I assume you are being treated for high blood pressure, and patients with CAD and very low BP can increase the risk for a stroke and heart attack. There is a study that 110 or lower for systolic pressure and 60 or lower for diastolic pressure may increase the risk. There are other doctors who want the blood pressure as low as possible without side effects such as fainting, dizziness, etc.
If you don't have any side effects with your low HP and your doctor approves your low reading may not be a problem...your high reading shouldn't be a problem. I don't believe one can sustain a static low level as there will be fluctuations...at least that has been my experience.
Thanks for your question and if you have any further questions or comments you are welcome to respond. Take care,
Ken