Non-invasive versus invasive assessment of pulmonary artery branches in pediatric patients with tetralogy of fallot

ABSTRACT

This study was based on two issues, the 1[st] one was that the pulmonary artery anatomy is the key factor that determines the type of surgical treatment required in tetralogy of Fallot [TOF]. The 2[nd] one was that many studies showed a good correlation of the echocardiographic measurements of cardiac structures with the angiographic and pathological findings. So, the aim of this work was to evaluate the reliability of echocardiography in assessment of the pulmonary blood flow status in pediatric patients with TOF. Only patients with the usual anatomy of TOF were included in this study. It included 68 patients distributed into two groups; group I included 18 patients [26.5%], their mean age was 29.1 +/- 21.4 months and their mean weight was 11.2 +/- 2.1 kg. Group II included 50 patients [73.5%], their mean age was 34 +/- 23 months, their mean weight was 12.6 +/- 4.1 kg. We tested the accuracy of the 2-D echocardiography in measuring the right and the left pulmonary arteries [RPA and LPA] and compared them to the measurements taken by angiography [group I] as well as to the measurements taken at surgery [group II]. The standard deviation unit [Z value] for the RPA and LPA was calculated as well as the pulmonary artery index [PAI] from echocardiographic and angiographic measurements for group I and from echocardiographic and surgical measurements for group II. The results showed that For group I patients, there was statistically significant difference in the measurements of RPA and LPA and consequently the calculated Z value and the PAI between echocardiographic and angiographic modalities. Similarly, group II patients demonstrated a statistically significant difference in the measurements of RPA and LPA and consequently the calculated Z value and the PAI between the echocardiographic and surgical methods. Despite these significant differences found in both groups, the echocardiographic measurements correlated well with the angiographic measurements in group I as well as with the surgical measurements in group II. The differences detected between the echocardiographic and the surgical measurements were less than the differences detected between the echocardiographic and angiographic measurements. This mostly related to our earlier experience in measurement of the pulmonary artery branches using 2-D echocardiography in group I, but with time, we got more experienced in this issue, thus the differences in measurements were minimized in group II. The maximum difference between the echocardiography and surgery for the RPA and LPA was 2.1 mm and 2.0 mm and the mean difference was 0.71 +/- 0.45 and 0.63 +/- 0.46 mm respectively. Our results reflect a clinically acceptable accuracy of 2-D echocardiography in estimation of the pulmonary artery branches and thus surgical management of TOF, guided by echocardiography alone, can be confidently performed in selected infants and children. Cardiac catheterization should be reserved for patients in whom the echocardiographic measurements are not fully certain or suggest association of cardiovascular malformation