PULMONARY VALVE ANNULUS GROWS AFTER BALLOON DILATATION OF NEONATAL CRITICAL PULMONARY VALVE STENOSIS

Background Neonates with critical pulmonary valve stenosis often demon strate small or hypoplastic right ventricular structures. Relief of th e obstruction enhances forward flow across the right ventricle and red uces its pressure load. Growth of the right ventricle and especially o f the pulmonary valve annulus was evaluated after balloon dilatation. Methods Ten consecutive neonates with critical pulmonary valve stenosi s who underwent balloon valvuloplasty were studied by serial echocardi ography to assess growth of right ventricular structures at follow-up. Results The mean diameter of the pulmonary valve annulus increased fr om 6.1 +/- 1.4 mm to 12.6 +/- 3.5 mm (z scores from -2.9 +/- 1.0 SD to -1.3 +/- 1.2 SD, p < 0.0001) after a mean follow-up period of 2.7 +/- 2.0 years. The mean diameter of the tricuspid valve annulus increased from 12.9 +/- 3.8 mm to 19.0 +/- 3.1 mm; however, the respective z sc ore did not change significantly (from 0.5 +/- 2.4 SD to -0.5 +/- 1.0 SD). Right ventricular cavity size was hypoplastic in four patients in itially and normal in all patients at latest follow-vp. Conclusions Ba lloon dilatation of critical pulmonary valve stenosis encourages catch -up growth of the pulmonary valve, and surgery may be avoided even in a hypoplastic pulmonary valve annulus.