Medical management of congenital portosystemic shunts in 27 dogs--a retrospective study

Computed tomographic evaluation of portal vein indices in cats with the extrahepatic portosystemic shunts

IMPORTANCE

The portal vein to aorta (PV/Ao) ratio is used to assess the clinical significance of extrahepatic portosystemic shunt (EHPSS). Previous studies using computed tomography (CT) were conducted in dogs but not in cats.

OBJECTIVE

This study aimed to establish normal reference values for PV indices (PV/Ao ratio and PV diameter) in cats and determine the usefulness of these for predicting symptomatic EHPSS.

METHODS

This study included 95 dogs and 114 cats that underwent abdominal CT. The canine normal (CN) group included dogs without EHPSS. The cats were classified into feline normal (FN, 88/114), feline asymptomatic (FA, 16/114), and feline symptomatic (FS, 10/114) groups. The PV and Ao diameters were measured in axial cross-sections.

RESULTS

The group FN had a higher PV/Ao ratio than the group CN (p < 0.001). Within the feline groups, the PV indices were in the order FN > FA > FS (both p < 0.001). The mean PV diameter and PV/Ao ratio for group FN were 5.23 ± 0.77 mm and 1.46 ± 0.19, respectively. The cutoff values between groups FN and FS were 4.115 mm for PV diameter (sensitivity, 100%; specificity, 97.7%) and 1.170 for PV/Ao ratio (90%, 92.1%). The cutoff values between group FA and FS were 3.835 mm (90%, 93.8%) and 1.010 (70%, 100%), respectively.

CONCLUSIONS AND RELEVANCE

The results demonstrated significant differences in PV indices between dogs and cats. In cats, the PV/Ao ratio demonstrated high diagnostic performance for symptomatic EHPSS. The PV diameter also performed well, in contrast to dogs.

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.

Congenital Portosystemic Shunts in Dogs and Cats: Classification, Pathophysiology, Clinical Presentation and Diagnosis

Congenital portosystemic shunts (CPSS) are abnormal vascular communications between the portal and the systemic circulation, bypassing the hepatic parenchyma and resulting in liver hypoplasia and hepatic insufficiency. Such connections develop in utero and persist postnatally. CPSS are among the two most common congenital vascular anomalies of the liver in small animals, along with primary hypoplasia of the portal vein without portal hypertension (PHPV without PH). CPSS can be extrahepatic (ECPSS), most commonly diagnosed in small and toy breed dogs and cats, or intrahepatic (ICPSS), most commonly seen in large breed dogs. Single ECPSS is the most common type encountered in both dogs and cats. Clinical signs of CPSS are non-specific and may wax and wane, while laboratory findings can raise clinical suspicion for CPSS, but they are also not specific. Definitive diagnosis will be established by evaluation of liver function tests, such as determination of fasting plasma ammonia (FA) levels, and pre- and postprandial serum bile acids concentrations, and diagnostic imaging. The purpose of this article is to review the definition, classification, pathogenesis, clinical presentation, and diagnosis of CPSS in dogs and cats, highlighted by the authors' clinical experience.

Characterization of the Fecal Microbiome in Dogs Receiving Medical Management for Congenital Portosystemic Shunts

Background

The GI microbiome has not been characterized in dogs being medically managed for congenital portosystemic shunts (CPSS).

Objectives

To characterize the fecal microbiome in a population of dogs being medically managed for CPSS.

Animals

27 client-owned dogs.

Methods

Prospective cohort study enrollment of fecal samples was performed with follow-up data collected retrospectively. The overall fecal dysbiosis index (DI) and individual bacterial abundances were determined using real-time qPCR. Medical management, clinical findings, clinicopathologic, and outcome variables were collected, and logistic regression analyses were performed to evaluate associations between these variables and overall DI and bacterial abundances. Numerical variables were evaluated with general linear models for normality and equal variance using Shapiro-Wilk test and Levene's test, respectively.

Results

All dogs were administered a hepatic diet and lactulose, while antibiotics were used in 22 (81.5%) and acid suppressants in 7 (25.9%). Seventeen dogs (63.0%) had a DI >2. The median DI in this population was 3.02 (range 4.23–8.42), and the median DI in dogs receiving and not receiving antibiotics was 4.3 (range −4.23–8.42) and 1.52 (range −1.62–5.43), respectively. No significant association between any of the analyzed variables and the DI was identified. There was a significant association between the use of metronidazole and a larger abundance of E. coli (p = 0.024).

Conclusions and Clinical Importance

Dysbiosis appears to be common in dogs that are being medically managed for CPSS, though the clinical significance remains unclear.

Comparison of diet, lactulose, and metronidazole combinations in the control of pre-surgical clinical signs in dogs with congenital extrahepatic portosystemic shunts

BACKGROUND

Hepatic supportive diet (HSD), lactulose, and antimicrobials are medical treatments for dogs with congenital extrahepatic portosystemic shunts (cEHPSS). The relative contribution of these treatment components is currently unknown.

OBJECTIVES

To determine which treatment combinations are most efficacious in pre-surgical control of clinical signs of cEHPSS in dogs.

ANIMALS

Thirty-six dogs with untreated cEHPSS.

METHODS

Three-arm randomized clinical trial. At inclusion (T0), dogs were divided into 3 groups: HSD (n = 12), HSD + lactulose (n = 12), or HSD + metronidazole (n = 12) and received the randomized treatment for 4 weeks (T1) followed by combined treatment of HSD + lactulose + metronidazole for 2 weeks or until cEHPSS attenuation (T2). Clinical score as well as fasting ammonia (FA) and C-reactive protein (CRP) concentrations were compared among groups and time points.

RESULTS

Thirty-four dogs were evaluated. Thirty-four dogs reached T1 and 29 dogs T2. At T1, clinical scores decreased in the HSD + lactulose (n = 11; P = .001), but not in the HSD (n = 8; P = .96) and HSD + metronidazole (n = 10; P = .06) groups. Adding metronidazole to HSD + lactulose (n = 11) did not result in further clinical score improvement (T2; P = 1.000). Moderate and weak correlation between clinical score and FA and clinical score and CRP was present (ρ = .35, P < .001; ρ = .27, P = .01, respectively) with FA decreasing over time on medical treatment (P = .001).

CONCLUSIONS AND CLINICAL IMPORTANCE

Combined HSD + lactulose seems sufficient for pre-surgical cEHPSS stabilization unlike sole HSD or HSD + metronidazole. Medical treatment of cEHPSS clinical signs decreases FA.

[Use of antimicrobials in acute canine diarrhea - overview of potential risks, indications and alternatives]

In Germany, antibiotics are frequently used in dogs with gastrointestinal disorders such as acute diarrhea. In line with global efforts to limit antibiotic use, this literature review aims to provide a guideline for the rational and judicious use of antibiotics in acute canine diarrhea. Antibiotics can lead to gastrointestinal side effects and may exert a negative influence on the intestinal microbiota in addition to increasing the occurrence of resistant bacteria. There is also evidence that chronic immunological diseases may be triggered by the administration of antibiotics. Therefore, these should not be administered in uncomplicated acute diarrhea without signs of sepsis or systemic inflammatory reaction. In addition, enteropathogenic bacteria usually do not play a role in the etiology of acute diarrhea. For select clinical entities such as acute hemorrhagic diarrhea syndrome, antibiotic therapy should only be recommended in cases displaying signs of bacterial translocation with subsequent sepsis. In the case of parvovirosis, on the other hand, the administration of antibiotics is unavoidable due to the immunological incompetence of the dog caused by the accompanying severe neutropenia.

Outcome of non-surgical dietary treatment with or without lactulose in dogs with congenital portosystemic shunts

Background

Congenital portosystemic shunts (CPSS) are vascular anomalies, allowing portal blood to bypass the hepatic parenchyma, thereby accumulating toxic substances such as ammonia in the systemic circulation resulting in hepatic encephalopathy.

Aim

To evaluate the outcome of non-surgically treated dogs with a CPSS.

Methods

Case records of 78 dogs with a single congenital CPSS confirmed by ultrasound and/or computed tomography between September 2003 and February 2015 were reviewed. Median age at diagnosis of CPSS in dogs was 10.8 months (range 2–133 months). Non-surgical treatment was started as an adjusted diet (a diet restricted in protein) with or without lactulose. Owners were contacted by telephone to determine survival time and presumed cause of death, if applicable. In addition, a questionnaire was used to retrospectively assess quality of life (QoL) and CPSS scores in 37 dogs before and during non-surgical treatment. Differences between Kaplan–Meier curves were tested by a Log rank test.

Results

Overall estimated median survival time (EMST) was 38.5 months (range 1 day − 91 months; 78 dogs). No significant differences between EMSTs were found between dogs with extra- (n = 48) or intrahepatic (n = 29) shunts, nor between treatment with only an adjusted diet, or an adjusted diet combined with lactulose. During non-surgical treatment, significant improvement in perceived QoL and CPSS scores were found (P < 0.01).

Conclusion

Our study demonstrated that an overall median EMST of 3.2 years was reached and that owners retrospectively perceived that non-surgical treatment resulted in an improved QoL and clinical performance, irrespective of intrahepatic or extrahepatic CPSS location.

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.

Astrocyte lesions in cerebral cortex and cerebellum of dogs with congenital ortosystemic shunting

Background

Congenital portosystemic shunt (cPSS) is one of the most common congenital disorders diagnosed in dogs. Hepatic encephalopathy (HE) is a frequent complication in dogs with a cPSS and is a major cause of morbidity and mortality. Despite HE been a major cause of morbidity in dogs with a cPSS, little is known about the cellular changes that occur in the central nervous system of dogs with a cPSS.

Objectives

The objective of this study was to characterise the histological changes in the cerebral cortex and cerebellum of dogs with cPSS with particular emphasis on astrocyte morphology.

Methods

Eight dogs with a confirmed cPSS were included in the study.

Results

Six dogs had substantial numbers of Alzheimer type II astrocytes and all cases had increased immunoreactivity for glial fibrillary acidic protein in the cerebral cortex, even if there were minimal other morphological changes.

Conclusions

This study demonstrates that dogs with a cPSS have marked cellular changes in the cerebral cortex and cerebellum. The cellular changes that occur in the cerebral cortex and cerebellum of dogs with spontaneously arising HE are similar to changes which occur in humans with HE, further validating dogs with a cPSS as a good model for human HE.

Diagnostic value of blood variables following attenuation of congenital extrahepatic portosystemic shunt in dogs

BACKGROUND

The aims of this study were to determine if extrahepatic portosystemic shunt (EHPSS) postoperative closure could be predicted based on preoperative blood analyses and to determine the accuracy of blood variables to evaluate persistence of portosystemic shunting postoperatively (multiple acquired portosystemic shunts (MAPSS) or persistent EHPSS).

METHODS

Retrospectively, 62 dogs treated surgically for congenital EHPSS that underwent postoperative trans-splenic portal scintigraphy or CT angiography three to six months postoperatively were included.

RESULTS

None of the studied preoperative blood variables could unambiguously predict surgical outcome. Elevated postoperative fasting venous ammonia (FA) concentration always indicated surgical failure (persistent shunting or MAPSS), but normal FA did not provide any information on the postoperative shunting status. Paired serum bile acids (SBA) were not reliable enough to confirm or exclude postoperative shunting. In the presence of low normal postoperative FA levels, elevated preprandial SBA was more likely in dogs with persistent shunting (sensitivity of 0.79, specificity of 0.83), whereas postprandial SBA below reference limit was more often observed in case of surgical success (sensitivity of 0.93, specificity of 0.67).

CONCLUSION

Blood variables, and more specifically the combination of FA and SBA, are not a valuable alternative to advanced medical imaging to reliably assess the surgical outcome after EHPSS surgery.

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.

Genome-wide based model predicting recovery from portosystemic shunting after liver shunt attenuation in dogs

Background

In dogs with congenital portosystemic shunt (CPSS), recovery after surgical CPSS attenuation is difficult to predict.

Objectives

Our aim was to build a model with plasma albumin concentration and mRNA expression levels of hepatic gene products as predictors of recovery from portosystemic shunting after surgery.

Animals

Seventy‐three client‐owned dogs referred for surgical attenuation of CPSS.

Methods

A prediction model was constructed using 2 case‐control studies of recovered and nonrecovered dogs after surgical CPSS attenuation. In the 1st study, a dog‐specific gene expression microarray analysis was used to compare mRNA expression in intraoperatively collected liver tissue between 23 recovered and 23 nonrecovered dogs. In the 2nd study, preoperative plasma albumin concentration and the expression of microarray‐selected genes were confirmed by RT‐qPCR in intraoperatively collected liver samples of 31 recovered and 31 nonrecovered dogs, including 35 dogs from the 1st study.

Results

In the 1st study, 43 genes were differently expressed in recovered and nonrecovered dogs. The mean preoperative plasma albumin concentration in recovered dogs was higher compared to nonrecovered dogs (23 and 19 g/L, respectively; P = .004). The best fitting prediction model in the 2nd study included preoperative plasma albumin concentration and intraoperative DHDH, ERLEC1, and LYSMD2 gene expression levels.

Conclusion and Clinical Importance

A preclinical model was constructed using preoperative plasma albumin concentration and intraoperative hepatic mRNA expression of 3 genes that were unbiasedly selected from the genome to predict recovery from portosystemic shunting after shunt ligation. Further development is essential for clinical application.

Haematology and coagulation profiles in cats with congenital portosystemic shunts

Objectives The objectives of this study were, first, to report the haematological parameters and coagulation times for cats with a congenital portosystemic shunt (CPSS) and the influence of surgical shunt attenuation on these parameters; and, second, to identify any association between prolongation in coagulation profiles and incidence of perioperative haemorrhage. Methods This was a retrospective clinical study using client-owned cats with a CPSS. Signalment, shunt type (extra- or intrahepatic), degree of shunt attenuation (complete or partial), haematological parameters, prothrombin time (PT) and activated partial thromboplastin time (aPTT) test results, and occurrence of any perioperative clinical bleeding complications were recorded for cats undergoing surgical treatment of a CPSS at the Royal Veterinary College, UK, between 1994 and 2011. Results Forty-two cats were included. Thirty-six (85.7%) had an extrahepatic CPSS and six (14.3%) had an intrahepatic CPSS. Preoperatively, mean cell volume (MCV) and mean cell haemoglobin (MCH) were below the reference interval (RI) in 32 (76.2%) and 31 (73.8%) cats, respectively. Red blood cell count and mean cell haemoglobin concentration (MCHC) were above the RI in 10 (23.8%) and eight (19.1%) cats, respectively. Postoperatively, there were significant increases in haematocrit ( P = 0.044), MCV ( P = 0.008) and MCH ( P = 0.002). Despite the significant increase in MCV postoperatively, the median MCV postoperatively was below the RI, indicating persistence of microcytosis. Preoperatively, PT was above the upper RI in 14 cats (87.5%), and aPTT was above the upper RI in 11 cats (68.8%). No cat demonstrated a perioperative clinical bleeding complication. Conclusions and relevance Cats with a CPSS are likely to present with a microcytosis, but rarely present with anaemia, leukocytosis or thrombocytopenia. Surgical attenuation of the CPSS results in a significant increase in the HCT and MCV. Coagulation profiles in cats with a CPSS are likely to be prolonged, irrespective of shunt type, but do not appear to be associated with an increased risk of clinical bleeding.

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.

Splenophrenic portosystemic shunt in dogs with and without portal hypertension: can acquired and congenital porto-caval connections coexist?

The possible existence of the same pattern of porto-caval connection in dogs having a single congenital portosystemic shunt (CPSS) and in dogs having multiple acquired portosystemic shunt (MAPSS) secondary to portal hypertension (PH) was evaluated. Retrospective evaluation of all CT examinations of patients having portosystemic shunt (PSS) was performed in a 4-year time period. All anomalous porto-caval connections were assessed for anatomical pattern and compared with published veterinary literature. Records of 25 dogs were reviewed. 16 dogs had a single CPSS (CPSS group), and 9 dogs had multiple acquired PSS secondary to PH (APSS group). The splenophrenic shunt pattern was found in 3 dogs of the CPSS group as a single congenital anomaly without PH and in 2 dogs of the APSS group associated with MAPSS and ascites due to different hepatic diseases causing PH. These findings corroborate two hypotheses: 1) Splenophrenic PSS should be considered as a classical CPSS but if this is not sufficient to alleviate a PH developed after birth because of eventual hepatic or portal diseases, in this case ascites and acquired portal collaterals may develop. In this case, MAPSS and CPSS may coexist. 2) The pattern of splenophrenic PSS, classically described among CPSS, may develop as acquired portal collateral in dogs with PH and it should also be included in the category of APSS. These preliminary findings may be helpful in reconsidering the classical haemodynamics of porto-caval diseases, enrich the classification of APSS in dogs and refine the imaging evaluation of patients with PH.

Hepatic encephalopathy in dogs and cats

OBJECTIVE

To comparatively review the pathogenesis, clinical presentation, diagnosis, and management of hepatic encephalopathy (HE) in dogs and cats.

DATA SOURCES

The Medline database was searched for articles related to HE in people, dogs, and cats. Articles published within the last 5 years were given special importance.

HUMAN DATA SYNTHESIS

The pathogenesis of HE is complex and incompletely understood, but ammonia appears to play a central role. Hyperammonemia leads to accumulation of glutamine in astrocytes, with subsequent astrocyte swelling and neurological dysfunction. The development of HE in patients with hepatic cirrhosis is a poor prognostic indicator. The fermentable disaccharide lactulose and the antimicrobial rifaximin are US Food and Drug Administration approved treatments for human HE. Severe protein restriction is no longer recommended for patients with this condition.

VETERINARY DATA SYNTHESIS

HE is often associated with portosystemic shunting in dogs and cats. Ammonia plays a central role in the pathogenesis of HE in dogs and cats, but other factors such as manganese and endogenous benzodiazepines may also contribute. Recently, a soy protein-based diet was found to be beneficial in treating canine HE. Severe dietary protein restriction is likely to be detrimental in affected animals. There have been no clinical trials of drugs routinely used in the management HE in veterinary medicine, but lactulose and antimicrobials such as metronidazole are well-established treatments.

CONCLUSIONS

HE is a potentially life-threatening condition that is probably underdiagnosed in companion animals. Although various treatment recommendations have been proposed, there is a lack of evidence in the veterinary literature regarding optimal strategies for the management of this condition. As our understanding of the pathogenesis of HE in dogs and cats evolves, novel diagnostic tests and therapeutic agents may become available.

Effects of repeated gas sterilization on closure rates of ameroid ring constrictors in vitro

OBJECTIVE

To determine the effect of repeated gas sterilization on rate of closure of ameroid ring constrictors in vitro.

SAMPLE

Twenty-four 3.5-mm ameroid ring constrictors.

PROCEDURES

Ameroid ring constrictors were allocated to 1 of 4 treatment groups (6/group) to undergo gas sterilization 0, 1, 5, or 10 times. After sterilization, constrictors were incubated in canine plasma at a protein concentration of 3 g/dL for 27 days. A digital camera was used to obtain images of the constrictors prior to and at various points during incubation, and lumen diameter was measured.

RESULTS

Mean ± SD percentage of lumen closure for all groups of ameroid ring constrictors combined was 85.2 ± 1.6% at day 0 (prior to plasma incubation) and 95.4 ± 0.8% at day 27. Mean lumen area was 3.64 ± 0.43 mm(2) (95% confidence interval, 2.67 to 4.77 mm(2)) at day 0 and 1.32 ± 0.25 mm(2) (95% confidence interval, 0.76 to 2.04 mm(2)) at day 27. None of the ameroid ring constrictors had closed completely by day 27.

CONCLUSIONS AND CLINICAL RELEVANCE

Overall closure rates for ameroid ring constrictors appeared to be unaffected by repeated gas sterilization up to 10 times. Findings suggested that veterinary surgeons can resterilize ameroid ring constrictors up to 10 times with confidence that ring properties would remain suitable for clinical use.

Long-term survival and quality of life in dogs with clinical signs associated with a congenital portosystemic shunt after surgical or medical treatment

OBJECTIVE

To compare long-term survival and quality of life data in dogs with clinical signs associated with a congenital portosystemic shunt (CPSS) that underwent medical or surgical treatment.

DESIGN

Prospective cohort study.

ANIMALS

124 client-owned dogs with CPSS.

PROCEDURES

Dogs received medical or surgical treatment without regard to signalment, clinical signs, or clinicopathologic results. Survival data were analyzed with a Cox regression model. Quality of life information, obtained from owner questionnaires, included frequency of CPSS-associated clinical signs (from which a clinical score was derived), whether owners considered their dog normal, and (for surgically treated dogs) any ongoing medical treatment for CPSS. A Mann-Whitney U test was used to compare mean clinical score data between surgically and medically managed dogs during predetermined follow-up intervals.

RESULTS

97 dogs underwent surgical treatment; 27 were managed medically. Median follow-up time for all dogs was 1,936 days. Forty-five dogs (24 medically managed and 21 surgically managed) died or were euthanized during the follow-up period. Survival rate was significantly improved in dogs that underwent surgical treatment (hazard ratio, 8.11; 95% CI, 4.20 to 15.66) than in those treated medically for CPSS. Neither age at diagnosis nor shunt type affected survival rate. Frequency of clinical signs was lower in surgically versus medically managed dogs for all follow-up intervals, with a significant difference between groups at 4 to 7 years after study entry.

CONCLUSIONS AND CLINICAL RELEVANCE

Surgical treatment of CPSS in dogs resulted in significantly improved survival rate and lower frequency of ongoing clinical signs, compared with medical management. Age at diagnosis did not affect survival rate and should not influence treatment choice.

Endovascular evaluation and treatment of intrahepatic portosystemic shunts in dogs: 100 cases (2001-2011)

OBJECTIVE

To evaluate short- and long-term outcome following endovascular treatment of intrahepatic portosystemic shunts in dogs.

DESIGN

Retrospective case series.

ANIMALS

100 dogs.

PROCEDURES

All patients had angiographic evaluation with or without endovascular shunt attenuation. The medical records were reviewed for pertinent data, complications, outcome, and survival time.

RESULTS

95 dogs with congenital intrahepatic portosystemic shunts received 111 procedures (83% [79/95] had 1 treatment, and 17% [16/95] had > 1 treatment; 5 dogs had no treatment because of excessive portal venous pressure-central venous pressure gradients). Angiography identified 38 right, 33 left, and 19 central divisional single shunts (n = 90) and 10 complex or multiple shunts. Partial shunt attenuation was performed in 92 dogs by means of caval stent placement and insertion of thrombogenic coils within the shunt, and 3 had complete acute shunt occlusion. Major intraoperative complications (3/111 [3%]) included temporary severe portal hypertension in 2 dogs and gastrointestinal hemorrhage in 1 dog. Major postoperative (< 1 week after surgery) complications (14/111 [13%]) included seizures or hepatoencephalopathy (7/111 [6%]), cardiac arrest (2/111 [2%]), jugular site bleeding (2/111 [2%]), pneumonia (1/111 [1%]), suspected portal hypertension (1/111 [1%]), and acute death (1/111 [1%]). Median follow-up time was 958 days (range, 0 to 3,411 days). Median survival time for treated dogs was 2,204 days (range, 0 to 3,411 days). Outcome was considered excellent (57/86 [66%]) or fair (13/86 [15%]) in 70 of 86 (81%) treated dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that endovascular treatment of intrahepatic shunts in dogs may result in lower morbidity and mortality rates, with similar success rates, compared with previously reported outcomes for open surgical procedures. Gastrointestinal ulceration was a common finding among this population of dogs, and lifelong gastroprotectant medications are now recommended.

Clinical and clinicopathologic abnormalities in young dogs with acquired and congenital portosystemic shunts: 93 cases (2003-2008)

OBJECTIVE

To determine whether clinical and clinicopathologic data could assist differentiation of congenital portosystemic shunts (CPSSs) from acquired portosystemic shunts (APSSs) in young dogs.

DESIGN

Retrospective case series.

ANIMALS

Dogs < 30 months of age with CPSSs (n = 62) or APSSs (31).

PROCEDURES

Medical records from 3 referral centers identified 31 dogs with APSSs and 62 dogs with CPSSs diagnosed from July 2003 to July 2008. Signalment, clinical signs, physical examination, and clinicopathological data were recorded, and statistical analyses were performed to determine differences between groups.

RESULTS

Univariable analysis showed APSS patients were older, heavier, and in poorer body condition, compared with CPSS patients. In CPSS patients, diarrhea was less prevalent, and neurologic signs were more prevalent. Ascites was more prevalent in APSS (Fisher exact test; OR, 50.2; 95% confidence interval [CI], 6.2 to 409.7), with no significant difference in albumin concentration between groups. The logistic regression model used to assess clinicopathological parameters showed lower Hct (OR, 1.42 × 10(-12); 95% CI, 1.42 × 10(-17) to 4.0 × 10(-6)), higher mean corpuscular volume (OR, 1.27; 95% CI, 1.08 to 1.50), and higher alanine aminotransferase concentrations (OR, 1.005; 95% CI, 1.001 to 1.009) were more likely in APSS patients.

CONCLUSIONS AND CLINICAL RELEVANCE

Several clinicopathologic differences between dogs with congenital and acquired shunts were identified; however, assessed alone, these would be unlikely to enable differentiation between the 2 conditions. Awareness of the rarity of ascites in CPSS cases should prompt recognition of a likely diagnosis of APSS, allowing the veterinarian to target further diagnostics and counsel the owner appropriately.

Treatment of extrahepatic congenital portosystemic shunts in dogs - what is the evidence base?

A variety of surgical treatments and medical therapies are recommended for dogs with extrahepatic congenital portosystemic shunts (CPSS). The objective of this review was to assess the evidence base for the management of extrahepatic CPSS in dogs. An online bibliographic search was performed in November 2010 to identify articles relating to the question "Which of the treatment options for extrahepatic CPSS in dogs offers the best short- and long-term outcomes?" Articles were assigned a level of evidence based on a modified grading system. Thirty-eight articles were included in the review. Thirty-six articles were classified as grade 4 and two as grade 5. The timings and methods of assessment of short- and long-term outcomes varied widely between studies. One prospective study (grade 4a) showed that surgically treated dogs survived significantly longer than medically treated dogs. Four retrospective studies (grade 4b) compared the outcome of two surgical techniques but there were no statistically significant differences between treatment groups in terms of complications or outcome. The review found that the evidence base for the treatment of extrahepatic CPSS is weak. There is a lack of evidence of short- and long-term outcomes to recommend one treatment over another.

Owners’ perceptions of quality of life in geriatric horses: a cross-sectional study

Quality of life (QoL) is increasingly recognised as a more important measure of treatment success than prolongation of life. Assessment of QoL may aid decision-making for treatment or euthanasia. This study aimed to evaluate owners’ perceptions of factors affecting their horse's QoL and those factors that may contribute to their decision-making process for treatment or euthanasia of geriatric horses. A cross-sectional study was conducted, surveying a randomly selected sample of veterinary registered owners (n = 1,144) with horses aged ≥ 15 years, using a self-administered postal questionnaire. A section of this questionnaire contained 16 mixed-mode questions about the horse's QoL and factors influencing decisions on treatment. Horses from the cross-sectional survey were enrolled in a longitudinal study and, for cases of euthanasia, a further telephone questionnaire was completed to investigate factors influencing the owner's decision. Owners reported that the majority of geriatric animals enjoyed a high QoL, with 95% of owners rating their horse's QoL as good or excellent on an average day. However, increasing age corresponded negatively with many of the health-related QoL factors. Owners considered long-term diseases that cause chronic pain to affect their animal's QoL more than a disease causing a single episode of acute pain. The most important factors influencing choice of treatment options for a severe illness or injury were QoL after procedure, life-threatening disorders, painful/stressful procedures and veterinary advice. In conclusion, owner ratings and perceptions of factors affecting QoL of geriatric horses may prove useful in the development of a QoL assessment tool for ageing horses.

Anatomy of extrahepatic portosystemic shunts in dogs as determined by computed tomography angiography

Congenital extrahepatic portosystemic shunts are anomalous vessels joining portal and systemic venous circulation. These shunts are often diagnosed sonographically, but computed tomography (CT) angiography produces high-resolution images that give a more comprehensive overview of the abnormal portal anatomy. CT angiography was performed on 25 dogs subsequently proven to have an extrahepatic portosystemic shunt. The anatomy of each shunt and portal tributary vessels was assessed. Three-dimensional images of each shunt type were created to aid understanding of shunt morphology. Maximal diameter of the extrahepatic portosystemic shunt and portal vein cranial and caudal to shunt origin was measured. Six general shunt types were identified: splenocaval, splenoazygos, splenophrenic, right gastric-caval, right gastric-caval with a caudal shunt loop, and right gastric-azygos with a caudal shunt loop. Slight variations of tributary vessels were seen within some shunt classes, but were likely clinically insignificant. Two shunt types had large anastomosing loops whose identification would be important if surgical correction were attempted. A portal vein could not be identified cranial to the shunt origin in two dogs. In conclusion, CT angiography provides an excellent overview of extrahepatic portosystemic shunt anatomy, including small tributary vessels and loops. With minor variations, most canine extrahepatic portosystemic shunts will likely be one of six general morphologies.

Intravascular occlusion for the correction of extrahepatic portosystemic shunts in dogs

BACKGROUND

Congential extrahepatic portosystemic shunts (EHPSS) are common in dogs. An effective minimally invasive technique for correction of EHPSS could result in reduced morbidity, reduced costs, and reduced hospitalization times.

HYPOTHESIS

Use of an intravascular occlusion device can effectively and safely result in acute complete occlusion of EHPSS in dogs.

ANIMALS

Seven dogs with naturally occurring EHPSS that presented to the Purdue University Veterinary Teaching Hospital.

METHODS

Prospective, clinical trial. The 7 dogs were consecutively enrolled over a 2-year period. Results of serum biochemistry, total serum bile acids, fasting plasma ammonia, abdominal radiography, and ultrasonography suggested the diagnosis of portosystemic shunts in all dogs. Definitive diagnosis of EHPSS was achieved with cranial mesenteric arterial portography and acute occlusion was attempted by the deployment of the Amplatzer vascular plug (AVP).

RESULTS

EHPSS were identified in all dogs consisting of 5 portocaval and 2 portoazygous variants; 1/7 dogs (14%) were intolerant to temporary complete occlusion of the EHPSS. Of the remaining 6 dogs, 5 (83%) had complete occlusion of the EHPSS by the AVP. There were no complications and resolution of abnormal clinical signs and laboratory values was achieved in 4/5 (80%) dogs with complete occlusion.

CONCLUSIONS AND CLINICAL IMPORTANCE

Intravascular correction of EHPSS by the AVP is a viable option to surgical correction while larger studies will be required to determine the clinical applicability of this procedure in the broader portosystemic shunt population.

Diagnosis of congenital portosystemic shunt in miniature schnauzers 7 years of age or older (1997-2006)

Dogs with congenital portosystemic shunt (PSS) are typically diagnosed before 2 years of age. The objective of this study was to determine if miniature schnauzers are more likely to be diagnosed with congenital PSS at an older age than are other breeds. This retrospective study examined the case records of 171 dogs diagnosed with congenital PSS; dogs were included if they were definitively diagnosed as having congenital PSS by nuclear scintigraphy, contrast portography, and/or exploratory surgery. Seven (23%) of 31 miniature schnauzers diagnosed with congenital PSS were 7 years of age or older at the time of diagnosis, compared to 3.4% for all other breeds. Miniature schnauzers had a relative prevalence ratio of 6.3 (95% confidence interval 2.2 to 18.6; P=0.001) for being diagnosed at or after 7 years of age when compared to all other breeds of dogs. Clinical signs of congenital PSS may not manifest sufficiently to cause an owner to seek veterinary care for some dogs until they are older. Congenital PSS should be considered in mature dogs, particularly miniature schnauzers, that are presented with signs potentially consistent with hepatic encephalopathy.

Comparison of survival after surgical or medical treatment in dogs with a congenital portosystemic shunt

OBJECTIVE

To compare survival of dogs with a congenital portosystemic shunt (CPSS) that received medical or surgical treatment.

DESIGN

Prospective cohort study.

ANIMALS

126 client-owned dogs with a single CPSS.

PROCEDURES

Dogs were examined at 1 of 3 referral clinics, and a single CPSS was diagnosed in each. Dogs received medical or surgical treatment without regard to signalment, clinical signs, or results of hematologic or biochemical analysis. Survival data were analyzed via a Cox regression model.

RESULTS

During a median follow-up period of 579 days, 18 of 126 dogs died as a result of CPSS. Dogs treated via surgical intervention survived significantly longer than did those treated medically. Hazard ratio for medical versus surgical treatment of CPSS (for the treatment-only model) was 2.9 (95% confidence interval, 1.1 to 7.2). Age at CPSS diagnosis did not affect survival.

CONCLUSIONS AND CLINICAL RELEVANCE

Both medical and surgical treatment can be used to achieve long-term survival of dogs with CPSS, although results of statistical analysis supported the widely held belief that surgery is preferable to medical treatment. However, the study population consisted of dogs at referral clinics, which suggested that efficacy of medical treatment may have been underestimated. Although surgical intervention was associated with a better chance of long-term survival, medical management provided an acceptable first-line option. Age at examination did not affect survival, which implied that early surgical intervention was not essential. Dogs with CPSS that do not achieve acceptable resolution with medical treatment can subsequently be treated surgically.

Soy protein isolate versus meat-based low-protein diet for dogs with congenital portosystemic shunts

BACKGROUND

Both presurgical preparation and long-term support of nonoperable dogs with congenital portosystemic shunts (CPSS) require optimal dietary management. Studies suggested that protein source may play an important role, with vegetable and dairy protein sources having better effects on hepatic encephalopathy (HE) than meat proteins.

OBJECTIVES

Determine whether a low-protein test diet with soy as its main protein source results in better scores than a control diet with the same composition but with poultry as its main protein source in dogs with CPSS.

METHODS

In a double-blind cross-over study, 16 dogs received each diet for 4 weeks. Dogs in group T first received the test diet and then the control diet, whereas dogs in group C were fed the diets in the opposite order. Different variables (body weight, body condition score, HE score, fecal score, CBC, plasma tests of liver function including NH3, and coagulation tests) were measured at the start of the study and after completion of each diet.

RESULTS

One-way repeated measures ANOVA was performed. Plasma NH3 was significantly lower after the test diet than after the control diet. The test diet also resulted in significantly higher fibrinogen concentrations and lower prothrombin times. The HE score improved with both diets, with no significant difference between the 2 diets.

CONCLUSIONS

Both diets achieved a significant improvement in HE score. The influence of the soy-based diet on plasma NH3 concentration and coagulation parameters suggests that such a diet decreases the risk for HE and gives better support of liver function.

Congenital Portosystemic Shunts in Five Mature Dogs With Neurological Signs

Congenital portosystemic shunts are a common cause of hepatic encephalopathy and are typically first identified when dogs are &lt;2 years of age. This case series describes five dogs with congenital portosystemic shunts; the dogs were presented for severe encephalopathic signs during middle or old age. Three dogs had portoazygos shunts, and four dogs had multifocal and lateralizing neurological abnormalities, including severe gait abnormalities and vestibular signs. All five dogs responded to medical or surgical treatment, demonstrating that older animals can respond to treatment even after exhibiting severe neurological signs.

Evaluation of cellophane banding with and without intraoperative attenuation for treatment of congenital extrahepatic portosystemic shunts in dogs

OBJECTIVE

To evaluate the effect of intraoperative attenuation of congenital extrahepatic portosystemic shunts (CEPSSs) during cellophane banding procedures in dogs.

STUDY DESIGN

Retrospective case series and prospective study.

ANIMALS

18 cases evaluated retrospectively and 14 dogs evaluated prospectively.

PROCEDURES

Gradual occlusion of CEPSSs was performed via cellophane banding. Shunts were occluded to a diameter < 3.0 mm during surgery in dogs prospectively enrolled in the partial attenuation group, whereas the shunt was not attenuated during surgery in dogs prospectively enrolled in the no-attenuation group or in dogs that had previously undergone surgery and were retrospectively evaluated. Postprandial serum bile acids (PPSBA) concentrations were measured before surgery and at various time points after surgery.

RESULTS

Mean +/- SD PPSBA concentrations were 26.8 +/- 24.5 micromol/L at < 2.25 months after surgery (n = 16 dogs), 22.1 +/- 14.0 micromol/L from 2.25 to 6 months after surgery (12 dogs), and 34.9 +/- 32.5 micromol/L at > 6 months after surgery (22 dogs). In the prospectively enrolled dogs, mean PPSBA concentrations increased over time in dogs in the partial attenuation group, but not in dogs in the no-attenuation group.

CONCLUSIONS AND CLINICAL RELEVANCE

Cellophane banding may be used to occlude larger CEPSSs and may decrease the need for intraoperative monitoring of portal vein blood pressure. The technique may facilitate minimally invasive treatment of CEPSSs in dogs. Intraoperative attenuation of CEPSSs to a diameter < 3.0 mm is not necessary and may result in a less favorable outcome.

Effect of protein concentration on rate of closure of ameroid constrictors in vitro

OBJECTIVE

To evaluate the effect of protein concentration on rate of closure of ameroid constrictors in vitro.

SAMPLE POPULATION

Twenty-four 3.5-mm ameroid constrictors.

PROCEDURE

Ameroid constrictors were equally allocated into 4 treatment groups; constrictors were placed in saline (0.9% NaCl) solution (control) or plasma diluted with saline solution to obtain protein concentrations of 1.5, 3, or 6 g/dL. Ameroid constrictors were incubated for 27 days. A digital camera was used to image ameroid constrictors in culture at 1, 6, 11, 16, 21, and 27 days, and the lumen diameter of each constrictor was measured.

RESULTS

None of the rings were completely closed at 27 days. Mean final lumen diameter was 0.205 +/- 0.22 mm. Mean final lumen diameter of constrictors in the control group was significantly larger than that of constrictors in the 1.5, 3, and 6 g/dL groups. Constrictors in the 1.5 g/dL group closed to a larger diameter than that of constrictors in the 6 g/dL group. Constrictors in the control group had the smallest overall change in lumen diameter, compared with constrictors in the 3 and 6 g/dL groups. Constrictors in the 1.5 g/dL group had a significant decrease in overall lumen diameter, compared with constrictors in the 3 and 6 g/dL groups. The diameter of the ameroid lumen was a function of time and protein concentration.

CONCLUSIONS AND CLINICAL RELEVANCE

High plasma protein concentrations resulted in rapid closure of the ameroid constrictor lumen. Complete closure of ameroid constrictors may not be attributable to imbibition of casein.

Evaluation of ameroid ring constrictors for treatment for single extrahepatic portosystemic shunts in dogs: 168 cases (1995-2001)

OBJECTIVES

To evaluate use of an ameroid ring constrictor (ARC) for treatment for single extrahepatic portosystemic shunts (PSSs) and identify factors associated with postoperative death, continued portosystemic shunting, and long-term outcome in dogs.

DESIGN

Retrospective study.

ANIMALS

168 dogs with a single extrahepatic PSS.

PROCEDURE

Medical records of dogs that had a single extrahepatic PSS and were treated with an ARC were reviewed. Signalment, history, clinical signs, results of preoperative blood analyses and portal pressure measurements, PSS location, ARC size, postoperative complications, and postoperative scintigraphy results were recorded. Owners were interviewed 6 months to 6 years after surgery. Results-Postoperative complications developed in 10% of dogs. Postoperative mortality rate was 7.1%. Predictive factors for postoperative death included high preoperative WBC count and postoperative complications. Twenty-one percent of dogs in which portal scintigraphy was performed 6 to 10 weeks after surgery had continued shunting. Predictive factors for persistent shunting included low preoperative plasma albumin concentration, high portal pressure after complete occlusion, and high portal pressure difference (postocclusion minus baseline). Clinical outcome in 108 dogs was classified as excellent (80%), good (14%), or poor (6%). Predictive factors for excellent long-term clinical outcome included high preoperative plasma albumin concentration, low preoperative leukocytosis, low portal pressure after complete occlusion, absence of postoperative seizures, and absence of continued shunting.

CONCLUSIONS AND CLINICAL RELEVANCE

Use of an ARC for treatment for a single extrahepatic PSS resulted in low morbidity and mortality rates. Certain preoperative factors were associated with increased risk of postoperative death, continued portosystemic shunting, and long-term outcome.

Association of breed with the diagnosis of congenital portosystemic shunts in dogs: 2,400 cases (1980-2002)

OBJECTIVE

To determine the annual and overall proportion of diagnoses of congenital portosystemic shunts (CPSS) in dogs and identify breeds at increased risk for CPSS.

DESIGN

Retrospective study.

ANIMALS

2,400 dogs with CPSS from veterinary teaching hospitals that reported to the Veterinary Medical Database (VMDB) from January 1, 1980 to February 28, 2002.

PROCEDURE

The proportion of diagnoses of CPSS was calculated for all dogs and each breed recorded in the VMDB annually and for the 22.2-year period. Odds ratios and adjusted confidence intervals were calculated for breeds with at least 100 accessions by comparing odds of each breed with a diagnosis of CPSS with that of mixed-breed dogs.

RESULTS

Congenital portosystemic shunts were reported in 0.18% of all dogs and 0.05% of mixed-breed dogs. The proportion of diagnoses of CPSS increased from 5 in 10,000 dogs in 1980 to 5 in 1,000 dogs in 2001. Yorkshire Terriers had the greatest total number of diagnoses of CPSS. Thirty-three breeds were significantly more likely to have a diagnosis of CPSS, compared with mixed-breed dogs. The greatest proportions of diagnoses were found in Havanese (3.2%), Yorkshire Terriers (2.9%), Maltese (1.6%), Dandie Dinmont Terriers (1.6%), and Pugs (1.3%).

CONCLUSIONS AND CLINICAL RELEVANCE

Certain breeds appear to be at increased risk for CPSS, compared with mixed-breed dogs. The increased odds ratios among specific breeds support the hypothesis of a genetic predisposition for CPSS. Clients and veterinarians should consider appropriate diagnostic tests for dogs with clinical signs and those used for breeding from breeds with increased risk of CPSS.

A new dissection technique for approach to right-sided intrahepatic portosystemic shunts: anatomic study and use in three dogs

OBJECTIVE

To determine the feasibility of indirect suture passage around the right portal vein for attenuation of right-sided intrahepatic portosystemic shunts (IHPSS).

STUDY DESIGN

Anatomic study of cadavers and prospective evaluation of clinical cases.

ANIMALS

Nine canine cadavers (median weight, 20.5 kg) and 6 client-owned dogs suspected of having right-sided IHPSS.

METHODS

Silicone casts of the caudal vena cava and pre- and intrahepatic portal veins were made in fresh canine cadavers. A suture was passed dorsal to the portal vein above and below its bifurcation and pulled laterally so that it surrounded the right portal vein. The number and size of portal and caudal vena cava branches that interfered with the suture passage were recorded. Intra- and postoperative complications were evaluated in 3 dogs with right-sided IHPSS and 3 dogs suspected of having right-sided IHPSS that had right portal vein dissection and occlusion using this technique.

RESULTS

Suture passage and placement around the right portal vein were easily accomplished in all 9 specimens. A 1 mm branch from the dorsal surface of the right portal vein was included in the encircling ligature in 4 specimens. The dissection technique was used successfully in 3 dogs with right-sided IHPSS and 2 other clinical cases. The portal branch to the papillary process of the caudate lobe interfered with suture placement in 1 dog with a central IHPSS.

CONCLUSIONS

Indirect suture passage for ligation of the right portal vein can be successfully performed in normal dogs and dogs with congenital portosystemic shunts.

CLINICAL RELEVANCE

Hemorrhage, vascular trauma, and surgery time may be reduced using this technique for attenuation of right-sided IHPSS.

Survival and prognostic indicators for dogs with intrahepatic portosystemic shunts: 32 cases (1990-2000)

OBJECTIVE

To determine prognostic indicators for short-term outcome and long-term survival for dogs with intrahepatic portosystemic shunts (IPSS).

STUDY DESIGN

Retrospective study.

ANIMALS

Thirty-two dogs of various breeds.

METHODS

Clinical data extracted from medical records of dogs with IPSS were reviewed and included gender, age at surgery, weight, preoperative packed cell volume (PCV), total plasma protein concentration (TP), albumin (ALB), serum activities of alanine aminotransferase (ALT) and alkaline phosphatase (ALP), preprandial and postprandial bile acid concentrations (pre-BA, post-BA), blood urea nitrogen (BUN), glucose concentration, band neutrophils, per-rectal nuclear scintigraphy shunt fraction, whether an angiogram was performed, shunt location at surgery, whether a partial or complete attenuation of the shunt was performed, rectal temperature at the end of surgery, and duration of surgical procedure. Follow-up was determined from visits to the veterinary teaching hospital or by telephone communications with the owner or referring veterinarian.

RESULTS

Median survival time was 35.68 months, and 1- and 2-year probabilities of survival were 60% and 55%, respectively. Body weight, TP, ALB, and BUN were identified as prognostic indicators for short-term outcome. PCV and TP were identified as prognostic indicators for long-term survival.

CONCLUSIONS

PCV and TP were identified as prognostic indicators for long-term survival, whereas body weight, TP, ALB, and BUN were identified as indicators for short-term outcome in dogs with IPSS. Shunt location at surgery did not have any effect on short-term outcome and long-term survival.

CLINICAL RELEVANCE

Total protein, ALB, BUN, and PCV can be used to determine prognosis of dogs with intrahepatic shunt.

Evaluation of ameroid ring constrictors for the management of single extrahepatic portosystemic shunts in cats: 23 cases (1996-2001)

OBJECTIVE

To document the signalment; history; clinical signs; clinicopathologic, diagnostic imaging, and surgical findings; perioperative complications; and long-term clinical results of ameroid ring constrictor (ARC) placement on single extrahepatic portosystemic shunts (PSS) in cats.

DESIGN

Retrospective study.

ANIMALS

23 cats treated with an ARC on a single extrahepatic PSS.

PROCEDURE

An ARC was placed surgically around the PSS. Portal pressure was measured prior to ARC placement, with complete temporary PSS occlusion, and after ARC placement. Cats were scheduled for recheck transcolonic portal scintigraphy 8 to 10 weeks after surgery. Follow-up information was obtained by telephone interview with the owners.

RESULTS

An ARC was successfully placed in 22 of 23 cats. Intraoperative complications, consisting of PSS hemorrhage, occurred in 2 cats. Mean (+/- SD) portal pressure (n = 15) was 6.7+/-2.9 mm Hg before PSS manipulation, 18.6+/-7.7 mm Hg with complete temporary PSS occlusion, and 6.9+/-2.7 mm Hg after ARC placement. Postoperative complications developed in 77% (17 of 22) of cats after ARC placement, and included central blindness, hyperthermia, frantic behavior, and generalized motor seizures. Perioperative mortality rate was 4.3% (1 of 23). Persistent shunting was identified in 8 of 14 cats. Overall, 75% (15 of 20) of cats had an excellent long-term outcome.

CONCLUSIONS AND CLINICAL RELEVANCE

Placement of an ARC on single extrahepatic PSS in cats resulted in low surgical complication and perioperative mortality rates, but most cats did have substantial postoperative complications. Persistent shunting was common, although many cats with persistent shunting were clinically normal.

Evaluation of a portocaval venograft and ameroid ring for the occlusion of intrahepatic portocaval shunts in dogs

OBJECTIVE

To evaluate the use of a portocaval venograft and ameroid constrictor in the surgical management of intrahepatic portosystemic shunts (PSS).

STUDY DESIGN

Prospective, clinical study.

ANIMAL POPULATION

Ten client-owned dogs with intrahepatic PSS.

METHODS

Portal pressure was measured after temporary suture occlusion of the intrahepatic PSS. In dogs with an increase in portal pressure greater than 8 mm Hg, a single extrahepatic portocaval shunt was created using a jugular vein. An ameroid ring was placed around the venograft and the intrahepatic PSS was attenuated. Transcolonic pertechnetate scintigraphy was performed before surgery, 5 days after surgery, and 8 to 10 weeks after surgery. Dogs with continued portosystemic shunting were evaluated further by laparotomy or portography. Clinical outcome and complications were recorded.

RESULTS

Mean (+/- SD) portal pressure increased from 6 +/- 3 to 19 +/- 6 mm Hg with PSS occlusion; in all 10 dogs, the increase in portal pressure was greater than 8 mm Hg. There were no intraoperative complications, and, after creation of the portocaval shunt, the intrahepatic PSS could be completely ligated in 8 of 10 dogs. The final portal pressure was 9 +/- 4 mm Hg. Postoperative complications included coagulopathy and death (1 dog), ascites (3 dogs), and incisional discharge (3 dogs). Five of 8 dogs had continued portosystemic shunting at 8 to 10 weeks after surgery. Multiple extrahepatic PSS were demonstrated in 4 of these dogs. Clinical outcome was excellent in all 9 surviving dogs.

CONCLUSIONS AND CLINICAL SIGNIFICANCE

The surgical technique resulted in a high incidence of multiple extrahepatic PSS. Short-term clinical results were promising, but long-term outcome must be evaluated further.

Hemostatic profiles in 39 dogs with congenital portosystemic shunts

OBJECTIVES

To determine if there were significant changes in prothrombin time (PT), partial thromboplastin time (PTT), and fibrinogen levels in dogs with naturally occurring congenital portosystemic shunts (CPSS) and to determine if there was any association between these values, serum albumin concentration, and the ability to attenuate the shunt vessel.

STUDY DESIGN

Retrospective clinical study.

ANIMALS

Thirty-nine client-owned dogs.

METHODS

Medical records of 60 dogs with confirmed CPSS were retrospectively evaluated. Hemostatic profiles had been performed before surgery in 39 cases.

RESULTS

Dogs with CPSS had significantly higher values for PTT (P < .001) when compared with normal dogs. Of the total number of dogs, 64.1% had a PTT greater than 16 seconds (25/39). PTT was prolonged by 25% or more in 51.3% of dogs (20/39). PT tended to be higher in dogs with CPSS (P = .036), although only 7.7% (3/39) of dogs had a PT greater than 12 seconds (the maximum reference value). Dogs with CPSS had significantly lower values for albumin and fibrinogen (P < .001). Platelet numbers were within the normal range in 87.2% of cases (34/39). Of the 5 dogs with platelet numbers outside the normal range, 3 were mildly thrombocytopenic. Fibrin degradation product concentrations were not elevated in any dogs tested (N = 22). There was no significant difference in any of the measured variables between dogs with extrahepatic shunts and those with intrahepatic shunts (P > .1). For PT, PTT, albumin, and fibrinogen, there was no significant difference between dogs that underwent total, partial, or no attenuation (P > .3).

CONCLUSIONS

Dogs with CPSS have a tendency to have a prolonged PTT. There was no significant difference in hemostatic profile results between dogs with intrahepatic shunts versus extrahepatic shunts. Preoperative hemostatic profile abnormalities were not useful as predictors of ability to attenuate CPSS.

CLINICAL RELEVANCE

Prolonged PTT was not associated with bleeding tendencies in any of the dogs. Assays of individual clotting factors may help to further characterize the abnormalities present in animals with CPSS and may identify specific factor deficiencies. This might enable identification of a noninvasive diagnostic or prognostic indicator.