Daniel J. Brockman

Complications and long-term outcomes of the ligation of congenital portosystemic shunts in 49 cats

Only two of 49 cats undergoing surgical ligation of congenital extra- and intrahepatic portosystemic shunts died perioperatively, a mortality rate comparable with the mortality rates of dogs undergoing surgical attenuation of congenital portosystemic shunts and cats in which the shunts are attenuated with an ameroid ring constrictor. Thirty (83 per cent) of the 36 cats for which long-term information was available were still alive at a median follow-up period of 47 months (range six to 105 months); the outcome was excellent (no clinical signs) in 20 of them (median follow-up 37 months, range six to 105 months) and good (minimal clinical signs) in seven (median follow-up 39 months, range 10 to 73 months) and none of these 27 cats was on any long-term medication or special diet. The only major cause of morbidity was the development of neurological signs in 18 (37 per cent) of the cats. These included seizures and a wide variety of other neurological signs, and their development and persistence was not affected by the presence of preoperative seizures, the type of shunt, the degree of shunt attenuation or the age of the cat. The serum concentrations of ammonia and preprandial bile acids were normal or significantly below normal in the cats with neurological signs. Liver histopathology was similar in the cats with and without neurological signs. Ten (56 per cent) of the 18 cats that developed neurological signs recovered normal neurological function long term.

Passive ventricular constraint to improve left ventricular function and mechanics in an ovine model of heart failure secondary to acute myocardial infarction

OBJECTIVE This study investigated the effects on global cardiac function and myocardial energetics of limiting progressive dilatation after infarction by means of a woven polyester jacket cardiac support device. We hypothesized that placement of the cardiac support device results in a decrease in myocardial wall stress and improvement in cardiac function and myocardial energetics. METHODS To investigate the effect of passive constraint on left ventricular function and mechanics, a total of 10 sheep were studied with pressure-volume analysis and magnetic resonance imaging. A baseline study was followed by the creation of an anterior infarct. After 1 week, the animals underwent a second study. The cardiac support device was then placed over the epicardium in 5 sheep; the remaining animals served as controls. A terminal study was performed at 2 months after the infarct. RESULTS The cardiac support device group at the terminal study exhibited a decrease in end-diastolic volume (control 110.3 +/- 19.8 mL vs cardiac support device 67.6 +/- 4.7 mL, P =.006) and an improved ejection fraction (control 15.5% +/- 5.7% vs cardiac support device 29.46% +/- 4.42%, P =.008) relative to the control group. Myocardial energetics were also enhanced in the cardiac support device group, as evidenced by the significant improvements in potential energy (control 2015 +/- 503 mL. mm Hg/beat vs cardiac support device 885 +/- 220 mL. mm Hg/beat, P =.006), efficiency (control 39.4% +/- 13.6% vs cardiac support device 59.8% +/- 8.5%, P =.044), and oxygen consumption (control 0.072 +/- 0.013 mL O(2)/beat vs cardiac support device 0.052 +/- 0.007 mL O(2)/beat, P =.034). CONCLUSION Passive constraint with the cardiac support device after infarct prevents further remodeling and may stimulate reverse remodeling in heart failure secondary to acute myocardial infarction. These results suggest that in human beings placement of the cardiac support device after a large anterior myocardial infarction may be effective in halting the remodeling process that often leads to end-stage heart failure. If proved effective, placement of a cardiac support device after large heart attacks has the potential to decrease the incidence of heart failure that results after large myocardial infarctions.

Double Chambered Right Ventricle in 9 Cats

BACKGROUND Double-chambered right ventricle (DCRV) is a frequently recognized cardiac congenital abnormality in humans. It has been described in dogs and in 1 cat. However systemic description of clinical and echocardiographic features of the disease in cats is currently lacking from the veterinary literature. ANIMALS Nine cats with DCRV are described. RESULTS The cats ranged from 4 months to 10 years of age. Eight cats at presentation were asymptomatic and 1 cat had chylothorax. In all cases echocardiography revealed abnormal fibromuscular bundles obstructing the mid-right ventricle, dividing the chamber into 2 compartments. The proximal right ventricular compartment was markedly hypertrophied, and right atrial dilation was usually present. The mean pressure gradient measured across the stenotic area was 130 +/- 50 mm Hg. Concurrent abnormalities included a ventricular septal defect (n = 2); aortic malalignment, aortic insufficiency (n = 1); and congenital peritoneal-pericardial diaphragmatic hernia (n = 1). Two cats had systolic anterior motion of the mitral valve, one of which had concurrent left ventricular hypertrophy. Five cats have remained asymptomatic for a median period of 3.6 years (range, 3.3-5 years) and 3 cats have developed clinical signs associated with congestive heart failure (at 2, 3.3, and 9 years). One cat showed progressive lethargy and exercise intolerance and underwent partial ventriculectomy at the age of 2 years. This cat died during the operation with electromechanical dissociation. CONCLUSIONS DCRV is a congenital cardiac abnormality that may be more common than previously recognized.

Association of mesenteric portovenographic findings with outcome in cats receiving surgical treatment for single congenital portosystemic shunts

OBJECTIVE To determine whether hepatic portal vascularity assessed via intraoperative mesenteric portovenography (IMP) is related to outcome in cats undergoing surgical attenuation of a congenital portosystemic shunt (CPSS). DESIGN Retrospective case series. ANIMALS 25 cats, each with 1 CPSS, in which IMP was performed before and after temporary complete occlusion of the shunting vessel to provide complete (n=9) or partial (16) shunt attenuation. PROCEDURES Medical records were reviewed for signalment, clinical history, postoperative complications, clinical outcome, and results of bile acids stimulation testing. Portovenograms obtained before and after shunt occlusion were graded to determine whether degree of intrahepatic portal branching was correlated with degree of shunt attenuation, clinical or biochemical factors, postoperative complications, or outcome. In 12 of the 16 cats that had partial CPSS attenuation, procedures were later repeated to achieve complete (n=9) and additional partial (1) CPSS attenuation. RESULTS Degree of opacification of the intrahepatic portal vessels increased significantly (higher portovenogram grade) after CPSS attenuation. The median portovenogram grade assigned after temporary shunt occlusion at the first surgery was significantly higher in cats that did not have postattenuation neurologic complications or neurologic signs at follow-up than in cats that did. It was also higher in cats that had a better clinical response to surgery versus those that had a poor response and in cats with reduced preprandial and postprandial serum bile acids concentrations at follow-up versus those that did not. CONCLUSIONS AND CLINICAL RELEVANCE IMP may be used to help predict complications and outcome following surgical treatment of CPSS in cats.

Association between hepatic histopathologic lesions and clinical findings in dogs undergoing surgical attenuation of a congenital portosystemic shunt: 38 cases (2000–2004)

OBJECTIVE To review hepatic histopathologic lesions in dogs undergoing surgical attenuation of a congenital portosystemic shunt (CPSS) in relation to clinical findings and tolerance of complete surgical attenuation. DESIGN Retrospective case series. ANIMALS 38 dogs that underwent surgical attenuation of a CPSS. PROCEDURES Hepatic histologic examination findings and medical records of dogs undergoing surgical attenuation of a single CPSS between August 2000 and July 2004 were reviewed. Liver biopsy specimens were obtained from 38 dogs during surgery prior to complete (n = 16) or partial (22) attenuation of a CPSS and from 13 of the same dogs a median of 3 months following surgical attenuation. RESULTS Portal tracts were inadequate for interpretation in 2 liver biopsy specimens. Liver biopsy specimens obtained prior to surgical attenuation of a CPSS had a lack of identifiable portal veins (13/36 dogs), hepatic arteriolar proliferation (25/36), ductular reaction (5/36), steatosis (16/38), and iron accumulation (32/38). Lack of identifiable portal veins on histologic examination was associated with increased hepatic arteriolar proliferation, decreased tolerance to complete surgical CPSS attenuation, and decreased opacification of intrahepatic portal vessels on portovenography. Ductular reaction was always associated with failure to tolerate complete surgical attenuation of a CPSS. Surgical CPSS attenuation resulted in significant clinical, serum biochemical, and portovenographic changes indicative of improved liver function, but only subtle changes in hepatic histologic examination findings. CONCLUSIONS AND CLINICAL RELEVANCE Dogs without identifiable intrahepatic portal veins that had a ductular reaction on hepatic histologic examination were less likely to tolerate complete attenuation of a CPSS.

Spontaneous gastroduodenal perforations in dogs - a retrospective study of 15 cases

The clinical findings and outcomes following surgical management of spontaneous gastroduodenal perforations in 15 dogs were reviewed in a retrospective study to identify related risk factors. Clinical and clinicopathological findings were diverse. Use of multiple diagnostic procedures yielded a strong index of suspicion for gastrointestinal perforation. There was a trend towards improved survival for animals with perforation of the gastric fundus/body compared to pyloric or duodenal perforation, although the difference was not statistically significant. Five dogs were euthanased at surgery; two dogs died within two days after surgery. Seven of the eight surviving dogs had a favourable long-term outcome. Previous administration of NSAIDs was the only identified predisposing factor in ten of 10 of the dogs.

Lateral exploration of fistulas developing after total ear canal ablations: 10 cases (1989-1993)

A lateral approach was used successfully in seven of 10 dogs to resolve fistulas which developed after total ear canal ablations and bulla osteotomies. The approach facilitated identification and removal of horizontal ear canal remnants in four of the 10 cases. Facial nerve function was worsened temporarily by lateral exploration in two cases. Seven cases had no fistula recurrence during follow-up, which ranged from 12 to 72 months. Three cases each had fistula recurrence one-to-two months after fistula exploration.

Prevalence, outcome and risk factors for postoperative pyothorax in 232 dogs undergoing thoracic surgery

Objective To determine the prevalence, outcome and risk factors for postoperative pyothorax in dogs undergoing thoracic surgery. Methods Case records were reviewed retrospectively to identify dogs with post thoracic surgery pyothorax, defined as septic neutrophilic inflammation within the pleural space based on cytology and/or a positive bacterial culture of pleural fluid. Those identified were reviewed for potential risk factors for postoperative pyothorax based on biological plausibility and previously published data. These potential risk factors were explored by multivariable logistic regression. Results Of 232 dogs undergoing thoracic surgery, 15 (6·5%) dogs developed pyothorax. Bacteria cultured included methicillin-resistant Staphylococcus aureus and multi-resistant Escherichia coli. Of these dogs, six died, four were euthanased and five were treated successfully. A diagnosis of idiopathic chylothorax [Odds Ratio (OR)=12·5, 95% Confidence Interval (CI)=2·7-58·5, P=0·001], preoperative intrathoracic biopsy (OR=14·3, 95% CI=1·7-118·7, P=0·014) and preoperative thoracocentesis (OR=11·2, 95% CI=1·6-78·2, P=0·015) were identified as independent risk factors for development of postoperative pyothorax. Clinical Significance Idiopathic chylothorax, intrathoracic biopsy and prior thoracocentesis are independent risk factors for postoperative pyothorax, which was associated with a 67% mortality rate.

Clinical Outcome following Pneumonectomy for Management of Chronic Pyothorax in Four Cats

Pneumonectomy is the resection of all lung lobes from one side of the thorax. The clinical findings, treatment and outcome of four cases of feline chronic pyothorax managed with exploratory thoracotomy and pneumonectomy are reported. All cases were initially medically managed with thoracic drain placement and antibiosis. However, resolution was not achieved with medical therapy and diagnostic imaging findings consistent with an area of abscessation or marked lung lobe consolidation were identified, supporting a decision for surgical management. Surgical exploration was performed via median sternotomy and, on the basis of gross inspection, non-functional lung was removed. A left-sided pneumonectomy was performed in three cats and a right-sided pneumonectomy in one. All cases survived to discharge and an excellent quality of life was reported on long-term follow-up. Pneumonectomy appears to be well tolerated in the cat.

Uterine rupture and septic peritonitis following dystocia and assisted delivery in a Great Dane bitch.

A Great Dane bitch was treated for presumed primary uterine inertia with repeated doses of oxytocin and manually assisted whelping. She was diagnosed with uterine rupture and septic peritonitis the following day. The uterine rupture is hypothesized to have occurred as a result of the management strategy used to treat dystocia. The dog underwent ovariohysterectomy, and the septic peritonitis was managed with open peritoneal drainage. The dog recovered well and was discharged 5 days later. No previous reports of canine uterine rupture associated with manual intervention appear to have been published. This report highlights the potential dangers involved in such an approach.