[1] Concord Hosp, CV Serv, Concord, NH 03301 USA
[2] Catholic Med Ctr, Manchester, NH USA
[3] Concord Hosp, Concord, NH 03301 USA
[4] Fletcher Allen Hlth Care, Cardiothorac Surg, Burlington, VT USA
[5] Dartmouth Coll, Geisel Sch Med, Northern New England Cardiovasc Dis Study Grp, Hanover, NH 03755 USA
[6] Maine Med Ctr, Div Cardiothorac Surg, Portland, ME USA
[7] Eastern Maine Med Ctr, Bangor, ME USA
[8] Portsmouth Reg Hosp, Portsmouth, NH USA
[9] Dartmouth Coll, Geisel Sch Med, Lebanon, NH 03756 USA
[10] Dartmouth Hitchcock Med Ctr, Lebanon, NH 03766 USA
[11] Northern New England Cardiovasc Dis Study Grp, Ann Arbor, MI USA
[12] Univ Michigan, Sch Med, Ann Arbor, MI USA
[13] Cent Maine Med Ctr, Cent Maine Heart & Vasc Inst, Lewiston, ME USA
[14] Geisel Sch Med Dartmouth, Northern New England Cardiovasc Dis Study Grp, Dartmouth, NS, Canada