Regression of right ventricular pressure in ventricular septal defect in infancy: A longitudinal color-flow Doppler echocardiographic study

To determine the course of right ventricular pressure (RVP) in patients wit h isolated ventricular septal defect (VSD) and factors influencing it, unse lected 148 infants were followed-up longitudinally with color-Doppler echoc ardiography from a median age of 1 month for 201 patient-years. The patient s were divided into three groups by absolute echographic size of VSD: group I, less than or equal to 4.0 mm; group II, >4 to less than or equal to 7 m m; group III, >7 mm. Sixty percent belonged to group I. Muscular defects do minated in group I, perimembranous defects dominated in group II, and those with outlet extensions dominated in group III. Peak systolic RVP was obtai ned by Doppler-estimated difference between systolic brachial artery and pe ak gradient across the VSD. Initial RVP ranged between 15 and 95 mmHg and i ncreased in parallel to the size of defect. According to the regression equ ations RVP decreased in general by 0.17 mmHg per month. This correlated sig nificantly with the size of the defect. In group I, the rate of decrease wa s Very fast and is best expressed by a log function of time (r = -0.67, r(2 ) = 0.45). In groups II and III the rate of decrease was less steep and had a greater variability. RVP normalized in 100% in those of group I and in 9 0% of group II, at median ages of 0.17 and 0.33 years, respectively. Median Q(p):Q(s) values were 1.5, 2.2, and 3.0 in groups I-III, respectively. The outcome depended on the size of VSD. Spontaneous closure was observed in 5 1% of group I, 10% of group II, and none of group III. The rate was higher in muscular defects. Congestive heart failure was present in 53% and 100% i n groups II and Ill, respectively. Death rate was 2.03%, all in patients wi th large defects. It is concluded that the temporal course of RVP with time can be estimated fairly well by the regression equation presented in relat ion to the initial size of the VSD.