When the kidney shrinks due to the accumulated scar tissue, it is harder for the blood to filter through. There is a backup of blood into the arteries and an increase in blood pressure. Elderly cats not in actual kidney failure may also have hypertension by the same mechanism. Not all forms of heart failure cause hypertension. However, there are at least two forms that have been shown to cause hypertension in cats.
Hypertrophic cardiomyopathy is a disease of the heart muscle with an unknown, cause.
It makes the heart muscle thicken, resulting in blood being pumped more forcefully. This increase in cardiac output of blood results in hypertension. Hyperthyroidism is another cause of heart disease that may cause hypertension. The thyroid is a gland located in the neck. It plays a very important role in regulating the body's rate of metabolism.