My logic is this. As coronaries get their blood in diastole, they always have lesser pressure on the wall compared to brain vessels

Thanks Martin, right, but in brain we do not have bleedings from large vessels but more terminal intracerebral branches (unless aneurysm), that may be comparable of that from intramural vessels rather than epicardiac

Thanks everybody for nice discussion. I think consistency of brain tissue and character of small vessels of brain is also important. Even if small bleed occurs in heart, squeeging effect because of cardiac contraction will probably restrict  it's expansion which is absent in brain.