Doppler echocardiographic assessment of shunting via the ductus arteriosus in newborn infants

Prophylactic and early targeted treatment of patent ductus arteriosus

Treatment of a haemodynamically significant patent ductus arteriosus (PDA) in the very preterm infant has been an accepted approach for several decades. However, the rationale for closure of PDA has recently been challenged due to reports of success with conservative approaches and the lack of evidence for longer-term benefits from treatment. In this article, we address an approach to assess treatment of those babies most likely to benefit.

Incidental Finding on MDCT of Patent Ductus Arteriosus: Use of CT and MRI to Assess Clinical Importance

OBJECTIVE

The purpose of this article is to describe the imaging features of patent ductus arteriosus (PDA) identified on chest MDCT performed for other indications and to describe the additional functional information that cardiac MRI can provide about these lesions.

CONCLUSION

The daily use of MDCT studies for the evaluation of pulmonary embolic disease or aortic abnormalities can reveal incidental PDAs. Small incidental PDAs can be identified on chest MDCT angiography timed for either the pulmonary arteries or the aorta. Using multiplanar reformations, one can assess PDA location, caliber, length, and presence of calcifications. The presence of a "positive" or a "negative contrast jet" verifies a patent shunt. Cardiac MRI shows the detailed anatomic and morphologic features of a PDA. Hemodynamic information revealing the presence and severity of a significant shunt is obtainable using velocity-encoded MRI, allowing accurate shunt calculation. Using MDCT and MRI, information regarding the clinical significance of an incidental PDA can influence management decisions. The imaging information was used to determine that one PDA required intervention.

Treatment of patent ductus arteriosus

Patent ductus arteriosus (PDA) continues to be one of the most common problems found in premature infants. The incidence is inversely related to gestation, but may be reduced by use of antenatal steroids, lower volume fluid regimen and judicious use of phototherapy. However, there continues to be controversy as to the appropriate indications for treatment, varying from prophylaxis on the basis of gestation to treatment only when a PDA is demonstrably significant. The situation is further complicated by differing diagnostic criteria for ductal patency or significance. Prophylactic treatment is likely to result in up to 64% of babies being treated unnecessarily. Early treatment of significant or symptomatic PDA depends upon accurate diagnosis. PDA closure can then be achieved using medical means, with surgery reserved for patients in whom this fails or in whom there are contra-indications. However, the optimum timing for intervention remains unknown.

Diagnostic accuracy of transesophageal echocardiography for detecting patent ductus arteriosus in adolescents and adults

To compare the accuracy of transesophageal echocardiography (TEE) with that of transthoracic echocardiography (TTE) in the detection of patent ductus arteriosus (PDA) in the adolescent and the adult, 40 patients with PDA and 50 patients with other congenital heart diseases were studied. All echocardiograms were recorded before cardiac catheterization and surgery. The echocardiographic diagnosis of PDA was made by direct visualization of a shunt flow in the duct. A mosaic flow in the pulmonary artery without direct visualization of the duct was considered possible but not definitely diagnostic of PDA. TEE showed greater sensitivity and negative predictive value than TTE (97% vs 42%, and 98% vs 68%, respectively; p < 0.001) in confirming the diagnosis of PDA. The specificity and positive predictive value in establishing the diagnosis of PDA were the same for both techniques. In the subgroup of patients with Eisenmenger's syndrome, the sensitivity of TEE and TTE in confirming diagnosis of PDA was 100% and 12% (p < 0.01), respectively. The sensitivity of monoplane and biplane TEE in the diagnosis of PDA was comparable (95% and 100%, respectively; p = NS). In conclusion, TEE was highly sensitive and specific in detecting PDA in adolescents and adults. It was also highly valuable for detecting the cause of pulmonary hypertension in patients with Eisenmenger's syndrome.

Bidirectional flow through the ductus arteriosus in normal newborns: evaluation by Doppler color flow imaging

To determine the duration of bidirectional flow through the ductus arteriosus and to confirm the time of functional closure of the ductus arteriosus, 25 normal full-term newborns were studied serially using Doppler color flow imaging beginning at 2-7 h after birth and continuing until no ductal flow was detected (defined as functional closure). At the first examination, blood flow was bidirectional in 19 of 25 infants and continuously left-to-right in the remaining six. Subsequent studies revealed that bidirectional ductal flow changed to continuous left-to-right flow in 17 of 19 infants, whereas two of 19 abolished the flow completely at the second examination. Three of the 19 infants still had bidirectional flow through the ductus arteriosus at 12, 18.5, and 24 h after birth. The percentage of newborns who had bidirectional flow through the ductus arteriosus decreased roughly as a negative exponential function of age. The earliest functional closure of the ductus arteriosus was at 8 h after birth: by 24 hours 44% and by 48 h, 88% were functionally closed. By 72 h of age, the ductus arteriosus was functionally closed in all 25 infants. This study shows that bidirectional flow through the ductus arteriosus changes to continuous left-to-right flow before the functional closure, but can persist up to 24 h after birth.

Echocardiography as a tool for determining the incidence of congenital heart disease in newborn babies: a pilot study in Hong Kong

We studied, with echocardiography as the main tool, the incidence of congenital heart disease in newborn babies in Hong Kong. The population examined was the 20,928 babies who were born alive in the Prince of Wales Hospital from January 1987 to December 1989. All had a thorough physical examination by a paediatrician after birth, and an estimated 95% of the babies who were discharged from hospital received another routine physical examination at one of the five local Maternal and Child Health Centres within two months of birth. All babies with either suspected congenital heart disease or multiple congenital abnormalities were referred to the paediatric cardiologists in the Prince of Wales Hospital for further cardiovascular assessment that included echocardiographic examination. In all, 492 babies had Doppler and cross-sectional echocardiographic studies. Various abnormalities of the cardiovascular system were diagnosed in 216 babies. Almost all the babies who died within two months of life underwent autopsy. This proved the presence of congenital cardiac malformations in 15 babies, of whom 10 had correct echocardiographic diagnoses during life. One had a patent arterial duct which was missed by the echocardiography. The other four babies did not have echocardiographic examination while alive, either because of early death or absence of clinical suspicion. In total, congenital cardiac malformations were confirmed in 221 babies by echocardiographic examination and autopsy. Excluding 82 premature babies with patency of the arterial duct, and 6 babies with transient tricuspid regurgitation, there were 133 cases of structural cardiac malformation in the studied population, giving an incidence of 6.35 per thousand live births.(ABSTRACT TRUNCATED AT 250 WORDS)

Topical prostaglandin E2 gel for cervical ripening and closure of the ductus arteriosus in the newborn

The closure time of the ductus arteriosus was investigated in 29 full term babies born vaginally after induction with prostaglandin E2 and in 22 controls. Serial Doppler echocardiography studies showed a significantly prolonged closure time in babies induced by prostaglandin E2. Whether the difference is related to changes in fetal prostaglandin E2 concentration remains to be established.