[Effects of age in the correction of isthmus stenosis on postoperative stiffness of the aorta].

Operative surgery for coarctation aims to eliminate the narrowed segment of the aorta and to restore a normal function of the aortic Windkessel, which depends on normal elastic properties of the aorta. To evaluate the effect of age at coarctectomy on the postoperative aortic elasticity, parameters of regional wall stiffness within the aortic arch were determined in 24 children after coarctectomy by means of echocardiography and blood pressure measurements. Actual data were compared with reference data (mean value normalized to body weight: mn +/- SD) obtained from n = 43 children, adolescents and young adults (age 1 month to 28 years; mean 12.6 years): elastic modulus Epn = 0.20 +/- 0.07 Mdyn/cm2/kg0.11; stiffness index beta = 3.45 +/- 1.3; diameter Dn = 0.52 +/- 0.08 cm/kg0.37. The results revealed that 4.9 years (mean) after 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 years 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 years at operation the elastic modulus was increased 7.6 years later: Epn = 0.28 +/- 0.11 Mdyn/cm2/kg0.11; (p < 0.01). The diameter of the proximal aortic arch was significantly reduced (DN =0.42 +/- 0.08 cm/kg0.37., P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)