Early Re-intervention in Infants and Small Children After Correction of Tetralogy of Fallot

Overview

Tetralogy of Fallot is one of the most frequent congenital heart malformations. In many cases re-interventions, surgical or catheter-based, are necessary after the repair of tetralogy of Fallot in infancy. At present, informations in the literature about the myocardial benefit and the timing of re-interventions are missing in this age group. On the other hand, Fallot patients are dependent on solid criteria for re-interventions, because further interventions like replacement of the pulmonary valve or balloon dilatations of peripheral pulmonary stenoses are common. The objective of this study is to assess the benefit of such interventions for the right ventricular function. By performing extensive standardised examinations (including MRI, echocardiography, tissue Doppler,,3D-echocardiography, holter monitoring and quality of life assessments) before and 6 to 9 months after the re-intervention data of the right ventricular function are collected. Based on these quantitative data predictive parameters concerning the right ventricular recovery and information about the time of re-intervention should be determined.

In the repair of tetralogy of Fallot, pulmonary insufficiency used to be tacitly accepted as a result of extensive transannular patching (TAP) and considered unobjectionable. In fact, this is well tolerated during the first postoperative years, but today there is increasing evidence that the resulting chronic volume stress to the right ventricle is harmful on the long run, in particular if there are stenoses of the pulmonary artery in addition. Such stenoses, partly due to distortions after shunt surgery, together with pulmonary insufficiency, lead to a combined volume and pressure load of the right ventricle. The chronic volume stress results in a decrease in biventricular function and exercise tolerance, associated with increasing electrical instability with frequent, mostly ventricular, dysrhythmias. This constellation brings about a significantly increased risk of cardiac death. Pulmonary valve replacement can improve haemodynamics, exercise tolerance and dysrhythmia. However, it is still unclear, which criteria best indicate the need for re-intervention, such as balloon dilatations of peripheral pulmonary stenoses, and what may be the best point in time in infancy. The objective of this study is to assess the effectiveness of such interventions to the right ventricular function in small children. The data obtained are supposed to determine predictive parameters of the right ventricular recovery and to help to establish criteria for the necessity and time of re-intervention.