Coarctation of the aorta: Prenatal assessment, postnatal management and neonatal outcomes.

Coarctation of the aorta (Coa) is a potentially life threatening diagnosis. It occurs in 0.3 per 1000 live births and accounts for 6-8% of all infants with congenital heart defects. Neonates with severe Coa may be completely asymptomatic at birth, as the ductus arteriosus can provide flow to the lower body. Those who are not diagnosed prenatally may be diagnosed only after constriction of the ductus arteriosus, when they present in cardiogenic shock. This group has a higher risk for mortality and morbidity relative to those diagnosed prenatally. Despite the increasing practice of universal pulse oximetry screening, many cases with significant coarctation of the aorta still go undiagnosed in the newborn period. In this article, we present the pathophysiology, diagnosis, presentation, treatment and outcomes of Coa.

Differences in Cost of Care by Palliation Strategy for Infants With Ductal-Dependent Pulmonary Blood Flow.

BACKGROUND: In infants with ductal-dependent pulmonary blood flow, initial palliation with patent ductus arteriosus (PDA) stent or modified Blalock-Taussig (BT) shunt have comparable mortality but discrepant length of stay, procedural complication rates and reintervention burdens, which may influence cost. The relative economic impact of these palliation strategies is unknown. METHODS AND RESULTS: Retrospective study of infants with ductal-dependent pulmonary blood flow palliated with PDA stent (n=104) or BT shunt (n=251) from 2008 to 2015 at 4 centers of the Congenital Catheterization Research Collaborative. Inflation-adjusted inpatient hospital costs were calculated for first year of life using Pediatric Health Information System data. Costs derived from outpatient catheterizations not in Pediatric Health Information System were imputed. Costs were compared using propensity score-adjusted multivariable models, to account for baseline differences between groups. After propensity score adjustment, first year of life costs were significantly lower in PDA stent ($215 825 [190 644-244 333]) than BT shunt ($249 855 [230 693-270 609]) patients ( P=0.05). After addition of imputed costs, first year of life costs were not significantly different between PDA stent ($226 403 [200 274-255 941]) and BT shunt ($252 072 [232 955-272 759]) groups ( P=0.15). Patient characteristics associated with higher costs included: younger gestational age, genetic syndrome, noncardiac diagnoses, procedural complications, extracorporeal membrane oxygenation, duration of ventilation, intensive care unit and hospital length of stay and reintervention ( P≤0.02 for all). CONCLUSIONS: In this first multicenter comparative cost study of PDA stent or BT shunt as palliation for infants with ductal-dependent pulmonary blood flow, adjusted for baseline differences, PDA stent was associated with lower to equivalent costs over the first year of life. Combined with previous evidence suggesting clinical noninferiority, these findings suggest that PDA stent provides competitive health care value.

Application of NPE in the assessment of a patent ductus arteriosus.

In many preterm infants, the ductus arteriosus remains patent beyond the first few days of life. This prolonged patency is associated with numerous adverse outcomes, but the extent to which these adverse outcomes are attributable to the hemodynamic consequences of ductal patency, if at all, has not been established. Different treatment strategies have failed to improve short-term outcomes, with a paucity of data on the correct diagnostic and pathophysiological assessment of the patent ductus arteriosus (PDA) in association with long-term outcomes. Echocardiography is the selected method of choice for detecting a PDA, assessing the impact on the preterm circulation and monitoring treatment response. PDA in a preterm infant can result in pulmonary overcirculation and systemic hypoperfusion, Therefore, echocardiographic assessment should include evaluation of PDA characteristics, indices of pulmonary overcirculation with left heart loading conditions, and indices of systemic hypoperfusion. In this review, we provide an evidence-based overview of the current and emerging ultrasound measurements available to identify and monitor a PDA in the preterm infant. We offer indications and limitations for using Neonatologist Performed Echocardiography to optimize the management of a neonate with a PDA.

Photoplethysmographic assessment of pulse transit time correlates with echocardiographic measurement of stroke volume in preterm infants with patent ductus arteriosus.

OBJECTIVE: We aimed to correlate photoplethysmographic parameters with stroke volume in infants with PDA. Photoplethysmography constitutes the optical signal in pulse oximetry. STUDY DESIGN: Stroke volume was determined echocardiographically. Pulse transit time, right hand to foot arrival time difference, and relative amplitude were measured from pulse oximeter and ECG waveforms. Photoplethysmographic parameters before and after PDA closure were compared with stroke volume. RESULTS: After PDA closure, pulse transit time to the hand and to the foot were prolonged (54.7 ± 6.7 vs 65.5 ± 9.8 ms, p < 0.001, 82.5 ± 12.8 vs 88.6 ± 10.6 ms, p = 0.03), arrival time difference decreased (27.7 ± 7.6 vs 23.1 ± 5.6 ms, p = 0.021), and relative amplitude decreased (from 2.1 ± 0.7% to 1.5 ± 0.5%, p = 0.003). The time-based photoplethysmographic parameters correlated with stroke volume. CONCLUSIONS: Photoplethysmographic waveform parameters are significantly different before and after PDA closure and the time-based parameters correlate well with stroke volume. Monitoring pulse transit time may assist in evaluation for spontaneous PDA closure or response to therapy.

Toward the integration of global longitudinal strain analysis in the assessment of neonatal aortic coarctation? A preliminary study.

BACKGROUND: Coarctation of the aorta (CoA) is still challenging to diagnose in neonates with patent ductus arteriosus (PDA). Speckle tracking echocardiography allows reliable analysis of myocardial deformation in newborns and seems to provide important insides into regional changes in patients with left ventricular (LV) outflow tract obstruction. AIMS: To assess the interest of LV global longitudinal strain (GLS) measurement for predicting CoA in neonates with PDA and prenatal suspicion. METHODS: Prospective single-center study. Twenty-two newborns with prenatal suspicion of CoA were included. All newborns were evaluated in the first 12 hours of life. To assess the feasibility and the reproducibility of GLS, 14 healthy full-term newborns with PDA (group 3) were screened. CoA was diagnosed when DA closed, according to usual echocardiographic criteria. RESULTS: Six neonates developed CoA after DA closure (group 1) whereas 16 did not (group 2). Mean gestational age and birth weight were not different between the groups. GLS measurements were possible in 100%. Intra- and inter-observer variability of strain measurements was acceptable. GLS values were significantly lower in neonates who developed CoA (P=0.015). To predict CoA, cut-off value of -17.42% gave the best compromise for sensitivity (83%) and specificity (72%). Aortic arch dimensions were modestly correlated with strain values. The presence of a bicuspid aortic valve was not associated with significant lower GLS values. CONCLUSION: LV GLS analysis is a feasible and reproducible echocardiographic technique in newborns with PDA. Newborns who will develop CoA seem to have lower values of GLS than healthy neonates. Further studies are needed to confirm these preliminary results.

Hemodynamic assessment of the patent ductus arteriosus: Beyond ultrasound.

Assessment and management of a patent ductus arteriosus (PDA) in premature infants remains problematic. The more immature the infant, the more likely a PDA is to be present, due to lower spontaneous PDA closure rates. Clinicians now recognize that not all PDAs require treatment and that selection of the group of infants with a more hemodynamically relevant PDA, often manifesting as an increasing systemic-to-pulmonary shunt, is increasingly important. Ultrasound is the mainstay of diagnosis and physiological assessment of the PDA; however, there are other methodologies used to assess hemodynamic importance of the PDA. These range from assessment of clinical signs through biomarkers and finally to physiological assessment of the end-organ effect of the PDA, using methods such as cerebral Doppler or near infra-red spectroscopy. Extended assessment of a PDA's physiological effect may lead to a more individualized approach to PDA treatment.

Role of neonatologist-performed echocardiography in the assessment and management of patent ductus arteriosus physiology in the newborn.

Neonatologist-performed echocardiography (NPE) is an indispensable tool in the haemodynamic management of critically ill newborn infants. NPE is used to facilitate timely diagnosis of a patent ductus arteriosus (PDA) in preterm infants and to assess its haemodynamic significance. Before treatment is considered, it is obligatory to confirm structural cardiac normality. Importantly, NPE offers the ability to guide therapeutic interventions, allowing an individualised haemodynamic management approach to the PDA. After discussing PDA pathophysiology, an overview is provided on the role of NPE in the assessment and management of PDA in preterm infants.

The Effect of a Significant Patent Ductus Arteriosus on Doppler Flow Patterns of Preductal Vessels: An Assessment of the Brachiocephalic Artery.

Systemic hypoperfusion secondary to a patent ductus arteriosus (PDA) is thought to only affect post-ductal vessels. In a prospective observational study of 51 preterm infants, we demonstrated that a persistent PDA by day 5-7 is associated with reversed diastolic flow in the brachiocephalic artery when compared with those without a PDA.

Nursing Assessment, Education, and Care of Extremely Premature Neonates with Patent Ductus Arteriosus.

The care of extremely premature neonates with suspected or confirmed diagnosis of patent ductus arteriosus (PDA) is a frequent challenge for pediatric nurses. It is important for nurses to have adequate knowledge of the normal postnatal changes in cardiovascular and pulmonary function to recognize any adverse symptoms. Nurses caring for these vulnerable neonates must have a thorough understanding of the pathophysiology of a PDA in order to assess, plan, and implement patient-centered care. Recognition of characteristic symptoms of PDA in a timely manner is essential for optimal management and outcomes. Understanding the science behind treatment options is also imperative for pediatric nurses to provide the best care and effectively educate parents. Pediatric nurses are a significant resource in managing extremely premature neonates through comprehensive assessment, effective parent education, and high-quality patient-centered care.

Pharmacotherapy for Patent Ductus Arteriosus: Current Options and Outstanding Questions.

Management of the patent ductus arteriosus (PDA) represents an ongoing challenge in the care of extremely premature neonates. Determining the optimal treatment strategy requires careful consideration of the potential risks and benefits of available therapies. Surgical ligation results in reliable ductal closure, but may result in numerous short-term complications and have a negative impact on long-term outcome. Intravenous indomethacin was the first pharmacologic agent widely utilized for PDA closure. Intravenous indomethacin effectively closes the ductus arteriosus and prevents pulmonary hemorrhage and severe intraventricular hemorrhage, but fails to mitigate short-term morbidities and improve long-term outcomes. Intravenous ibuprofen represents an alternative therapy with fewer renal adverse effects. However, intravenous ibuprofen does not prevent severe intraventricular hemorrhage and also has concerning adverse effects, including bilirubin displacement and the potential to increase the risk of chronic lung disease. Enteral ibuprofen has also been investigated, although gastrointestinal adverse effects limit widespread utilization. Acetaminophen (paracetamol) represents an enticing novel therapy due to wide availability, low cost, and an appealing safety profile. Ongoing investigation is required to determine the role of this agent in PDA treatment algorithms. Pending these results, clinicians must weigh the potential risks and benefits of each therapy for individual neonates considering all available evidence.

Longitudinal Assessment of Left and Right Myocardial Function in Preterm Infants Using Strain and Strain Rate Imaging.

BACKGROUND: There is a paucity of longitudinal data on left ventricular (LV) and right ventricular (RV) function in preterm infants of less than 29 weeks' gestation. OBJECTIVE: The aim of this study was to describe changes in tissue Doppler-derived basal longitudinal strain (BLS) and systolic (SRs), early (SRe) and late (SRa) diastolic strain rates in extremely premature infants from birth to 36 weeks postmenstrual age (PMA). METHODS: Echocardiographic assessments were carried out on days 1, 2, 5-7 and at 36 weeks PMA. We assessed the following associations: correlation with systemic vascular resistance (SVR) on day 1, influence of a patent ductus arteriosus (PDA) during days 5-7, and the effect of chronic lung disease (CLD). RESULTS: In total, 105 infants with a median gestation of 27.1 weeks (IQR 26.0-28.1) and a birthweight of 965 g (IQR 785-1,153) were included. There was an increase in most of the measurements across the four time points. On day 1, there was a weak negative correlation between SVR and LV BLS (r = -0.3, p = 0.01), SVR and septal BLS (r = -0.4, p < 0.001) and SVR and LV SRe (r = -0.4, p = 0.005). On days 5-7, infants with a PDA >1.5 mm had higher LV BLS [-13.0 (2.4) vs. -11.9 (1.9)%, p = 0.03]. At 36 weeks, infants with CLD (n = 28/47) had lower RV BLS [-26.4 (5.0) vs. -30.7 (5.5)%, p = 0.01] and lower RV SRa [4.2 (1.3) vs. 5.3 (1.9) s-1, p = 0.04]. CONCLUSION: Myocardial function undergoes important longitudinal changes in preterm infants. Left heart strain measurements appear to be weakly influenced by changes in preload and afterload. CLD appears to leave a negative impact on RV function.

Assessment of myocardial function in preterm infants with patent ductus arteriosus using tissue Doppler imaging.

OBJECTIVE: To assess myocardial function in preterm infants with different degrees of ductal patency in the first week of life using tissue Doppler imaging. STUDY DESIGN: Infants <30 weeks of gestation underwent echocardiography on day 3. A total of 72 infants were recruited into the study and categorised into three groups (i) haemodyamically significant ductus arteriosus, (ii) patent ductus arteriosus and (iii) no patent ductus arteriosus. Those with haemodynamically significant ductus arteriosus were treated with indometacin and echocardiography was repeated after 48-72 hours following treatment. Peak systolic and diastolic myocardial velocities were obtained using tissue Doppler imaging, and myocardial performance index was calculated. RESULTS: Initial myocardial velocities were significantly lower and myocardial performance index significantly higher in the haemodynamically significant ductus arteriosus group compared with other groups. For the haemodynamically significant ductus arteriosus group, post-treatment myocardial velocities were higher and myocardial performance index lower than pre-treatment. CONCLUSION: Preterm infants with haemodynamically significant ductus arteriosus had lower myocardial velocities and higher myocardial performance index, suggesting relative systolic and diastolic myocardial dysfunction. Babies whose patent ductus arteriosus remained open despite indometacin had lower pre-treatment myocardial velocities and higher myocardial performance index than those babies whose patent ductus arteriosus closed, suggesting worse myocardial function in this group. Measurement of myocardial function using tissue Doppler imaging in preterm infants is feasible and may prove to be helpful in the management of babies with patent ductus arteriosus.

Quantitative, noninvasive assessment of patent ductus arteriosus shunt flow by measuring proximal isovelocity surface area on color Doppler imaging.

BACKGROUND: We evaluated the hemodynamic status of patent ductus arteriosus (PDA) by measuring vena contracta width (VCW) and effective shunt orifice area (ESOA) using proximal isovelocity surface area (PISA) on color Doppler imaging. METHODS AND RESULTS: Study subjects were 21 patients with PDA (mean age, 3.6 years). We measured VCW (mm/m(2)) and ESOA (cm(2)) by the PISA method using echocardiography. Color images were obtained from parasternal long-axis views. VCW (mm/m(2)) was measured at the narrowest region of PDA flow. ESOA by PISA (PDA-ESOA) was defined on color Doppler flow imaging as a hemispheric area of laminar flow with aliased velocities [PDA-ESOA (cm(2))=2π[PDA radius (cm)]^2×aligning velocity (cm/s)/PDA peak velocity (cm/s)]. Upon examining the relationships with catheterization parameters by univariate analysis, VCW correlated with diastolic blood pressure (DBP), % left ventricular end-diastolic volume (%LVEDV), pulmonary blood flow index, pulmonary blood flow/systemic blood flow ratio (Qp/Qs), left-right (LR) shunt ratio, left atrial to aortic root ratio (LA/AO), chest-thoracic ratio and N-terminal pro-brain natriuretic peptide (NTproBNP); and PDA-ESOA correlated with DBP, Qp/Qs, average pulmonary artery pressure, pulmonary/systemic pressure ratio, %LVEDV, LR shunt ratio, LA/AO and NTproBNP. When stepwise multiple linear regression analysis was performed with the correlations that were significant on univariate analysis, significant correlations with Qp/Qs were noted (VCW; R(2)=0.836, ß=0.914, P<0.001, PDA-ESOA; R(2)=0.621, ß=0.788, P<0.001). CONCLUSIONS: Measurement of VCW and PDA-ESOA by the PISA method can noninvasively evaluate the hemodynamic status of PDA.

Assessment and treatment of post patent ductus arteriosus ligation syndrome.

OBJECTIVE: To compare differences in tissue Doppler imaging, global longitudinal strain (GLS), and cardiac troponin T (cTnT) between infants with low (<200 mL/kg/min) and high (>200 mL/kg/min) left ventricular (LV) output 1 hour after duct ligation and assess the impact of milrinone treatment on cardiac output and myocardial performance. STUDY DESIGN: LV function was assessed preoperatively and 1 and 18 hours postoperatively. Infants were categorized into a low-output or a normal-output group based on the echocardiographic assessment of LV output at 1 hour. RESULTS: Thirty infants with a mean gestation of 25.3 weeks were enrolled. LV basal lateral S', basal septal S', and basal right ventricular S' were lower in the low-output group (n = 19) at 1 hour postoperatively, with no significant difference in GLS (low-output -10.3% vs high-output -14.4%, P >.05) or cTnT between the groups. Patients in the low-output group were treated with milrinone, and by 18 hours LV performance recovered to levels comparable with the high output group. cTnT values increased at 18 hours in the whole cohort with no significant difference between the groups. CONCLUSION: Tissue Doppler imaging and GLS provide novel insights and further characterization of myocardial performance immediately after patent ductus arteriosus ligation. A reduction in tissue Doppler-derived LV systolic velocity may further help in monitoring cardiac performance after patent ductus arteriosus ligation and for monitoring the effects of treatment.

Left atrial volume is superior to the ratio of the left atrium to aorta diameter for assessment of the severity of patent ductus arteriosus in extremely low birth weight infants.

BACKGROUND: This study was undertaken to establish the appropriate correction of left atrial volume (LAV) to body surface area (BSA) to provide reference values and to assess the hypotheses that LAV is useful for assessing patent ductus arteriosus (PDA) severity in extremely low birth weight infants (ELBWI) and could overcome the limitations of the LA-to-aortic dimension ratio (LA/Ao). METHODS AND RESULTS: Echocardiograms with 318 data points from 53 consecutive ELBWIs were assessed. PDA surgery was performed within the first 2 weeks in 6 patients. LAV was measured using the biplane (LAV) and single-plane (LAV(4CV)) area-length methods. The allometric model was used to correlate LAV to BSA. LAV(4CV) had a good correlation with LAV (R=0.93). Although LAV/BSA(1) had a residual relationship with BSA, LAV/BSA(1.54) (23.5±9.3 ml/m(3.08)) and LAV(4CV)/BSA(1.52) (21.4±9.4 ml/m(3.04)) did not. Receiver-operating characteristic analysis to detect hemodynamic status just before PDA surgery showed the superiority of LAV/BSA(1.54) (area under the curve (AUC) 0.97) and LAV(4CV)/BSA(1.52) (AUC 0.98) over LA/Ao (AUC 0.92). Moreover, LAV/BSA(1.54) and LAV(4CV)/BSA(1.52) were better correlated with left pulmonary arterial end-diastolic velocity than was LA/Ao. CONCLUSIONS: This study provided appropriate BSA correction of LAV and its reference values in ELBWIs. LAV indices may be superior to LA/Ao for PDA severity assessment. Measurement of single-plane LAV is easy, with similar usefulness to biplane LAV.

Assessment of ductal blood flow in newborns with obstructive left heart lesions by cardiovascular magnetic resonance.

BACKGROUND: Newborns with obstructive left heart lesions often depend on a patent ductus arteriosus to sustain the systemic circulation. Our aims were to validate the direct measurement of ductal flow, and to characterize the magnitude, determinants and hemodynamic effects of patent ductus arteriosus in newborns with obstructive left heart lesions by cardiovascular magnetic resonance (CMR). METHODS: In this retrospective study, the CMR and clinical information of newborns with obstructive left heart lesions were reviewed. The feasibility and validity of measuring ductal flow and the correlations between ductal flow and ventricular volumes, ascending aortic flow, post-ductal oxygen saturation and Qp:Qs were assessed. RESULTS: The CMR examinations of 32 newborns were included. It was possible to measure the ductal flow in all of them, with moderate-to-good agreement between measured and calculated ductal flow volume. The flow was bidirectional in all patients, with a net right-to-left shunt in 72%. Net ductal flow correlated inversely with ascending aortic flow (Rho -0.63; p 0.0002), post-ductal oxygen saturation (Rho -0.58; p 0.0004), Qp:Qs (Rho -0.43; p 0.02), and with left ventricular end-diastolic volume index (Rho -0.38; p 0.04). There was no correlation with the diameter of the ductus. The contribution of ductus flow to the systemic circulation correlated with the left ventricular end-diastolic volume index (Rho -0.47; p 0.02). CONCLUSIONS: Direct measurement of ductal flow in newborns with obstructive left heart lesions is feasible. From these measurements, we were able to demonstrate that patients with smaller left ventricles and lower ascending aortic flow have a greater contribution of ductal flow to the systemic circulation. The size of the ductus arteriosus does not predict net ductal flow. Phase-contrast CMR can be an adjunct method for the assessment of the physiology for very ill neonate patients.

Assessment of PDA shunt and systemic blood flow in newborns using cardiac MRI.

Patent ductus arteriosus (PDA) remains common in preterm newborns, but uncertainty over optimal management is perpetuated by clinicians' inability to quantify its true haemodynamic impact. Our aim was to develop a technique to quantify ductal shunt volume and the effect of PDA on systemic blood flow volume in neonates. Phase contrast MRI sequences were optimized to quantify left ventricular output (LVO) and blood flow in the distal superior vena cava (SVC) (below the azygos vein insertion), descending aorta (DAo) and azygos vein. Total systemic flow was measured as SVC + DAo-azygos flow. Echo measures were included and correlated to shunt volumes. 75 infants with median (range) corrected gestation 33(+6) (26(+4) -38(+6) ) weeks were assessed. PDA was present in 15. In 60 infants without PDA, LVO matched total systemic flow (mean difference 2.06 ml/kg/min, repeatability index 13.2%). In PDA infants, ductal shunt volume was 7.9-74.2% of LVO. Multiple linear regression analysis correcting for gestational age showed that there was a significant association between ductal shunt volume and decreased upper and lower body flow (p = 0.01 and p < 0.001). However, upper body blood flow volumes were within the control group 95% confidence limits in all 15 infants with PDA, and lower body flow volumes within the control group limits in 12 infants with PDA. Echocardiographic assessment of reversed diastolic flow in the descending aorta had the strongest correlation with ductal shunt volume. We have demonstrated that quantification of shunt volume is feasible in neonates. In the presence of high volume ductal shunting the upper and lower body flow volume are somewhat reduced, but levels remain within or close to the normal range for preterm infants.

Echocardiographic assessment of ductal significance: retrospective comparison of two methods.

BACKGROUND: Patent ductus arteriosus (PDA) in preterm infants is often assessed with echocardiographic parameters, especially colour Doppler ductal diameter and pulsed Doppler flow pattern. Clinical algorithms have been proposed in which PDA treatment is indicated by either large diameter or a particular flow pattern, however it is unknown whether ductal diameter and flow pattern provide equivalent stratification of infants. AIM: Retrospectively assess both parameters in 197 echocardiograms from 104 infants (gestational age <31 weeks). METHODS: Echocardiograms were independently reviewed and the internal colour Doppler diameter of the PDA and the pulsed Doppler flow pattern were characterised for each study (169 records had both parameters recorded). RESULTS: Diameter varied widely within each group but was significantly associated with flow pattern: mean diameter was greatest in the pulmonary hypertension (PH) group (2.6 mm), progressively narrowed across growing and pulsatile groups, and was smallest in the closing group (1.3 mm). When echocardiograms were categorised using previously published diameters, 82.4% of the PH group had diameters >2.0 mm, large diameters predominated in the growing and pulsatile groups but to a progressively smaller extent, and 98.1% of closing group had diameters <2.0 mm. CONCLUSION: Ductal diameter and flow patterns are significantly associated, consistent with a narrowing of the ductus until closure. Overall, the two parameters are in good agreement but will result in different treatment decisions in some cases. Clinicians might consider using both methods as a cross check against each other, to assist in the management of preterm infants with a clinically detectable PDA.

Quantitative assessment of the degree of ductal steal using celiac artery blood flow to left ventricular output ratio in preterm infants.

BACKGROUND: Determining the significance of a patent ductus arteriosus (PDA) remains difficult in preterm neonates and current echocardiographic markers give little information about ductal steal. We hypothesized that the relationship between celiac artery flow (CAF) and left ventricular output (LVO) in the presence of a PDA may determine haemodynamic significance. OBJECTIVES: To examine CAF to LVO ratio (CAF:LVO) in the presence and the absence of a PDA in preterm neonates, and to compare CAF:LVO to current echocardiographic markers of a significant PDA. METHODS: This was a prospective observational study of neonates <1,500 g. Echocardiography was performed at 12 h and day 3. PDA, LVO and CAF were measured by echocardiography. The infants were divided into those who developed a significant PDA (PDA >1.4 mm and left atrial to aortic ratio >1.5 on day 3) and controls. A further assessment was carried out following successful PDA treatment with ibuprofen or surgical ligation. RESULTS: A total of 33 infants were enrolled. 19 infants had a PDA (median gestation 27 weeks, birth weight 915 g), and 14 controls (gestation 28.7 weeks, birth weight 1,110 g). At 12 h, there was no difference in CAF, LVO or CAF:LVO. On day 3, there was a significant difference in CAF:LVO between PDA versus control groups. CAF:LVO significantly correlated with conventional markers of ductal significance. A CAF:LVO value of 0.10 had a sensitivity of 93% and a specificity of 78% for the presence of a significant PDA. Following successful PDA treatment CAF:LVO returned to levels similar to controls. CONCLUSION: CAF:LVO may be used to determine which PDA warrants treatment and serve as a marker of treatment success. Trials are needed to correlate CAF:LVO with outcome and the impact of basing PDA treatment on this ratio.