Removable vena cava filter for reduced trauma in collapsed configuration

A method of capturing thrombi in a blood vessel, the method comprising:

• delivering a removable filter in a collapsed state within the blood vessel;
• deploying the filter to an expanded state within the blood vessel to capture thrombi;
• and
• retrieving the filter in the collapsed state from the blood vessel, wherein the filter includes:
• a plurality of primary struts each having a first length, the primary struts having first ends attached together along a longitudinal axis and housed within a hub, wherein the primary struts emanate from a first end of the hub, each primary strut having an arcuate segment including a first curved portion extending from the first end and a second curved portion extending from the first curved portion and terminating at an anchoring hook for engaging with the blood vessel in the expanded state, the first and second curved portions defining a soft-S shape, each primary strut extending arcuately along the longitudinal axis and linearly radially, wherein each primary strut crosses another primary strut along the longitudinal axis in the collapsed state such that the arcuate segments occupy a first diameter, the first diameter being the distance between opposite arcuate segments of the primary struts in the collapsed state, the first diameter being greater than a second diameter occupied by the anchoring hooks in the collapsed state for filter retrieval or delivery, the second diameter being the largest diameter occupied by the anchoring hooks in the collapsed state;
• a plurality of secondary struts each having a second length, the secondary struts having connected ends attached together along the longitudinal axis and housed within the hub, wherein the secondary struts emanate from the first end of the hub and extend arcuately therefrom to free ends to centralize the filter in the expanded state in the blood vessel, each secondary strut extending arcuately along the longitudinal axis and linearly radially, each secondary strut having a first arc extending from the connected end away from the longitudinal axis and a second arc extending from the first arc towards the longitudinal axis, the second arc extending to the free end without a hook, the secondary struts having a smaller diameter than the primary struts, each primary strut having two secondary struts in side-by-side relationship with the primary strut, wherein the length of the filter is defined by the first length of the primary struts;
• and
• a retrieval hook extending from the hub opposite the plurality of primary and secondary struts for removal of the filter from the blood vessel.