Bruniaux J, Touchot A, Planche C. Surgery for tetralogy of Fallot at less than six months of age. Is palliation “old-fashioned”? Eur J Cardiothorac Surg 1995;9: 453– 460. 10. Chiu IS, Chu SH, Wang JK, Wu MH, Chen MR, Cheng CF, Hung CR. Evolution of coronary artery pattern according to short-axis aortopulmonary rotation: a new categorization for complete transposition of the great arteries. J Am Coll Cardiol 1995;26:250 –258. 11. Chiu IS, Wang JK, Wu MH, Chen MR, Cheng CF, Lue HC, Chu SH. Angiographic evidence of long-axis rotation in addition to short-axis aortopul- monary rotation: its implication in transposition of the great arteries. Cathet Cardiovasc Diagn 1996;39:21–30. 12. Gittenberger-de Groot AC, Sauer U, Oppenheimer-Dekker A, Quaegebeur J. Coronary arterial anatomy in transposition of the great arteries: a morphologic study. Pediatr Cardiol 1983;4(suppl I):15–24. 13. Shaher RM, Puddu GC. Coronary arterial anatomy in complete transposition of the great vessels. Am J Cardiol 1966;17:355–361. 14. Neufeld HN, Schneeweiss A. Coronary arterial patterns in congenital heart diseases. Tetralogy of Fallot. In: Neufeld HN, Schneeweiss A, eds. Coronary Artery Disease in Infants and Children. Philadelphia: Lea & Febiger, 1983:79 – 84. 15. White RI Jr, Frech RS, Castaneda A, Amplatz K. The nature and significance of anomalous coronary arteries in tetralogy of Fallot. Am J Roentgenol 1972; 114:350 –354. 16. Sharma S, Sundaram U, Loya Y, Desai D. Selective coronary angiography in tetralogy of Fallot. Cardiol Young 1993;3:39 – 42. 17. Norusis MJ. SPSS/PC (Statistical Package for the Social Science). Chicago: SPSS Inc., 1984:C35–C38. 18. Landolt CC, Anderson JE, Zorn-Chelton S, Guyton RA, Hatcher CR Jr, Williams WH. Importance of coronary artery anomalies in operations for con- genital heart disease. Ann Thorac Surg. 1986;41:351–355. 19. Fellows KE, Freed MD, Keane JF, Van Praagh R, Bernhard WF, Castaneda AC. Results of routine preoperative coronary angiography in tetralogy of Fallot. Circulation 1975;51:561–566. 20. Ishikawa T, Brandt PWT. Anomalous origin of the left main coronary artery from the right anterior aortic sinus: angiographic definition of anomalous course. Am J Cardiol 1985;55:770 –776. 21. Bogers AJ, Gittenberger-de Groot AC, Poelmann RE, Peault BM, Huysmans HA. Development of the origin of the coronary arteries, a matter of ingrowth or outgrowth? Anat Embryol 1989;180:437– 441. Plasminogen Activator Inhibitor Type 1 in Adults With Down Syndrome and Protection Against Macrovascular Disease William E. Hopkins, MD, Naomi K. Fukagawa, MD, PhD, Burton E. Sobel, MD, and David J. Schneider, MD A lthough most subjects with Down syndrome now live well into adulthood, the incidence of sys- temic hypertension and atherosclerotic vascular dis- ease appears to be low. 1–5 In fact, in 1977 Murdoch et al 3 suggested that Down syndrome may represent “an atheroma-free model.” The reason for the apparent lack of macroangiopathy is unknown. Obesity is com- mon, premature aging is evident in other organ sys- tems, and lipid levels are unfavorable compared with those in unaffected siblings. 6–8 Conversely, mentally retarded subjects without Down syndrome are not spared from either systemic hypertension or athero- sclerosis. 3–5 Some have suggested that a genetic “tri- ple-dose effect” is responsible for the apparent pro- tection because the genes for cystathionine beta syn- thase and superoxide dismutase are located on chromosome 21. 4,9 Plasminogen activator inhibitor type-1 (PAI-1), the primary physiologic inhibitor of plasminogen activa- tion, has been associated with myocardial infarction in epidemiologic studies and appears to be a marker or determinant for recurrent myocardial infarction. 10,11 We have recently implicated increased PAI-1 in vessel walls as a potential determinant of accelerated athero- sclerosis and particularly the development of lipid- laden plaques vulnerable to rupture. 12 The relative protection against atherosclerosis in Down syndrome may imply that the expression of 1 determinant, in- cluding PAI-1, is less prominent than in age, gender, and body habit-matched unaffected subjects. If such a poten- tial determinant were to be identified, the likelihood that the factor would indeed be a causally connected contrib- utor to atherogenesis would be increased. ••• The study groups consisted of 24 adults with Down syndrome and 26 control subjects. Body mass index was measured in each subject and expressed as kg/m 2 . No subject with Down syndrome and no control sub- ject was known to have diabetes mellitus, systemic hypertension, overt atherosclerotic vascular disease, or a history of smoking. Venous blood was sampled from the antecubital vein with as brief a period of tourniquet time as possible. The times of day at which samples were drawn in controls and in subjects with Down syn- drome were comparable; an important consideration in view of the well known diurnal variation of con- centrations of PAI-1 in blood. All blood samples were random rather than fasting samples. Samples were placed immediately on ice, and plasma was separated by centrifugation at 2,000 g for 10 minutes and stored at -70°C until assayed for PAI-1, PAI-1 activity, tissue plasminogen activator (tPA), and homocysteine. Total PAI-1 and tPA were assayed by enzyme- linked immunosorbent assay (Tint Elise, Biopool, Umea, Sweden, and American Diagnostica, Green- wich, Connecticut, respectively) with results ex- pressed as pM. Functional activity of PAI-1 was de- termined with a kinetic, chromogenic substrate assay that quantifies inhibition of activation of plasminogen by exogenous tPA with results expressed as AU/ml. 13 Total homocysteine in plasma (M) was measured by high-perfromance liquid chromatography with the use of a method described by Araki and Sako. 14 From the Department of Medicine, University of Vermont College of Medicine, Burlington, Vermont. Dr. Hopkins’ address is: University of Vermont College of Medicine, McClure 1, MCHV Campus, 111 Colchester Avenue, Burlington, Vermont 05401. E-mail: william. hopkins@vtmednet.org. Manuscript received August 23, 1999; re- vised manuscript received and accepted October 28, 1999. 784 ©2000 by Excerpta Medica, Inc. All rights reserved. 0002-9149/00/$–see front matter The American Journal of Cardiology Vol. 85 March 15, 2000 PII S0002-9149(99)00864-4