Homograft insertion for pulmonary regurgitation after repair of tetralogy of Fallot improves cardiorespiratory exercise performance

Surgical repair of tetralogy of Fallot (TOF) with reconstruction of the rig ht ventricular (RV) outflow tract invariably results in pulmonary regurgita tion. Chronic pulmonary regurgitation has been associated with RV dysfuncti on and decreased exercise performance. The present study assessed the influ ence of pulmonary valve replacement (PVR) for severe pulmonary regurgitatio n after previous TOF repair on cardiorespiratory exercise performance and R V function. Eighteen patients, between the ages of 8 and 18 years, underwen t on exercise test and a cardiac magnetic resonance imaging scan at least 1 year after PVR. The exercise data were compared with those obtained from 2 4 age-matched normal controls and 27 age-matched patients with repaired TOF and a moderate degree of pulmonary regurgitation. A subgroup of 11 patient s had an exercise test performed before and after PVR. Cardiopulmonary exer cise performance was evaluated by determination of the ventilatory anaerobi c threshold (VAT) and by the steepness of the slope of oxygen uptake versus exercise intensity (S(V) over dot O-2). After PVR there was a significant increase in VAT (86 +/- 11% before to 106.9 +/- 14% after, p = 0.03) and in S(V) over dot O-2 (1.71 +/- 0.47 to 2.3 +/- 0.39, p = 0.004). In patients examined after PVR, the VAT and S(V) over dot O-2 values were not significa ntly different from the values in the normal controls (104 +/- 15% [p >0.05 ] and 2.03 +/- 0.77 after PVR vs 2.42 +/- 0.68 [p >0.25], respectively). In contrast, patients with repaired TOF and a moderate degree of pulmonary re gurgitation had a significantly lower VAT (86 +/- 11%, p <0.05) and S(V) ov er dot O-2 (1.8 +/- 0.74 vs 2.42 +/- 0.68, p <0.05) than normal controls. M agnetic resonance imaging studies revealed residual RV dilatation and dysfu nction. However, there was no correlation between RV dilatation and RV dysf unction and aerobic exercise capacity. It is concluded that aerobic exercis e capacity substantially improves after PVR for severe pulmonary regurgitat ion after previous TOF repair. Although the right ventricle remains signifi cantly dilated and hypocontractile, there is no relation between RV functio n and exercise performance. (C) 2000 by Excerpta Medico, Inc.