1. From the Division of Cardiac Surgery, Johns Hopkins School of Medicine, Baltimore (J.S.G.), and the Division of Cardiovascular Sciences (M.A.M., W.C.T.-P.), National Heart, Lung, and Blood Institute (N.O.J.), National Institutes of Health, Bethesda — both in Maryland; the Division of Cardiac Surgery, Western University, London Health Sciences Centre, London, ON (M.W.A.C.), and the Division of Cardiovascular Surgery, Toronto General Hospital and University of Toronto, Toronto (R.W.), Institut...