1. From the BHF Glasgow Cardiovascular Research Centre, Division of Cardiovascular and Medical Sciences (S.A.-B., C.A.H., J.D.M., C.D., A.F.D.), and Robertson Centre for Biostatistics (I.F.), University of Glasgow; the Department of Vascular Surgery (P.N.R.), Gartnavel General Hospital; and Department of Cardiothoracic Surgery (G.A.B.), Western Infirmary, Glasgow, United Kingdom.