Clot engagement element comprising bundle of unwoven fibers can be assembled to form an acute stroke treatment device. The device has the capability of forming a three dimensional filtration matrix comprising effective pores with a distribution of sizes. The bundle of fiber design allows the device to be effectively delivered into circuitous cerebral arteries to remove clot that causes stroke. The fiber bundle based filtration matrix offers the advantages of conforming to the changing inner perimeter of a blood vessel during a clot removal process and thus the capability to effectively retain and remove a clot in the vessel. The filtration matrix offers the additional advantage to trap any break-off of the clot during the removal process. A plurality of fiber bundles can be combined to form an effective clot engagement element. Supplemental engagement structure as well as mechanical treatment structure can be integrated into the stroke treatment device. The deployment of the fiber based elements can be facilitated by actuation tool. Aspiration can be employed during the clot removal process.