Provided are the compound -4-carboxystyryl-4-chlorobenzyl sulfone, pharmaceutically acceptable salts thereof, and pharmaceutical compositions thereof. Hinged flaps are provided at each end of the catcher and operate to allow inflow but block outflow of debris from the catcher. 0 m as measured by a light scattering method using a Fraunhofer forward scattering in a proportion of approximately 45 vol.