What is PRAA Ligation/Transection?
Persistent right aortic arch, PRAA, is a condition occurring in dogs in which the blood vessels of the heart form a constricting ring around the esophagus during fetal development. The resulting congenital condition is best addressed with early surgical intervention by a qualified veterinarian. The sooner intervention is conducted the less likely permanent damage to the esophagus will occur. The condition manifest in puppies, usually when they are weaned and solid food is introduced. The puppy is unable to eat properly, fails to thrive, and may experience coughing and gagging when eating. The procedure to ligate and transect the abnormal blood vessel is performed as soon as the puppy is able to safely undergo surgery at two to six months of age, under general anesthetic. The outcome is usually good with the condition being resolved.
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PRAA Ligation/Transection Procedure in Dogs
In the days prior to surgery your dog should be fed a high calorie diet, in the form of a high calorie gruel, while elevating the puppy’s front end to ease constriction of the esophagus. This process will strengthen the puppy and prevent regurgitation and aspiration which could result in aspiration pneumonia, which would complicate administration of general anesthetic and surgery. If pneumonia is present it will be treated with antibiotics and therapy prior to surgery.
The night before surgery the puppy will be fasted. On the day of surgery an intravenous line will be set up to provide IV fluids and sugar to the puppy. It is important they do not become dehydrated or experience low blood sugar. Sedation and anesthetic will be provided by IV, followed by gaseous anesthetic. The chest area is shaved and prepared antiseptically. A thoracoscopy is performed by incision into the left side of the chest. The fourth and fifth ribs are gently sprea to expose the constricting band of vessels around the esophagus. Nerves located by the constricting band, the phrenic, laryngeal, and vagus, are identified and avoided during the procedure. The vessels are double litigated and then transected. Any fibrous tissue present that is also constricting the esophagus is dissected away. A gastric tube is placed down the esophagus to ensure that it passes through smoothly and no constriction remains. A chest tube will be placed in the thoracic cavity to provide drainage.
Tissue is repaired, the thoracic cavity inspected for hemorrhage, and incisions sutured. The young dog is put in recovery and provided with supportive care.
Efficacy of PRAA Ligation/Transection in Dogs
This procedure is usually performed as early as possible to achieve the best results and minimize permanent damage to the esophagus and prevent aspiration pneumonia. Usually, puppies need to be two to six months of age to be ready for this type of surgical intervention. Supportive care consisting of high calorie liquid diet and elevation during feeding to minimize the effect of constriction until the puppy is able to undergo surgery will result in the best outcome.
Although it is recommended that young dogs receive PRAA ligation and transection surgery as soon as possible for the best outcome, adult dogs have successfully received this procedure.
Generally, most dogs recover well if treated early and provided supportive care.
If surgery is not possible, the puppy may need to be fed in an upright position and held in that position after their meals for a specified amount of time. Dogs can continue to thrive if provided this supportive care if surgery is not an option.
PRAA Ligation/Transection Recovery in Dogs
After surgery, your dog will be hospitalized for 24 to 48 hours, provided painkiller and the chest tube will be monitored. Intravenous fluids will be continued. The tube is usually removed in 12 to 24 hours and prior to your dog being released home. You will be provided with analgesics and antibiotics as appropriate. Restrict your dog's activity and prevent them from interfering with the incision. An e-collar may be necessary. Restricted activity should continue for 3 weeks or more. Sutures will need to be removed and follow up will be scheduled with your veterinarian. A modified diet will be prescribed with soft, liquified food following surgery and continued support of the puppy in an upright position until healing occurs. Normal food and feeding can gradually be introduced and is usually achieved at about 4 weeks post-surgery.
Cost of PRAA Ligation/Transection in Dogs
Thoracic surgery is resource intensive, requires pre-surgery care, supportive care during and after surgery, general anesthesia, and hospitalization. The cost of surgery ranges from $2,000 to $6,000 depending on the cost of living in your area.
Dog PRAA Ligation/Transection Considerations
Although usually associated with good prognosis, some puppies do not regain proper functioning of the esophagus and mortality can be an issue. Pneumonia prior to or after surgery is a risk. There is an additional risk of infection or hemorrhage with surgery.
Surgery should be performed as soon as possible, however, complications in puppies less than 2 months of age are more frequent and achieving a balance of maturity, supportive care, and timely intervention is required.
PRAA Ligation/Transection Prevention in Dogs
Dogs that present with PRAA should be removed from a breeding program so that this genetic anomaly does not pass to future generations. Siblings of PRAA dogs should also be screened for PRAA. Parents of PRAA puppies should also be removed from breeding programs.