Prevention of reperfusion injury in surgically induced gastric dilatation-volvulus in dogs

Canine gastric dilatation-volvulus (GDV) is a naturally acquired condition of large-breed dogs primarily and is associated with high mortality. The clinical course suggests that reperfusion injury may be important in the pathogenesis of GDV. To evaluate the role of xanthine oxidase and iron-dependent lipid peroxidation (which are purported mechanisms of reperfusion injury) in the pathogenesis of GDV-related mortality, we created experimental GDV in 21 dogs. These dogs were then treated with either allopurinol (a xanthine oxidase inhibitor), U74006F (an experimental lipid peroxidation inhibitor), or saline solution (NaCl, 0.85%). Three of 8 dogs died in the allopurinol-treated group, none of 5 died in the U74006F-treated group, and 4 of 8 died in the saline solution-treated group. Tissue malondialdehyde concentration, a nonspecific indicator of lipid peroxidation, was significantly (P less than 0.05) greater in the duodenum, jejunum, colon, liver, and pancreas of the saline-solution treated and allopurinol-treated dogs than in the same tissues of the U74006F-treated dogs after surgical correction of the GDV (ie, during reperfusion), compared with malondialdehyde concentrations determined before inducing GDV. The results of this study support the concept that lipid peroxidation associated with reperfusion injury is important in the pathogenesis and high mortality of canine GDV. Furthermore, this lipid peroxidation and mortality may be preventable by appropriate and timely treatment.     

Hypertonic saline/dextran resuscitation of dogs with experimentally induced gastric dilatation-volvulus shock.

We investigated small-volume (5 ml/kg) 7% NaCl in 6% dextran 70 (HS/D70) as an alternative to large-volume (60 ml/kg) 0.9% NaCl for treatment of experimentally induced canine gastric dilatation-volvulus (GDV) shock. The stomach was surgically displaced and then distended with an intragastric balloon in 11 dogs anesthetized with pentobarbital. All dogs were subjected to GDV for 180 minutes before partial decompression and resuscitation. Hemodynamic values, blood gas values, and plasma volume were measured during control, shock, and resuscitation periods. Resuscitation started with 1 group (n = 6) receiving 5 ml of HS/D70/kg, iv, over 5 minutes, and the other group (n = 5) receiving 60 ml of 0.9% NaCl/kg, IV, over 60 minutes. Both groups received a surgical maintenance dosage (20 ml/kg/h) of 0.9% NaCl after initial resuscitation. Resuscitative effects of small-volume HS/D70 were similar to large-volume 0.9% NaCl during the first hour of treatment; however, cardiac output was significantly higher in the HS/D70 group for the last 2 hours of resuscitation. Changes in heart rate, left ventricular pressure change, and systemic vascular resistance appeared to be responsible for improved perfusion. Mixed venous oxygen partial pressure data supported improved perfusion in the HS/D70 group. Packed cell volume remained higher in the HS/D70 group, indicating less hemodilution and improved oxygen delivery. Resuscitation of this GDV-induced shock model was better sustained with small-volume HS/D70, compared with conventional large-volume 0.9% NaCl.     

Effects of gastric distention-volvulus on coronary blood flow and myocardial oxygen consumption in the dog

Gastric distention-volvulus (GDV; at 50 mm of Hg gastric inflation pressure) was experimentally induced in 8 dogs anesthetized using pentobarbital. Hemodynamic indices including heart rate, mean arterial pressure, cardiac output, and coronary blood flow (4 dogs) were measured during a 20-minute period of GDV and for 10 minutes after decompression. Arterial and coronary venous oxygen tensions were also measured for calculation of myocardial oxygen extraction (7 dogs) and myocardial oxygen consumption (4 dogs). Dogs were monitored for 72 hours postoperatively for the occurrence of arrhythmias, then were euthanatized for gross and histologic examination of the heart. Experimental GDV resulted in significant (P less than 0.05) decreases in cardiac output (89%), mean arterial pressure (45%), and coronary blood flow (50%) compared with control values. Myocardial oxygen extraction increased (30%) and overall myocardial oxygen consumption decreased (50%), compared with control values. Evidence of subendocardial necrosis was seen in 6 dogs, 4 of which had developed ventricular arrhythmias 8 to 24 hours postoperatively.     

Evaluation of splenectomy as a risk factor for gastric dilatation-volvulus

Objective-To evaluate whether dogs undergoing splenectomy had an increased risk of gastric dilatation-volvulus (GDV), compared with a control group of dogs undergoing enterotomy. Design-Retrospective case-control study. Animals-219 dogs that underwent splenectomy for reasons other than splenic torsion (splenectomy group; n = 172) or enterotomy (control group; 47) without concurrent gastropexy. Procedures-Medical records were reviewed for information on signalment, date of surgery, durations of surgery and anesthesia, reason for splenectomy, histopathologic findings (if applicable), whether gastropexy was performed, duration of follow-up, and date of death (if applicable). Follow-up information, including occurrence of GDV, was obtained via medical records review and a written client questionnaire. Results-Reasons for splenectomy included splenic neoplasia, nonneoplastic masses, infarction, traumatic injury, and adhesions to a gossypiboma. Incidence of GDV following surgery was not significantly different between dogs of the splenectomy (14/172 [8.1 %]) and control (3/47 [6.4%]) groups. Median time to GDV for the 17 affected dogs was 352 days (range, 12 to 2,368 days) after surgery. Among dogs that underwent splenectomy, sexually intact males had a significantly higher incidence of GDV (4/16) than did castrated males and sexually intact or spayed females (10/156). Incidence of GDV among sexually intact male dogs did not differ between groups. Conclusions and Clinical Relevance-Results did not support a recommendation for routine use of prophylactic gastropexy in dogs at the time of splenectomy. Other patient-specific risk factors should be assessed prior to recommending this procedure.     

Measurement of urinary 11-dehydro-thromboxane B2 excretion in dogs with gastric dilatation-volvulus

OBJECTIVE: To measure 11-dehydro-thromboxane B2 (11-dTXB2) in urine of healthy control dogs, dogs undergoing ovariohysterectomy, and dogs with gastric dilatation-volvulus (GDV) and assess the relationship between urinary 11-dTXB2 concentrations in dogs with GDV and postoperative outcomes. SAMPLE POPULATION: Urine samples from 15 nonsurgical control dogs, 12 surgical control dogs, and 32 dogs with GVD. PROCEDURE: Urine samples were obtained from healthy pet dogs (ie, nonsurgical control dogs), dogs undergoing ovariohysterectomy at anesthetic induction and 1 hour following surgery (ie, surgical control dogs), and dogs with GDV at hospital admission and 1 hour following surgical derotation of the stomach (ie, GDV dogs). Urinary 11-dTXB2 concentrations were determined with an ELISA and normalized to urinary creatinine (Cr) concentrations by calculation of the 11-dTXB2 -to-Cr ratio. Differences in median 11-dTXB2 -to-Cr ratios among dogs and before and after surgery were analyzed. RESULTS: Urinary 11-dTXB2-to-Cr ratios did not differ between nonsurgical control dogs and surgical control dogs before or after surgery. Urinary 11-dTXB2-to-Cr ratios were significantly higher in GDV dogs at the time of hospital admission and 1 hour after surgery, compared with those of nonsurgical control dogs. Postoperative urine samples from GDV dogs had significantly higher 11-dTXB2-to-Cr ratios than postoperative urine samples from surgical control dogs. Median urinary 11-dTXB2-to-Cr ratios increased significantly in GDV dogs that developed postoperative complications. CONCLUSIONS AND CLINICAL RELEVANCE: Urinary 11-dTXB2 concentration is increased in GDV dogs at the time of hospital admission and after surgical derotation of the stomach, compared with that of healthy dogs. An increased urinary 11-dTXB2-to-Cr ratio following surgery is associated with an increased incidence of postoperative complications in dogs with GDV.     

The effects of allopurinol on the ultrastructure of ischaemic and reperfused large intestine of sheep

Objective To test the possible inhibitory effect of allopurinol on reperfusion injury, caused by oxygen-derived free radicals, of sheep large intestine.
Design An ultrastructural study on caecal tissues from control and treated groups.  

Animals

Fifty sheep in four ischaemic and reperfused (treatment) groups and one control group. Three of the treatment groups were subdivided for half to be injected with allopurinol and the other half with its solvent, potassium hydroxide (KOH).
Procedure Ischaemia of the caecum was induced in the four treatment groups for 60 minutes by clamping the apex. Allopurinol and its KOH solvent were injected intravenously in three treatment groups prior to ischaemia. Samples were collected before and 1 hour after induction of ischaemia and 1 min, 1 h and 8 h after reperfusion. Tissues were processed and examined with an electron microscope.
Results Untreated and solvent injected sheep showed minor ultrastructural changes following ischaemia. With reperfusion, there was severe mitochondrial, goblet cell and basement membrane damage. Tissues from allopurinoltreated sheep were preserved and appeared similar to tissues from the control group.  

Conclusion:

Pre-treatment with allopurinol prevented damage to tissues whereas untreated or allopurinol solventtreated showed severe damage following reperfusion. It is believed that allopurinol, an analogue of hypoxanthine and xanthine, prevents reperfusion injury by competitively binding with xanthine oxidase. This reduces or inhibits the xanthine oxidase mediated conversion of hypoxanthine to xanthine thereby preventing the formation of oxygen-derived free radicals.     

Occurrence and recurrence of gastric dilatation with or without volvulus after incisional gastropexy

This study investigated recurrence of gastric dilatation without (GD) or with volvulus (GDV) after incisional gastropexy (IG) in dogs that underwent IG for prevention of GDV. Signalment, concurrent surgical procedures, presence of GD or GDV at the time of IG were obtained from medical records of dogs that underwent IG. Owners were contacted to determine whether the dogs experienced GD or GDV after IG, dates of postoperative GD or GDV episodes, survival status, date of death for deceased dogs. Gastric dilatation and GDV recurrence rates were calculated for 40 dogs that had at least 2 y follow-up from the time when IG was performed and for dogs that experienced GD or GDV during the follow-up period. No dogs experienced GDV after IG and 2 dogs (5.0%) experienced GD after IG. The results suggest that GD and GDV rates after IG may be comparable to recurrence rates after other methods of gastropexy.     

Plasma lactate concentration as a predictor of gastric necrosis and survival among dogs with gastric dilatation-volvulus: 102 cases (1995-1998).

OBJECTIVE: To determine relationships between plasma lactate concentration and gastric necrosis and between plasma lactate concentration and outcome for dogs with gastric dilatation-volvulus. DESIGN: Retrospective study. ANIMALS: 102 dogs. PROCEDURE: Information on signalment, history, plasma lactate concentration, medical and surgical treatment, cost of hospitalization, and outcome was retrieved from medical records. RESULTS: 69 of 70 (99%) dogs with plasma lactate concentration < 6.0 mmol/L survived, compared with 18 of 31 (58%) dogs with plasma lactate concentration > 6.0 mmol/L (1 dog euthanatized for economic reasons was not included). Gastric necrosis was identified in 38 (37%) dogs. Median plasma lactate concentration in dogs with gastric necrosis (6.6 mmol/L) was significantly higher than concentration in dogs without gastric necrosis (3.3 mmol/L). Specificity and sensitivity of using plasma lactate concentration (with a cutoff of 6.0 mmol/L) to predict which dogs had gastric necrosis were 88 and 61%, respectively. Sixty-two of 63 (98%) dogs without gastric necrosis survived, compared with 25 of 38 (66%) dogs with gastric necrosis. CONCLUSIONS AND CLINICAL RELEVANCE: Preoperative plasma lactate concentration was a good predictor of gastric necrosis and outcome for dogs with GDV. Preoperative measurement of plasma lactate concentration may assist in determining prognosis of dogs with GDV.     

Comparison of the Recurrence Rate of Gastric Dilatation with or Without Volvulus in Dogs after Circumcostal Gastropexy Versus Gastrocolopexy

OBJECTIVE: To compare the recurrence rate of acute gastric dilatation with or without volvulus (GDV) after circumcostal gastropexy (CCGP) or gastrocolopexy (GCP) in dogs. STUDY DESIGN: A prospective, double-blind, multicenter, randomized, controlled, clinical trial with two groups (A and B). ANIMALS: Fifty-four client-owned dogs presented for treatment of GDV. METHODS: Dogs with acute GDV that had not previously had a gastropexy performed were included. The preoperative treatment before gastropexy was standardized. A CCGP was performed on dogs in group A, and a GCP was performed on dogs in group B. Postoperative treatment was standardized, but deviation did occur according to the special needs of particular patients. A minimal follow-up time of 180 days was required for dogs not excluded from the study. The median follow-up time in group A was 700 days; in group B, it was 400 days. The occurrence of abdominal pain and gastrointestinal problems after surgery were recorded by the owners. RESULTS: There was no significant difference in the recurrence rate of GDV between the two groups. At the end of the study, the recurrence rate was 9% and 20% in group A and in group B, respectively. CONCLUSIONS: Both surgical techniques are effective in preventing recurrence of GDV.     

Effects of Flunixin Meglumine on Dogs with Experimental Gastric Dilatation-Volvulus

Gastric dilatation-volvulus (GDV) was created experimentally and maintained for 90 minutes in 16 anesthetized, mixed-breed dogs. After the GDV was corrected, normal saline solution (0.044 mL/kg intravenously [IV]) was administered to eight dogs (controls), and flunixin meglumine (2.2 mg/kg IV) was administered to eight dogs. Microspheres labeled with radioactive cobalt, scandium, tin, or niobium were injected intravenously at baseline (before GDV) and minutes 90, 100, and 270, respectively, to determine tissue blood flows. Plasma endotoxin and prostacyclin were measured at the same intervals. Electrocardiogram, mean arterial pressure, portal pressure, and cardiac output were recorded continuously. Dogs were euthanatized at minute 270 and necropsied. There was no significant difference between treatment groups for any measured variable at any time. Endotoxin levels increased significantly during GDV. Prostacyclin levels were lower in dogs treated with flunixin meglumine than in controls at minutes 210 and 270. Histopathologic findings were similar for all dogs and consistent with those associated with endotoxemia. Flunixin meglumine treatment did not alter cardiac indices or tissue blood flows significantly. However, elevation of prostacyclin was inhibited by flunixin meglumine, which suggested that continued effects of endotoxic damage might be attenuated or inhibited.     

Gastric emptying of nondigestible radiopaque markers after circumcostal gastropexy in clinically normal dogs and dogs with gastric dilatation-volvulus.

Using radiopaque particles mixed with food, gastric emptying was assessed in healthy dogs not subjected to surgery, in healthy dogs 9 to 35 days after circumcostal gastropexy, and, in dogs 1 to 54 months after surgical treatment and recovery from gastric dilatation-volvulus (GDV). Circumcostal gastropexy surgery did not alter the 90% gastric emptying time for radiopaque particles in healthy dogs. However, 90% gastric emptying time was significantly (P less than 0.05) increased after circumcostal gastropexy in dogs with GDV, compared with healthy dogs after the same surgical procedure and recovery period. These results imply that dogs with GDV have delayed gastric emptying of solid particles. Whether delayed gastric emptying of markers detected in affected dogs after surgical treatment and recovery was the result or the cause of GDV was not determined. Results indicate that circumcostal gastropexy could be recommended as a prophylactic procedure for GDV in large breeds with deep thorax, because delayed gastric emptying of markers secondary to the surgical procedure is unlikely.     

Treatment of reperfusion injury in dogs with experimentally induced gastric dilatation-volvulus.

In dogs, gastric dilatation-volvulus (GDV) is characterized by cardiogenic shock, with resulting hypoperfusion. Treatment goals include reperfusion of transiently ischemic tissues, which indicates that reperfusion injury may be a factor in the physiopathogenesis of GDV. Recently, we obtained data that indicate that reperfusion injury may be involved in experimentally induced GDV. Using this GDV model, we evaluated mortality in 24 dogs of 4 equal groups, treated with deferoxamine (an iron chelator), dimethylsulfoxide (a free radical scavenger), a combination of the 2 drugs, or isotonic saline solution. All 6 dogs that were given deferoxamine survived; however, 3 dogs of the dimethylsulfoxide-treated group, 2 dogs of the combination-treated group, and 4 dogs of the saline-treated group died. Results of the study indicate that mortality associated with experimentally induced GDV is reduced by appropriate and timely pharmacologic intervention to prevent or attenuate reperfusion injury, and that deferoxamine may be more effective than dimethylsulfoxide.     

Diet-related risk factors for gastric dilatation-volvulus in dogs of high-risk breeds

A nested case-control study was conducted among 1634 dogs with complete diet information in a 5-year prospective study to determine diet-related risk factors for gastric dilatation-volvulus (GDV). Cases included 106 dogs that developed GDV; controls included 212 dogs without GDV that were frequency matched to cases by year of GDV onset. Proportionate energy consumed from major food types and from carbohydrates was determined. Dogs were categorized as consuming either a low volume or high volume of food based on the median number of cups of food fed per kg of body weight per meal. Dogs fed a larger volume of food per meal were at a significantly (P<0.05) increased risk of GDV, regardless of the number of meals fed daily. For both large- and giant-breed dogs, the risk of GDV was highest for dogs fed a larger volume of food once daily.     

Vasopressor therapy using vasopressin prior to crystalloid resuscitation in irreversible hemorrhagic shock under isoflurane anesthesia in dogs

In the present study, we tested the hypothesis that vasopressin administration prior to crystalloid resuscitation can be used to improve hemodynamic and oxygen delivery functions. Hemorrhagic shock was experimentally induced by maintaining mean arterial pressure at 60 mmHg for 30 min in sixteen healthy dogs weighing from 8 to 10.6 kg. Vasopressin was administered and then volume resuscitation was performed for the 6 dogs of V-C group, while vasopressin was administered at the end of volume resuscitation in the 5 dogs of C-V group. The control group (n=5) was administered 0.4 IU/kg of vasopressin after induction of shock without fluid resuscitation. In all groups, hemodynamic parameters were measured pre- and post-hemorrhage and for 60 min after fluid resuscitation. The dogs in V-C group had substantially increased systolic arterial pressure (SAP) for 60 min and improved pulmonary capillary wedge pressure (PCWP), cardiac output (CO), oxygen delivery, and oxygen consumption indexes compared with C-V and control groups. Diastolic pressure and systemic vascular resistance was significantly lower in the V-C group than those in the C-V and control groups (P<0.05). In the V-C group, there was effective and rapid restoration of the SAP, CO, PCWP, and oxygen delivery parameters after treatment. This study indicates that vasopressin administration before crystalloid resuscitation is a more efficient way of improving hemodynamic and oxygen delivery functions in hemorrhagic shock in dogs.     

Gastric Myoelectric Activity after Experimental Gastric Dilatation-Volvulus and Tube Gastrostomy in Dogs

Gastric myoelectric activity was measured after experimental gastric dilatation-volvulus (GDV), GDV and tube gastrostomy, or tube gastrostomy in 12 dogs. Gastric myoelectric activity was recorded for 1 hour before (hour 0) and at hours 5, 24, 48, 72, and 96 after surgically induced GDV in six dogs. Three dogs with induced GDV and tube gastrostomy, and three dogs with tube gastrostomy only were also studied at hours 120, 144, and 168. The only significant change in the slow wave appearance or frequency from hours 0 to 48 was bradygastria at hour 5 in all three groups. A relative increase in the mean percentages of dysrhythmia from hours 72 to 168 in the dogs with a tube gastrostomy was caused by increases in tachygastria and arrhythmias. Dogs with GDV and tube gastrostomy had the greatest mean percentages of dysrhythmia, which were significantly more than those in dogs with GDV alone at hours 48, 72 and 96. The mean percentage of spike activity was less than or equal to 31 and varied widely. In general, there was less spike activity when the frequency of dysrhythmias was high. Thus, gastric myoelectric activity was disrupted from hours 48 to 168 after GDV with tube gastrostomy and after tube gastrostomy alone. Surgically induced GDV alone did not produce any significant or sustained dysrhythmias.     

Intracellular magnesium concentrations in dogs with gastric dilatation-volvulus

OBJECTIVE: To quantify and compare intracellular magnesium concentrations (Mgi) in clinically normal dogs (control dogs) and dogs that have gastric dilatation-volvulus (GDV dogs) and to determine whether there is a difference in Mgi and serum magnesium concentrations (Mgs) between GDV dogs with and without cardiac arrhythmias. ANIMALS: 41 control dogs and 21 GDV dogs. PROCEDURE: Rectus abdominis muscle specimens were obtained from control and GDV dogs for determination of Mgi. Blood samples were obtained from GDV dogs for determination of Mgs, and dogs were monitored for 48 hours for cardiac arrhythmias. Muscle specimens were frozen at -40 C, oven dried at 95 C, and digested with concentrated nitric acid. Multielemental analyses were performed by simultaneous/sequential inductively coupled plasma-atomic emission spectroscopy with fixed-cross flow nebulization. The Mg, was standardized to sulfur content to correct for the amount of fat and fascia in the muscle specimen. Mean (+/- SEM) values were recorded in parts per million (ppm). Results-There were no significant differences in Mgi between control (627 +/- 11.1 ppm) and GDV (597 +/- 20.5 ppm) dogs, in Mgi between GDV dogs with (590 +/- 34 ppm) and without (584 +/- 29 ppm) cardiac arrhythmias, and in Mgs between GDV dogs with (1.77 +/- 0.26 ppm) and without (1.51 +/- 0.09 ppm) cardiac arrhythmias. There was no correlation between Mgs and Mgi (R2 = 0.0001). CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that Mg depletion is not pathophysiologically important in dogs with GDV and does not play a role in the cardiac arrhythmias detected in these patients.     

Effects of small intestinal ischemia and reperfusion on expression of tumor necrosis factor-alpha and interleukin-6 messenger RNAs in the jejunum, liver, and lungs of dogs

OBJECTIVE: To determine the effects of intestinal ischemia and reperfusion on the expression of tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 mRNAs in the jejunum, liver, and lungs of dogs. ANIMALS: 8 healthy adult Beagles. PROCEDURES: In each dog, the cranial mesenteric artery was occluded for 0 (control group; n=4) or 60 (I-R group; 4) minutes, followed by reperfusion for 480 minutes; serum TNF-alpha and IL-6 activities and expression levels of TNF-alpha and IL-6 mRNAs in jejunal, hepatic, and lung tissues were measured before and at the end of the ischemic period and at intervals during reperfusion. For each variable, values were compared between the control and I-R groups at each time point. RESULTS: Compared with the control group, serum IL-6 activity increased significantly after 180 minutes of reperfusion in the I-R group; also, jejunal TNF-alpha mRNA expression increased significantly after 60 (peak) and 180 minutes of reperfusion. In the I-R group, expressions of IL-6 mRNA in the liver and TNF-alpha and IL-6 mRNAs in the lungs increased significantly at 480 minutes of reperfusion, compared with the control group. Serum TNF-alpha activity, expression of IL-6 mRNA in the jejunum, and expression of TNF-alpha mRNA in the liver in the control and I-R groups did not differ. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that the liver, lungs, and jejunum contributed to the production of TNF-alpha and IL-6 after intestinal ischemia and reperfusion in dogs, suggesting that intestinal ischemia and reperfusion induce a systemic proinflammatory cytokine response in dogs.     

Serial determination of biomarkers of oxidative stress and antioxidant status in dogs with naturally occurring gastric dilatation-volvulus

Objective: To serially determine the biomarkers of oxidative stress and antioxidant status of dogs with gastric dilatation‐volvulus (GDV) over 48 hours. Design: Prospective study. Setting: Veterinary teaching hospital intensive care unit. Animals: Thirteen client‐owned dogs with GDV. Interventions: None. Measurement and main results: For all dogs, biomarkers of oxidative stress and antioxidant status were ascertained. Indicators of oxidative stress measured included F_2α‐isoprostanes (isoprostanes) and malondialdehyde (MDA). Vitamin C, vitamin E, glutathione peroxidase (GSHPx), and oxygen radical absorbance capacity (ORAC) were measured to assess antioxidant status. Oxidants and antioxidants were measured at the time of admission and at 24 and 48 hours post‐admission. There were significant decreases in vitamin E (P=0.002), vitamin C (P=0.001), ORAC (P=0.02), and MDA (P=0.001) during hospitalization. There was no significant change in GSHPx and isoprostane concentrations over time. Conclusion: Oxidative stress and antioxidant capacity in dogs with GDV change over time. Further studies measuring oxidative stress in more severely affected dogs and performing measurements earlier in the disease process may be beneficial in determining when oxidative stress is most severe during the course of GDV management.     

The effect of experimental gastric dilatation-volvulus on adenosine triphosphate content and conductance of the canine gastric and jejunal mucosa

The objective of this study was to determine if experimental gastric dilatation volvulus (GDV) would decrease adenosine triphosphate (ATP) concentration and increase membrane conductance of the canine gastric and jejunal mucosa. Male dogs (n = 15) weighing between 20 and 30 kg were used. Dogs were randomly assigned to 1 of 3 equal groups: Group 1 was control, group 2 was GDV, and group 3 was ischemia. All dogs were anesthetized for 210 min. Group 1 had no manipulation. Group 2 had GDV experimentally induced for 120 min followed by decompression, derotation, and reperfusion for 90 min. Group 3 had GDV experimentally induced for 210 min. Gastric (fundus and pylorus) and jejunal tissue was taken at 0, 120, and 210 min from all of the dogs. Tissue was analyzed for ATP concentration, mucosal conductance, and microscopic changes. The ATP concentration in the fundus did not change significantly from baseline in group 2, but decreased significantly below baseline at 210 min in group 3. The ATP concentration in the jejunum decreased significantly below baseline in groups 2 and 3 at 120 min, remaining significantly decreased in group 3 but returning to baseline at 210 min in group 2. Mucosal conductance of the fundus did not change significantly in any dog. Mucosal conductance of the jejunum increased at 120 min in groups 2 and 3, and became significantly increased above baseline at 210 min. The jejunal mucosa showed more profound cellular changes than the gastric mucosa. The jejunum showed substantial decreases in ATP concentration with an increase in mucosal conductance, suggesting cell membrane dysfunction. Dogs sustaining a GDV are likely to have a change in the activity of mucosal cells in the jejunum, which may be important in the pathophysiology of GDV.     

Prospective evaluation of laparoscopic-assisted gastropexy in dogs susceptible to gastric dilatation

OBJECTIVE: To determine long-term outcome associated with laparoscopic-assisted gastropexy in prevention of gastric dilatation-volvulus (GDV) in susceptible dogs and to evaluate use of laparoscopy to correct GDV. DESIGN: Prospective study. ANIMALS: 25 client-owned large-breed dogs. PROCEDURE: 23 dogs susceptible to GDV were referred as candidates for elective gastropexy. These dogs had a history of treatment for gastric dilatation, clinical signs of gastric dilatation, or family members with gastric dilatation. Laparoscopic-assisted gastropexy was performed. One year after surgery, abdominal ultrasonography was performed to evaluate the attachment of the stomach to the abdominal wall. Two dogs with GDV were also treated with laparoscopic-assisted derotation of the stomach and gastropexy. RESULTS: None of the dogs developed GDV during the year after gastropexy, and all 20 dogs examined ultrasonographically had an intact attachment. Another dog was euthanatized at 11.5 months for unrelated problems. Two dogs with GDV successfully underwent laparoscopic-assisted gastropexy after the stomach was repositioned. CONCLUSIONS AND CLINICAL RELEVANCE: Laparoscopic-assisted gastropexy resulted in a persisting attachment between the stomach and abdominal wall, an absence of GDV development, and few complications. Dogs with a high probability for development of GDV should be considered candidates for minimally invasive gastropexy. Carefully selected dogs with GDV can be treated laparoscopically.