As you have rightly asked, you can use either of the approaches for your study. To narrow down the approach, you need to understand the actual objective of your simulation. If you are looking to study both the deformation as well as its effect on the fluid, then you will need a 2-way FSI. Otherwise, you could perhaps get away with either 1-way FSI. But, you will need to know the exact deformed geometry of the artery.