PERSISTENT HYPERDYNAMIC CARDIOVASCULAR STATE AT REST AND DURING EXERCISE IN CHILDREN AFTER SUCCESSFUL REPAIR OF COARCTATION OF THE AORTA

Objectives. The purposes of this study were to evaluate left ventricul ar performance and contractility at rest and during exercise to determ ine mechanisms and correlates for alterations in performance and blood pressure in pediatric patients after successful repair of coarctation of the aorta. Background. Blood pressure and left ventricular functio n are elevated in children despite successful repair. The mechanisms f or these changes are not understood. Methods. Thirty asymptomatic pedi atric patients with successful coarctation repair (mean age [+/-SD] 12 .5 +/- 4 years) underwent echocardiographic determination of left vent ricular mass, performance (shortening fraction), preload (indexed dias tolic dimension), afterload (end-systolic wall stress), contractility (velocity of circumferential fiber shortening/wall stress relation) an d Doppler gradient at rest and during exercise. Data were compared wit h those of 24 control subjects (mean age 21.0 +/- 4 years). Because of the age discrepancy between groups, age dependent echocardiographic d ata were indexed by body surface area. Results. The mean age at operat ion was 5 +/- 4 years, and the average follow-up period was 7.5 +/- 3 years. The average blood pressure gradient between upper and lower lim bs was 4 mm Hg. Left ventricular mass was higher in the postoperative group than in the control group (1.58 vs. 1.31 g/ht(2.7), p = 0.04), a s were values at rest for performance (44% vs. 31%, p = 0.0001), prelo ad (3.9 vs. 3.7 cm/body surface area(0.5)), indexed systolic blood pre ssure (1.05 vs. 0.91, p = 0.0001) and contractility (0.23 vs. -0.05 ci rcumferences/s, p = 0.001). Afterload was lower at rest (36 vs. 52 g/c m(2), p = 0.0004). These differences between groups persisted during a nd after exercise. Contractility underwent an exaggerated increase aft er exercise in the postoperative group. Conclusions. Left ventricular performance in children after coarctation repair is higher at rest and during exercise than in control subjects as a result of higher preloa d and contractility and lower afterload. These changes may be due to a ssociated hypertrophy. Persistent postoperative hypertension may be du e to a hyperdynamic, hypercontractile state caused by residual gradien ts manifested only during exertion.