Arteriovenous Fistulae in Dogs: Causes, Symptoms & Treatment
An arteriovenous fistula (AVF) in dogs is an abnormal connection between an artery and a vein that bypasses the normal capillary system, leading to inefficient oxygen delivery to tissues. This vascular defect forces the dog’s heart to pump blood at an increased rate to compensate, which can result in congestive heart failure if left untreated.
These fistulae can form in various parts of a dog's body, including:
- Head
- Neck
- Ear
- Tongue
- Limbs
- Flanks
- Spinal cord
- Cerebrum (part of the brain)
- Lungs
- Liver
- The major artery leading to the heart
- Gastrointestinal tract
Breeds Most at Risk
Though any dog can develop an AVF, certain breeds are more predisposed, such as the English Bulldog puppies, which are particularly susceptible. Responsible owners should ensure they breed from reputable breeders to reduce hereditary risks.
Recognising Symptoms of Arteriovenous Fistulae
Symptoms vary depending on the fistula's location. Typically, a warm, painless lesion develops at the site. For example, if the lesion is on a limb, signs may include:
- Swelling with pitting oedema (where pressing leaves an imprint)
- Ulceration and scabbing
- Lameness
- Gangrene, indicating tissue death and a greenish discoloration
If the fistula affects the heart, it may present as congestive heart failure, with symptoms such as:
- Difficulty breathing (dyspnoea)
- Coughing
- Increased respiratory rate (tachypnoea)
- Reluctance to exercise
Internal organ involvement causes specific signs, including:
- Abdominal distension (liver involvement)
- Seizures (brain involvement)
- Weakness or paralysis (spinal cord involvement)
What Causes Arteriovenous Fistulae?
Most AVFs in dogs are acquired rather than congenital. Common causes include:
- Traumatic injury damaging blood vessels
- Tumours affecting vascular structures
- Complications during or after surgery
- Improper intravenous injections near blood vessels
Diagnosing the Condition
A thorough veterinary examination is essential, involving:
- A full medical history and symptom onset details
- Blood tests such as complete blood count, biochemistry profile, urinalysis, and electrolyte panels to identify complications
- Diagnostic imaging including thoracic X-rays to assess heart size and strain
- Doppler ultrasound to evaluate abnormal blood flow in lesions
- Echocardiogram to determine heart functionality
- Selective angiography or advanced imaging like CT angiography for lesion mapping
Treatment Options for Arteriovenous Fistulae
Surgical correction is the primary treatment to eliminate the fistula, though it carries risks such as blood loss and the possibility of recurrence. In severe cases, amputation of the affected limb may be necessary to prevent life-threatening complications.
A minimally invasive alternative is transcatheter embolisation, a technique where a catheter blocks abnormal blood vessels, redirecting blood flow. This approach is effective and reduces recovery time.
Living with a Dog Diagnosed with an Arteriovenous Fistula
Post-treatment management requires regular veterinary check-ups to monitor for recurrence or complications. Maintaining a safe environment to prevent trauma and following the vet’s advice on exercise and care are crucial for your dog’s wellbeing.
If you are considering adding an English Bulldog puppy or any susceptible breed to your family, ensure you find them from reputable breeders to minimise health risks including vascular issues such as AVF.
Frequently Asked Question: Can Arteriovenous Fistulae in Dogs Be Prevented?
Quick Answer: While congenital AVFs are rare, preventing traumatic injuries and ensuring proper veterinary care during injections and surgery can reduce the risk of acquired fistulae.
Prevention focuses primarily on avoiding trauma to blood vessels. Always seek skilled veterinary care for injections or surgeries and monitor your dog for any unusual swellings or lesions, especially if they belong to a predisposed breed. Early veterinary intervention improves outcomes.
Summary
Arteriovenous fistulae, though serious, can be effectively diagnosed and treated through veterinary care. Recognising breed risk, symptoms, and treatment options helps responsible owners support their dog’s health and quality of life.
