Abstract 21484: Session Title: Wider Conal Septal Angle In Neonates with Tetralogy of Fallot Is Associated With Rapid Progression of Right Ventricular Outflow Tract Obstruction
Introduction: Some neonates with tetralogy of Fallot (TOF) have rapid progression of right ventricular outflow tract (RVOT) obstruction irrespective of initial Doppler gradient. Presently no method exists to identify this higher-risk group.
Hypothesis: Abnormal infundibular morphology in neonates with TOF is associated with rapid progression of RVOT obstruction.
Methods: Patients with TOF undergoing surgical repair from 2003-2009 were studied. First neonatal echocardiogram was analyzed to measure conal septal angle (angle between conal septum and horizontal plane passing through the center of the aortic valve in parasternal short axis view - with larger angle denoting more anterocephalad deviation of conal septum), conal septal thickness and length, degree of aortic dextroposition, size and z-scores of pulmonary annulus, main and branch pulmonary arteries. Outcomes included rate of progression of RVOT gradient, occurrence of hypercyanotic spells and need for neonatal surgery. Statistical analysis was performed using Wilcoxon tests, Spearman rank test and multivariable regression analysis.
Results: Fifty patients were studied. Median age at first echo was 2 days (25th-75th percentile: 0-7 days). Median age at surgery was 94 days (25th - 75th percentile: 44-139 days); hypercyanotic spells occurred in 19 (38%) and 10 (20 %) underwent neonatal repair. By multivariable regression analysis, patients with wider conal septal angle had significantly higher rate of RVOT gradient progression (p = 0.009). Patients with hypercyanotic spells tended to have wider conal septal angles (59 ± 21 versus 46 ± 13 degrees, p = 0.013). Patients who underwent neonatal surgery also tended to have wider conal septal angles (67± 13 versus 48± 16, p = 0.001). Importantly, Doppler RVOT gradient at initial echocardiogram, conal septal length, conal septal thickness, degree of aortic dextroposition and pulmonary valve size were not associated with these outcomes.
Conclusions: Wider conal septal angle is independently associated with rapid progression of RVOT obstruction, hypercyanotic spells and the need for neonatal surgery.
- © 2010 by American Heart Association, Inc.