Custo-Efetividade Incremental do Tratamento Cirúrgico vs. Percutâneo da Persistência do Canal Arterial com o Amplatzer® Duct Occluder em Crianças: Revisão Sistemática / Incremental Cost-Effectiveness of Surgical vs. Percutaneous Treatment of Patent Ductus Arteriosus with the AmplatzerTM Duct Occluder in Children: A Systematic Review

Introdução: A persistência do canal arterial (PCA) é uma cardiopatia congênita relativamente comum e as alternativas para o tratamento de canais > 2,5 mm são a cirurgia ou a oclusão percutânea com próteses do tipo rolha. Essas últimas, apesar de consideradas o método de escolha, não estão previstas pelo Sistema Único de Saúde (SUS). Nosso objetivo foi comparar a razão de custo-efetividade incremental (RCEI) de ambas as estratégias. Métodos: Revisão sistemática em relação a desfechos clínicos e criação de modelo de decisão para avaliação da RCEI do Amplatzer® Duct Occluder (ADO) em comparação ao tratamento cirúrgico, para o fechamento da PCA. Os custos para ambos os métodos foram aqueles reembolsados pelo SUS em 2010, e o custo do conjunto (dispositivo + materiais de apoio) foi estimado em R$ 10.000,00. Foi considerado como limiar uma disposição para pagar equivalente a três vezes o Produto Interno Bruto brasileiro, resultando em R$ 57.000,00 por ano de vida salvo. Resultados: As duas técnicas foram seguras e eficazes, com menor morbidade e tempo de internação no fechamento percutâneo. A expectativa de vida ajustada foi similar nos dois grupos, sendo um pouco melhor para o ADO. O custo total foi calculado em R$ 8.507,00 para cirurgia e em R$ 11.000,00 para o ADO. A RCEI foi calculada em R$ 71.380,00 por ano de vida ganho. Uma análise de limiar demonstrou que a redução do valor do conjunto completo do ADO em R$ 492,65 traria a RCEI para o limiar aceitável para incorporação ao SUS nos dias de hoje. Conclusões: O tratamento percutâneo apresentou morbidade e tempo de internação menores, além de efetividade incremental semelhante àquela do tratamento cirúrgico. Com os...

Background: Patent ductus arteriosus (PDA) is a relatively common congenital heart disease and the alternatives for the treatment of PDA > 2.5 mm are surgery or percutaneous occlusion with plugs. The latter, although considered the method of choice, are not provided by the Brazilian National Health System (Sistema Único de Saúde - SUS). Our objective was to compare the incremental cost-effectiveness ratio (ICER) of both strategies. Methods: Systematic review of clinical outcomes and development of a decision-making algorithm to evaluate the ICER of AmplatzerTM Duct Occluder (ADO) vs. surgical treatment for the closure of PDA. Costs for both methods were calculated based on the reimbursement figures paid by the SUS in 2010 and the cost of the percutaneous kit (device + support materials) was estimated at R$ 10,000.00. We used as a threshold the willingness to pay the equivalent of three times the Brazilian Gross Domestic Product, i.e., R$ 57,000.00 per year of life saved. Results: Both techniques were safe and effective with less morbidity and shorter hospitalization time for percutaneous closure. Adjusted life expectancy was similar in both groups, and slightly better for the ADO group. Total cost was calculated as R$ 8,507 for surgery and R$ 11,000.00 for ADO. ICER was calculated as R$ 71,380.00 per year of life saved. A threshold analysis showed that a reduction of R$ 492.65 in the cost of the ADO kit would reduce the ICER to an acceptable value for the incorporation of this technology by the SUS. Conclusions: Percutaneous occlusion was associated with less morbidity and shorter hospital stay with similar incremental effectiveness when compared to the surgical treatment. With the direct costs used in this study and considering that the entire population with PDA is treated with the ADO, percutaneous occlusion was less cost-effective. However, a slight reduction in the costs of the percutaneous kit would result...

Transcatheter closure of patent ductus arteriosus and atrial septal defect without on-site surgical backup: a two-year experience in an African community.

Congenital heart disease contributes significantly to the health burden of children in Nigeria. Interventions for congenital heart disease have been available in the developed world since the first report on device closure of patent ductus arteriosus (PDA) in 1967 by Porstmann. However, this did not start in Nigeria until October 2010. This study aimed to document the profiles of the patients who had undergone interventions for congenital heart diseases since the availability of the procedure, the challenges encountered, and the prospects associated with the interventions at the study site. All the patients referred to undergo interventions for congenital heart disease at the study center between October 2010 and 2012 were studied. The profile of the patient, including diagnosis at referral, indication for interventions, and interventions performed, were documented. The patients ranged in age from 3 to 62 years (mean age, 13.54 ± 17.7 years), and the male-to-female ratio was 1:3. The diagnosis at referral included PDA in 10 (83 %) of the 12 patients and secundum atrial septal defect in 2 patients (17 %). They all had transcatheter closure of the defects. Interventional procedures for congenital heart diseases currently are available locally, but the high degree of manpower training required, the cost, and the local availability of consumables are major factors limiting their use. Regional and international collaboration could be mutually beneficial.

Prevalence and management of patent ductus arteriosus in a pediatric medicaid cohort.

BACKGROUND: Widespread use of echocardiography has made earlier diagnosis of patent ductus arteriosus (PDA) possible, but pharmacological or surgical intervention is highly variable. Herein, we investigate the prevalence of PDA and its management in a routine care system. METHODS: A 15-year retrospective dataset (1996-2010) was analyzed. Selection criteria included age ≤17 years, enrollees in South Carolina State Medicaid, and diagnosed as having PDA on 1 or more service visits to a pediatrician or pediatric cardiologist. RESULTS: The 15-year treated prevalence rate of PDA was 0.25/1000 pediatric cases of congenital heart disease (CHD). PDA was more prevalent in non-African American patients (adjusted odds ratio [aOR]: 1.12), but not in females after controlling for all other CHDs diagnosed in the cohort. Associated CHDs were present in 57.6% of the cases, primarily atrial or ventricular septal defects, and fewer patients (5.5%) developed pulmonary hypertension. Of 3627 PDA cases examined, 70.0% received no medications or PDA repair. Therapeutic ibuprofen was used for closure in 24.4% of the cases, and a PDA repair was performed in 7.8%. Younger children (aOR: 0.82), those who received an atrial septal defect closure (aOR: 5.18), and those who were treated with digoxin (aOR: 1.86) or with diuretics or preload/afterload reducing agents (ie, calcium channel blockers or angiotensin-converting enzyme inhibitors) (aOR: 5.72) were significantly more likely to have a PDA repair procedure. CONCLUSIONS: The majority of diagnosed PDA cases did not require pharmacological or surgical intervention. Those receiving pharmacological or surgical intervention were treated conservatively in relation to the presence of distress symptoms or concomitant CHDs requiring intervention.

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.

Cardi-O-Fix duct occluder versus Amplatzer duct occluder for closure of patent ductus arteriosus.

BACKGROUND: We sought to investigate the safety, efficacy, and follow-up results of percutaneous patent ductus arteriosus (PDA) closure using the novel Cardi-O-Fix duct occluder (CDO), a device similar to but less expensive than the Amplatzer duct occluder (ADO). We also aimed to compare these two devices in terms of results. METHODS: Between March 2005 and May 2012, 167 patients diagnosed with moderate-to-large PDA underwent transcatheter closure. ADO was used in 56 (33.5%) patients with a mean age of 8.1 ± 11.9 years (3.6 months-56 years), whereas CDO was used in 111 (66.5%) patients with a mean age of 12.6 ± 14.6 years (4.8 months-63 years). RESULTS: The narrowest PDA diameter, the used device diameter, procedure time, fluoroscopy time, and residual shunt rates were similar between the two groups. Procedural success rate was 100% in both groups. Although the residual shunt rate was higher in the CDO group immediately after the procedure, the difference was not statistically significant (12.6 vs. 8.9%; P = 0.3). There was no statistically significant difference between groups at discharge and during follow-up. No deaths occurred in any of the groups, and there were no differences in complication rates during the short- and mid-term follow-up periods (CDO 7/111 vs. ADO 5/56; P = 0.5 π). CONCLUSION: The CDO can be used for PDA closure because of its safety, effectiveness, and simplicity in use. It is available in bigger sizes and can be used in patients with large defects. According to our short- and mid-term findings, the results it yields are similar to those of the ADO; thus, it may be the preferred choice owing to its low cost and large size variability.

B-type natriuretic peptide for assessment of haemodynamically significant patent ductus arteriosus in premature infants.

AIM: Haemodynamically significant patent ductus arteriosus (hsPDA) is frequently observed in premature infants. This study was conducted to explore whether the blood BNP can be a valuable biomarker to assess the necessity of treatment for hsPDA in premature infants. METHODS: Serial measurements of the blood BNP were performed during the first 5 days of life in premature infants with hsPDA (Group I) and those without hsPDA (Group N). The definition of the hsPDA was the PDA requiring treatment, such as indomethacin administration and/or surgical ligation. RESULTS: Forty-six subjects were enrolled. Compared with Group N, Group I showed significantly higher level of blood BNP at postnatal 24-96 h and demonstrated the peak value at postnatal 24-48 h. With the ROC curve using the data at postnatal 24-48 h in Group I, we deduced the predictive value of 250 pg/mL of blood BNP for indomethacin treatment. Similarly, with the ROC curve using the maximal value of blood BNP within the first 5 days of life, the predictive value of 2000 pg/mL for surgical ligation was deduced. CONCLUSIONS: Blood BNP during early postnatal period can be a useful biomarker to assess the necessity of treatment for hsPDA in premature infants.

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.

[First SIBEN clinical consensus: diagnostic and therapeutic approach to patent ductus arteriosus in premature newborns]. / Primer consenso clínico de SIBEN: enfoque diagnóstico y terapéutico del ductus arterioso permeable en recién nacidos pretérmino.

OBJECTIVE: To report the process and results of the first neonatal clinical consensus of the Ibero-American region. DESIGN AND METHODS: Two recognized experts in the field (Clyman and Van Overmeire) and 45 neonatologists from 23 countries were invited for active participation and collaboration. We developed 46 questions of clinical-physiological relevance in all aspects of patent ductus arteriosus (PDA). Guidelines for consensus process, literature search and future preparation of educational material and authorship were developed, reviewed and agreed by all. Participants from different countries were distributed in groups, and assigned to interact and work together to answer 3-5 questions, reviewing all global literature and local factors. Answers and summaries were received, collated and reviewed by 2 coordinators and the 2 experts. Participants and experts met in Granada, Spain for 4.5 h (lectures by experts, presentations by groups, discussion, all literature available). RESULTS: 31 neonatologists from 16 countries agreed to participate. Presentations by each group and general discussion were used to develop a consensus regarding: general management, availability of drugs (indomethacin vs. ibuprofen), costs, indications for echo/surgery, etc. Many steps were learnt by all present in a collaborative forum. CONCLUSIONS: This first consensus group of Ibero-American neonatologists SIBEN led to active and collaborative participation of neonatologists of 16 countries, improved education of all participants and ended with consensus development on clinical approaches to PDA. Furthermore, it provides recommendations for clinical care reached by consensus. Additionally, it will serve as a useful foundation for future SIBEN Consensus on other topics and it could become valuable as a model to decrease disparity in care and improve outcomes in this and other regions.

Tratamiento de conducto arterioso permeable: Comparación de costos del cierre quirúrgico y transcateterismo en una institución pública / Treatment of patent ductus arteriosus: Comparison of costs between surgical and trans-catheter closures in a public institution

El costo del tratamiento transcateterismo del conducto arterioso permeable en comparación con el quirúrgico es un asunto controvertido en nuestro medio. El propósito de este estudio fue estimar y comparar los costos directos relacionados con ambos procedimientos. Método: Se incluyeron 57 pacientes tratados con intervencionismo y 26 con cirugía. Se obtuvo información sobre las características sociodemográficas, el número y tipo de exámenes de laboratorio y de gabinete, el tipo y duración de anestesia, la duración del procedimiento y la estancia hospitalaria y de terapia intensiva. Se construyó una matriz que integró los costos del sistema institucional de costos unitarios vigente. Resultados: Ambos grupos compartían características sociodemográficas. El diámetro del conducto fue mayor en el grupo quirúrgico (p<0.05). Tanto la estancia hospitalaria como el número de complicaciones post intervención fueron menores en los pacientes tratados con intervencionismo (p<0.05). El tratamiento con dispositivo Amplatzer® es más costoso que el tratamiento quirúrgico y ambos más costosos que el oclusor tipo resorte. En el tratamiento quirúrgico el 86.5% de los costos totales lo consumen la estancia hospitalaria, con el Amplatzer® este rubro fue del 36%, sin embargo el dispositivo representa el 40% del costo total. Conclusiones: No obstante el costo del tratamiento con dispositivo Amplatzer® es mayor que el quirúrgico, el cierre con oclusor representa ventajas con relación a menor estancia hospitalaria, consumo de recursos y número de complicaciones, lo que permite la optimización de los recursos hospitalarios.

The costs of transcatheter closure of patent ductus arteriosus in relation to the surgical closure still a controvertial issue in our hospitals. The aim of the study was compared the costs of both treatments. Methods: We included 57 patients treated with transcatheter occlusion and 26 underwent surgery. Information about laboratory tests, average in hospital days of stay, anesthesia type and duration, operating and hemodinamic room costs, was gather. A database containing the costs from the institution unitary costs system in force was designed. Results: sociodemographyc characteristics were similar in both groups. Ductus size was larger in patients treated with surgery (p<0.05). In hospital stay, as well as, the number of complications after the procedure were less in the patients treated with transcatheter occlusion (p<0.05). The closure with Amplatzer® device was more expensive than the surgical one, and both were more expensive than coil. With surgical treatment, 86.5% of the costs are due to in hospital stay, with the Amplatzer® this issues represented a 36%, however, the cost of the devices by itself represents a 40% of the total treatment cost. Conclusions: Even though total charges of Amplatzer® devices are more expensive than surgery, transcatheter occlusion represents advantages in relation to less in hospital stay, resources used and number of complications, which allows hospital resources optimization.

[Treatment of patent ductus arteriosus. Comparison of costs between surgical and trans-catheter closures in a public institution]. / Tratamiento de conducto arterioso permeable. Comparación de costos del cierre quirúrgico y transcateterismo en una institución pública.

UNLABELLED: The costs of transcatheter closure of patent ductus arteriosus in relation to the surgical closure still a controvertial issue in our hospitals. The aim of the study was compared the costs of both treatments. METHODS: We included 57 patients treated with transcatheter occlusion and 26 underwent surgery. Information about laboratory tests, average in hospital days of stay, anesthesia type and duration, operating and hemodinamic room costs, was gather. A database containing the costs from the institution unitary costs system in force was designed. RESULTS: sociodemographyc characteristics were similar in both groups. Ductus size was larger in patients treated with surgery (p<0.05). In hospital stay, as well as, the number of complications after the procedure were less in the patients treated with transcatheter occlusion (p<0.05). The closure with Amplatzer device was more expensive than the surgical one, and both were more expensive than coil. With surgical treatment, 86.5% of the costs are due to in hospital stay, with the Amplatzer this issues represented a 36%, however, the cost of the devices by itself represents a 40% of the total treatment cost. CONCLUSIONS: Even though total charges of Amplatzer devices are more expensive than surgery, transcatheter occlusion represents advantages in relation to less in hospital stay, resources used and number of complications, which allows hospital resources optimization.

Comprehensive assessment of patent ductus arteriosus by echocardiography before transcatheter closure.

BACKGROUND: Anatomic type and angiographic measurements of patent ductus arteriosus (PDA) are used to determine the suitability of transcatheter closure (TCC). The purpose of this study is to evaluate whether these PDA features can be obtained by 2-dimensional echocardiography (2DE). METHODS: We retrospectively compared PDA measurements and type from 36 patients submitted to TCC between November 1995 and October 2000. RESULTS: The patient age ranged between 2 months to 10.5 years (median = 1.2 years). A significant correlation was found between measurements of PDA minimal diameter (R(2) = 0.88) and diameter at aortic ostium (R(2) = 0.72); whereas a poor correlation existed between measurements of the ampulla length. The 2DE and angiographic PDA classification were concordant in 31 of 36 (86%) patients. CONCLUSION: Our data support the use of 2DE measurements of PDA minimal diameter and PDA diameter at the aortic end to assess suitability for TCC. In the majority of cases, PDA type can be diagnosed by 2DE.

Serial pulsed Doppler assessment of early left ventricular output in critically ill very low-birth-weight infants.

Serial, detailed assessments of left ventricular output (LVO) in critically ill very low-birth-weight (VLBW) infants of four different gestational ages were performed in the early neonatal period using pulsed Doppler echocardiography. Initially, the LVO values of all groups at 3 hours of age were relatively high. However, LVO dropped transiently at 12 hours and then increased again after 24 hours reaching a steady level of 160-180 ml/kg/min after 48 hours of age. In all four groups, heart rate also decreased significantly at 12 hours of age but did not increase at 24 hours of age. Both the left ventricular stroke volume and the left ventricular ejection fraction in all groups exhibited similar longitudinal changes to those observed for LVO. The LVO values observed in the lower gestational age group were significantly lower than those observed in the upper gestational group before 24 hours of age. Both patent ductus arteriosus and mechanical ventilation did not significantly influence the changes in LVO of VLBW infants at least before 36 hours of age. Our results suggest that in the early neonatal period, there are drastic changes in LVO of VLBW infants that reflect not only changes in heart rate but also changes in myocardial contractility.

Plasma levels of natriuretic peptides and hemodynamic assessment of patent ductus arteriosus in preterm infants.

UNLABELLED: The main purpose of this study was to investigate whether circulating natriuretic peptides in premature infants reflect the hemodynamic significance of a patent ductus arteriosus (PDA). The study comprises 120 examinations in 55 premature infants with a mean gestational age of 27.2 wk and a mean birthweight of 933 g. Based on clinical and echocardiographic findings, the hemodynamic influence of ductal shunting was classified as small, moderate or large. Blood samples for N-terminal proatrial natriuretic peptide (Nt-proANP) and brain natriuretic peptide (BNP) were analysed after completion of the clinical part of the study. Linear regression indicated a very strong association between Nt-proANP and BNP (adjusted R = 0.89). The mean levels of Nt-proANP and BNP increased with the size of the shunt through a PDA, and peptide values followed hemodynamic alterations. The size of PDA accounted for 50% and 47% of the total variation in the plasma values of Nt-proANP and BNP, respectively. In detecting an echocardiographically significant PDA, the area under a ROC curve was 0.94 for Nt-proANP and 0.90 for BNP. CONCLUSION: The magnitude of shunting through a PDA is the main determinant of plasma levels of natriuretic peptides in premature infants. Nt-proANP and BNP seem to have the same pattern of secretion. Our findings indicate that measurements of natriuretic peptides may provide clinically relevant information in the hemodynamic assessment of premature infants.

Echocardiography and cardiac catheterization in the preoperative assessment of ventricular septal defect in infancy.

BACKGROUND: Cardiac catheterization is commonly performed before repair of ventricular septal defect (VSD) in infancy. No study has addressed the accuracy of echocardiography alone in defining all of the important anatomic features in this population. METHODS: Consecutive infants undergoing VSD repair between 1991 and 1995 (n = 156) were reviewed. The number of additional VSDs and the presence of commonly associated lesions were recorded for each technique and compared with a reference standard consisting of a combination of surgical findings plus postoperative echocardiography and clinical findings. The associated lesions were right ventricular muscle bundles, subaortic ridge, and persistent ductus arteriosus. RESULTS: The sensitivity and specificity of echocardiography in the detection of additional VSDs was 60% and 99% compared with 53% and 97% for cardiac catheterization and 73% and 96% for both techniques. These differences were not statistically significant. No differences were seen in the detection of commonly associated lesions. CONCLUSION: Routine preoperative cardiac catheterization for infants with a primary diagnosis of VSD is probably no longer justified.

[The spiroergometric assessment of the level of exercise hyperventilation in patients with heart defects before and after their surgical correction]. / Spiroérgometricheskaia otsenka urovnia nagruzochnoi giperventiliatsii u bol'nykh s porokami serdtsa do i posle khirurgicheskoi korrektsii.

The paper is concerned with elaboration of criteria for spiroergometric assessment of the level of load hyperventilation (LHV) in patients with heart diseases before and after surgical correction. Study of the dynamics of the correlation between CO2 production and ventilation underlies the method suggested. Four grades of LHV are distinguished: mild, moderate, pronounced and dramatic. It is shown that the pronounced and dramatic grades of LHV may provide indirect evidence for high pulmonary hypertension (stage II or III).

Doppler flow characteristics in the assessment of pulmonary artery pressure in ductus arteriosus.

The Doppler spectral pattern of flow through the ductus arteriosus was studied in 117 patients. In 37 who underwent catheterisation, Doppler records and aortic and pulmonary artery pressure were available (21 simultaneously with two catheters) for review while the others had surgical ligation of the duct on the basis of the results of non-invasive tests. Four flow patterns were obtained: (a) continuous flow, maximum velocity in late systole with gradual fall throughout diastole; (b) continuous flow, high systolic flow with rapid fall to a very low early diastolic velocity maintained throughout diastole; (c) continuous low velocity, maximum in late diastole; and (d) bidirectional flow. Flow pattern (a) was associated with normal or slightly raised pulmonary artery pressure; (b) with raised pulmonary artery pressure; and (c) and (d) with pulmonary artery pressure at systemic values. Comparison of the Doppler and measured pressure differences between the great arteries was reasonably good for peak values but poor for the trough readings. Doppler ultrasound clearly showed ductal flow; the flow pattern gave an indication of the pulmonary artery pressure, but pressure measurement by application of the Bernoulli equation to the flow velocities cannot yet be regarded as reliable.