High blood pressure affects a large number of cats and results in significant clinical disease.  In cats, hypertension is almost always secondary to another disease. The most common underlying diseases are kidney disease, thyroid disease, heart disease and diabetes.

Hypertension causes damage too many organs but the most severely affected are the eyes, heart, kidneys and brain. Before blood pressure was routinely measured, acute blindness was frequently the first sign of hypertension. When blood pressure rises, bleeding can occur within the eye and result in retinal detachment. When the heart is the target organ, it responds by increasing the thickness of its walls resulting in abnormal heart sounds and gallop rhythms that can be recognized clinically. When the kidney is the target organ hypertension can lead to rapid progression of kidney disease. Finally hypertension can cause hemorrhage within the brain producing clinical signs that can be extremely variable including behavior changes, dementia, depression and seizures.

Routine blood pressure evaluation in veterinary medicine is a recent advancement and allows us to recognize hypertension prior to clinical signs. One of the common methods to measure feline blood pressure is the use of a Doppler devise that provides an audible sound of blood flow over a small peripheral artery. It is able to provide a good measure of systolic pressure.

When the systolic pressure is between 160mmmHg and 180mmHg and there are no underlying diseases or clinical signs, the pressure should be monitored every 3 months. When the systolic blood pressure is greater than 180mmHg management is initiated and the underlying disease is identified, managed and the blood pressure is monitored weekly until pressures between 120mmHg and 170mmHg are maintained. Once pressure has been stabilized it is monitored every six to twelve months.

The following medications are most commonly used alone or in combination to control hypertension in cats. Treatment is based on the needs of each patient.

Amplodipine (Calcium Channel blocker) is a vasodilator that is safe and effective in cats. In most cats it can be given once daily and good control is obtained. It is the first choice for treating hypertension in cats.

Benazepril (ACE inhibitor) is also a vasodilator and will lower blood pressure but may not move those patients who are severely hypertensive into the normal range. It is frequently used when patients have kidney disease that is characterized by protein in the urine.

Atenolol (beta blocker) is useful when an increased heart rate and thickened heart muscles are present in hypertensive patients.

 High blood pressure is a dangerous but treatable condition. With careful management damage to the eyes, heart, brain and kidneys can be prevented.

 ~By Annette Cowell D.V.M.