Predisposition to gastric dilatation-volvulus in relation to genetics of thoracic conformation in Irish setters

Outcomes and complications of prophylactic incisional gastropexy in 766 dogs (2009-2019)

OBJECTIVE

To report the outcomes and complications associated with prophylactic incisional gastropexy performed in dog breeds at risk for GDV.

RESULTS

Seven hundred and sixty-six dogs underwent prophylactic incisional gastropexy of which 61 were electively performed at the time of castration or spay and 705 were adjunctively performed at the time of emergency abdominal surgery. All dogs had short-term follow-up, and 446 dogs (58.2%) had additional follow-up with a median long-term follow-up time of 876 days (range 58-4450). Only 3 dogs (0.4%) had a direct complication associated with the gastropexy site including hemorrhage causing hemoabdomen (2) and infection with partial dehiscence (1). No dogs with long-term follow-up experienced gastric dilatation (GD), gastric dilatation volvulus (GDV), or persistent GI signs following gastropexy. Results of this study found that complications directly associated with prophylactic gastropexy were rare and limited to hemorrhage causing hemoabdomen and infection with partial dehiscence. Transient postoperative GI signs may occur. Gastropexy malpositioning and bowel entrapment were not encountered. There was no occurrence of GD or GDV.

Computed tomographic assessment of principal bronchial anatomy in dogs of various thoracic conformations: 93 cases (2012-2017)

OBJECTIVE

To better understand spatial relationships between principal bronchi and other intrathoracic structures by use of CT images of dogs of various somatotypes.

ANIMALS

93 dogs that underwent thoracic CT.

PROCEDURES

Information was collected from medical records regarding signalment and physical examination and echocardiographic findings. Two investigators recorded multiple measurements on a thoracic axial CT image from each dog.

RESULTS

Thoracic height-to-width ratio (H:W) was associated with left principal bronchus (LPB) and right principal bronchus (RPB) H:W, aortic-LPB separation, focal LPB narrowing, and aortic-vertebral overlap. Thoracic H:W was not associated with dog age, weight, sex, or brachycephalic breed. Twenty-five (27%) dogs had focal LPB narrowing, compared with 5 (5%) dogs with focal RPB narrowing (P < 0.001). Ten of 25 dogs had overlap or contact between vertebrae, aorta, LPB, and heart, suggesting a cumulative compressive effect on the LPB, while 15 had LPB-aorta contact and lack of contact between the aorta and thoracic vertebrae, suggesting an aortic constrictive effect on the LPB. None had LPB narrowing without contact from surrounding structures. Inter-rater agreement was high.

CLINICAL RELEVANCE

In dogs that underwent CT and were not selected for clinical suspicion of bronchial disease, principal bronchial morphology was associated with thoracic conformation. Focal LPB narrowing occurred more often than RPB narrowing. Focal LPB narrowing occurred with evidence of extraluminal compression, with or without contact between aorta and vertebrae. Brachycephalic breed could not be used for predicting thoracic H:W.

Identification of Genetic Susceptibility Factors Associated with Canine Gastric Dilatation-Volvulus

Canine gastric dilatation-volvulus (GDV) is a common life-threatening condition occurring primarily in large and giant breeds with a 3.9% to 36.7% lifetime risk. The genetic correlates of GDV have not previously been systematically explored. We undertook an inter-breed genome-wide association analysis (GWAS) of 253 dogs from ten breeds including 106 healthy dogs and 147 dogs with at least one GDV episode. SNP array genotyping followed by imputation was conducted on 241 samples to identify GDV-associated single-nucleotide polymorphisms (SNPs) and copy number variations (CNVs). A subset of 33 dogs (15 healthy dogs and 18 GDV patients from the three most represented breeds) was characterized by whole genome sequencing (WGS). After genome-wide Bonferroni correction, we identified a significant putatively protective intergenic SNP (rs851737064) across all breeds. The signal was most significant in Collies, German Shorthaired Pointers, and Great Danes. Subsequent focused analysis across these three breeds identified 12 significant additional putatively protective or deleterious SNPs. Notable significant SNPs included those occurring in genes involved in gastric tone and motility including VHL, NALCN, and PRKCZ. These data provide important new clues to canine GDV risk factors and facilitate generation of hypotheses regarding the genetic and molecular underpinnings this syndrome.

Lethal mechanisms in gastric volvulus

A 55-year-old wheelchair-bound woman with severe cerebral palsy was found at autopsy to have marked distention of the stomach due to a volvulus. The stomach was viable, and filled with air and fluid and had pushed the left dome of the diaphragm upwards causing marked compression of the left lung with a mediastinal shift to the right (including the heart). There was no evidence of gastric perforation, ischaemic necrosis or peritonitis. Removal of the organ block revealed marked kyphoscoliosis. Histology confirmed the viability of the stomach and biochemistry showed no dehydration. Death in cases of acute gastric volvulus usually occurs because of compromise of the gastric blood supply resulting in ischaemic necrosis with distention from swallowed air and fluid resulting in perforation with lethal peritonitis. Hypovolaemic shock may also occur. However, the current case demonstrates an alternative lethal mechanism, that of respiratory compromise due to marked thoracic organ compression.

Efficacy of Incisional Gastropexy for Prevention of GDV in Dogs

Incisional gastropexy (IG) is routinely performed as either a prophylactic procedure to prevent occurrence of gastric dilatation-volvulus (GDV) or at the time of surgical correction of GDV to prevent recurrence. Despite its common use, the long-term efficacy of the IG procedure has not been reported. The hypothesis of this study was that IG performed either during surgical treatment of GDV or as a prophylactic measure would effectively prevent GDV. Medical records of 61 dogs undergoing IG following either gastric derotation for treatment of GDV or as a prophylactic procedure were evaluated retrospectively. Median follow-up time for all dogs was 717 days (range, 49–2,511 days). Of the 61 dogs, 27 had prophylactic IG performed. The remaining 34 dogs presented for GDV and had an IG performed during surgical treatment of GDV. No dog experienced GDV after IG. Recurrence of gastric dilatation (GD) alone was noted in 3 of 34 patients (8.8%) undergoing IG during surgery for GDV and in 3 of 27 patients (11.1%) treated prophylactically with IG. This study confirmed the efficacy of IG for the long-term prevention of GDV in dogs.

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.

Clinical results and complications of preventive laparoscopic assisted gastropexy in 17 dogs: preliminary study

In terms of GDV prevention, a number of non-surgical measures are recommended. However, the only truly reliable method is gastropexy, most often as part of a surgical treatment of GDV. Gastropexy may be performed preventively either during laparotomy indicated for another reason than GDV, or newly laparoscopically, as independent preventive gastropexy. Preventive laparoscopic assisted gastropexy (PLAG) was performed in 17 patients at the Department of Surgery and Orthopaedics of the Small Animal Clinic at the University of Veterinary and Pharmaceutical Sciences in Brno. Clinical results and complications of PLAG were evaluated 3-12 months after surgery. The most frequent clinical finding of PLAG was a skinfold at the site of gastropexy immediately after the surgery (n = 8; 47%), or still on day 12 after the surgery (n = 1; 6%). As for PLAG complications, in one case a seroma formation was found at the site of gastropexy (6%); in two patients iatrogenic perforation of the splenic capsule (12%) occurred, which in one case gave reason to converting laparoscopy into laparotomy (6%). In none of the patients, death, gastropexy failure, GDV development, dehiscence, infection of or haemorrhage from the surgical wound were noted. Laparoscopic assisted gastropexy appears as a reliable and miniinvasive surgical method of GDV prevention and it may be recommended for high-risk breeds of dogs.

Gastric dilatation–volvulus associated with diaphragmatic hernia in three cats: Clinical presentation, surgical treatment and presumptive aetiology

Three cats were examined because of acute dyspnoea and sudden abdominal enlargement. In all cats, radiographs revealed gastric dilatation–volvulus (GDV) and diaphragmatic hernia. Cardiovascular shock and dyspnoea were treated by intravenous fluid-therapy, oxygen administration and relief of diaphragmatic pressure by means of stomach decompression and in one case placing the patient in an inclined position. Gastric decompression was performed by needle gastrocentesis, placement of a rhino-gastric tube, or a combination of these. Diaphragmatic herniorrhaphy was performed in either case; one cat also underwent gastropexy. The immediate postoperative period resolved uneventfully and the cats were doing well at follow-up. Feline GDV is a rare event in which diaphragmatic hernia may be a predisposing factor.

Vertebral column kyphoscoliosis and unexpected death

A case of spontaneous gastric perforation is reported in a 75-year-old woman due to massive hemorrhaging from a benign gastric ulcer. Blood was prevented from leaving the stomach due to posterior displacement and rotation of the stomach associated with marked underlying vertebral column kyphoscoliosis. Significant deformity of the spine had caused malpositioning of the stomach as a result of the abnormal shape of the peritoneal and chest cavities. This in turn had led to mechanical obstruction and prevented egress of blood arising from a bleeding arteriole in the base of a chronic gastric ulcer. Rapid distension had resulted from the inability to spontaneously decompress the stomach, which in turn had led to rupture.

Risk factors associated with short-term outcome and development of perioperative complications in dogs undergoing surgery because of gastric dilatation-volvulus: 166 cases (1992–2003)

OBJECTIVE

To evaluate risk factors associated with death and development of perioperative complications in dogs undergoing surgery for treatment of gastric dilatation-volvulus (GDV).

DESIGN

Retrospective case series.

ANIMALS

166 dogs.

PROCEDURES

Records of dogs with confirmed GDV that underwent surgery were reviewed. Logistic regression was performed to identify factors associated with development of complications (ie, hypotension, arrhythmias, gastric necrosis necessitating gastrectomy, disseminated intravascular coagulation, peritonitis, sepsis, postoperative dilatation, postoperative vomiting, and incisional problems) and with short-term outcome (ie, died vs survived to the time of suture removal).

RESULTS

Short-term mortality rate was 16.2% (27/166). Risk factors significantly associated with death prior to suture removal were clinical signs for > 6 hours prior to examination, combined splenectomy and partial gastrectomy, hypotension at any time during hospitalization, peritonitis, sepsis, and disseminated intravascular coagulation. Partial gastrectomy was not a significant risk factor for death but was for peritonitis, disseminated intravascular coagulation, sepsis, and arrhythmias. Age, gastrectomy, and disseminated intravascular coagulation were risk factors for development of hypotension. Use of a synthetic colloid or hypertonic saline solution was associated with a significantly decreased risk of hypotension.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that the prognosis for dogs undergoing surgery because of GDV is good but that certain factors are associated with an increased risk that dogs will develop perioperative complications or die.

Benefits of prophylactic gastropexy for dogs at risk of gastric dilatation-volvulus

The lifetime probability of death from gastric dilation-volvulus (GDV) for five dog breeds was estimated based on published breed-specific longevity and GDV incidence. These breeds were Great Dane, Irish Setter, Rottweiler, Standard Poodle and Weimaraner. Lifetime risk (95% CI) of GDV in these breeds ranged from 3.9% (0-11.2%) for Rottweiler to 36.7% (25.2-44.6%) for Great Dane. A decision-tree analysis for prophylactic gastropexy--using lifetime probability of death from GDV and expected cost savings for veterinary services as outcome measures--was undertaken to determine the preferred course of action in several dog breeds. Prophylactic gastropexy was the preferred choice of action for all breeds examined, with the reduction in mortality (versus no gastropexy) ranging from 2.2-fold (Rottweiler) to 29.6-fold (Great Dane). Assuming a prophylactic gastropexy costs US$ 400, the procedure was cost-effective when the lifetime risk of GDV was > or = 34%. The maximum and minimum estimated breakeven costs for the gastopexy procedure ranged from US$ 20 (Rottweiler) to US$ 435 (Great Dane). The cost-effectiveness of prophylactic gastropexy was most sensitive to the cost of treating GDV (US$ 1500). Prophylactic gastropexy raises ethical issues that need to be considered by veterinarians and dog breeders.

Gastric dilatation-volvulus syndrome in dogs

Gastric dilatation-volvulus is a medical and surgical emergency that principally affects large-breed dogs. Surgical treatment should be undertaken as soon as the patient has been stabilized with fluid therapy and decompression. A gastrectomy might be required if the stomach is becoming necrotic. A gastropexy is required to prevent recurrence.

Gastric distension, cerebral palsy and unexpected death

Two cases of unexpected death from massive gastric dilatation in individuals with severe spastic quadraparesis aged 14 and 20 years, respectively, are reported. Spontaneous rupture of the stomach occurred in one case. Predisposing factors to gastric dilatation associated with cerebral palsy include autonomic neuropathy, neuromuscular incoordination, air swallowing and malposition of the stomach. Death may be due to compromise of respiratory function caused by lung compression by the dilated stomach, or to peritonitis with sepsis. Acute gastric dilatation, with or without rupture, should be considered a potential cause of unexpected death in individuals with severe mental and physical disabilities.

Gastrointestinal emergencies

The animal with a surgical gastrointestinal emergency usually requires a rapid, thorough physical examination with concurrent resuscitation. As the diagnosis is being made, the animal must be made as stable as possible before undergoing general anesthesia. During surgery, there must be a critical evaluation of gastrointestinal viability and the use of precise technical skills to achieve the best outcome. Adept postoperative management, including careful monitoring and an index of suspicion for potential complications, is vital.