An implantable blood pump includes an impeller rotatable about a rotational axis, having a body with a bottom surface at a downstream end and a central opening centered about the axis extending at least partially through the body from the bottom surface. A projecting element, e.g., a shaft, extends from below the bottom surface into or through the opening to support the impeller. The body can be configured to drive a primary downstream blood flow along an exterior of the body to beyond a peripheral edge of the bottom surface, and to provide a secondary downstream blood flow through the opening and along the bottom surface to beyond the peripheral edge, the secondary flow improving washing of a bearing surface.