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How Long Can a Dog Live with Pulmonary Hypertension?

Author:
rott

If your dog was diagnosed with high blood pressure in the lungs, you may be wondering how long a dog can live with pulmonary hypertension (PH). The life expectancy of dogs with pulmonary hypertension can vary based on several individual factors. Factors to consider are the underlying cause of the pulmonary hypertension, how advanced the disease is and how quickly treatment is initiated. While it is often difficult determining life expectancy in dogs affected by canine pulmonary hypertension, it is possible to draw some rough estimates based on several individual factors and by taking a look at clinical data and studies. A consult with a veterinary cardiologist or a veterinary internal medicine specialist can be insightful.

dog lung heart

Increased Lung Pressure in Dogs

To better understand the life expectancy of a dog with pulmonary hypertension, it may help to better understand what pulmonary hypertension exactly is and how it affects the dog's body and overall health.

Pulmonary hypertension consists of increased pressure of the blood circulating thought the large arteries (arterial pressure).

Under normal conditions, the dog's arteries are elastic with extendable walls and the blood flows freely through them. Problems start when when the arteries between the dog's heart and lungs, responsible for transporting blood to the lungs, become narrowed or the flow is constricted for some reason.

At this point, the narrowed passages ultimately lead to a disrupted blood flow (sort of like water trying to go through a kink in a hose) causing the heart to work extra hard so to effectively pump blood to the lungs. This extra workload on the heart may in the long term lead to weakening and failure in delivering sufficient quantities of oxygen to the dog's body. Progression can ultimately lead to right heart failure with fatal consequences.

Dogs are commonly diagnosed with pulmonary arterial hypertension though an ultrasound of the heart (echocardiogram) which can measure the flow of speed of the blood through the pulmonary arteries. While x-rays can be capable of showing show mild pulmonary artery enlargement, it's not reliable as a sole diagnostic tool.

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Of course, this is a serious medical condition that requires to be addressed as soon as possible. In order to address it correctly, it's important to first find out exactly the underlying cause.

"The echocardiogram is the gold standard noninvasive diagnostic tool for pulmonary hypertension. The maximal tricuspid valve regurgitation velocity is the most common echocardiographic method used to diagnose systolic pulmonary hypertension."~ Dr. Matthew W. Miller, veterinarian specializing in cardiology.

Some Underlying Conditions 

Panting in dogs on steroids

Panting in dogs on steroids

Almost always, pulmonary hypertension in dogs takes place secondary to other underlying conditions. In order to determine the lifespan of dogs with pulmonary hypertension it's therefore important to find out what caused the onset of pulmonary hypertension in the first place. The most common conditions known to cause canine pulmonary hypertension include congenital heart defects, heartworm disease, and more commonly, left-sided heart disease. Following are some more details on potential underlying causes of increased lung pressure in dogs.

Congenital Heart Defects 

Congenital heart defects are abnormalities of the heart's structure that are present from birth. The presence of a hole or a small passage that allows fluid to seep from one part of the body to another can be a culprit for pulmonary hypertension. Potential congenital heart defects include patent ductus arteriosus ( where the connection between the aorta and pulmonary artery remains open after birth), atrial septal defects ("holes" in the wall separating the top two chambers of the heart) and ventricular septal defects ( "holes" in the wall separating the two lower chambers of the heart).

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Heartworm Disease 

The popular heartworm Dirofilaria immitis known to wreck major problems to the health of dogs is also a culprit for pulmonary hypertension. The disease is caused by an infected mosquito delivering D. immitis larvae to the dog through a bite. Soon, over the course of several months, the larvae mature into adult heartworms and settle to the right side of the dog's heart and the pulmonary artery. Signs of pulmonary hypertension typically develop when several dead heartworms block the passage of blood flow or when living heartworms establish in large quantities in the dog's pulmonary arteries.

Left-Sided Heart Disease

Left-sided heart diseases remains the primary cause of pulmonary hypertension in dogs. Mitral valve disease, most commonly affecting small, elderly dogs remains the main cause of canine pulmonary hypertension compared to dilated cardiomyopathy, which is more common in larger dogs.

Diseases of the Lungs

In some cases, increased pressure in the lungs may be triggered by diseases affecting the lungs. Such diseases may include chronic obstructive airway disease, interstitial lung disease, pulmonary fibrosis (scarring of the lungs), pneumonia, tracheobronchial disease, pulmonary thromboembolism and cancer. 

life expectancy of addison disease in dogs

Considering Several Factors

As mentioned, the life expectancy of dogs with pulmonary hypertension can vary due to individual factors. The pulmonary hypertension can be caused by different conditions as seen above and each of them can have a different impact on the dog's overall life span. How advanced the pulmonary hypertension is can also play a role.

Pulmonary hypertension is divided in different functional classes based on the dog's clinical signs. Dogs categorized under Functional class I do not have exercise intolerance and are capable of exercising without manifesting fatigue, trouble breathing, chest pain or fainting. Functional class II patients do fine during rest, but exercise can trigger trouble breathing, fatigue, chest pain or fainting. Functional class III patients do fine during rest but show significant signs with minimal activity. Signs include severe labored breathing, fatigue, chest pain or fainting. Finally, Functional class IV patients cannot tolerate any activity. Even at rest, these dogs show symptoms and develop right-sided heart failure as a result of their severe pulmonary hypertension.

There is currently no treatment for pulmonary hypertension, but it can be managed to keep it under control. The earlier the diagnosis, the higher the chances for a better quality of life. Underlying conditions will need to be treated and these treatment may include oxygen supplementation, anti-inflammatory or bronchodilating drugs, chemotherapy for cancer, drugs to kill heartworms for heartworm disease or diuretics for congestive heart failure.

The standard of care for managing canine pulmonary hypertension is giving affected dogs the drug Viagra, explains veterinarian Dr. Gary. On top of sildenafil (Viagra), another drug also used for increased lung pressure is tadalafil (Cialis).

Life Expectancy of Dogs with Pulmonary Hypertension

Some time ago, the life expectancy for dogs with pulmonary hypertension was quite grave. Several dogs were often surviving only days after they were diagnosed. Nowadays, fortunately things have changed for the better. The prognosis for pulmonary hypertension no longer is grave nowadays courtesy of the availability of the drug sildenafil, points out Justin G. Williams, a board-certified veterinarian specializing in cardiology.

With the introduction of sildenafil, survival in affected dogs was reported to be 91 days, with some dogs surviving even almost two years. Of course, these are just estimates and the prognosis worsens the more advanced the disease and the more severe the right ventricular dysfunction. Consult with your vet or veterinary cardiologist for an accurate assessment. 

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References:

  • Serres F, Nicolle AP, Tissier R, et al. Efficacy of oral tadalafil, a new long-acting phosphodiesterase-5 inhibitor, for the short-term treatment of pulmonary arterial hypertension in a dog. J Vet Med A Physiol Pathol Clin Med2006;(53):129-130
  • Brown AJ, Davidson E, Sleeper MM. Clinical efficacy of sildenafil in treatment of pulmonary arterial hypertension in dogs. J Vet Intern Med 2010;24:850-854.
  • DVM360: Canine pulmonary hypertension, Part 2: Diagnosis and treatment

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