HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Coles, J. G. Articles by Williams, W. G. Search for Related Content PubMed PubMed Citation Articles by Coles, J. G. Articles by Williams, W. G.

The Journal of Thoracic and Cardiovascular Surgery, Vol 94, 526-534, Copyright © 1987 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association

ARTICLES

Age-related differences in the response to myocardial ischemic stress

JG Coles, T Watanabe, GJ Wilson, LN Benson, GM Kent, DA Mickle, AD Romaschin, J Villamater, H Ujc and WG Williams
Department of Cardiovascular Surgery, Hospital for Sick Children, Toronto, Ontario, Canada.

Clinical experience indicates that the risk of reparative cardiac operations is increased in the neonatal period relative to that in older infants and children. Age-related differences in the susceptibility to myocardial ischemic dysfunction were evaluated by comparison of left ventricular function and metabolism in neonatal (mean age = 7 days) and weanling (mean age = 96 days) piglets. Six animals in each group supported on cardiopulmonary bypass were subjected to (1) 120 minutes of hypothermic crystalloid cardioplegic arrest (CP-120) and (2) 15 minutes of normothermic ischemic arrest (NA- 15) after a 60 minute interval of reperfusion. Left ventricular systolic and diastolic function was measured after each intervention via endocardially implanted ultrasonic dimension crystals in a septolateral minor-axis position. In both groups, systolic dysfunction was evidenced by an increase in the dimension-axis intercept (p = 0.001), but not the slope of the end-systolic pressure-dimension relation. Left ventricular end-diastolic stiffness, expressed as left ventricular end-diastolic pressure versus Lagrangian strain, increased to a similar degree in both groups (p = 0.001). Adenosine triphosphate levels declined significantly (p = 0.001) in both groups in response to the ischemic interventions with no evident intergroup differences. Lactate levels increased significantly during the course of the experiment (p = 0.04); however, the increases were greater (p = 0.009) at all intervals in the neonatal group. This study demonstrates age- related metabolic differences in response to ischemia consistent with a greater dependence on glycolysis in neonatal myocardia. However, the fact that discriminating age-related differences in left ventricular function were not evident suggests that factors other than young age per se account for the increased surgical mortality in the neonatal period.

This article has been cited by other articles:

				T. Murashita and K. Yasuda The role of Na+/H+ exchange in the efficacy of multidose hypothermic cardioplegia in immature rabbit hearts Eur. J. Cardiothorac. Surg., December 1, 2002; 22(6): 944 - 950. [Abstract] [Full Text] [PDF]

				I. M. Cheifetz, F. H. Kern, S. R. Schulman, W. J. Greeley, R. M. Ungerleider, and J. N. Meliones Serum Lactates Correlate With Mortality After Operations for Complex Congenital Heart Disease Ann. Thorac. Surg., September 1, 1997; 64(3): 735 - 738. [Abstract] [Full Text]

				W. S. McMahon, P. C. Gillette, R. B. Hinton, J. R. Stratton, F. A. Crawford, and F. G. Spinale DEVELOPMENTAL DIFFERENCES IN MYOCYTE CONTRACTILE RESPONSE AFTER CARDIOPLEGIC ARREST J. Thorac. Cardiovasc. Surg., June 1, 1996; 111(6): 1257 - 1266. [Abstract] [Full Text]

				F. X. McGowan Jr., H. Cao-Danh, K. Takeuchi, P. J. Davis, and P. J. del Nido Prolonged neonatal myocardial preservation with a highly buffered low-calcium solution J. Thorac. Cardiovasc. Surg., October 1, 1994; 108(4): 772 - 779. [Abstract] [Full Text]