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

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.

Surgical treatment and outcome of intrahepatic shunts in 12 cats

CASE SERIES SUMMARY

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

RELEVANCE AND NOVEL INFORMATION

Few papers exist that describe the presentation, intraoperative imaging, treatment and outcome of IHPSSs in cats. This is the first to describe surgical attenuation with a thin film band in a cat with an IHPSS. This case series reports excellent long-term outcomes in a majority of surgically treated cats with IHPSS.

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.

Evaluation of blood urea nitrogen concentration and anorexia as predictors of nonsurvival in client-owned rabbits evaluated at a veterinary referral center

OBJECTIVE To determine the prognostic relevance of BUN concentration in client-owned rabbits evaluated at a veterinary referral center. ANIMALS 246 healthy or clinically ill client-owned rabbits with BUN concentrations measured at a veterinary referral center. PROCEDURES In a retrospective cohort study design, medical records of rabbits were retrieved, and data were collected on BUN concentration (exposure variable of interest) and other variables, including outcome (survival status at 15 days after BUN concentration measurement). Univariate, multivariate, and subgroup analyses were performed to identify variables associated with outcome. RESULTS BUN concentrations ranged from 6.5 to 251.1 mg/dL (median, 18.7 mg/dL). Univariate analysis revealed that the risk of nonsurvival over the 15-day period for rabbits with a high BUN concentration (≥ 23.3 mg/dL) was 33% higher (relative risk, 1.33; 95% confidence interval [CI], 1.06 to 1.69) than that for rabbits with unremarkable BUN values. Subgroup analysis revealed that for rabbits with anorexia, a high (vs unremarkable) BUN concentration was associated with an increased risk of nonsurvival (relative risk, 1.69; 95% CI, 1.05 to 2.71). In the final multivariate model that controlled for age, sex, and appetite (anorexia vs no anorexia), the odds of nonsurvival for rabbits with BUN values > 24.74 mg/dL were 3 times that for rabbits with BUN values < 14.00 mg/dL (OR, 2.92; 95% CI, 1.29 to 6.58). CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that a high BUN concentration increased the risk of nonsurvival over a 15-day period for client-owned rabbits, particularly those with anorexia. Blood urea nitrogen concentration should be used together with other clinical indicators to provide prognostic information for rabbits receiving veterinary care.

Abramov P, M. Abdelhamid F. Clinical Characteristics, Serum Biochemical Changes, and Expression Profile of Serum Cfa-miRNAs in Dogs Confirmed to Have Congenital Portosystemic Shunts Accompanied by Liver Pathologies

Computed tomography angiography (CTA) and biochemical parameters cannot specify liver pathologies in dogs with congenital portosystemic shunts (CPSS) that are easily determined by invasive histopathology. This study aims to assess the possibility of using circulating serum canine familiaris (cfa) microRNAs (miRNAs) as novel non-invasive serum-based fingerprints for liver injuries associated with various morphologies of extrahepatic and intrahepatic portosystemic shunts (EHPSS and IHPSS). Data were obtained from 12 healthy dogs and 84 dogs confirmed to have EHPSS (splenocaval, splenophrenic, splenoazygos, right gastrocaval (RGC), right gastrocaval with caudal loop (RGC-CL)) and IHPSS (right divisional and left divisional) using CTA. Hepatic pathologies were determined by histopathology. Serum expression of miRNAs was assessed by real-time polymerase chain reaction. Based on the nature of liver injuries in each shunt type, cfa-miR-122 was significantly upregulated in all CPSS groups. Meanwhile, serums cfa-miR-34a and 21 were not significantly expressed in splenophrenic or splenoazygos groups, but they were extensively upregulated in splenocaval, RGC, RGC-CL groups and less frequently in right or left divisional groups. Also, serum cfa-miR126 was significantly upregulated in both IHPSS groups but less significantly expressed in RGC, RGC-CL, and splenocaval groups. Overall, estimated cfa-miRNAs could serve as novel biomarkers to mirror the histopathological and molecular events within the liver in each shunt type.

Welfare-Adjusted Life Years (WALY): A novel metric of animal welfare that combines the impacts of impaired welfare and abbreviated lifespan

Currently, separate measures are used to estimate the impact of animal diseases on mortality and animal welfare. This article introduces a novel metric, the Welfare-Adjusted Life Year (WALY), to estimate disease impact by combining welfare compromise and premature death components. Adapting the Disability-Adjusted Life Year approach used in human health audits, we propose WALY as the sum of a) the years lived with impaired welfare due to a particular cause and b) the years of life lost due to the premature death from the same cause. The years lived with impaired welfare are the product of the average duration of each welfare impediment, reflecting the actual condition that compromises animal welfare, the probability of an incident case developing and impaired welfare weights, representing the degree of impaired welfare. The years of life lost are calculated using the standard expected lifespan at the time of premature death. To demonstrate the concept, we estimated WALYs for 10 common canine diseases, namely mitral valve disease, dilated cardiomyopathy, chronic kidney disease, diabetes mellitus, atopic dermatitis, splenic haemangiosarcoma, appendicular osteosarcoma, cranial cruciate ligament disease, thoracolumbar intervertebral disc disease and cervical spondylomyelopathy. A survey of veterinarians (n = 61) was conducted to elicit impaired welfare weights for 35 welfare impediments. Paired comparison was the primary method to elicit weights, whereas visual analogue scale and time trade-off approaches rescaled these weights onto the desired scale, from 0 (the optimal welfare imaginable) to 1 (the worst welfare imaginable). WALYs for the 10 diseases were then estimated using the impaired welfare weights and published epidemiological data on disease impacts. Welfare impediment “amputation: one limb” and “respiratory distress” had the lowest and highest impaired welfare weights at 0.134 and 0.796, rescaled with a visual analogue scale, and 0.117 and 0.857, rescaled with time trade-off. Among the 10 diseases, thoracolumbar intervertebral disc disease and atopic dermatitis had the smallest and greatest adverse impact on dogs with WALYs at 2.83 (95% UI: 1.54–3.94) and 9.73 (95% uncertainty interval [UI]: 7.17–11.8), respectively. This study developed the WALY metric and demonstrated that it summarises welfare compromise as perceived by humans and total impact of diseases in individual animals. The WALY can potentially be used for prioritisation of disease eradication and control programs, quantification of population welfare and longitudinal surveillance of animal welfare in companion animals and may possibly be extended to production animals.

Interventional Radiology Management of Vascular Malformations: Portosystemic Shunts and Vascular Fistulae/Malformations

Vascular malformations are abnormal connections between blood vessels that can have various endothelial characteristics. Although uncommon, these malformations can present challenging diagnostic and therapeutic scenarios. The use of interventional radiology techniques in the management of various vascular malformations is an attractive option because of the ability to treat these malformations at the most appropriate anatomic location and in the most effective manner. Techniques such as coil embolization of intrahepatic portosystemic shunts and liquid embolization of arteriovenous fistulae/malformations have shown tremendous potential as treatments for these challenging diseases.

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.

Trends in popularity of some morphological traits of purebred dogs in Australia

BACKGROUND

The morphology of dogs can provide information about their predisposition to some disorders. For example, larger breeds are predisposed to hip dysplasia and many neoplastic diseases. Therefore, longitudinal trends in popularity of dog morphology can reveal potential disease pervasiveness in the future. There have been reports on the popularity of particular breeds and behavioural traits but trends in the morphological traits of preferred breeds have not been studied.

METHODS

This study investigated trends in the height, dog size and head shape (cephalic index) of Australian purebred dogs. One hundred eighty-one breeds derived from Australian National Kennel Council (ANKC) registration statistics from 1986 to 2013 were analysed. Weighted regression analyses were conducted to examine trends in the traits by using them as outcome variables, with year as the explanatory variable and numbers of registered dogs as weights. Linear regression investigated dog height and cephalic index (skull width/skull length), and multinomial logistic regression studied dog size.

RESULTS

The total number of ANKC registration had decreased gradually from 95,792 in 1986 to 66,902 in 2013. Both weighted minimal height (p = 0.014) and weighted maximal height (p < 0.001) decreased significantly over time, and the weighted cephalic index increased significantly (p < 0.001). The odds of registration of medium and small breeds increased by 5.3 % and 4.2 %, respectively, relative to large breeds (p < 0.001) and by 12.1 % and 11.0 %, respectively, relative to giant breeds (p < 0.001) for each 5-year block of time.

CONCLUSIONS

Compared to taller and larger breeds, shorter and smaller breeds have become relatively popular over time. Mean cephalic index has increased, which indicates that Australians have gradually favoured breeds with shorter and wider heads (brachycephalic). These significant trends indicate that the dog morphological traits reported here may potentially influence how people select companion dogs in Australia and provide valuable predictive information on the pervasiveness of diseases in dogs.

Balloon occlusion of the caudal vena cava for vascular contrast studies as an aid to intravascular coil embolisation for the treatment of intrahepatic portosystemic shunts in three dogs

CASE REPORT

Three dogs were treated with fluoroscopically guided coil embolisation of intrahepatic portosystemic shunts. A large-diameter vascular occlusion balloon was used to improve the vascular contrast studies required to perform this procedure. This technique improved identification of vascular structures and allowed completion of the procedures without the need for digital subtraction angiography.

CLINICAL SIGNIFICANCE

Interventional radiological procedures are an emerging area of veterinary medicine and procedural modifications may help expand their use in clinical practice.

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.

Coagulation in hepatobiliary disease

OBJECTIVE

To review the pathogenesis and clinical consequences of coagulation abnormalities accompanying hepatobiliary disorders and to highlight the need for further studies to characterize these derangements and their treatment options in small animal patients.

DATA SOURCES

Veterinary and human medical literature: original research articles, scientific reviews, consensus statements, and recent texts.

SUMMARY

The liver plays an important role in the production and clearance of many components of coagulation. A wide range of hemostatic derangements can occur in patients with hepatobiliary disease including alterations in platelet number and function, coagulation factor levels, anticoagulants, vascular endothelial function, and fibrinolysis. As these hemostatic alterations include both pro- and anticoagulation pathways, the net result is often a rebalanced hemostatic system that can be easily disrupted by concurrent conditions resulting in either clinical bleeding or thrombosis. Conventional coagulation tests are inadequate at identifying the spectrum of coagulation alterations occurring in patients with hepatobiliary disease, but their evaluation is necessary to assess bleeding risk and provide prognostic information. A paucity of information exists regarding the treatment of the coagulation derangements in small animals with hepatobiliary disease. Extrapolation from human studies provides some information about potential treatment options, but further studies are warranted in this area to elucidate the best management for coagulation abnormalities in dogs and cats with hepatobiliary disease.

CONCLUSION

Hepatobiliary disease can have profound effects on coagulation function leading to hypercoagulable or hypocoagulable states. Overall coagulation status with hepatobiliary disease depends on both the type and severity of disease and the presence of associated complications.

Epidemiologic factors associated with the anatomic location of intrahepatic portosystemic shunts in dogs

OBJECTIVE

To determine whether breed, sex, country of origin, and age are associated with anatomic location of intrahepatic portosystemic shunts (IHPSS) in dogs.

STUDY DESIGN

Multi-institutional retrospective case series.

SAMPLE POPULATION

Dogs (n=125) with IHPSS from the veterinary teaching hospitals of the University of Florida (21), Sydney University (44), and the University of California-Davis (60).

METHODS

Dogs with surgical/necropsy confirmation of single IHPSS were identified. Data were analyzed using logistic regression for associations between age, breed, sex, and country with the anatomic location of IHPSS.

RESULTS

Right (34%), left (34%), and central divisional IHPSS (32%) were prevalent with approximately equal frequency in Australia; in the United States, the prevalence of right (24%) and central divisional (26%) combined was similar to left divisional IHPSS (51%). Country (P=048), sex (P=.016), and Australian cattle dog ([ACD], P=.025) were significantly associated with IHPSS location. Dogs in Australia had 2.5-fold higher odds of having right versus left divisional IHPSS. Males and ACD had 2.8- and 5.6-fold higher odds of having right versus left divisional IHPSS. Australian dogs were significantly older than those in the United States (P<.0001) and ACD were significantly older than other breeds (P=.0067).

CONCLUSIONS

Although country of origin, breed, and sex had significant associations with anatomic location of IHPSS, signalment does not appear to be a strong predictor of shunt location when used alone.

CLINICAL RELEVANCE

For the common breeds in this report, signalment is only occasionally helpful in predicting likelihood of anatomic division in IHPSS. Australian cattle dogs and male dogs have a statistical association with right (versus left) divisional IHPSS. If advanced imaging techniques are not available, veterinary surgeons should be prepared to locate and address any anatomic configuration of IHPSS in a dog.

Surgical Management of Left-Divisional Intrahepatic Portosystemic Shunts: Outcome After Partial Ligation of, or Ameroid Ring Constrictor Placement on, the Left Hepatic Vein in Twenty-Eight Dogs (1995?2005)

OBJECTIVES

To evaluate outcome in dogs with left divisional intrahepatic portosystemic shunts (PSS) treated by partial ligation (PL) or ameroid ring constrictor (ARC) placement on the left hepatic vein.

DESIGN

Retrospective study.

ANIMALS

Dogs (n=28) with left divisional intrahepatic PSS.

METHODS

Retrieved data from medical records of dogs with left divisional intrahepatic PSS that had PL (n=17) or ARC (n=11) were signalment, history, clinical signs, preoperative blood work, portal pressure measurements, ARC size, complications and postoperative technetium scintigraphy. Outcome assessed by owner interview 6 months-10 years after surgery was classified as excellent, good or poor. Differences were tested by exact chi2 test.

RESULTS

Major complications occurred in 3 dogs: coagulopathy (1 PL dog died), ascites (1 PL dog survived) and seizures (1 ARC dog died). Eight PL dogs had technetium portal scintigraphy; 1 dog was negative and 7 dogs positive for persistent shunting. Seven ARC dogs had scintigraphy; 4 dogs were negative and 3 positive for persistent shunting. In PL dogs, long-term clinical outcome was excellent (92%) or good (8%) whereas, in ARC dogs it was excellent (20%), good (50%) or poor (30%). This outcome difference between treatment groups was significant (P=.0012).

CONCLUSION

Dogs treated by PL had significantly better long-term outcome compared with ARC treated dogs.

CLINICAL RELEVANCE

Based on these data, ARC placement on the left hepatic vein in dogs with left-divisional intrahepatic PSS cannot be recommended.

Outcome associated with use of a percutaneously controlled hydraulic occluder for treatment of dogs with intrahepatic portosystemic shunts

OBJECTIVE

To evaluate efficacy of a hydraulic occluder (HO) used for treatment of dogs with an intrahepatic portosystemic shunt (IHPSS).

DESIGN

Prospective study.

ANIMALS

10 dogs with an IHPSS.

PROCEDURES

Serum biochemical and postprandial bile acids (PPBA) analyses and transcolonic scintigraphy were performed before surgery. Laparotomy was performed, and an uninflated HO was placed around the portal vein branch leading to the IHPSS. After surgery, 0.9% NaCl solution was injected into subcutaneous injection ports at 2, 4, 6, and 8 weeks to achieve staged occlusion of the HO. Serum biochemical analyses, PPBA analysis, and scintigraphy were performed 2 weeks after occlusion. Serum biochemical analyses were repeated 1 year after surgery.

RESULTS

Implant revision was required in 3 dogs because of rupture of the HO (n = 2) or detachment of the actuating tubing (1). Serum biochemical values and clinical signs improved in all dogs after surgery. Six of 10 dogs had PPBA concentration within reference range 2 weeks after occlusion, and 2 additional dogs had concentrations within reference range at 1 year. Only 5 of 10 dogs had complete resolution of portosystemic shunting 2 weeks after occlusion. Two dogs were lost to follow-up, and 8 dogs remained alive with no recurrence of clinical signs at a median of 22 months after surgery.

CONCLUSIONS AND CLINICAL RELEVANCE

Use of the HO appeared to be an effective method for surgical treatment for dogs with IHPSS, although problems with implant reliability indicate a need for modifications in design and manufacturing.

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.

Outcomes of Intrahepatic Portosystemic Shunts Occluded with Ameroid Constrictors in Nine Dogs and One Cat

OBJECTIVE

To report outcome after ameroid constrictor (AC) use for single intrahepatic portosystemic shunts (IPSS).

STUDY DESIGN

Retrospective study.

ANIMALS

Nine dogs and 1 cat.

METHODS

Medical records (1999-2003) of dogs and cats with surgically confirmed IPSS were reviewed. Recorded data was: breed, sex, weight, age at surgery, clinical signs, serum biochemical and hematologic data, shunt anatomy, AC size, hospitalization, complications, and owner perception of their animal's response to surgery. Owners were contacted twice postoperatively (between 20 and 75 months) and asked to complete a simple questionnaire.

RESULTS

With this technique, complication rate was low and postligation neurologic dysfunction was not observed. In the cat and 7 dogs, clinical signs attributed to IPPS resolved and animals were fed a non-prescription diet without medication. One dog died suddenly 18 months after surgery from causes unrelated to hepatic disease. One dog was euthanatized 23 months after surgery because of repeated, increasingly refractory episodes of hepatic encephalopathy.

CONCLUSION

AC provides a safe and effective method for occlusion of some IPPS.

CLINICAL RELEVANCE

AC should be considered for occlusion of some IPPS in dogs and cats.

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.

USE OF INTRAOPERATIVE MESENTERIC PORTOVENOGRAPHY IN CONGENITAL PORTOSYSTEMIC SHUNT SURGERY

A retrospective study of the use of intraoperative mesenteric portovenography (IOMP) in the surgical management of congenital portosystemic shunts in 100 dogs and cats was performed. Each portovenogram was scored using a subjective visual analogue scale (VAS) and was assessed for the presence of portal atresia or hypoplasia. VAS scores and portal hypoplasia assessments were obtained for portovenogram images obtained for each animal both before shunt manipulation (preligation) and following the temporary, complete ligation of the vessel (postligation). In each patient, surgical records were reviewed to ascertain the degree of shunt attenuation that was achieved at surgery. Hepatic portal vasculature was significantly different on postligation compared with preligation IOMP. Sixty-two percent of animals had apparent portal hypoplasia or atresia on their preligation IOMP. The majority of these (81%) had an improvement in portal vasculature on postligation IOMP. It was concluded that both preligation and postligation IOMP provided valuable information regarding the morphology of congenital portosystemic shunts. An accurate assessment of an animal's portal vasculature could only be made following the interpretation of a postligation portovenogram, and these findings significantly influenced the surgical management of the patient. Although individuals with high postligation VAS scores were more likely to achieve full shunt attenuation at surgery, there was no quantifiable relationship between IOMP findings and the degree of shunt attenuation achieved.