By Eoin Kilkenny, European Specialist in Small Animal Cardiology

Luna presented to Highcroft Cardiology after her primary vet detected a loud, continuous heart murmur. Her owner’s described her as having less energy than they would expect from a Labrador puppy so they were very keen to have her assessed by our team. Echocardiography was performed and revealed a patent ductus arteriosus (PDA) (figure 1).

Figure 1. Echocardiography showing Luna’s PDA permitting flow from the aorta into the pulmonary artery. Ao: aorta; PDA: patent ductus arteriosus; PA: pulmonary artery.

Figure 2. Diagram of a normal heart and the heart of a dog with a patent ductus arteriosus.

The ductus arteriosus is an essential feature of the normal foetal heart. Since the lungs are not yet working, it has the important function of diverting most of the blood from the pulmonary artery into the aorta. Shortly after birth, the ductus arteriosus should close completely; when it does not, it is called a patent ductus arteriosus (PDA).

The presence of a persistent PDA in dogs causes profound changes to heart function. A portion of the oxygenated blood that should be carried to the body via the aorta will be diverted through this communication into the pulmonary artery. This blood adds to the blood passing through the lungs and returning to the left side of the heart (figure 2). Eventually, most dogs with this condition will develop congestive heart failure and die if it is untreated.

Figure 3. Angiogram highlighting the position and size of Luna’s Patent Ductus arteriosus (PDA).

Following her diagnosis, we advised closure of Luna’s PDA with a minimally invasive procedure. Her owners were very keen for us to take her to theatre where we accessed her aorta via her femoral artery. An angiogram was performed at the base of the heart, highlighting the position and size of Luna’s shunt (figure 3). Based on our measurements, an appropriately sized device called an Amplatz Canine Duct Occluder (ACDO) was chosen and used to “plug” her PDA.

Four weeks later, Luna had a repeat heart scan; the ACDO can be seen sitting securely in position (figure 4), preventing any abnormal flow. Her heart chambers had decreased in size and her owners reported that her energy levels were higher than ever following her procedure. Luna can now live a happy life as every puppy should!

Figure 4. The ACDO (Amplatz Canine Duct Occluder) occluding the Ductus arteriosus, evident on radiography and echocardiography.

Luna enjoying life after her procedure.

Although owners are understandably concerned when their pet has a murmur, puppies with a PDA are just some of the cases that can have a normal life if they are diagnosed early enough. Therefore, we always advise a referral for any patient with a loud heart murmur. To assist owners and vets in this regard, we are now offering a Cardiology Puppy Clinic at Highcroft Referrals at a discounted fee of £450; this includes a full consultation and echocardiography with a cardiology specialist. Please contact us on cardiology@highcroftvet.co.uk if you would like to discuss or refer a case.