Patency of foramen ovale--does it influence haemodynamics in newborn infants?

Interatrial Communications: Prevalence and Subtypes in 12,385 Newborns-a Copenhagen Baby Heart Study

The prevalence of interatrial communications in newborns, i.e., patent foramen ovale or atrial septal defect, was previously reported to be between 24 and 92%, but the area has been impeded by lack of a universal classification method. A recently published novel echocardiographic diagnostic algorithm for systematic classification of interatrial communications had inter-and intraobserver agreements superior to standard expert assessment. This study aimed to determine the prevalence of subtypes of interatrial communications on transthoracic echocardiography in newborns. Echocardiograms of newborns aged 0-30 days were prospectively collected in the population-based cohort study Copenhagen Baby Heart Study in 2017-2018 and analyzed according to the new diagnostic algorithm, classifying interatrial communications into three subtypes of patent foramen ovale and three subtypes of atrial septal defects. Echocardiograms from 15,801 newborns were analyzed; 3416 (21.6%) were excluded due to suboptimal image quality or severe structural heart disease (n = 3), leaving 12,385 newborns (aged 12 [interquartile range 8; 15] days, 48.2% female) included in the study. An interatrial communication was detected in 9766 (78.9%) newborns. According to the algorithm, 9029 (72.9%) had a patent foramen ovale, while 737 (6.0%) fulfilled criteria for an atrial septal defect, further divided into subtypes. An interatrial communication was seen on echocardiography in almost 80% of newborns aged 0-30 days. Patent foramen ovale was 12 times more frequent than atrial septal defects. The observed prevalence of atrial septal defects was higher than previously reported. Follow up studies could distinguish which interatrial communications require follow-up or intervention. ClinicalTrial.gov, NCT02753348, posted April 27, 2016, [ https://classic.clinicaltrials.gov/ct2/show/NCT02753348 ].

Extended period of ventilation before delayed cord clamping augments left-to-right shunting and decreases systemic perfusion at birth in preterm lambs

Previous studies have suggested that an extended period of ventilation before delayed cord clamping (DCC) augments birth-related rises in pulmonary arterial (PA) blood flow. However, it is unknown whether this greater rise in PA flow is accompanied by increases in left ventricular (LV) output and systemic arterial perfusion or whether it reflects enhanced left-to-right shunting across the ductus arteriosus and/or foramen ovale (FO), with decreased systemic arterial perfusion. Using an established preterm lamb birth transition model, this study compared the effect of a short (∼40 s, n = 11), moderate (∼2 min, n = 11) or extended (∼5 min, n = 12) period of initial mechanical lung ventilation before DCC on flow probe-derived perinatal changes in PA flow, LV output, total systemic arterial blood flow, ductal shunting and FO shunting. The LV output was relatively stable during initial ventilation but increased after DCC, with similar responses in all groups. Systemic arterial flow patterns displayed only minor differences during brief and moderate periods of initial ventilation and were similar after DCC. However, an increase in PA flow was augmented with an extended initial ventilation (P < 0.001), owing to an earlier onset of left-to-right ductal and FO shunting (P < 0.001), and was accompanied by a pronounced reduction in total systemic arterial flow (P = 0.005) that persisted for 4 min after DCC (P ≤ 0.039). These findings suggest that, owing to increased left-to-right shunting and a greater reduction in systemic arterial perfusion, an extended period of ventilation before DCC does not result in greater perinatal circulatory benefits than shorter periods of initial ventilation in the birth transition. KEY POINTS: Previous studies suggest that an extended period of initial ventilation before delayed cord clamping (DCC) augments birth-related rises in pulmonary arterial (PA) blood flow. It is unknown whether this greater rise in PA flow is accompanied by an increased left ventricular output and systemic arterial perfusion or whether it reflects enhanced left-to-right shunting across the ductus arteriosus and/or foramen ovale, with decreased systemic arterial perfusion. Anaesthetized preterm fetal lambs instrumented with central arterial flow probes underwent a brief (∼40 s), moderate (∼2 min) or extended (∼5 min) period of ventilation before DCC. Perinatal changes in left ventricular output were similar in all groups, but extended initial ventilation augmented both perinatal increases in PA flow, owing to earlier onset and greater left-to-right ductal and foramen ovale shunting, and perinatal reductions in total systemic arterial perfusion. Extended ventilation before DCC does not confer a greater perinatal circulatory benefit than shorter periods of initial ventilation.

Current treatment for childhood arterial ischaemic stroke

Paediatric arterial ischaemic stroke is an important cause of neurological morbidity in children, with consequences including motor disorders, intellectual impairment, and epilepsy. The causes of paediatric arterial ischaemic stroke are unique compared with those associated with stroke in adulthood. The past decade has seen substantial advances in paediatric stroke research and clinical care, but many unanswered questions and controversies remain. Shortage of prospective evidence for the use of recanalisation therapies in patients with paediatric stroke has resulted in little standardisation of disease management. Substantial time delays in diagnosis and treatment continue to challenge best possible care. In this Review, we highlight on some of the most pressing and productive aspects of research in the treatment of arterial ischaemic stroke in children, including epidemiology and cause, rehabilitation, secondary stroke prevention, and treatment updates focusing on advances in hyperacute therapies such as intravenous thrombolysis, mechanical thrombectomy, and critical care. Finally, we provide a future perspective for improving outcomes and quality of life for affected children and their families.

The Successful Immediate Neonatal Transition to Extrauterine Life

Purpose:

To define and describe the processes underlying the successful neonatal transition to extrauterine life and methods to assess the transition.

Method:

Cumulative Index to Nursing and Allied Health Literature (CINAHL), Embase, Web of Science, and Google Scholar were searched using a combination of the key words neonate, neonatal, newborn, transition, respiratory OR pulmonary, cardiac, metabolic, pH, umbilical cord, and assessment. Articles in English and German were reviewed. The final sample of articles consisted of one randomized controlled trial, 30 observational studies using human neonates, one observational study using rabbit pups, one secondary analysis, three systematic reviews, and 23 review articles.

Major Findings:

The pertinent findings in regard to normal events in the respiratory, cardiovascular, and metabolic transitions are reviewed and summarized. We address the underlying factors necessary for the transition to extrauterine life, specify the consequences of a successful transition, and review common assessment approaches.

Conclusion:

Available evidence indicates that the successful immediate transition to extrauterine life should be completed within 1–3 hr after birth, though some adaptive processes can fail as late as 24–48 hr after birth. Further research is necessary to identify a feasible, easily used, noninvasive method to assess the status of a neonate’s transition to extrauterine life.

Electrical Cardiometry to Monitor Cardiac Output in Preterm Infants with Patent Ductus Arteriosus: A Comparison with Echocardiography

BACKGROUND

Electrical cardiometry (EC) is an impedance-based monitoring that provides noninvasive cardiac output (CO) assessment. Through comparison to transthoracic echocardiography (Echo), the accuracy of EC has been verified. However, left-to-right patent ductus arteriosus (PDA) shunting is a concern because PDA shunts aortic flow to the pulmonary artery and may interfere with EC in measuring CO.

OBJECTIVE

To determine the agreement between EC and Echo in preterm infants with a hemodynamically significant PDA (hsPDA).

METHODS

We reviewed our hemodynamic database in which simultaneous CO measurements by Echo and EC (Aesculon®) were recorded. Preterm infants with left-to-right shunting hsPDA were enrolled.

RESULTS

A total of 105 paired measurements in 36 preterm infants were compared. Infants' median (range) age and weight at measurement were 27+2 weeks (24+0-33+1) and 1,015 g (518-1,880), with mean (95% CI) ductal diameter 2.11 mm (1.99-2.22) or 2.15 mm/kg (2.00-2.30). Mean COEC and COEcho were 252 ± 32 and 258 ± 45 mL/kg/min, respectively, which demonstrated a moderate correlation and without a significant between-measurement difference. Bland-Altman analysis showed a bias, limits of agreement, and error percentage of -5.3 mL/kg/min, -78.3 to 67.7 mL/kg/min, and 28.6%, respectively. There was a trend of increased bias and error percentage of infants with high CO ≥280 mL/kg/min and supported with high-frequency ventilator.

CONCLUSIONS

EC and Echo have a wide but clinically acceptable agreement in measuring CO in preterm infants with hsPDA. However, for infants with high CO or ventilated by high-frequency ventilation, interpretation of COEC should be approached with caution.

The methodology of Doppler-derived central blood flow measurements in newborn infants

Central blood flow (CBF) measurements are measurements in and around the heart. It incorporates cardiac output, but also measurements of cardiac input and assessment of intra- and extracardiac shunts. CBF can be measured in the central circulation as right or left ventricular output (RVO or LVO) and/or as cardiac input measured at the superior vena cava (SVC flow). Assessment of shunts incorporates evaluation of the ductus arteriosus and the foramen ovale. This paper describes the methodology of CBF measurements in newborn infants. It provides a brief overview of the evolution of Doppler ultrasound blood flow measurements, basic principles of Doppler ultrasound, and an overview of all used methodology in the literature. A general guide for interpretation and normal values with suggested cutoffs of CBFs are provided for clinical use.

A follow-up study of neonatal interatrial shunt with echocardiography until twelve to fifteen months of age

OBJECTIVES

To assess the incidence and natural history of full-term neonates with interatrial shunt (IAS).

METHODS

A follow-up study of 1389 neonates who received screening echocardiography between 2003 and 2006. Babies with IAS at 2 to 4 days of life underwent follow-up echocardiography at 2 to 4 months, 6 to 9 months and 12 to 15 months of age until closure of IAS.

RESULTS

The ratio of IAS was 68.3% initially. No significant demographic differences were identified between infants with and without initial IAS. Among 949 neonates with initial IAS, 84.5% infants had a left-to-right interatrial shunt, 13.5% had bidirectional shunt and 2% had predominantly right-to-left shunt. The persistence rate of IAS at 12 to 15 months of age was 3.8% (44/1166). The initial size of IAS ranged from 1.2 to 7.7mm (4.3+/-1.1 mm) detected by color Doppler flow mapping and cases were divided into three groups: small (< or =5 mm), medium (5 to 8 mm) and large group (> or =8 mm). There were 74.6% infants in the small group and 25.4% in the medium group initially. The neonates in the initial small group would always see their IAS close or else they would remain in the small group. Those in the final medium and large size groups always came from the initial medium group. The late closure rate of IAS was 93.9% of infants with initial IAS. The closure curves of initial small and medium sized groups were significantly different, and their late closure rates were 95.1% and 90.4%, respectively.

CONCLUSIONS

IAS was very common during early neonatal stage, but most cases would close after 1 year. The late closure rate of initial IAS was different if using a cutpoint of 5 mm.

Natural history of innocent heart murmurs in newborn babies: controlled echocardiographic study

AIM

To define the origin and the natural history of innocent heart murmurs in newborn infants.

METHODS

Fifty healthy babies born at term with the clinical diagnosis of an innocent heart murmur and 50 controls without a murmur were studied. Each baby had a complete two dimensional and pulsed Doppler echocardiogram and those with any abnormality were followed up at 6 weeks, 3 months, and 6 months until the murmur had disappeared or the heart was totally normal. Babies with congenital heart disease were excluded from the study.

RESULTS

Pulmonary branch stenosis (PBS) was found in 25 (50%) of the study group and in six (12%) controls; patent ductus arteriosus (PDA) in 30 (60%) subjects and in six (12%) controls; and a patent foramen ovale (PFO) in 50 (100%) subjects and in 41 (82%) controls. At 6 weeks the murmur had disappeared in 64% of babies. PBS was still present in eight of 22 (36%) babies at 6 weeks, in 12% at 3 months, but in none at 6 months. At 6 weeks, seven of the eight with PBS still had a murmur compared with two of 14 (14%) babies in which the PBS had resolved (P < 0.005). At 6 weeks the PDA had closed in all patients but the foramen ovale was still patent in 29 of 44 (66%) subjects and nine of 33 (27%) controls. The closure of the PFO was not influenced by its size at birth.

CONCLUSIONS

An innocent heart murmur in a baby born at term is often related to PBS, particularly if the murmur is still present after 24 hours of age, when most PDA have closed. At 6 weeks the murmur had disappeared and the PBS had resolved in 64% of the babies. PBS had resolved in all babies at 6 months.

Predictive factors for spontaneous closure of atrial septal defects diagnosed in the first 3 months of life

OBJECTIVES

To establish the rate of spontaneous closure of atrial septal defects diagnosed before age 3 months, 101 infants (mean age 26 days) with an interatrial shunt confirmed by Doppler echocardiography were followed up for an average of 265 +/- 190 days.

BACKGROUND

Even if interatrial shunts in the newborn are frequently encountered, little is known about their natural history.

METHODS

Defect diameter on two-dimensional echocardiography and width of color flow jet were measured in the subcostal view. Right and left ventricular diameters and atrial septal curvature were also studied. Kaplan-Meier curves were obtained to predict age of spontaneous closure in relation to initial defect diameter.

RESULTS

There was no significant correlation between the diameter of the atrial septal defect and right ventricular/left ventricular ratio or type of septal curvature (vertical or concave toward the left atrium). The classic predominance of girls over boys was observed only for defects > 5 mm. An overall rate of spontaneous closure of 87% was observed. Frequency and timing of closure were inversely correlated to atrial septal defect diameter: closure occurred in 100% (32 of 32) of defects in group 1 (diameter < 3 mm), 87% of defects (39 of 45) in group 2 (diameter 3 to 5 mm), 80% of defects (16 of 20) in group 3 (diameter 5 to 8 mm). Spontaneous closure did not occur in four patients of group 4 (defect > or = 8 mm) during an average follow-up interval of 417 days (range 294 to 597 days).

CONCLUSIONS

These results suggest that infants with an atrial septal defect < 3 mm need not be followed up as 100% of these defects will be closed by age 18 months; those with a defect 3 to 5 or 5 to 8 mm should be evaluated by the end of the 12th and the 15th month, respectively, when > 80% of these defects will be closed. An atrial septal defect with a diameter > or = 8 mm may have little chance of closing spontaneously and the possibility of surgical correction should be considered. Defects < 3 mm probably do not constitute a cardiac malformation in light of their natural evolution and gender distribution.