) consisting of polyolefin fiber or ameroid ring constrictor (ARC) placement in dogs.

DESIGN

Retrospective, two-center clinical study.

ANIMALS

Client-owned dogs (n = 123) with single CEHPSS undergoing gradual attenuation via TFB (n = 85) or ARC (n = 38).

METHODS

Medical records of dogs with CEHPSS were reviewed. Follow-up data were collected from the referring veterinarian and/or owner via standardized questionnaire. Data were analyzed to compare short-term mortality rate and long-term outcome (>6 months).

RESULTS

Dogs in the TFB group were older than dogs in the ARC group (median age, 19 vs 12 months, respectively; P = .01). There was no difference in survival to discharge between dogs in the TFB (81/85 [95.3%]) and ARC (37/38 [97.4%]; P > .99) groups. Preoperative levetiracetam was more frequently administered to dogs treated with TFB (64/85 [75.3%]) than to dogs treated with ARC (15/38 [39.5%;] P = .0002). Postoperative seizures were reported in 10 (8.1%) dogs; their prevalence did not differ between dogs treated with TFB (9/85 [10.6%]) and dogs treated with ARC (1/38 [2.6%]; P = .17). Median follow-up time for dogs treated with TFB (58.0 months, range 8-130) and ARC (63.3 months, range 7-138; P = .24) did not differ.

CONCLUSION

Gradual attenuation of a single CEHPSS with either TFB or ARC resulted in similar long-term clinical outcomes and low postoperative morbidity and mortality rates.

CLINICAL SIGNIFICANCE

Thin film banding (polyolefin fiber) offers an alternative leading to clinical outcomes similar to ARC in dogs with single CEHPSS.

Treatment of congenital extrahepatic portosystemic shunts in dogs: A systematic review and meta-analysis

Background

Several options have been proposed for the treatment of congenital extrahepatic portosystemic shunts (cEHPSS) in dogs, but formal comparisons among different treatment options are currently unavailable. A previous evidence‐based review (2012) found low quality of evidence for papers assessing the treatment of cEHPSS in dogs.

Objectives

To assess the quality of evidence available in the treatment of cEHPSS, summarize the current state of knowledge with respect to outcome after cEHPSS management, and compare different treatment techniques.

Animals

Not used.

Methods

A bibliographic search was performed without date or language restrictions. Studies were assessed for quality of evidence (study design, study group sizes, subject enrollment quality, and overall risk of bias) and outcome measures reported (perioperative outcome, clinical outcome, and surgical or interventional outcome), all reported with 95% confidence intervals. A network meta‐analysis was performed.

Results

Forty‐eight studies were included. Six retrospective studies (grade 4b) compared 2 techniques and 7 were abstracts (grade 5). The quality of evidence was low and risk of bias high. Regarding surgical outcome, statistically significant superiority of ameroid constrictor over thin film band was observed (P = .003). No other comparisons were statistically significant.

Conclusions and Clinical Importance

The evidence base of choice of treatment of cEHPSS in dogs remains weak despite recent publications on the subject. Ameroid is superior to thin film band in causing EHPSS closure. Blinded randomized studies comparing different treatment modalities, which routinely include postoperative imaging to assess cEHPSS closure and acquired portosystemic shunt development are essential.

Outcomes of dogs treated for extrahepatic congenital portosystemic shunts with thin film banding or ameroid ring constrictor

OBJECTIVE

To compare the outcomes of dogs treated at a single institution for single extrahepatic congenital portosystemic shunts (CPSS) by thin film banding (TFB) or by placement of an ameroid constrictor (AC).

STUDY DESIGN

Retrospective case series.

ANIMALS

Seventy-six client-owned dogs with CPSS treated with TFB (n = 53) or AC (n = 23).

METHODS

Records were reviewed for signalment, preoperative, intraoperative, and postoperative management and short-term outcomes. Data on second surgeries were reviewed. Long-term outcomes were obtained via an owner-directed health-related quality of life questionnaire. The rates of complications, mortality, and revision surgery were compared between the treatment groups.

RESULTS

Postoperative complications occurred in 15 (28%) dogs with TFB (9% mortality, n = 5) and 8 (35%) dogs with an AC (4% mortality, n = 1). Long-term follow-up was available in 41 of 56 dogs at a median of 55 months (range, 15-89). Revision surgery for persistent shunting was performed in 14 (29%) dogs treated initially with TFB and in no dogs treated initially with AC (P = .007). Median long-term outcome scores were good in both groups; nine of 14 revision surgeries led to favorable outcomes.

CONCLUSION

Persistent shunting requiring revision surgery was more common when CPSS were treated with TFB than with an AC, but both treatments achieved favorable long-term outcomes.

CLINICAL SIGNIFICANCE

Treatment of CPPS by placement of an AC rather than TFB seems more reliable for shunt attenuation and prevention of revision surgeries.

Changes in chemical and ultrastructural composition of ameroid constrictors following in vitro expansion

OBJECTIVE

To (1) characterise the chemical and ultra-structural composition of ameroid constrictors, at a native state and during in vitro expansion and (2) determine the presence of irritant compounds at the surface or within the bulk of the constrictor.

METHODS

Twelve sterile, commercially packaged ameroid constrictors (3 repeats of 3.5 mm, 5 mm, 6 mm and 7 mm internal diameter) were analysed by time-of-flight secondary ion mass spectrometry, Raman spectroscopy, attenuated total reflectance Fourier transform infrared spectroscopy and scanning electron microscopy.

RESULTS

Ameroid constrictors have a composition commensurate with casein with little-to-no intra- or inter- constrictor variation. Microscopic analysis indicated that the topographical features of the constrictor surfaces were consistent between all constrictors. Following in vitro expansion there was a reproducible decrease in Ca+ ion content, little-to-no variation in secondary protein structure and morphological changes including the presence of surface aggregates present only at the inner surface of the ameroid constrictor. The potential irritant polydimethylsiloxane was found on the constrictor surface. A trace quantity of an ion fragment assigned as formaldehyde was detected; however, the extremely low level is thought highly unlikely to play a role as an inflammatory trigger clinically.

DISCUSSION

There is a high degree of inter- and intra-constrictor homogeneity from different batches, and reproducible ultrastructural changes following in vitro expansion. Variations occur in both the surface chemistry and topography of the device during closure, which can potentially affect the biomaterial-host interface. Ameroid constrictor closure mechanism is likely involving calcium-mediated inter-protein interactions rather than the imbibition of water only.

Health-related quality of life following surgical attenuation of congenital portosystemic shunts versus healthy controls

OBJECTIVES

To design a health-related quality of life questionnaire for dogs with congenital portosystemic shunts, use it in a cohort of dogs treated with suture attenuation and compare results with those obtained from a healthy control cohort.

MATERIALS AND METHODS

Data were collected from the hospital records of dogs treated with suture ligation of an intrahepatic or extrahepatic congenital portosystemic shunt at two referral centres. Owners were asked to complete a questionnaire assessing their dog's health-related quality of life preoperatively (retrospectively) and at the time of follow-up. Owners of control dogs also completed the questionnaire.

RESULTS

One hundred and twenty-eight dogs with congenital portosystemic shunts and 131 control dogs were recruited. Median follow-up time was 64 months (range 19.7 to 157.2). The median long-term health-related quality of life score was excellent for both intrahepatic and extrahpatic shunt cases and similar to that of control dogs. The long-term portosystemic shunt clinical sign scores for both intrahepatic and extrahepatic congenital portosystemic shunt dogs were significantly worse than the those of the control group.

CLINICAL SIGNIFICANCE

Suture attenuation of congenitial portosystemic shunts is associated with an excellent health-related quality of life score at long-term follow-up.

Incidence of Postoperative Neurologic Complications in Pugs Following Portosystemic Shunt Attenuation Surgery

Postoperative seizures occur in 5–12% of dogs following surgical attenuation of congenital extrahepatic portosystemic shunts (CEPSS) and are often refractory to treatment. Because pugs are predisposed to necrotizing meningoencephalitis, they may be at higher risk of developing neurologic complications after CEPSS attenuation. We hypothesized that pugs have a higher prevalence of postoperative neurologic complications and that pugs who died due to neurologic complications would have evidence of encephalitis at necropsy. Records were searched for pugs that had undergone surgical correction of a single extrahepatic CEPSS. Fourteen pugs met the inclusion criteria and were compared with a control group of 30 dogs of varying breeds who also underwent surgical attenuation for a single CEPSS. Four of 14 pugs (28.6%) died or were euthanized within 1 mo after surgery for neurologic complications, compared with only 1 of 30 dogs in the control group (P &lt; .029). No evidence of necrotizing meningoencephalitis was seen on necropsy. Pugs may be at an increased risk of developing fatal neurologic complications following surgical attenuation for CEPSS. Further studies are indicated to investigate reasons for this increased risk, as well as to determine any factors that may indicate which pugs are at higher risk.

Prospective evaluation of outcome of dogs with intrahepatic portosystemic shunts treated via percutaneous transvenous coil embolization

OBJECTIVE

To report outcome and complications after percutaneous transvenous coil embolization (PTCE) and evaluate the clinical, laboratory, and imaging changes in dogs with intrahepatic portosystemic shunts (IHPSS) pre-PTCE and post-PTCE.

STUDY DESIGN

Prospective clinical trial.

ANIMALS

Twenty-five dogs (15 dogs in imaging subgroup) with IHPSS.

METHODS

Clinical signs, hematologic, and biochemical parameters were recorded before and 3 months after PTCE. All dogs received the same medical treatment and underwent PTCE. In the imaging subgroup, ultrasonography, hepatic portal scintigraphy, and computed tomography-angiography were performed pre-PTCE and post-PTCE.

RESULTS

All evaluated bloodwork values improved by at least 50% of their initial value, by 3 months post-PTCE. Liver volume increased after PTCE (P = .001), but remained lower than normal in 11/15 dogs. Hepatic arterial fraction decreased after PTCE (P = .029), consistent with increased portal blood flow to the liver. Twenty-four of 25 dogs were available for reevaluation at 3 months, and all abnormal clinical signs had resolved in 22/24 dogs.

CONCLUSION

PTCE appears promising as a treatment for IHPSS, as clinical signs resolved in most cases, bloodwork abnormalities often normalized, and the procedure was performed safely with minimal complications. PTCE increased hepatic portal perfusion and liver volume in most dogs. These promising results justify a future randomized clinical trial comparing PTCE, other attenuation options, and medical management alone.

Attenuation of congenital portosystemic shunt reduces inflammation in dogs

Liver disease is a major cause of morbidity and mortality. One of the most significant complications in patients with liver disease is the development of neurological disturbances, termed hepatic encephalopathy. The pathogenesis of hepatic encephalopathy is incompletely understood, which has resulted in the development of a wide range of experimental models. Congenital portosystemic shunt is one of the most common congenital disorders diagnosed in client owned dogs. Our recent studies have demonstrated that the pathophysiology of canine hepatic encephalopathy is very similar to human hepatic encephalopathy, which provides strong support for the use of dogs with a congenital portosystemic shunt as a naturally occurring model of human hepatic encephalopathy. Specifically, we have demonstrated an important role for ammonia and inflammation in the development of hepatic encephalopathy in dogs with a congenital portosystemic shunt. Despite the apparent importance of inflammation in driving hepatic encephalopathy in dogs, it is unclear whether inflammation resolves following the successful treatment of liver disease. We hypothesized that haematological and biochemical evidence of inflammation, as gauged by neutrophil, lymphocyte and monocyte concentrations together with C-reactive protein concentrations, would decrease following successful treatment of congenital portosystemic shunts in dogs. One hundred and forty dogs with a congenital portosystemic shunt were enrolled into the study. We found that the proportion of dogs with a monocyte concentration above the reference range was significantly greater in dogs with hepatic encephalopathy at time of initial diagnosis. Importantly, neutrophil and monocyte concentrations significantly decreased following surgical congenital portosystemic shunt attenuation. We also found a significant decrease in C-reactive protein concentrations following surgical attenuation of congenital portosystemic shunts. Our study demonstrates that haematological and biochemical indices of inflammation reduce following successful treatment of the underlying liver disorder.