Canine High Blood Pressure

What You Need to Know About High Blood Pressure In Dogs:

"High blood pressure in dogs (also called systemic hypertension or SAHT) is caused by constricted blood vessels that do not allow the blood to flow normally. It is caused by a number of diseases. In dogs usually only systolic pressure (blood flowing from the heart) is measured, which is the equivalent of the top number in people. It is seen in .5% to 10% of all dogs, usually between ages 2 and 14. Most cases are triggered by another disease, with the hypertension being referred to as being secondary (80% of cases). There are not specific symptoms for hypertension and blood pressure is not taken during routine veterinary visits. If you are bringing your dog to the vet for problems related to the eyes, skin, ears and gastrointestinal issues, ask if the dog's BP (blood pressure) should be taken.

Diagnosis and management of hypertension is based on the measurement of the patient's blood pressure using devices such as a compression cuff. Note that a dog's blood pressure could be elevated due to anxiety or stress associated with being in a veterinary office.(3)  Signs of high blood pressure in dogs are often incorrectly attributed to aging and not high blood pressure. These include inactivity, light sensitivity with frequent blinking, lethargy, increase in appetite or a decrease in appetite. If blood pressure is too high it can trigger problems such as organ damage (called target-organ or end-organ damage), blindness, and stroke. Signs of kidney problems include high levels of protein, glucose, bacteria, blood or white blood cells in the urine.(5) Hypertension can be a silent, slowly progressive condition. A decision to start a dog on lifelong treatment depends on blood pressure readings and blood pressure readings. A normal dog BP is 120, but ranges up to 160 often are not treated and are interpreted based on the circumstance such as if your dog is under stress during the examination and the size of the measurement cuff. Treatment involves medications to lower blood pressure, identification and treatment of the underlying cause, and possible changes in the diet."

Dog Blood Pressure Overview
Discover what high blood pressure medications can be used to lower a dog's blood pressure.

Overview

High blood pressure in dogs is caused by the narrowing of veins that in turn cause the blood to not flow as easily as it should. Since the narrow parts of the veins keep blood from getting through, yet the amount of blood doesn't change, pressure builds against the narrow points. This is what causes the high blood pressure.

Areas of the body where the smallest blood vessels exist are the most vulnerable. These spots include the vessels in the eye or retina and the kidney, which is why both are susceptible to canine blood pressure problems. High blood pressure can cause damage to multiple organs such as the blood vessels, heart and brain, not to mention the eyes and kidneys referenced earlier. Problems in the kidneys manifest as decreased renal function, renal death or proteinuria (high levels of proteins in the urine).

Diseases in these areas such as kidney failure can cause the high blood pressure for the same reason. The disease itself is restricting the flow of blood.

In dogs almost all cases are caused by some other disease where high blood pressure is a symptom of that disease.

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What Causes of High Blood Pressure In Dogs?

There are many causes of high blood pressure in dogs such as:

  • Diseases of the endocrine system, such as Cushing's disease, hyperthyroidism, and diabetes mellitus
  • Chronic kidney disease
  • Central nervous system disorders
  • Certain medications
  • Red Blood Cell Over Production (Polycythemia)
  • Administration of therapeutic agents such as glucocorticoids, mineralocorticoids, erythropoietin, sodium chloride, phenylpropanolamine, and nonsteroidal anti-inflammatory drugs
  • Some cases of high blood pressure have no known cause and are referred to as Idiopathic Hypertension

Measurement of Canine Blood Pressure

When you measure blood pressure, you measure two numbers - the systolic pressure and the diastolic pressure. The systolic pressure is the highest number. That is the pressure when the heart contracts and pumps blood. The diastolic pressure is the lower number. It's the pressure when the heart relaxes and fills with blood. For dogs only the systolic pressure (top umber) is measured.

There are two types of devices used to measure BP. The first is similar to devices used on humans and the second uses a Doppler. The Doppler has a transducer on the end that is placed over the artery. A sound is heard as the heart beats. The Doppler is placed under the rear or front paw. A cuff is also placed above the transducer on the leg or arm.

It is recommended that blood pressure be checked regularly in dogs over nine years of age. When you take your dog to the vet for his yearly check-up, ask your vet to check his blood pressure. Pressure is measured using a cuff that is at the level of the right atrium. To avoid a false reading due to anxiety, it should be done in a quiet room about 5 to 10 minutes after the dog is able to acclimate to the environment. Guidelines suggest that the first measurement be discarded, and the average of 3 to 7 consecutive additional readings be used.(3)

Standard Blood Pressure Readings and Implications (1)

Blood pressure values vary to reflect the differences between dogs, techniques and the way dogs are handled when measured. More research is needed on dogs to understand the impact of age and sex. In general known effects of breed, sex and age are small with the exception of higher blood pressure seen in sighthounds. Research does show higher blood pressure in males and lower levels in intact females.(3)

There are also differences between breeds and based on obesity.(4)

Blood Pressure Reading

150/95

Indication

Minimal risk, no treatment is indicated

150/99 to 159/95

No treatment indicated, mild risk of organ damage.

160/119 to 179/100

Treatment needed to reduce risk to the dog and to protect the organs. Considered a moderate risk.

180/120

Treatment required to limit complications. Severe risk to organ damage.

Symptoms of High Blood Pressure in Dogs

Signs of high blood pressure in dogs include:

  • Depression
  • Sudden blindness
  • Behavioral changes
  • Seizures
  • Disorientation
  • Dilated pupils
  • Heart murmurs
  • Blood in urine
  • eye hemorrhage
  • Nose bleed
  • Shrunken or swollen kidneys
  • Detached retina
  • Weakness
  • Rolling of the eyeballs

There may also be symptoms of some of the aforementioned causes such as kidney disease or Cushings Disease.

Diagnosis

In a healthy dog, the systolic pressure should be no higher than 170 - 180. The diastolic pressure should be no higher than 100 - 110. Anything higher than that is considered high.

Canine high blood pressure is diagnosed by measuring the blood pressure with a cuff similar to that used to measure blood pressure on a child. However, a stethoscope cannot be used on dogs the way it is on humans. Instead, a Doppler device is used to determine the pressure. Dogs may have an "artificially" elevated pressure due to the stress and excitement of being at the vet called "white coat syndrome", so the vet may need to do several readings over a period of time.

The vet will also examine the dog to check the "target" organs listed above for signs of damage.

Organ Damage

A veterinarian will look for signs of organ damage in dog's with high blood pressure. 

Tissue/Organ

Clinical Findings

Kidneys

Increases in SCr readings or a decrease in GFR levels. Diagnosed with a urine test.

Eyes

Blindness (sudden), Detached retina, papiledema (blood in the optic disk), Glaucoma, Retinal degeneration. Diagnosed with an opthalmic examination.

Brain

Heart

Stroke. Diagnosed with a neurological examination.

Heart failure. Diagnosis with tests such as ultrasound or electrocardiogram.

Canine High Blood Pressure Treatment

Treatment for canine high blood pressure involves treating the underlying cause of the condition, if a cause can be identified. The goal is to provide a 1x a day therapy designed to reduce the blood pressure while avoiding sudden increases in pressure. Many dogs require more than one medication to control hypertension.

In addition, dog high blood pressure medications such as amlodipine, benazepril, enalapril, or a beta-blocker may be prescribed.

If eye disease is present, special medicated drops are prescribed.

If a dog is overweight, weight reduction will help to lower the blood pressure. There is some debate as to whether a low sodium diet will help or hurt the patient. Evidence suggests that substantial salt restriction alone does not reduce blood pressure in dogs. Talk to your vet about the best diet for your pet.

List of Dog High Blood Pressure Medications (D:=Dog, C:=Cat)
table of dog high blood pressure medications

Source: American College of Veterinary Internal Medicine Consensus Statements, Louisville, KY - 2006, Guidelines for the Identification, Evaluation, and Management of Systemic Hypertension  in Dogs and Cats 

Canine High Blood Pressure Natural Remedies

Natural medicine also offers several remedies for canine high blood pressure that are known for their ability to support the heart, circulatory system and blood pressure. When researching this approach a good option to explore and review with your veterinarian is offered by PetAlive. Their product contains a blend of multiple homeopathic ingredients believed to support canine heart health:

  • Arnica 3X: pulse feeble and irregular, strained heart in sportsman, consequence of hard physical labor.
  • Calc fluor 6C: enlarged veins, weakening of supporting tissue.
  • Kali phos 6C: one of the greatest nerve remedies; prostration, weakness, marked disturbance of the sympathetic nervous system.
  • Lachesis 30C: palpitations, irregular beats, hot flushes, congestive headaches.

Note that these approaches often do not have the clinical research associated with prescription medicines. Claims listed above are based on the Homeopathic Materia Medica, a system of medicine practiced around the world for over 20 years. There are no federally recognized scientific or clinical studies regarding the efficacy of these products and is not accepted by all medical experts. We do not discourage these types of conversations with a Veterinarian. If your Veterinarian believes it will do no harm, it might be worth trying, 

Brochure For Additional Reading

Sources

(1) PetMd

(2) Marvistavet.com

(3) Guidelines for the Identification, Evaluation and Management of Systemic Hypertension in Dogs and Cats, S. Brown, C. Atkins et al; Vet Intern Med 2007; 21:542-558

(4) Joes JA. Obesity in dogs: Effects on renal function, blood pressure, and renal disease. Vet Q 1998:20:117-120.

(5) Do cats and dogs need blood pressure medicine? by George Cuellar, DVM, ABVP C/F.