At what diastolic pressure is the blood flow?

Diastolic pressure: The ormal diastolic pressure in an adult is 80mmhg. The blood flows at that pressure, however could be higher and/or lower and still flows.

Unclear: Some people have diastolic blood pressures of zero (as measured by an arm cuff) and live to talk about it. (in fact, don't even know they have it). You're right though, if diastolic pressure in the aortic falls below about 30, there's poor perfusion pressure to fill the coronaries and ischemia results - since the coronaries so, indeed, fill during diastole.