Perioperative outcomes after three different single extrahepatic portosystemic shunt attenuation techniques in dogs: partial ligation, complete ligation and ameroid constrictor placement

OBJECTIVE: To compare the perioperative outcomes of single extrahepatic portosystemic shunt occlusion by complete and partial silk ligation and ameroid constrictor placement in dogs. DESIGN: A retrospective analysis of 30 dogs with single congenital extrahepatic shunts. PROCEDURE: Records between 1990 and 2000 were reviewed. Patient age, breed, weight, presenting clinical signs, clinical pathology results, diagnostic imaging results, the surgery procedure performed, implant used, time taken, intra operative complications and perioperative complications were recorded. Mortality rates were calculated. RESULTS: Twenty dogs had a silk ligation procedure, 10 partially occluded and 10 completely. Ten dogs had an ameroid constrictor placement procedure. Ameroid constrictor surgery was significantly shorter in duration than silk ligation. Time for silk ligation was 91.8 +/- 35.2 minutes (median 90.0); time for ameroid constrictor placement was 71.5 +/- 12.0 (median 72.5, P = 0.049). A reduction in intraoperative complications was also noted in the ameroid constrictor surgery group. CONCLUSION: The ameroid constrictor offered a surgical occlusion procedure of single extrahepatic portosystemic shunts in dogs that was clinically as effective as silk ligation in the perioperative period, with a significantly shorter surgery time.     

Use of portocaval venografts with ameroid constrictor placement and hepatic lobectomy for treatment of intralobular intrahepatic portocaval shunts in four dogs

Liver lobectomy for complete attenuation of intrahepatic portosystemic shunts appears to be a safe and effective surgical treatment. When the intrahepatic shunt vessel can be definitively palpated within a liver lobe or its presence confirmed portographically, liver lobectomy represents a technically simple and effective method of complete shunt attenuation. To maintain portal pressure at an acceptable value after lobectomy, an extrahepatic portocaval shunt vessel can be created by use of an external jugular vein graft. A second shunt vessel can be created if portal pressure remains increased after placement of 1 shunt. Gradual and safe attenuation of the shunt vessel is achieved by placement of an ameroid constrictor on the extrahepatic graft at the time of the initial surgery.     

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.     

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.     

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.     

Histologic examination of hepatic biopsy samples as a prognostic indicator in dogs undergoing surgical correction of congenital portosystemic shunts: 64 cases (1997-2005)

OBJECTIVE:To determine whether results of histologic examination of hepatic biopsy samples could be used as an indicator of survival time in dogs that underwent surgical correction of a congenital portosystemic shunt (PSS). DESIGN: Retrospective case series. ANIMALS: 64 dogs that underwent exploratory laparotomy for an extrahepatic (n = 39) or intrahepatic (25) congenital PSS. PROCEDURES: All H&E-stained histologic slides of hepatic biopsy samples obtained at the time of surgery were reviewed by a single individual, and severity of histologic abnormalities (ie, arteriolar hyperplasia, biliary hyperplasia, fibrosis, cell swelling, lipidosis, lymphoplasmacytic cholangiohepatitis, suppurative cholangiohepatitis, lipid granulomas, and dilated sinusoids) was graded. A Cox proportional hazards regression model was used to determine whether each histologic feature was associated with survival time. RESULTS: Median follow-up time was 35.7 months, and median survival time was 50.6 months. Thirty-eight dogs were alive at the time of final follow-up; 15 had died of causes associated with the PSS, including 4 that died immediately after surgery; 3 had died of unrelated causes; and 8 were lost to follow-up. None of the histologic features examined were significantly associated with survival time. CONCLUSIONS AND CLINICAL RELEVANCE: Findings suggested that results of histologic examination of hepatic biopsy samples obtained at the time of surgery cannot be used to predict long-term outcome in dogs undergoing surgical correction of a PSS.     

Association of portovenographic findings with outcome in dogs receiving surgical treatment for single congenital portosystemic shunts: 45 cases (2000-2004)

OBJECTIVE: To determine whether hepatic portal vascularity, as assessed by intraoperative mesenteric portovenography (IMP), is related to outcome in dogs undergoing attenuation of single congenital portosystemic shunts (CPSSs). DESIGN: Retrospective case series. ANIMALS: 45 dogs, each with a single CPSS, in which IMP was performed before and after temporary complete occlusion of the shunting vessel and that underwent complete (17 dogs) or partial (28 dogs) CPSS attenuation (surgery 1). PROCEDURES: Medical records were reviewed for signalment, clinical history, and bile acids stimulation test results. Intrahepatic portal vessel (IPV) opacification in pre- and postocclusion portovenograms was graded to determine whether the degree of opacification was correlated with the degree of shunt attenuation, clinical or biochemical factors, or long-term clinical outcome. In 17 of 28 dogs that had partial CPSS attenuation, these procedures were subsequently repeated (surgery 2) to achieve complete (14 dogs) or further partial (3 dogs) CPSS attenuation. RESULTS: Compared with preattenuation findings, IPV opacification increased significantly after partial or complete CPSS attenuation. The degree of IPV opacification before and after CPSS occlusion (surgery 1) was greater in dogs that tolerated complete versus partial CPSS attenuation and was correlated positively with age. The degree of IPV opacification following CPSS occlusion (surgery 1) was maximal in all dogs without encephalopathy and was correlated negatively with follow-up preprandial serum bile acids concentrations and positively with clinical improvement. CONCLUSIONS AND CLINICAL RELEVANCE: Data suggest that IMP can be used to assess changes in IPV blood flow and help predict outcome following attenuation of single CPSSs in dogs.     

Clinical findings, treatment, and outcome of dogs with status epilepticus or cluster seizures: 156 cases (1990-1995)

OBJECTIVE: To report clinical findings, treatments, and outcomes of dogs admitted to the hospital for status epilepticus or cluster seizures and evaluate factors associated with outcome. DESIGN: Retrospective study. ANIMALS: 156 dogs admitted for status epilepticus or cluster seizures. PROCEDURE: Medical records were reviewed for seizure and medication history, diagnostic test results, types of treatment, hospitalization costs, and outcome of hospital visits. RESULTS: Dogs were admitted for seizures on 194 occasions. Of 194 admissions, 128 (66%), 2 (1%), 32 (16.5%), 2 (1%), and 30 (15.5%) were of dogs with a history of clusters of generalized seizures, clusters of partial complex seizures, convulsive status epilepticus, partial status epilepticus, and > 1 type of seizure, respectively. Underlying causes of seizures were primary epilepsy (26.8%; 52/194), secondary epilepsy (35.1%; 68), reactive epileptic seizures (6.7%; 13), primary or secondary epilepsy with low serum antiepileptic drug concentrations (5.7%; 11), and undetermined (25.8%; 50). One hundred and eighty-six hospital visits resulted in admission to the intensive care unit (ICU). Treatments with continuous i.v. infusions of diazepam or phenobarbital were initiated during 66.8% (124/186) and 18.7% (35) of ICU hospital stays for 22.3 +/- 16.1 hours (mean +/- SD) and 21.9 +/- 15.4 hours, respectively. Of 194 admissions, 74.7% (145) resulted in discharge from the hospital, 2.1% (4) in death, and 23.2% (45) in euthanasia. A poor outcome (death or euthanasia) was significantly associated with granulomatous meningoencephalitis, loss of seizure control after 6 hours of hospitalization, and the development of partial status epilepticus. CONCLUSIONS AND CLINICAL RELEVANCE: Granulomatous meningoencephalitis, loss of seizure control after 6 hours of hospitalization, or the development of partial status epilepticus may indicate a poor prognosis for dogs with seizures.     

Clinical outcome of congenital extrahepatic portosystemic shunt attenuation in dogs aged five years and older: 17 cases (1992-2005)

OBJECTIVE: To assess the outcome of extrahepatic portosystemic shunt (EHPSS) treatment in dogs aged 5 years and older. DESIGN: Retrospective case series. ANIMALS: 17 client-owned dogs. PROCEDURES: Medical records for dogs (> or = 5 years old) that underwent surgical attenuation of an EHPSS (1992 through 2005) were evaluated; data, including clinical signs, clinicopathologic findings, surgical procedure, and outcome, were recorded. Follow-up information was obtained via patient examination or telephone interview with veterinarians and owners. RESULTS: Dogs (5 to 9 years old [median age, 6.6 years]) had neurologic (n = 12), urinary tract (8), and gastrointestinal tract (6) EHPSS-associated clinical signs. Serum bile acids and ammonia concentrations were abnormal in all evaluated dogs. Treatment of EHPSSs included complete (n = 6 dogs) or partial (2) suture attenuation or ameroid constrictor placement (9). Two dogs died following surgery. Follow-up information (6 to 120 months) was available for 13 dogs. Deaths were attributable to heart failure (n = 1), bacterial hepatitis (2; with pyelonephritis in 1 dog), and unknown causes (3). At a median of 23 and 25 months, serum bile acids concentrations had almost normalized in 5 of 8 dogs and ammonia concentrations were within reference limits in 3 of 5 dogs, respectively; dogs with abnormal liver function test results had no associated clinical signs. Median long-term survival time was 72 months. CONCLUSIONS AND CLINICAL RELEVANCE: Attenuation of EHPSS in > or = 5-year-old dogs ameliorated signs of liver dysfunction in surviving dogs, although return of normal liver function occurred less frequently than expected.     

Oncologic outcome after curative-intent treatment in 39 dogs with primary chest wall tumors (1992-2005)

Objective— To describe the clinical features and determine oncologic outcome and prognostic factors for dogs with primary tumors of the osseous chest wall. Study Design— Historical cohort. Animals— Dogs (n=39) with spontaneous tumors involving the chest wall. Methods— Medical records were reviewed for dogs with rib and/or sternal tumors treated by chest wall resection and reconstruction. Signalment, preoperative clinical features, reconstruction technique, and oncologic outcome (local tumor recurrence, metastasis, and survival time) were determined from medical records and by telephone contact with owners and referring veterinarians. Oncologic outcome and prognostic factors were determined using Kaplan–Meier survival analysis and Cox proportional hazards. Logistic regression was used to determine if increased serum alkaline phosphatase (ALP) concentration was associated with tumor type. Results— Of the 39 dogs with tumors arising from the chest wall, 25 had osteosarcoma, 12 had chondrosarcoma, and 2 dogs had hemangiosarcoma. Median survival time (MST) for dogs with rib osteosarcoma was 290 days. Increased activity of total ALP significantly decreased survival in dogs with osteosarcoma (210 days versus 675 days, P=.0035). MST for dogs with rib chondrosarcoma was not reached (mean 1301 days) and survival was significantly greater than all other types of rib tumors (P=.0321). Conclusion— Rib tumors should be resected with wide margins to decrease the risk of incomplete excision, because local tumor recurrence has a significant impact on the survival time. The prognosis for dogs with rib chondrosarcoma is very good, but guarded for other types of tumors. Clinical Relevance— Osteosarcoma and chondrosarcoma are the most common primary tumors of the chest wall. Prognosis for dogs with primary rib chondrosarcoma is very good with surgery alone, but surgery and adjunctive chemotherapy is recommended for dogs with primary rib osteosarcoma and the prognosis remains guarded.     

Parenteral nutrition in neonatal foals: clinical description, complications and outcome in 53 foals (1995-2005)

This retrospective study describes the use of and complications associated with parenteral nutrition (PN) administration to 53 equine neonates at the University of California Veterinary Medical Teaching Hospital. Medical records were examined and information obtained on signalment, physical examination, clinical diagnosis, outcome, total hospitalization time, insulin administration, microbiology culture results, other complications (i.e. thrombophlebitis) and necropsy findings. Complete blood count and serum biochemistry analytes, venous blood gas, serum electrolyte and glucose concentrations, and blood lactate concentration results were compared before and during PN administration in all foals. Seventeen foals (32%) developed hypertriglyceridemia (>200mg/dL). Triglyceride concentrations >200mg/dL were significantly (P=0.049) associated with non-survival. Forty-seven foals (89%) developed hyperglycemia (blood glucose >120mg/dL) and eight (15%) developed catheter-related complications (thrombosis or local sepsis). Packed cell volume, total protein, creatinine, blood urea nitrogen, and sorbitol dehydrogenase concentrations decreased while foals were on PN, while serum chloride concentration increased. This study highlighted that hypertriglyceridemia during the acute phase of neonatal illness may be detrimental to outcome, and that the safety of lipid-containing solutions in foals warrants further study.     

Recurrence of thoracolumbar intervertebral disk extrusion in chondrodystrophic dogs after surgical decompression with or without prophylactic fenestration: 265 cases (1995-1999)

OBJECTIVES: To evaluate a population of chondrodystrophic dogs treated for Hansen type 1 intervertebral disk (IVD) disease by surgical decompression with or without prophylactic fenestration and determine the rate and location of surgically confirmed recurrence of intervertebral disk extrusion. ANIMALS: 265 dogs. STUDY DESIGN: Retrospective study. PROCEDURES: Medical records of dogs that underwent spinal decompression between 1995 and 1999 were reviewed. RESULTS: 3 (4.9%) dogs were euthanatized or died prior to discharge. Fenestration was performed in 252 dogs, including 37 (14.7%) at the site of decompression only, 48 (19%) at 3 to 4 disk spaces, and 167 (66%) at 5 to 7 disk spaces. There were 12 instances of recurrent disk extrusion confirmed by removal of disk at a second surgery 3.5 to 33 months after the first surgery. Recurrence was always at a new disk space, and rates did not significantly differ between dogs that underwent single or multiple fenestrations. Two recurrences were at a previously fenestrated disk space. Seven recurrences were at a site immediately adjacent to a fenestrated disk space, and 5 recurrences were at L4-5. CONCLUSIONS AND CLINICAL RELEVANCE: Prophylactic fenestration is generally successful in preventing future disk extrusions at fenestrated disk spaces. Prospective evaluation is still required to determine whether fenestration decreases the overall rate of recurrence. Prophylactic fenestration could promote disk extrusion at adjacent, nonfenestrated disk spaces. This could have a substantial clinical impact if recurrence develops at L4-5.     

Ventilatory failure, ventilator management, and outcome in dogs with cervical spinal disorders: 14 cases (1991-1999)

OBJECTIVE: To determine the incidence of and risk factors for ventilatory failure in dogs undergoing surgery for treatment of cervical spinal disorders and to document ventilator management, clinical course, and long-term outcome of dogs that experienced ventilatory failure in association with cervical spinal disorders or their management. DESIGN: Retrospective study. ANIMALS: 14 dogs. PROCEDURE: Dogs with cervical spinal disorders that required positive-pressure ventilation (PPV) were identified, and signalment, concurrent diseases, neurologic status at initial examination, clinical course, pulmonary function before, during, and after PPV, management techniques, complications, and outcome were recorded. Dogs that underwent surgery and required PPV were compared with dogs that underwent cervical spinal surgery during the same period that did not require PPV. RESULTS: 14 dogs with cervical spinal disorders required PPV to treat hypoventilation, including 13 of 263 (4.9%) dogs that underwent surgery for cervical spinal disorders. Lesions between the second and fourth cervical vertebrae and treatment by means of a dorsal decompressive laminectomy were associated with a significantly increased risk of perioperative hypoventilation. Pulmonary gas exchange function was normal or nearly normal throughout the course of PPV in dogs that survived. Ten dogs survived, and 9 of the 10 regained neurologic function. All 9 dogs that regained neurologic function had deep pain perception on initial examination at the veterinary teaching hospital. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that a small percentage of dogs with cervical spinal disorders may require perioperative ventilatory support. With prolonged PPV and aggressive management, a good outcome may be achieved in dogs similar to those described in the present study.     

Indications, management, and outcome of long-term positive-pressure ventilation in dogs and cats: 148 cases (1990-2001)

OBJECTIVE: To determine outcome of positive-pressure ventilation (PPV) for 24 hours or longer and identify factors associated with successful weaning from PPV and survival to hospital discharge in dogs and cats. DESIGN: Retrospective case series. ANIMALS: 124 dogs and 24 cats that received PPV for 24 hours or longer. PROCEDURES: Medical records were reviewed for signalment, primary diagnosis, reason for initiating PPV, measures of oxygenation and ventilation before and during PPV, ventilator settings, complications, duration of PPV, and outcome. Animals were categorized into 1 of 3 groups on the basis of the reason for PPV. RESULTS: Group 1 patients received PPV for inadequate oxygenation (67 dogs and 6 cats), group 2 for inadequate ventilation (46 dogs and 16 cats), and group 3 for inadequate oxygenation and ventilation (11 dogs and 2 cats). Of the group 1 animals, 36% (26/73) were weaned from PPV and 22% (16/73) survived to hospital discharge. In group 2, 50% (31/62) were weaned from PPV and 39% (24/62) survived to hospital discharge. In group 3, 3 of 13 were weaned from PPV and 1 of 13 survived to hospital discharge. Likelihood of successful weaning and survival to hospital discharge were significantly higher for group 2 animals, and cats had a significantly lower likelihood of successful weaning from PPV, compared with dogs. Median duration of PPV was 48 hours (range, 24 to 356 hours) and was not associated with outcome. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that long-term PPV is practical and successful in dogs and cats.     

Pulmonary function, ventilator management, and outcome of dogs with thoracic trauma and pulmonary contusions: 10 cases (1994-1998)

OBJECTIVE: To document pulmonary function, ventilator management, and outcome of dogs with thoracic trauma that required mechanical ventilation because of severe pulmonary contusions. DESIGN: Retrospective study. ANIMALS: 10 dogs that required mechanical ventilation because of severe pulmonary contusions caused by blunt thoracic trauma. PROCEDURE: Signalment, historical data, arterial blood gas values, oxygen tension-based indices, ventilator settings, peak inspiratory pressure, positive end-expiratory pressure, tidal volume, and minute ventilation values were retrieved from medical records. RESULTS: All 10 dogs required positive-pressure ventilation because of dyspnea following trauma and had severely abnormal pulmonary function. Survival rate to discharge was 30%. Dogs were categorized into 2 groups; group A included 5 dogs in which pulmonary function improved during ventilation, whereas group B included 5 dogs that were euthanatized because of progressive lung dysfunction (n = 4) or cardiac arrest (1). Mean +/- SD body weight of group-A dogs (30.9 +/- 15.9 kg [68 +/- 35 lb]) was significantly greater than that of group-B dogs (7.6 +/- 1.8 kg [16.7 +/- 4 lb]). Dogs with improved lung function had peak inspiratory pressure that decreased progressively, whereas lung compliance deteriorated in dogs in group B. CONCLUSIONS AND CLINICAL RELEVANCE: Dyspneic dogs with severe pulmonary contusions may require and benefit from positive-pressure ventilation Prognosis is better for dogs that weigh > 25 kg (55 lb).