What is the systolic pressure that should be used for the management of an aortic aneurysm?

Less than 120. I usually recommend beta blockers and aim for systolic less than 120. I also get echocardiogram to rule out bicuspid aortic valve and aortic regurgitation.
Heart rate. I think that as important as blood pressure control is the control of heart rate. I try to keep the heart rate around 60 beats per minute with a beta blocker. Every time your heart beats it's a jolt to the artery. If you slow the heart rate from 80 to 60 bpm, then that is 28, 000 beats a day - 200, 000 beats a week and more than 6 million in a month!