RFJ - I think the importance of the AA/EPA ratio is not so much that it's a surrogate marker but the possibility that it could be THE marker that triages patients to a risk category that determines treatment.
For example, a patient may have CVD on a statin but has a great ratio - it may be that they do not benefit from Vascepa. Or vice versa they are lower risk primary prevention with a terrible ratio and they have a great RRR with V use.