EFFECTS OF THE AGE AT COARCTECTOMY ON THE POSTOPERATIVE STIFFNESS OF THE AORTA

Operative surgery for coarctation aims to eliminate the narrowed segme nt of the aorta and to restore a normal function of the aortic Windkes sel, which depends on normal elastic properties of the aorta. To evalu ate the effect of age at coarctectomy on the postoperative aortic elas ticity parameters of regional wall stiffness within the aortic arch we re determined in 24 children after coarctectomy by means of echocardio graphy and blood pressure measurements. Actual data were compared with reference data (mean value normalized to body weight: mn +/- SD) obta ined from n = 43 children, adolescents and young adults (age 1 month t o 28 years; mean 12.6 years): elastic modulus Epn = 0.20 +/- 0.07 Mdyn /cm(2)/kg(0.11); stiffness index beta = 3.45 +/- 1.3; diameter Dn = 0. 52 +/- 0.08 cm/kg(0.37). The results revealed that 4.9 years (mean) af ter coarctation repair within the first year of life (mean 3.2 months, n = 10) the parameters of elasticity and the diameter did not differ from normal. In those n = 5 children operated on in the age of 4.7 yea rs there was a tendency towards increased aortic stiffness and reduced diameter 8.9 years later. In n = 9 children with a mean age of 9.2 ye ars at operation the elastic modulus was increased 7.6 years later: Ep n = 0.28 +/- 0.11 Mdyn/cm(2)/kg(0.11); (p < 0.01). The diameter of the proximal aortic arch was significantly reduced (Dn = 0.42 +/- 0.08 cm /kg(0.37); p < 0.01). In all patients the systolic blood pressure corr elated positively with the elastic modulus (p < 0.05). The postoperati ve stiffness of the aorta increases with the age at coarctectomy and c orrelates with the systolic blood pressure. Thus persistent functional abnormalities of the aortic Wind kessel after coarctectomy are relate d to the age at surgery.