1. From the Departments of Surgery (A.S.B., J.A., R.C.G., J.H.G., M.A.A.) and Radiology (J.J.P.), University of Pennsylvania Medical Center, Philadelphia; Division of Cardiothoracic Surgery (R.M., A.S.L., W.M.Y., J.T.M., J.W.H., R.E.S., J.E.M., F.G.S.), Medical University of South Carolina, Charleston; and Ralph H. Johnson Department of Veterans Affairs (F.G.S.), Charleston, SC.