We hate measuring it, but we must: A review of feline hypertension
At IndeVets, we have more than 50 employee veterinarians who work in over 200 client hospitals. Because we don’t work in the same hospital each day, we like to stay connected in different ways. One way is by having quarterly web meetings so our doctors from Virginia to NYC can see and talk to each other. Not only do we discuss company news at these meetings, but we also discuss industry news and review common clinical conditions, focusing on new advancements in veterinary medicine.
At our September meeting, we had a brief review of feline hypertension, inspired by a great lecture I heard at the AVMA Convention in Washington, DC this past August.
Feline hypertension is a disease we all know about, but its difficult diagnosis makes it challenging.
There are three types of feline hypertension – the kind caused by our white coats, primary (less common) and secondary. Secondary hypertension is what we are most familiar with because it occurs because of common feline diseases – hyperthyroidism, renal disease and cardiac disease. We worry about hypertension in cats for the same reasons we worry about it in humans – it causes target organ damage, most commonly in the eyes, kidneys, brain and heart.
The American College of Veterinary Internal Medicine (ACVIM) classifies hypertension based on the risk of target organ damage: prehypertensive (low risk or 140-159 mmHg), hypertensive (moderate risk or 160-179) and severely hypertensive (high risk or >180 mmHg). Although it can be difficult to obtain an accurate blood pressure from a cat, certain feline patients should be screened for hypertension, ideally using a Doppler device. Cats presenting with target organ damage, diseases known to be associated with hypertension and older cats should be routinely screened for hypertension using a consistent technique. Cats between 7 and 11 years of age should be screened every 12 months and cats greater than 11 years of age should be screened every 6 months. It is recommended to take 5-7 blood pressure measurements after throwing out the first and to look at trends rather than isolated values.
There are three main oral medications used to treat hypertension in cats. Amlodipine, a calcium-channel blocker, remains the first line of therapy, as it decreases blood pressure most drastically and is given once daily. A new antihypertensive labeled specifically for cats, Telmisartin (Semintra), decreases blood pressure less drastically than Amlodipine but can be used in conjunction with it if needed. Lastly, ACE-inhibitors like Benazepril are less commonly used as sole therapy for severely hypertensive cats because they decrease blood pressure the least.
After diagnosing and starting treatment, we aim for a target blood pressure of less than 140 mmHg, but less than 160 mmHg is acceptable. Blood pressure should be measured 7-10 days after starting anti-hypertensives or after a dose change. Once the target blood pressure is reached, cats should be monitored every 4-6 months. Hopefully we can keep our feline patients from target organ damage by educating our clients and screening our appropriate feline patients!