There is apparently no problems with the cat's kidney function or any other organs. The blood is flowing so turbulently through her heart that it has become enlarged and is putting stress on the major vessels going into the heart as well. Any other info. Mainly because we don't measure it very much. I am assuming you used a doppler ultrasound to measure pressure since this is the only reasonable reliable meathod known so far in veterinary medicine.
Oscillometric readings are pretty common in surgery situations.
In any case there is a lack of data as to normal ranges of BP in animals let alone abnormal ranges. Be that as it may, I can a couple of papers, which I have not read, regarding essential or idiopathic hypertension in cats. The abstract says they studied 24 cats with spontaneous hypertension, and tried various drug regimens to lower blood pressure. More recently at this year's American College of Veterinary Internal Medicine, a paper was presented by P.S.Snyder et al on Feline Systemic Hypertension. However I was not at the meeting and do not have the proceedings.