Diagnosing Feline Hypertension
"Half of what you have learned will be obsolete in the next five years."
I remember one of my professors uttering this terrifying statement when I was in veterinary school.
I knew when I entered the profession that it would require life-long continuing education if I wanted to stay up on the latest advances. But "half" in "five years"? That made me reconsider the wisdom of all the late nights that I was spending with my nose in a textbook.
Well, I kept studying anyway, graduated, went into practice, and 12 years later can report that I think his numbers may have been a bit high (or am I already a dinosaur?). But the overall sentiment was correct — change is inevitable.
One aspect of feline medicine that has really changed in the last ten-ish years is blood pressure monitoring. Even when I breathed the rarified air of the referral hospital associated with my veterinary school in the late 1990s, we didn’t routinely pull out the blood pressure monitor. Sure, we used it during surgery to stay on top of potential complications, or if a cat had a primary disease (e.g., kidney failure, diabetes, or hyperthyroidism) that put them at risk for hypertension, but as a routine screening tool … no way.
Well, times have changed. Blood pressure monitoring is now widely recognized as being an important part of the wellness care of middle-aged to older cats. In part, this is because of the high percentage of cats in this age range who do suffer from the diseases that make high blood pressure likely, but also because veterinarians have finally recognized that primary hypertension, meaning high blood pressure with no identifiable underlying cause, is a real problem for cats. Primary hypertension is fairly rare in dogs, which may explain why blood pressure monitoring has not received the attention it deserved in the past.
High blood pressure is dangerous for cats. It can lead to diseases of the heart, brain, kidneys, eyes, and other organs. Thankfully, medications are available (e.g., amlodipine) that typically do a very good job of keeping a cat’s blood pressure out of the danger zone.
Hypertension will be diagnostic when a cat’s systolic blood pressure (the higher of the two numbers reported when measuring human blood pressures) is above 160 to 180. These numbers have to be interpreted in light of a cat’s physical examination and stress levels, however. I’ve sent the blood pressure monitor home with owners so they could get several reading themselves when I’ve suspected that a cat’s abnormal readings were due primarily to the stress of being in the clinic.
Checking blood pressures is not quite as easy in cats as it is in people. The fur tends to get in the way, and a cat’s small size can present challenges as well. Different types of blood pressure monitors work in different ways, but no matter which I am using, I always get at least three of what appear to be reliable readings, averaging them to arrive at a final number.
If you’ve been to the doctor for a check-up yourself lately, the nurse or assistant probably got your weight and temperature, checked your pulse rate, and took your blood pressure before the doctor ever stepped into the room. My guess is that in the not too distant future, this is what a feline veterinary visit will look like too.
Dr. Jennifer Coates