A blood flow reducing assembly includes a catheter shaft and an expandable occlusion member assembled with the catheter shaft. The expandable occlusion member includes foldable protrusions. One or more manipulation members are connected to the foldable protrusions and operative to move the foldable protrusions closer to or further away from one other. Movement of the foldable protrusions modifies occlusion ability of the foldable protrusions.