"Perhaps the answer is obvious but when they state 31% risk reduction is that absolute risk reduction or relative risk reduction? I would assume it is RRR."

It is RRR. 

"The other observation is that there trial had 10,000 patients over 6 years in their full population compared to about 2500 for BETonMACE for it's targetted population. I'm assuming the BoM trial design was powered statistically to yield statistically significant results if they are evident. (at least I hope that is the case)."

If I recall correctly, the ~2400 patients in BETonMACE gives 80% power to detect a statistically significant 30% relative risk reduction. So well powered for a 30% RRR, but not so well powered if the RRR is more modest. I also recall that there is a sample size estimate analysis along the way, which gives them the option of adding more patients/target MACE events if needed.

"Looks like it has the potential to be a major breakthrough?"

Yes, and very encouraging for Resverlogix since apabetalone has a dramatic anti-inflammatory effect as one of its many cardioprotective actions.