An apparatus for defining an aperture in a tissue wall, comprising: a dilator (20, 22, 30) having a tapered distal end for piercing tissue in said tissue wall, and wherein said distal end of the dilator (20, 22, 30) has one or more threads which are configured for engaging the tissue and advancing the dilator (20, 22, 30) into the tissue upon rotation of the dilator (20, 22, 30); a cuff having a central aperture for receiving the cuff over the dilator, and wherein the cuff comprises one or more threads matching the one or more threads of the dilator (20, 22, 30), and wherein the one of more cuff threads are configured to further advance the cuff into the tissue upon rotation of the dilator (20, 22, 30); and a coring handle releasably coupled proximal to the cuff to form a coring assembly; wherein the coring assembly is configured to engage the dilator such that the dilator and coring assembly rotate as a single unit upon manual rotation of the dilator; wherein in an assembled configuration, the coring assembly is configured to seat on the dilator (20, 22, 30) at a location proximal to the distal end; wherein the cuff and dilator (20, 22, 30) in the assembled configuration are configured to be inserted into the tissue by introducing the distal end of the dilator (20, 22, 30) into the tissue and advancing the distal end of the dilator (20, 22, 30) to dilate the tissue until the cuff is seated within the tissue wall; wherein the dilator (20, 22, 30) is configured to be retracted from the coring assembly such that the cuff remains in the tissue wall to form a port via the central aperture of the cuff; and wherein the coring handle is configured to be detached from the cuff upon removal of the dilator (20, 22, 30). a dilator (20, 22, 30) having a tapered distal end for piercing tissue in said tissue wall, and wherein said distal end of the dilator (20, 22, 30) has one or more threads which are configured for engaging the tissue and advancing the dilator (20, 22, 30) into the tissue upon rotation of the dilator (20, 22, 30); a cuff having a central aperture for receiving the cuff over the dilator, and wherein the cuff comprises one or more threads matching the one or more threads of the dilator (20, 22, 30), and wherein the one of more cuff threads are configured to further advance the cuff into the tissue upon rotation of the dilator (20, 22, 30); and a coring handle releasably coupled proximal to the cuff to form a coring assembly; wherein the coring assembly is configured to engage the dilator such that the dilator and coring assembly rotate as a single unit upon manual rotation of the dilator; wherein in an assembled configuration, the coring assembly is configured to seat on the dilator (20, 22, 30) at a location proximal to the distal end; wherein the cuff and dilator (20, 22, 30) in the assembled configuration are configured to be inserted into the tissue by introducing the distal end of the dilator (20, 22, 30) into the tissue and advancing the distal end of the dilator (20, 22, 30) to dilate the tissue until the cuff is seated within the tissue wall; wherein the dilator (20, 22, 30) is configured to be retracted from the coring assembly such that the cuff remains in the tissue wall to form a port via the central aperture of the cuff; and wherein the coring handle is configured to be detached from the cuff upon removal of the dilator (20, 22, 30).