Accuracy of echocardiography in low birth weight infants with congenital heart disease.

OBJECTIVE: Echocardiography has been shown to be highly accurate in infants and children, but its accuracy has not been studied in detail in low birth weight (LBW) infants with structural congenital heart disease (CHD). This study was undertaken to examine the diagnostic accuracy of echocardiography in the evaluation of CHD in these infants.

METHODS: All echocardiograms performed between 1995 and 2000 on infants who had structural CHD and weighed 2.5 kg, matched for type of CHD, were control subjects (n = 319). The results of initial echocardiograms were compared for diagnostic accuracy with consensus diagnoses on the basis of all confirmatory data available. An observer who was blinded to patient group graded a sample of randomly selected echocardiograms (n = 100) for technical quality.

RESULTS: There were 13 major diagnostic errors in the LBW infants (5.2%) and 6 in the control subjects (1.9%). There were 20 minor errors in the LBW group (8.0%) and 21 in the control subjects (6.6%). The technical quality scores of the 2 groups were not significantly different, but a higher proportion of the LBW studies were graded as "poor" or "borderline" quality, compared with the control subjects (40% vs 28%). The majority (54%) of major errors in the LBW infants could potentially be explained by alterations in blood flow secondary to pulmonary hypertension.

CONCLUSIONS: Although echocardiography is an accurate imaging modality in premature and LBW infants with structural CHD, the incidence of clinically important diagnostic errors is higher than in infants who weigh >2.5 kg. As surgical and transcatheter interventions are extended to this population, heightened awareness of clinicians to pitfalls of echocardiography in this group of patients is warranted.