Systems and methods for screening a subject for a therapy are described. A mechanical stimulation device positioned near at target location of a blood vessel to provide a mechanical stimulus to the blood vessel. The mechanical stimulus increases strain in one or more regions of the blood vessel, such as by modifying the cross-sectional geometry and/or area of the blood vessel to have different regions of different curvature A baroreflex or related physiological response in response to the mechanical stimulation is detected. In response to the detected response, it is determined whether the subject is appropriate for the therapy and/or which of a plurality of implants with different geometries and/or cross-sectional areas is most optimally suited for deployment in the subject.