Scripties UMCG - Rijksuniversiteit Groningen
English | Nederlands

Impact and outcome of abnormal loading on the right ventricle in children and adults with repaired tetralogy of Fallot

(2016) Beurskens, N.E.G. (Niek)

1. Cross-sectional study Right ventricular remodeling in response to abnormal loading in repaired tetralogy of Fallot. Aims The long-term outcome of repaired tetralogy of Fallot (TOF) depends on multiple factors, including the pathophysiological remodeling of the right ventricle (RV) to abnormal loading. This multi-center study was designed to evaluate the impact of abnormal pressure and volume loading on RV morphology and function.
Methods Cardiac magnetic resonance imaging and echocardiographic data were retrospectively analyzed. We assessed the associations of RV volumes and mass with RV function, pulmonary regurgitation fraction (PRF) and echocardiographic derived pressures.
Results A total of 401 studies were included. PRF correlated with RV end-diastolic volume indexed for body surface area (RVEDVi)(r=0.57, p<0.001), RV mass index (r=0.26, p<0.001), volume ratio RV/ left ventricle (LV) (r=0.64, p<0.001), RV stroke volume index (r=0.58, p<0.001) and RV mass/ volume ratio (r=-0.40, p<0.001). The RV/LV volume ratio had a stronger relation with PRF than RVEDVi (r=0.64 vs. 0.57, p<0.001), and was more accurate in predicting severe PR (i.e. PRF ≥20%, c-statistic 0.83 versus 0.80, p<0.001). RV mass was independently associated with pulmonary valve peak gradient (β=0.2; Standard Error (SE)=0.03; p<0001) and RV systolic pressure (β=0.2; SE=0.04; p<0001) after adjustment for PRF and RV volumes. RV mass was an independent predictor of reduced RV ejection fraction (β = -0.10, SE=0.04, p=0.02).
Conclusion RV/LV volume ratio is superior to RVEDVi in the differentiation of severe from non-severe PR and is a more accurate reflection of RV dilatation due to chronic volume loading. RV hypertrophy, as a result of combined pressure and volume loading, is independently associated with RV systolic dysfunction in repaired TOF patients.

2. Longitudinal study Risk stratification in children and adults with repaired tetralogy of Fallot. Aims Cardiac arrhythmias are the leading cause of sudden cardiac death (SCD) in patients with repaired tetralogy of Fallot (TOF). We evaluated risk factors for SCD, ventricular tachyarrhythmias (VT) and atrial tachyarrhythmias (AT) in these patients.
Methods Consecutive TOF patients were included in this multi-center study. Cardiac magnetic resonance imaging (CMR), echocardiographic, electrocardiographic and clinical data were analyzed.
Results A total of 401 patients were included. During a median follow-up of 4.3 (1.3 - 6.1) years, 27 (7%) patients reached the primary endpoint of VT/SCD and 45 (11%) the secondary endpoint of AT. Right ventricular (RV) mass index ≥50.7g/m2 (Hazard ratio [HR] 6.45; 95% confidence interval [CI] 2.73 - 15.2; p<0.001), QRS-duration ≥164ms (HR 5.72; 95% CI 2.33 - 14.0; p<0.001) and age (HR 1.04; 95% CI 1.01 - 1.07; p=0.02) were independent predictors of VT/SCD. In patients with no risk factors 98%, one risk factor 82% and two risk factors 41% remained free from VT after nine years from CMR (log rank p<0.001). Body mass index (HR 1.13; 95% CI 1.09 - 1.21; p<0.001), age at TOF repair (HR 1.05; 95% CI 1.02 - 1.09; p=0.003) and age (HR 1.06; 95% CI 1.03 - 1.08; p<0.001) were independent predictors of AT. Percentage freedom from AT nine years from CMR were: no risk factor 97%; one risk factor 67%; two risk factors 52% [log rank p<0.001]).
Conclusion In patients with repaired TOF, RV hypertrophy, prolonged QRS-duration and older age are independent predictors of VT. Obesity, older age at TOF repair and age are independently associated with the occurrence of AT.

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