ECHOCARDIOGRAPHIC DETERMINANTS OF CLINICAL COURSE IN INFANTS WITH CRITICAL AND SEVERE PULMONARY VALVE STENOSIS

Objectives. The purposes of this study were to determine the growth pa ttern of the pulmonary valve (PV) annulus and right heart structures i n patients with critical and severe pulmonary stenosis (PS) after ball oon dilation, and to determine any morphometric or hemodynamic differe nces between cyanotic infants with critical PS and asymptomatic infant s with severe PS that may account for their varied clinical presentati ons. Background. Growth of the PV annulus and right heart structures i n patients with critical PS after balloon valvuloplasty has not clearl y been defined. In addition, the anatomic and hemodynamic factors that determine whether an infant with severe PS will present with cyanosis or without symptoms are not well understood. Methods. Measurements of the PV annulus, tricuspid valve (TV) annulus and main, right and left pulmonary arteries were obtained from initial and follow-up echocardi ograms, and Z values were calculated. Hemodynamic data and balloon pul monary valvuloplasty techniques were reviewed. Right ventricular (RV) volumes were measured from angiograms. Results. Fourteen patients with critical PS (mean [+/-SD] age 0.21 +/- 0.37 months) and 20 patients w ith severe PS (mean age 2.6 +/- 2.9 months) were evaluated at presenta tion and at 32 +/- 33 and 42 +/- 32 months of follow-up, respectively. Balloon pulmonary valvuloplasty was successful in 64% of patients wit h critical PS and in 90% of patients with severe PS. The PV, TV and pu lmonary arteries increased in size after balloon pulmonary valvuloplas ty in both groups at a rate that paralleled or exceeded the rate of so matic growth. The initial TV diameter and RV volume were smaller in pa tients with critical PS than in those with severe PS (p < 0.05 and p < 0.0008, respectively). Conclusions. After balloon pulmonary valvulopl asty in infants with critical and severe PS, right heart structures in crease in size at a rate that parallels or exceeds the rate of somatic growth. The primary morphometric differences between these groups are a smaller TV diameter and RV volume in infants with critical PS, This may contribute to increased right to left atrial shunting and account for the variations in clinical presentation. (C)1997 by the American College of Cardiology.