A few things about this study...the people in the study were people that already had heart disease. Doesn't mean that any conclusions can be extended to people that do not have heart disease. Also there have been studies that have shown the exact opposite (replacing sat fats with 06's reduce risk of heart disease). By no means is this study conclusive.
Just look at this graph from the study:
16 people out of 221 died in the group they said to increase o6, 10 out of 237 died in the control. Not much of a difference TBH.
Add in the fact that these people were supposed to be eating 15% of their calories from 06's and actually SUPPLEMENTING with margarine to do so is pretty ridiculous. That is a HUGE amount of calories. Also, it said that their levels of other fats (monounsaturated for one) were lower.
But you have to remember this is all just done by food questionnaire, which are notoriously inaccurate.
Basically this study means absolutely nothing.