When you get pinned down by a subspace anchor thingy, shoot it and kill it ASAP, not sure if Polarize Hull and Attack Pattern Omega provide immunity against those as effectively as they do against tractor beams.
I don't believe there is any boff skill to combat the constriction anchors effects other than destroying them.
I know one of the pilot skills does, that gives Evasive Maneuvers an immunity buff against holds.