Methods and apparatus for treating embolism

A clot treatment device for treating an embolism within a blood vessel, the clot treatment device comprising:

• a support member configured to extend through a delivery catheter, wherein the support member has a proximal portion and a distal portion;
• a plurality of first clot engagement members positioned about the circumference of the distal portion of the support member, wherein, in deployed state, individual first clot engagement members extend radially outwardly with respect to the support member and have a curved portion that includes a first radially furthest apex that extends a first radial distance from the support member;
• a plurality of second clot engagement members positioned about the circumference of the distal portion of the support member, wherein, in the deployed state, individual second clot engagement members have a curved portion that includes a second radially furthest apex that extends a second radial distance from the support member, and wherein the first radial distance is greater than the second radial distance;
• wherein, in the deployed state, individual curved portions of the first and second clot engagement members project radially outwardly relative to the support member in a curve that has a proximally extending section which defines a proximally facing concave portion, and wherein the curved portion of the first and second clot engagement members further includes an end section that curves radially inwardly from the proximally extending section;
• wherein the first clot engagement members have a first stiffness and the second clot engagement members have a second stiffness greater than the first stiffness, and
• wherein the clot engagement members are configured to penetrate clot material along an arcuate path and hold clot material to the clot treatment device.