Mary Allen
Hypertension is common in humans and can also occur in cats. In both cases, it is no joke. Damage to the heart, kidneys, eyes and central nervous system can result.
The inflating cuff at the doctors is a basic medical experience for most people, which they often have in their youth. Blood pressure is measured in cats in a very similar way: The blood flow is temporarily stopped with an inflatable pressure cuff on the front leg or on the tail. When the cuff pressure is released, the resumption of the arterial blood flow is made perceptible or measurable in various ways.
Unlike in humans, hypertension, as the increase in pressure is called in medicine, is rather rare in cats – contrary to what some reports circulating on the Internet suggest. Veterinarian Tony Glaus says: “At most one in 1000 cats suffers from high blood pressure.” It is also not necessary to measure blood pressure at every routine check-up. “That would be too much of a good thing,” says Glaus. The head of the cardiology department at the Clinic for Small Animal Medicine at the University of Zurich also points out that high blood pressure can also be caused by the stress caused by the examination. In the case of hormone and kidney diseases, heart patients, or diabetes, however, measurements would be carried out regularly.
Once the veterinarian has been consulted, treatment of the underlying cause should be the priority. Because unlike in humans, hypertension in animals is usually a symptom of a causative disease. In cats, for example, high blood pressure occurs as a result of renal insufficiency. But by no means every cat that suffers from kidney failure also has high blood pressure. Adrenal tumors can also be the cause. “For some, it is idiopathic, which means that there is no reason for hypertension,” says Glaus.
If High Blood Pressure is Not Detected, the Cat Can Go Blind
High blood pressure is not entirely harmless, even in cats. It can have a significant impact on quality of life and life expectancy and can lead to acute retinal hemorrhage, retinal detachment, and even blindness. If an animal goes blind from one day to the next, it is often preceded by a long phase of high blood pressure. However, it would be a mistake to draw the conclusion that every cat has chronic high blood pressure before going blind. The blood values of cats are basically comparable to those of humans: the upper blood pressure should be 110 to 140 millimeters of mercury (mmHg), the lower blood pressure by 80 to 100 mmHg. Sustained blood pressure above 160 mmHg is considered elevated. Tony Glaus advises always checking the animal’s eyes first during treatment. The ACE inhibitor is an approved drug for high blood pressure in cats. Glaus also uses the human preparation “Amlodipin” for treatment. However, the dosage must be adapted to the cat.
High blood pressure cannot be specifically prevented in cats, since other underlying diseases are usually the cause. It has just as little to do with obesity – as is often the case with humans – as with food. Likewise, no vasoconstriction due to deposits (arteriosclerosis) is observed in cats, as is known in bipeds. Veterinarian Glaus only recommends measuring the blood pressure of cats from the age of eight during a medical check-up.
This is How Blood Pressure Develops
The heart pumps blood into the circulatory system in bursts. Each heartbeat triggers a pressure wave that always fluctuates between two values: When contracting, the heart pumps blood into the arteries and blood pressure rises. When the heart has contracted to its maximum, the highest value has been reached (systolic blood pressure). Then the relaxation phase begins, in which the ventricles fill up and no blood is pumped into the arteries. Therefore, the blood pressure falls back to the lowest value (diastolic blood pressure). Although the heart does not pump blood during the relaxation phase (diastole), the lower pressure does not drop to zero: because the aorta is elastic, it dilates during systole. In the subsequent diastole, as soon as no more blood flows from the heart, it contracts again and thus also causes blood to flow during diastole (the so-called Windkessel effect).