This episode's headline: Heart Stents; School Shooting; Court of Inquiry. GUESTS: PAUL PFINGST; MARC NORMAN; JOAN KINLAN; JAY FIDELL; CORRESPONDENTS: KWAME HOLMAN; RAY SUAREZ; SPENCER MICHELS; MARGARET WARNER; GWEN IFILL; TERENCE SMITH; KWAME HOLMAN ANCHOR: JIM LEHRER