,Mark recently underwent surgery at Children's Hospital and had on 10/15/2007, replacement of pulmonary homograft valve, resection of a pulmonary artery pseudoaneurysm, and insertion of Gore-Tex membrane pericardial substitute. 
,Mark recently underwent surgery at Children 's Hospital and had on 10/15/2007 , replacement of pulmonary homograft valve , resection of a pulmonary artery pseudoaneurysm , and insertion of Gore - Tex membrane pericardial substitute .