My 87 Yr Old Father Fell And Broke His Hip

My 87 yr old father fell and broke his hip a week ago. The surgery has been delayed till tomorrow because of a problem valve in his heart. Cardiologist wanted to do an angioplast before he had his hip operated on. The angioplast was performed last Thursday. They have been giving him a low dose of blood pressure med. to keep his blood pressure low. Today it has been under 90 isn't this a little too low, before he goes for hip surgery tomorrow? Cardiologist does not seem to be concerned