RESUMO
Pulmonary vascular resistance [PVR] is an important hemodynamic parameter in patients with congenital heart disease [CHD]. Noninvasive estimation of PVR represents an attractive alternative to invasive measurements. The study included 175 patients with pulmonary hypertension [PH] secondary to CHD. All patients underwent full echocardiographic study and invasive hemodynamic measurements. The study population was then subdivided into four subgroups. Each of the following Doppler indices was measured in one of these four subgroups: peak tricuspid regurgitant velocity [TRV], the ratio of the TRV to the velocity time integral of the right ventricular outflow tract [TRV/TVIRVOT], peak velocity of tricuspid annular systolic motion [TSm], heart rate corrected acceleration time and infliction time of the proximal left pulmonary artery [ATc, InTc]. The data obtained was correlated with invasive PVR measurement. An ROC curve analysis was done to generate cutoff points with the highest balanced sensitivity and specificity to predict PVR > 6WU/m2. The receiver operating characteristics [ROC] curves were compared with each other to determine the most reliable cutoff point in predicting elevated PVR > 6WU/m2. There was a significant correlation between both the TRV and TSm and invasive measurement of PVR [r = -0.511, 0.387 and P value = 0.0002, 0.006 respectively]. The TSm and TRV cutoff values were the most reliable to predict elevated PVR > 6 WU/m2. A TSm cutoff value of 616.16 cm/s provided the best balanced sensitivity [85.7%] and specificity [66.7%] to determine PVRCATH > 6 WU/m2. A cutoff value less than 7.62 cm/s had 100% specificity to predict PVRCATH > 6 WU/m2. A TRV cutoff value of >3.96 m/s provided the best balanced sensitivity [66.7%] and specificity [100%] to determine PVRCATH > 6 WU/m2. Both TRV and TSm had the highest area under the ROC curve among the 5 DOPPLER indices studied. Prediction of elevated PVR in children with PH secondary to CHD could be achieved noninvasively using a number of Doppler indices. Among the five Doppler indices examined in the current study, the peak TRV and the TSm of the lateral tricuspid annulus had the highest balanced sensitivity and specificity to predict PVRI > 6 WU/m2.
RESUMO
Balloon pulmonary valvuloplasty [BPV] represents the standard of management for all patients with severe pulmonary stenosis [PS] irrespective of their age. Nevertheless neonates and infants with critical PS represent a high-risk group that needs to be studied. The study population included 72 infants with severe congenital valvular PS and four infants with imperforate pulmonary valve [PV] who were subjected to detailed history taking, full clinical examination, resting 12-lead ECG, Chest roentgenogram and transthoracic echocardiography. BPV was attempted in all infants with a peak-to-peak gradient across the PV of 50 mmHg or greater at catheterization-laboratory. Full echocardiographic evaluation was done 24 hours after the procedure as well as 3 and 6 months later. Seventy-six infants with severe PS or imperforate PV with a mean age of 5.63 +/- 2.99 months were subjected to BPV with or without wire perforation. Immediately after the procedure patients had a significant reduction of the right ventricular systolic pressure [RVSP] [104.69 +/- 24.98 mm Hg Vs 43.6 +/- 13 mm Hg, p < 0.001] and RV-PA systolic pressure gradient [PG] [82.5 +/- 23.76 mm Hg Vs 17.35 +/- 8.96 mm Hg, p < 0.001]. The immediate success rate defined as the drop in the RVSP to less than or equal to 50% of the baseline measurement was achieved in 85% of the cases. There was a progressive drop in the PG across the PV by Doppler echocardiogram throughout a follow-up period of six months from a mean of 93.3 +/- 28.2 mm Hg to a mean of 17.4 +/- 10.42 mm Hg [p < 0.001]. There was a significant increase of the mean PV annulus diameter after balloon dilatation [p < 0.001]. There was also a highly significant inverse correlation between the growth of the pulmonary annulus and the annular size at the baseline before dilatation [r = -0.74, p value <0.001]. The incidence of PR significantly increased immediately after BPV to 64% followed by a progressive decline over a 6 months period of follow-up to 20%. There was a significant decrease in the incidence of tricuspid regurgitation [TR] over the same period of follow-up [from 55.6% at baseline to less than 20% at follow-up]. BPV is safe and effective to relieve critical PS in infants during the first year of life. The balloon promotes advantageous changes in both, pulmonary annulus and PG across the RVOT. In addition, the Doppler gradient observations during the follow-up support the expectation that BPV is a "curative" therapy