Tiny Chihuahua Becomes Smallest Heart Surgery Patient

healthy chihuahua

Story at-a-glance -

  • Luna, a tiny long-haired Chihuahua weighing in at under 2 pounds has become possibly the smallest patient to receive surgery for patent ductus arteriosus (PDA)
  • PDA is a condition in which the ductus arteriosus blood vessel fails to close normally, interrupting the normal blood flow between the aorta and pulmonary arteries that carry blood from the heart
  • This congenital heart defect affects about 1 in 3,000 human babies every year and is also the most common congenital defect in dogs (it can occur in cats as well)
  • PDA symptoms include persistent cough, heart murmur, stunted growth, exercise intolerance and sleeping more than normal (in puppies)
  • PDA is typically treatable and, once corrected, your dog will recover to lead a long life

By Dr. Karen Shaw Becker

Luna, a tiny long-haired Chihuahua weighing in at under 2 pounds has become possibly the smallest patient to receive surgery for patent ductus arteriosus (PDA). PDA is a condition in which the ductus arteriosus blood vessel fails to close normally, interrupting the normal blood flow between the aorta and pulmonary arteries that carry blood from the heart. This congenital heart defect affects about 1 in 3,000 human babies every year and is also the most common congenital defect in dogs (it can occur in cats as well).1

When she was just 9.5 weeks old, Luna’s owner noticed she had a persistent, hacking cough. Her veterinarian discovered a heart murmur, but the symptoms continued. At that point, she received an echocardiogram, or ultrasound of the heart, and was diagnosed with PDA, which, if left untreated, has a more than 50 percent mortality rate by age 1. Symptoms of PDA range from mild to severe, but typically PDA causes left-sided congestive heart failure leading to cough and difficulty breathing.2

Some dogs with PDA may fail to grow and thrive, leading them to be the “runt” of their litter. Often, surgery to tie off the blood vessel is required to fix the defect. Chihuahuas, along with poodles, Pomeranians, Maltese, Keeshond, Bichon frise and German shepherds, are the breeds most likely to suffer from PDA, and it occurs more often in females than males.3

After discovering that Luna, who was under 3 months old, had PDA, her owner asked a veterinary cardiologist in her hometown of Seattle to perform the procedure, but he was reluctant due to her small size. This brought her on a 2,500-mile trek to get the life-saving surgery for her dog.

Tiny Chihuahua Undergoes PDA Surgery at Auburn’s College of Veterinary Medicine

Luna’s owner’s search for a veterinary hospital to perform PDA surgery on a tiny patient brought her to Auburn University’s College of Veterinary Medicine in Auburn, Alabama. The surgical team there was willing to perform the procedure, though it brought some special challenges. Lead veterinary surgeon Dr. Harry Boothe in the department of clinical sciences, explained in a press release:4

"Surgery in small, young patients is a challenge from both an anesthetic and a surgical perspective … An additional dimension of Luna's surgery was the fact that her thoracotomy necessitated placing her on a ventilator [breathing for her] during the surgical procedure. Specific challenges included minimizing hypothermia, avoiding hypoglycemia and gaining access to the heart and abnormal vasculature [i.e., Patent Ductus Arteriosus]."

However, the procedure was performed successfully in much the same way as a typical PDA procedure, though on a smaller scale, Boothe said. They did, however, require one special piece of equipment:5

"The exception [was] that a retractor that is typically used to separate the eyelids in horses was used to separate Luna's ribs during the procedure … A standard rib retractor would have been much too large to use in this situation.”

With the surgery being a success, Luna is expected to recover completely and live a normal life. Typically, a follow-up echocardiogram is recommended four to six months after the procedure to confirm that the PDA has been completely closed. As noted by the American College of Veterinary Internal Medicine (ACVIM), “Most dogs and cats that undergo correction of their PDA have good to excellent long-term prognosis, and most will lead a completely normal life after surgery.”6

Keep an Eye Out for These Signs and Symptoms of Heart Problems

PDA is a congenital condition that’s not always easy to identify or diagnose and, if the PDA defect is small, may cause no obvious symptoms. However, if you notice any of the following symptoms, it’s important to get your dog checked out by your veterinarian right away:

  • Persistent coughing
  • Decreased exercise endurance
  • Increased breathing rate
  • Bluish appearing tongue
  • Fatigue, weakness or loss of stamina

Puppies with PDA may also experience stunted growth and may sleep more than usual. If a heart murmur is detected in your dog, PDA could be one of the underlying causes. Because this is an inherited condition, prevention comes in the form of not breeding dogs with the condition. If you’ve adopted a puppy and were surprised with a PDA diagnosis, take comfort in the fact that this condition is typically treatable and your dog will recover to lead a long life.

While small dogs often require surgery to fix the procedure, sometimes a less invasive procedure using cardiac catheterization is an option. It’s important to seek treatment promptly, however, as the longer the defect remains, the higher the possibility of permanent heart damage and heart failure becomes. A board-certified veterinary cardiologist can provide you with more information about treatment options if you’ve been told your dog has a heart condition like PDA.

In addition to prompt treatment, I recommend all animals suffering from any heart pathology increase their intake of ubiquinol, the reduced form of CoQ10, and omega-3 fats, specifically krill oil. Additionally, holistic vets may recommend Chinese herbs, homeopathic remedies, supplemental amino acids such as taurine, arginine and acetyl-l-carnitine, d-ribose, and herbs such as Hawthorne berry and cayenne to support your dog’s heart health.