Persistent Right Aortic Arch

“… At this point my mind was only picking up on certain words, like Starvation and Strangling. I asked him, "what do I do? Do I have to put her to sleep?"  Luckily, he said NO”… - Lillie’s Mom, Paula


“…I noticed every time she ate her throat would make 'urping' noises and sometimes bulge out. She held down about 30% of her meals”... – Foster’s Mom, Anne



What is it?

PRAA, or vascular ring anomaly, is a congenital anomaly of the blood vessels of the heart that result in constriction of the esophagus.

PRAA Drawing


In the fetus, there are blood vessels that at first may serve a function, but then naturally deteriorate as the embryo grows.  Occasionally, vessels in the chest cavity, called the aortic arches, will fail to disappear. The right aortic arch passes near the esophagus.  If this blood vessel persists in the newborn, the esophagus is trapped between it and the heart. 

This inhibits the growth and function of the esophagus, thus restricting food passage to the stomach.

In 95% of the cases of a vascular ring anomaly, a constricting band prevents solid foods from passing to the stomach which prevents the puppy from thriving well.  In the remaining 5% of cases, a bizarre anomaly of the vessels is present (double aortic arch and aberrant subclavian artery), which may be difficult to correct and may not have a good prognosis.



Signs of this condition usually become apparent shortly after weaning, when a puppy begins eating semi-solid or solid food.  While milk will slide down nicely, bulky foods will “jam up” in the esophagus, leading to a stretched structure and the inability to get food down, hence the symptom known as regurgitation.

 “taking a thorough medical history to determine if the pup is regurgitating or vomiting is very important." - Dr. Michael Huddleston, DVM, Westheimer Animal Clinic, Bellaire, TX 

Regurgitation involves the puppy producing undigested food and mucus through the mouth with no effort; the pup tilts its head down and the food and mucus simply roll out.  By contrast, vomiting is an active process, meaning there are abdominal contractions (heaving) and a retching noise when food and mucus are expelled out the mouth.

Regurgitation is synonymous with PRAA and megaesophagus, whereas dozens of disorders may cause a pup to vomit.

Stunted growth (due to an inability to take in nutrients) and breathing problems (often the result of aspiration pneumonia secondary to regurgitation) are other common symptoms.

“It is important to note that the vast majority of dogs with vascular ring anomalies do not have true megaesophagus. The esophagus is merely dilated because of the obstruction caused by the vascular ring.” -Dr. David Holt, BVSc, Diplomate ACVS, Professor of Surgery, University of Pennsylvania


Surgery to correct PRAA

Surgical removal of the stricture (narrowing) caused by the persistent right aortic arch is the preferred treatment.  It is important to perform surgery early in the disease, before permanent growth damage has occurred.  Generally, puppies between the ages of 2-6 months, that are not severely emaciated or have severe aspiration pneumonia, are considered good candidates for surgery. Under the age of two months, surgery is considered risky due to anesthesia and surgery complications.  

Although it is recommended the sooner the vascular ring anomaly is corrected the better, there have been cases of adult dogs that have undergone surgery with success.

Opting out of surgery

In some cases, surgery is not possibleThese pups need to follow feeding instructions for Megaesophagus. They need to be fed in an upright position and kept upright for an appropriate amount of time after meals.  As long as the stricture or narrowing allows for nutrients to pass into the stomach, these dogs can continue to thrive.  Usually consistency of the food is “soupy” or a liquid gruel in order for it to pass by the stricture. 

Restricted diet, consisting of liquefied foods, will need to be followed closely to limit the damage to the esophagus due to constant regurgitation.

For those whom surgery is not a candidate, another option is a gastric feeding tube. This allows for nutrition to go directly to the stomach, bypassing the esophagus.  Although the idea of a feeding tube seems extreme, many dogs live long happy lives with feeding tubes in place. 

For more information please click on the tab marked “Feeding Tubes”.


  • Thoracic radiograph (X-Ray) made after a barium (a gastrointestinal contrast material) swallow.  The esophagus in front of the heart will appear dilated.  In some cases the esophagus behind the heart will also be dilated. This is a warning sign that the puppy could have poor function of the esophagus even if surgery is performed.  There is a slight chance the puppy could aspirate the barium and special precautions should be taken. The barium should be administered in an upright position and minimize the time the puppy is laying on his side. Sit the puppy back up quickly to allow safe passage of the barium to the stomach.



  • Thoracic radiographs (x-rays) are also used to determine if the puppy has aspiration pneumonia (AP)
  • Blood tests, including a complete blood count (CBC), chemistry profile and urinalysis are recommended to make sure that the puppy has healthy internal organs prior to surgery and may show signs of low blood sugar or a high white blood cell count if infection is present.
  • An ultrasound may also be recommended to rule out other congenital heart defects that may require attention.
  • The esophagus may also be evaluated with a flexible endoscope (under anesthesia).
  • A contrast CT may also be ordered.


There are two types of surgeries you can elect to have for your puppy.

  • Minimally Invasive Surgery  (MIS) – Thoracoscopy.  MIS allows diagnostic and/or therapeutic surgical procedures to be performed using very small incisions through which a camera and instruments are placed inside body cavities.  

Advantages of MIS include:

    •  decreased pain,
    • better visualization (due to the magnified high-resolution images produced)
    • reduced risk of wound complications and infections
    • shorter hospitalization times  

“you always have to be prepared to convert to an open procedure (thoracotomy) when doing MIS in cases of unexpected hemorrhage or poor exposure.” - Dr. James A Flanders, DVM Diplomate, ACVS, Associate Professor, Cornell University

Click Here to see a Thoracoscopic PRAA surgery being performed
  • Cost of surgery is between 2 and 6 thousand dollars, depending on the facility and geographic location. MIS surgery may run higher but may require minimal post-operative hospital care.


Thoracotomy Surgery

Prior to surgery, it is important to provide as much nutrition as possible to the puppy.  This may include feeding a high calorie gruel. During and after feeding a meal, the puppy must sit upright so to make sure that the food will pass into the stomach by means of gravity.

If pneumonia is present it should be treated with antibiotics, nebulization, and coupaging the chest to bring up phlegm.

On the day of surgery, an intravenous catheter will be placed to provide intravenous fluid therapy. Young puppies are also very susceptible to developing low blood sugar, therefore a sugar solution is typically incorporated in the intravenous fluids.

The photos below show Chloe being prepared for her surgery.

 Chloe PRAA1Chloe PRAA2

Chloe PRAA3Chloe PRAA4

Chloe PRAA5


An incision is made on the left side of the chest and the fourth and fifth ribs are spread to expose the band (ligamentum arteriosum), constricting the esophagus. The band is readily identified by running a finger or the tip of a surgical instrument along the esophagus. The phrenic, vagus and recurrent laryngeal nerves, located near the constricting band are identified and protected during the procedure.

Chloe Procedure 1

The constricting band is isolated using a surgical instrument, tied twice with suture and cut. The constricting band must be tied off, as the ligamentum arteriosum frequently still is a patent vessel in very young animals. After the constricting band is cut, fibrous tissue that may be constricting the esophagus is dissected off the esophagus. A tube is placed down the mouth and through the area of the esophagus to make sure that there are no additional constrictions.

Chloe Procedure2

Click below to see the resection of the band of tissue that was between the aorta and the pulmonary artery. This opens the blocked esophagus and allows food to travel to the stomach.

Click Here to see Chloe's PRAA Surgery WARNING: Graphic Images

More of Chloe's PRAA Surgery WARNING: Graphic Images


After surgery, medication is given to your puppy to ensure a pain-free recovery.  Intravenous fluids are administered at least over night or longer if indicated.  Once the puppy is eating and drinking well, intravenous fluids may be discontinued.

Chloe post Op incision Chloe post op bandaged

Your puppy may have a chest tube after surgery, which is used to remove fluid and air from the chest cavity. Typically, the tube can be removed after 12 to 24 hours. Some surgeons prefer to administer pain relieving medication (local anesthetic) through the tube to numb the incision.

Chloe Post Op Awake

Upright feedings may be required for an additional month after surgery.  If the puppy is no longer regurgitating, the upright feedings can be discontinued.  Once the puppy can swallow well and there is no regurgitation, solid foods can be gradually introduced.

Exercise must be restricted for 3 weeks after surgery so that the surgical site can heal properly.

 Click Here to see Chloe eating 48 hours after surgery WARNING: Cuteness Overload!

Just 48 hours after PRAA surgery, Chloe is ready to go home!

Chloe 48 hours after


Prognosis is very good!  Overall, about 90% of dogs having surgery to correct this condition will have resolution of the regurgitation and they thrive. The remaining dogs may do poorly or may be improved from the preoperative condition.

  • Special thanks to Dr. Mike Huddleston for pictures and videos of Chloe. Dr. Huddleston has performed over 24 PRAA successful surgeries.
  • Special thanks to Dr. Holt from the University of Pennsylvania and Dr. Flanders from the University of Cornell for their help in writing this article. Both these University Veterinarian Schools perform both classic thoracotomy and thoracoscopy (MIS) surgeries to correct PRAA.
Below is a complete list of Accredited Colleges of Veterinary Medicine throughout the world:

Click Here to see a complete lists of Accredited Veterinary Colleges in the world

24 thoughts on “PRAA

  1. Hi I have a Australian Labradoodle with PRAA. She will have the surgery in a couple of weeks, but until then I am struggling to keep weight on her. She is on antibiotics and has a feeding tube. She is 2 lbs 6oz and is 9 weeks old. The food the vet gave us caused her to vomit thick mucus and/or foam several times a day. And poop was black and hard like clay (before it hardens).I switched to the puppy formula and vomit of mucus dropped to 1 or 2 times a day(yesterday was the first full day of puppy formula). It’s been 8 days since putting in the feeding tube. She is very skinny and I worry about her weight. But I can’t seem to add weight at all. I read that most puppies gain 1- 1 1/2 lbs a week. But what is the average weight gain before surgery for puppies with this defect?I’ve added kefir to her formula in the hopes of fixing the good bacteria count and maybe add more calories.Also I have been feeding 2-3 hours apart.

    1. Hello Aline,

      I’m not sure I know the answer to your question about the weight gain. I know candidates for PRAA surgery should not be extremely emaciated or have a severe case of aspiration pneumonia. With a puppy that size and age, be careful that you are not feeding too much at one time since you are feeding several times a day. Be sure to have her elevated when tube feeding so that the food is going in the right direction. I’m sure you have but keep in close contact with your vet during this time for expert advice and guidance. I hope the surgery is a success!

  2. Hello – My wife and I are considering a puppy (about 6-7 months old) that has had the PRAA surgery (about 1 month ago). She is still limited to “Gruel”/mostly liquid diet. One of our concerns is long term care and affordability of that care ( it is just a reality for us and we don’t want to end up in a situation where we can’t afford her). Everything I have been able to find and read is basically short term focused. Do you have any information on the long term prognosis and potential on-going corrective procedures that may be required?

    1. I learned more about the pup – she is part of a study at U Penn. She had the MIS and seems to be doing very well so far (about one month since the surgery). Hoping to discuss her case with the surgeon today.

      1. Hoping everything as come out well. Upenn is great. We had a lot of success with Penn Vet with our dog who had myasthenia gravis. Keep us posted!

    2. Hi Josh,
      It’s good to think about everything that might come down the road. It really is hard to say with any pet you get how expensive it might be. Some dogs with PRAA surgery come away from it completely normal. Others still need to be fed upright but the ME is on the mild side. The biggest threat with ME is aspiration pneumonia and malnutrition. A puppy that has had a successful PRAA surgery should now be able to allow food to pass into the stomach since the stricture has been removed. Aspiration pneumonia can be treated successfully with antibiotics once it’s caught it time. Some dogs require supportive care such as overnight stays for fluids and oxygen. These expenses can add up. Management for ME is key. Many dogs with ME go onto lead very normal lives except for eating. Best of luck with your decision. It sounds like you have done a good deal of research already.

  3. My German Shepherd has PRAA and I was told he had a 0% chance of living without the surgery and we decided against the surgery and here he is almost 3 years later, literally, 30 pounds heavier than his sister who is his littermate and towers over her….. all it took was some thinking and love on our part to overcome this hurdle in his life and now the way we have to feed him has just become a way of life for us and them!!

    1. Hi Crystal! Yes I think it depends on the severity of the stricture. As you read Paula’s dog is 5 years old now and doing just wonderfully without the surgery. She is fed like any other ME dog and is fine unless she gets into something she shouldn’t. Paula feeds her in a high chair, miniature Schnauzer. Glad to here your GSD is doing well!

  4. My little Labrador of 4 months was operated for PRAA, it has been almost 2 months after the surgery. His growth is slow but is active in his daily movements. He vomits a little after his last evening meal. Still I am happy that he is eating etc. But he always is feeling to eat even after his meals. I can’t fee him more as may vomit. Still I am feeding him on semi solid food only in liquid form. If anyone can help or guide for further care to be taken I will be highly obliged and thank ful.

    1. Hi Rajnish,

      That is wonderful that he is active and has a great appetite! I would suggest smaller more frequent meals and also most do well not being fed too late at night. What does the surgeon say about the operation? Was it successful? Are you still feeding upright? Most often there are follow up barium xrays done to check the esophagus. Are you scheduled for that soon? Please join our facebook groups as well for help. There are many pet owners going through the same situation and can share what has worked for them! Best of luck with your little one!

      1. Hi Donna,

        Thanks a lot for your reply. Yes the operation was successful. Yes I am still feeding him upright. Only the problem is of his vomiting. I will again discuss the facts with the surgeon. As the hospital is almost 500 kms from my city where I stay. Anyways I will discuss things over phone and if required will request him for barium x rays for the follow up. Yeah I like your idea of more frequent smaller meals and evening time I have already changed from 9 pm I feed him by 7 pm as his last meal. one thing more he is always wanting more food even just after his meal.
        Thanks once again.

    2. Hi my name is malinda,my 5 month lab just had praa surgery on Dec 13-2016,she has been doing great with eating.n not vomiting but,I noticed today 6 days later she’s not acting herself.she keeps laying around n crying and,just doesn’t want to b botherd..the vet can not get her in until’s now 12:30pm..I took her temp n it’s fine.I was wondering if your pup acted like this after surgery?

    3. Hi my name is malinda,my 5 month lab just had praa surgery on Dec 13-2016,she has been doing great with eating.n not vomiting but,I noticed today 6 days later she’s not acting herself.she keeps laying around n crying and,just doesn’t want to b botherd..the vet can not get her in until’s now 12:30pm..I took her temp n it’s fine.I was wondering if your pup acted like this after surgery?

  5. Avi, is 7 weeks old, born on Veterans Day,into a disabled Marine’s family. Avi has been diagnosed with this anomaly. We are trying to raise funds for her surgery.
    This presentation is extremely helpful to us in understanding Avi’s situation and possible prignosis. It’s given our spirits a boost for a successful outcome for our little Trooper!
    Thank you Very Much for this presentation!

    1. Dear Kathy,

      Thank you! I am glad this article helped you! Best of luck with your little trooper! There is a lot of hope with pups with PRAA surgery. Hope all goes well! Please join the support groups on facebook for additional help.

      1. How long did it take for Chloe to eat normally? Is it canned food or dry?

        My then 11 week old German Shepherd puppy just had surgery for PRAA. She is still eating per the the doctor’s orders, which is very expensive. I am curious if she will eat normally. She always seems like she is starving when it’s feeding time. I’ve checked in several time with the vet and they insist I stick with the current diet.


        1. Hi Missy,

          I would follow your vets suggestions for now. You can shop around for better pricing. I know the prescription food does tend to be pricey but most vets are okay with giving you a prescription and letting you shop on line or at another place where prescription foods are sold. Chloe did have a successful recovery and does eat normally now. There is a lot of hope with PRAA surgery but I would take it slow transitioning to normal eating and on your vets advice. Your vet may want to check with an xray to see the esophagus before upright feeding and food modifications are changed. Best of luck with your pup!

          1. Thank you.

            This has been a very traumatic experience for both Daisy and our family as this is our first dog. We didn’t know if we should put her down or put her through the surgery. It has been 4 weeks since her surgery and I know we made the right decision for us, although it has been tough.

            Chloe gives us hope that Daisy will be able to be a normal healthy family member. I am so happy to hear that Chloe is well. Thank you for sharing.


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