I'm doing some research on DHA & EPA right now for Dr. James Wilson (the Adrenal Fatigue book author, I work for his company and they are about to bring to market a new high DHA fish oil).
It appears that EPA has some immune-suppressing qualities.
EPA may be the main coagulation-impairing partner of the two.
When supplementing DHA, both DHA and EPA levels rise in the body.
I'm considering switching to high-DHA supplementation for myself and my family (later I'll consider the patients, but I'm the guinea pig first).