Assessment of myocardial performance in preterm infants less than 29 weeks gestation during the transitional period

Challenges in clinical identification of right ventricular dysfunction in preterm infants with persistent pulmonary hypertension of the newborn

BACKGROUND

Right ventricular dysfunction, typically qualitatively diagnosed (Q-RVd) in preterm infants, requires echocardiography which is not always acutely available. We aimed to identify clinical indices of Q-RVd in very preterm infants (gestational age, GA <32 weeks) with persistent pulmonary hypertension of newborn (PPHN) and examine the reliability and validity of Q-RVd.

METHODS

Forty-seven infants with mean ± SD GA of 26.8 ± 2.7 weeks who had targeted neonatal echocardiography (TNE) ≤72 h old, during PPHN, were retrospectively studied. Three standard TNE clips were reviewed by two blinded assessors, and infants categorized as Q-RVd if moderate-severe RVd was diagnosed on ≥2 clips. Cardiopulmonary clinical indices at TNE and quantitative RV functional markers were compared between Q-RVd vs. no-RVd groups. Potential quantitative RVd definitions examined by classifying each measurement as "low" or "normal" using published data. Inter-rater agreement for Q-RVd assessed using Kappa statistics.

RESULTS

Mean age at TNE was 25.3 ± 20.4 h with Q-RVd diagnosed in 19(40 %) infants. Q-RVd group demonstrated higher peak oxygen requirements (96 ± 9 % vs. 84 ± 16 %, p < 0.01); however, no clinical parameters at TNE differentiated the groups. Quantitative measures were lower in Q-RVd patients, confirming classification validity. Among tested quantitative definitions, low RV stroke volume was associated with lower systolic blood pressure (41±7 vs. 47±9 mmHg, p = 0.02) and higher shock index (4.02±0.80 vs. 3.44±0.72, p = 0.02). Kappa for Q-RVd was 0.55 (95%CI 0.32-0.77).

CONCLUSIONS

The non-specific nature of clinical markers of RVd in preterm infants with PPHN necessitates echocardiographic diagnosis of RVd. Studies should examine prognostic relevance of RVd and establish outcome-based quantitative definitions in preterm infants.

Haemodynamic assessment and management of hypotension in the preterm

The management of low blood flow states in premature neonates is fraught with many challenges. We remain over-reliant on regimented stepwise protocols that use mean blood pressure as a threshold for intervention to guide treatment, without giving due consideration to the underlying pathophysiology. The current available evidence does not reflect the need to concentrate on the unique pathophysiology of the preterm infant and thus leads to widespread misuse of vasoactive agents that often do not provide the desired clinical effect. Therefore, understanding the underlying pathophysiological underpinnings of haemodynamic compromise may better guide choice of agent and assess physiological response to the selected intervention.

The association between patterns of early respiratory disease and diastolic dysfunction in preterm infants

BACKGROUND

This study aims to determine the association between clinical patterns of early respiratory disease and diastolic dysfunction in preterm infants.

METHODS

Preterm infants <29 weeks' gestation underwent cardiac ultrasounds around day 7 and 14-21. Respiratory dysfunction patterns were classified as stable (ST), respiratory deterioration (RD) or early persistent respiratory dysfunction (EPRD) according to oxygen need. Diastolic dysfunction was diagnosed using a multi-parameter approach including left atrial strain (LASR) to help differentiate between cardiac or pulmonary pathophysiology.

RESULTS

98 infants (mean 27 weeks) were included. The prevalence of ST, RD and EPRD was 53%, 21% and 26% respectively. Diastolic dysfunction was more prevalent in the RD and EPRD groups with patent ductus arteriosus and significant growth restriction as risk factors. Not all infants with a PDA developed diastolic dysfunction. LASR was lower in the EPDR group.

CONCLUSION

Respiratory dysfunction patterns are associated with diastolic dysfunction in preterm infants.

Relationship between cerebral oxygenation, cardiac output, and blood pressure during transitional period in extremely low gestational age neonates

Objective

To describe the relationship between cerebral oxygenation, cardiac output, arterial blood pressure (BP), and cerebral blood flow velocity in extremely low gestational age neonates (ELGANs) during transition.

Methods

This study comprises secondary analyses from a prospective observational study conducted at a tertiary Neonatal Intensive Care Unit. Recruited ELGANs underwent cerebral saturation (CrSO2) monitoring and serial echocardiography during 72 h from birth. Correlative analyses of CrSO2 and cerebral fractional tissue oxygen extraction (CFTOE) with left (LVO) and right ventricular output (RVO), superior vena cava (SVC) flow, middle cerebral artery blood flow mean velocity (MCA.MV), systolic (SBP), diastolic (DBP), and mean (MBP) BP were conducted.

Results

Fifty ELGANs with median (range) gestational age of 25.9 (23.1-27.9) weeks were recruited. Echocardiography was performed sequentially at a median (range) age 5.0 (3.8-6.6), 17.3 (15.4-19.4), 31.0 (27.0-34.1), and 53.7 (49.3-58.3) hours. RVO, LVO, CrSO2, and SBP increased over time but no changes in MBP, DBP, CFTOE, MCA.MV or SVC flow were noted. A weak correlation was identified between CrSO2 and SBP (r2 = 0.11, p = 0.047) and MBP (r2 = 0.12, p = 0.04) at 17.3 (15.4-19.4) hours. No correlation of either CrSO2 or CFTOE with any measures of blood flow was identified.

Conclusion

There is a weak correlation between measures of cardiac output, BP, and MCA.MV with both CrSO2 and CFTOE in ELGANs during transition. Whether this finding suggests intact cerebral autoregulation requires prospective evaluation in a cohort of sick ELGANs.

The value of pulmonary artery acceleration time in evaluating pulmonary vascular disease in preterm infants with bronchopulmonary dysplasia

OBJECTIVES

Early screening and dynamic monitoring of pulmonary vascular disease (PVD) in bronchopulmonary dysplasia (BPD) high-risk infants is of great clinical significance. Pulmonary artery acceleration time (PAAT) is a reliable and non-invasive method for assessing PVD in children over 1 year, but to date, few studies have used PAAT to assess pulmonary hemodynamics of preterm infants, especially those with BPD. Through dynamic monitoring the main hemodynamic indicators reflected PVD after birth, this study aimed to assess the value of PAAT in evaluating early PVD in BPD infants.

METHODS

All 81 preterm infants at risk of BPD were divided into BPD and non-BPD groups according to whether BPD occurred. Clinical characteristics, PAAT, right ventricular ejection time (RVET) and other main hemodynamic indicators at four different time points after birth were studied and compared.

RESULTS

PAAT and PAAT/RVET increased gradually within 72 h after birth in the BPD group (p < .05), but the curve tended to be flat over time after 72 h (p > .05). At PMA32 and 36 weeks, the PAAT (49.7 ± 4.8 vs. 54.8 ± 5.7, p = .001; 50.0 ± 5.3 vs. 57.0 ± 5.3, p = .001) and PAAT/RVET (.33 ± .04 vs. .35 ± .03, p = .001; .34 ± .03 vs. .37 ± .04, p = .001) in BPD group were significantly lower than those in the non-BPD group.

CONCLUSIONS

PAAT and PAAT/RVET in the BPD group infants showed different change patterns compared to non-BPD group infants. PAAT can be used as a noninvasive and reliable screening method for screening and dynamic monitoring of PVD in BPD high-risk infants.

Is perfusion index a surrogate indicator of left ventricular contractility in neonates? A prospective study

Introduction

Noninvasive blood pressure monitoring may not accurately reflect cardiac contractility in neonates due to low vascular tone. The perfusion index (PI) is a noninvasive method of assessing the strength of peripheral pulses. It is shown to have a significant correlation with the left ventricular output. This prospective study estimates the correlation between PI and cardiac contractility in neonates.

Methods and Results

All hemodynamically stable neonates who were on substantial enteral feeds and not on any respiratory or inotropic support underwent measurement of PI and echocardiography examination. Various indices of left ventricular contractility were estimated, and the correlation coefficient between them and PI was determined. Fifty-six neonates were studied. The median (interquartile range [IQR]) PI was 1.5 (1.25-1.75). The median (IQR) PI in preterm neonates was 1.5 (1.2-1.8) and that in term neonates was 1.8 (1.25-2.7) (P = 0.064). PI had a correlation of 0.205 with fractional shortening (P = 0.129) and 0.13 with left ventricular ejection fraction (P = 0.821). The Spearman's correlation coefficient between PI and velocity of circumference fiber shortening was 0.009 (P = 0.945). The Spearman's correlation coefficient between PI and cardiac output was -0.115 (P = 0.400).

Conclusion

The PI does not correlate with left ventricular contractility parameters in neonates.

Impact of Aortic Diameter Measurements at Three Anatomical Landmarks on Left Ventricular Output Calculation in Neonates

OBJECTIVES

To assess reproducibility and accuracy of left ventricular output (LVO) quantifications in neonates, when left ventricular outflow tract diameter (LVOTD) was measured at the hinges of the aortic valve (AV), at the aortic sinus (AS), and at the sinotubular junction (STJ).

METHODS

This was an observational study. In the first cohort of very preterm neonates, we assessed intraobserver and interobserver repeatability of LVOTD measured at the AV, AS, and STJ and of the corresponding LVO. In the second cohort of older neonates, we compared paired LVO measurements by echo and magnetic resonance imaging (MRI).

RESULTS

In the first cohort of 48 neonates, mean (standard deviation) weight and age at scan were 1046 (302) g and 28.1 (2.7) weeks. Interobserver bias (95% limits of agreement [LOA]) for LVOTD at the AV, AS, and STJ was 0 (-0.3 to 0.3) mm, 0 (-0.7 to 0.7) mm, and 0 (-0.8 to 0.7) mm, respectively. Interobserver bias (95% LOA) for the corresponding LVO was -1.3 (-31 to 33) ml/kg/min, -0.5 (-88 to 87) ml/kg/min, and -7.2 (-83 to 69) ml/kg/min, respectively. In the second cohort of 10 neonates, median (range) weight and age at scan were 1942 (970-3640) g and 37.2 (31.7-39.8) weeks. LVO measured at the AV showed stronger agreement with MRI: bias (LOA) -10.6 (-74 to 52) ml/kg/min, compared to LVO measured at AS and STJ: 194 (-0.5 to 388) ml/kg/min and 43 (-72 to 159) ml/kg/min respectively.

CONCLUSIONS

Reproducibility and accuracy of LVO quantification by echo were better when aortic diameter was measured at AV.

Feasibility, Reproducibility and Reference Ranges of Left Atrial Strain in Preterm and Term Neonates in the First 48 h of Life

Left atrial strain (LAS) is the most promising technique for assessment of diastolic dysfunction but few data are available in neonates. Our aim was to assess feasibility and reproducibility, and to provide reference ranges of LAS in healthy neonates in the first 48 h of life. We performed one echocardiography in 30 neonates to assess feasibility and develop a standard protocol for image acquisition and analysis. LAS reservoir (LASr), conduit (LAScd) and contraction (LASct) were measured. We performed echocardiography at 24 and 48 h of life in an unrelated cohort of 90 neonates. Median (range) gestational age and weight of the first cohort were 34.4 (26.4–40.2) weeks and 2075 (660–3680) g. LAS feasibility was 96.7%. Mean (SD) gestational age and weight of the second cohort were 34.2 (3.8) weeks and 2162 (833) g. Mean (SD) LASr significantly increased from 24 to 48 h: 32.9 (3.2) to 36.8 (4.6). Mean (SD) LAScd and LASct were stable: −20.6 (8.0) and −20.8 (9.9), −11.6 (4.9) and −13.5 (6.4). Intra and interobserver intraclass correlation coefficient for LASr, LAScd and LASct were 0.992, 0.993, 0.986 and 0.936, 0.938 and 0.871, respectively. We showed high feasibility and reproducibility of LAS in neonates and provided reference ranges.

Right ventricular function and vasoactive peptides for early prediction of bronchopulmonary dysplasia

BACKGROUND

To assess the prognostic value of early echocardiographic indices of right ventricular function and vasoactive peptides for prediction of bronchopulmonary dysplasia (BPD) or death in very preterm infants.

METHODS

Prospective study involving 294 very preterm infants (median [IQR] gestational age 28.4 [26.4-30.4] weeks, birth weight 1065 [800-1380] g), of whom 57 developed BPD (oxygen supplementation at 36 weeks postmenstrual age) and 10 died. Tricuspid annular plane systolic excursion (TAPSE), right ventricular index of myocardial performance (RIMP), plasma concentrations of mid-regional pro-atrial natriuretic peptide (MR-proANP) and C-terminal pro-endothelin-1 (CT-proET1) were measured on day 7 of life.

RESULTS

RIMP was significantly increased (median [IQR] 0.3 [0.23-0.38] vs 0.22 [0.15-0.29]), TAPSE decreased (median [IQR] 5.0 [5.0-6.0] vs 6.0 [5.4-7.0] mm), MR-proANP increased (median [IQR] 784 [540-936] vs 353 [247-625] pmol/L), and CT-proET1 increased (median [IQR] 249 [190-345] vs 199 [158-284] pmol/L) in infants who developed BPD or died, as compared to controls. All variables showed significant but weak correlations with each other (rS -0.182 to 0.359) and predicted BPD/death with similar accuracy (areas under receiver operator characteristic curves 0.62 to 0.77). Multiple regression revealed only RIMP and birth weight as independent predictors of BPD or death.

CONCLUSIONS

Vasoactive peptide concentrations and echocardiographic assessment employing standardized measures, notably RIMP, on day 7 of life are useful to identify preterm infants at increased risk for BPD or death.

Physiology of Low Blood Pressure During the First Day After Birth Among Extremely Preterm Neonates

OBJECTIVE

To investigate the circulatory physiology of hypotension during the first day after birth among stable extremely preterm neonates.

STUDY DESIGN

Case-control study of neonates born at ≤27^6/7 weeks gestational age with hypotension, defined as mean blood pressure in mmHg less than gestational age in weeks for at least 1 hour during the first 24 hours after birth, who underwent comprehensive echocardiography assessment before commencement of cardiovascular drugs. Neonates with hypotension (n = 14) were matched by gestational age and intensity of respiratory support with normotensive neonates (n = 27) who underwent serial echocardiography during the first day after birth, and relatively contemporaneous echocardiography assessments were used for comparison.

RESULTS

Neonates with hypotension had a higher frequency of patent ductus arteriosus ≥1.5 mm (71% vs 15%; P < .001) and ductal size (median diameter, 1.6 mm [IQR, 1.4-2.1] vs 1.0 mm [IQR, 0-1.3]; P = .002), higher echocardiography indices of left ventricular systolic function (mean shortening fraction, 34 ± 7% vs 26 ± 4%; P < .001; mean longitudinal strain, -16 ± 5% vs -14 ± 3%; P = .04; and mean velocity of circumferential fiber shortening, 1.24 ± 0.35 circ/s vs 1.01 ± 0.28 circ/s; P = .03), lower estimates of left ventricular afterload (mean end-systolic wall stress, 20 ± 7 g/cm² vs 30 ± 9 g/cm²; P < .001 and mean arterial elastance, 43 ± 19 mmHg/mL vs 60 ± 22 mmHg/mL; P = .01), without significant difference in stress-velocity index z-score (-0.42 ± 1.60 vs -0.88 ± 1.30; P = .33). Neonates with hypotension had higher rates of any degree of intraventricular hemorrhage (71% vs 22%; P = .006).

CONCLUSIONS

Low blood pressure in otherwise well extremely low gestational age neonates was associated with low systemic afterload and larger patent ductus arteriosus, but not left ventricular dysfunction.

Early targeted patent ductus arteriosus treatment in premature neonates using a risk based severity score: study protocol for a randomised controlled trial (PDA RCT)

A patent ductus arteriosus (PDA) in preterm infants is associated with increased ventilator dependence and chronic lung disease, necrotizing enterocolitis, intraventricular haemorrhage, and poor neurodevelopmental outcome. Randomised controlled trials of early PDA treatment have not established a drop in the aforementioned morbidities. Those trials did not physiologically categorise PDA severity. Incorporating the specific physiological features of a haemodynamic significant PDA may evolve our understanding of this phenomenon, allowing accurate triaging using echocardiography and targeted treatment.  Our group has recently demonstrated that a PDA severity score (PDAsc) derived at 36-48 hours of age can accurately predict the later occurrence of chronic lung disease or death (CLD/Death). Using echocardiography, we assessed PDA characteristics, as well as left ventricular diastolic function and markers of pulmonary overcirculation, and from this formulated a PDAsc. Gestation was also incorporated into the score. We hypothesise that in preterm infants at high risk of developing CLD/Death based on a PDAsc, early treatment with Ibuprofen compared with placebo will result in a reduction in CLD/Death. This is a single centre double-blind two arm randomised controlled trial conducted in the neonatal intensive care unit in the Rotunda Hospital, Dublin. Echocardiogram is carried out in the first 36-48 hours of life to identify preterm infants with a PDAsc ≥ 5.0 and these infants are randomised to Ibuprofen or placebo. Primary outcomes are assessed at 36 weeks post menstrual age. This pilot study's purpose is to assess the feasibility of performing the trial and to obtain preliminary data to calculate a sample size for a definitive multi-centre trial of early PDA treatment using a PDAsc. We aim to recruit a total of 60 infants with a high risk PDA over three years. Trial Registration: ISRCTN ISRCTN13281214 (26/07/2016) and the European Union Drug Regulating Authorities Clinical Trials Database 2015-004526-33 (03/12/2015).

Echocardiographic Assessment of Right Ventricular Afterload in Preterm Infants: Maturational Patterns of Pulmonary Artery Acceleration Time Over the First Year of Age and Implications for Pulmonary Hypertension

BACKGROUND

Assessment of pulmonary hemodynamics is critical in the diagnosis and management of cardiopulmonary disease of premature infants, but reliable noninvasive indices of pulmonary hemodynamics in preterm infants are lacking. Because pulmonary artery acceleration time (PAAT) is a validated noninvasive method to assess right ventricular (RV) afterload in infants and children, the aim of this study was to investigate the maturational changes of PAAT measures in preterm infants over the first year of age and to discern the impact of typical cardiopulmonary abnormalities on these measures.

METHODS

In a prospective multicenter study of 239 preterm infants (<29 weeks at birth), PAAT was assessed at days 1, 2, and 5 to 7, at 32 and 36 weeks' postmenstrual age, and at 1-year corrected age. To account for heart rate variability, PAAT was adjusted for RV ejection time. Premature infants who developed bronchopulmonary dysplasia or had echocardiographic findings of pulmonary hypertension were analyzed separately. Intra- and interobserver reproducibility analysis was performed.

RESULTS

PAAT was feasible in 95% of the image acquisitions, and there was high intra- and interobserver agreement (intraclass correlation coefficients > 0.9 and coefficients of variation < 6%). In uncomplicated preterm infants (n = 103 [48%]) PAAT and PAAT adjusted for RV ejection time increased longitudinally from birth to 1-year corrected age (P < .001) and were linearly associated with gestational age at birth (r = 0.81 and r = 0.82, P < .001) and increasing postnatal weight and postnatal age (r > 0.81, P < .001). PAAT measures were significantly reduced (P < .001) in infants with bronchopulmonary dysplasia and/or pulmonary hypertension (n = 119 [51%]) beyond 1 week of age.

CONCLUSIONS

PAAT measures increase in preterm infants from birth to 1-year corrected age, reflective of the physiologic postnatal drop in RV afterload. Bronchopulmonary dysplasia and pulmonary hypertension have a negative impact on PAAT measures. By demonstrating excellent reliability and establishing reference patterns of PAAT in preterm infants, this study suggests that PAAT and PAAT adjusted for RV ejection time can be used as complementary parameters to assess physiologic and pathologic changes in pulmonary hemodynamics in neonates.

Maturational patterns of left ventricular rotational mechanics in pre-term infants through 1 year of age

BACKGROUND

Pre-mature birth impacts left ventricular development, predisposing this population to long-term cardiovascular risk. The aims of this study were to investigate maturational changes in rotational properties from the neonatal period through 1 year of age and to discern the impact of cardiopulmonary complications of pre-maturity on these measures.

METHODS

Pre-term infants (<29 weeks at birth, n = 117) were prospectively enrolled and followed to 1-year corrected age. Left ventricular basal and apical rotation, twist, and torsion were measured by two-dimensional speckle-tracking echocardiography and analysed at 32 and 36 weeks post-menstrual age and 1-year corrected age. A mixed random effects model with repeated measures analysis was used to compare rotational mechanics over time. Torsion was compared in infants with and without complications of cardiopulmonary diseases of pre-maturity, specifically bronchopulmonary dysplasia, pulmonary hypertension, and patent ductus arteriosus.

RESULTS

Torsion decreased from 32 weeks post-menstrual age to 1-year corrected age in all pre-term infants (p < 0.001). The decline from 32 to 36 weeks post-menstrual age was more pronounced in infants with cardiopulmonary complications, but was similar to healthy pre-term infants from 36 weeks post-menstrual age to 1-year corrected age. The decline was due to directional and magnitude changes in apical rotation over time (p < 0.05).

CONCLUSION

This study tracks maturational patterns of rotational mechanics in pre-term infants and reveals torsion declines from the neonatal period through 1 year. Cardiopulmonary diseases of pre-maturity may negatively impact rotational mechanics during the neonatal period, but the myocardium recovers by 1-year corrected age.

Left ventricular ejection fraction using manual and semi-automated biplane method of discs in very preterm infants

BACKGROUND

Biplane left ventricular ejection fraction (LVEF) is a valuable echocardiographic parameter for assessment of LV systolic pump efficiency in adults and children, but not often reported in preterm infants. The primary aim of this study was to longitudinally measure biplane LVEF in very preterm infants during the neonatal intensive care period. Secondary aim was to compare manual and semi-automatic determination of LVEF for agreement and variability.

METHODS

Stable preterm infants less than 30 weeks gestation were scanned on day 3, day 28, and at 36 weeks postmenstrual age. The LV endocardium was traced manually and semi-automatically using integrated speckle tracking software in apical 4-chamber and apical 3-chamber images to obtain end-diastolic volume and end-systolic volume, and calculate LVEF. Agreement between methods and variability within and between observers was determined using an interclass correlation coefficient (ICC) and Bland-Altman analysis.

RESULTS

Sixty-six preterm infants with a mean birth weight of 1100 (239) g were analyzed. The average manual biplane LVEF was 58 (3)%, 59 (3)%, and 55 (4)% at the three respective time points. Manual LVEF showed good agreement with semi-automatic LVEF (ICC 0.76) with a small bias of -1.5 (3.0)%. Interobserver variability of LVEF improved with semi-automatic tracing of the LV endocardial border (ICC manual 0.68 vs semi-automatic 0.80).

CONCLUSION

Left ventricular systolic pump efficiency in preterm infants remains stable during the neonatal intensive care period. Semi-automatic biplane LVEF has less interobserver variability and can be used interchangeably with manual biplane LVEF.

Myocardial function in late preterm infants during the transitional period: comprehensive appraisal with deformation mechanics and non-invasive cardiac output monitoring

BACKGROUND

There is a paucity of functional data on mid-to-late preterm infants between 30+0 and 34+6 weeks gestation. We aimed to characterise transitional cardiopulmonary and haemodynamic changes during the first 48 hours in asymptomatic mid-to-late preterm infants.

METHODS

Forty-five healthy preterm newborns (mean ± standard deviation) gestation of 32.7 ± 1.2 weeks) underwent echocardiography on Days 1 and 2. Ventricular mechanics were assessed by speckle tracking-derived deformation, rotational mechanics, tissue Doppler imaging, and right ventricle-focused measures (tricuspid annular plane systolic excursion, fractional area change). Continuous haemodynamics were assessed using the NICOM™ system to obtain left ventricular output, stroke volume, heart rate, and total peripheral resistance by non-invasive cardiac output monitoring.

RESULTS

Right ventricular function increased (all measures p < 0.005) with mostly stable left ventricular performance between Day 1 and Day 2. NICOM-derived left ventricular output [mean 34%, 95% confidence interval 21-47%] and stroke volume [29%, 16-42%] increased with no change in heart rate [5%, -2 to 12%]. There was a rise in mean blood pressure [11%, 1-21%], but a decline in total peripheral resistance [-14%, -25 to -3%].

CONCLUSION

Left ventricular mechanics remained persevered in mid-to-late premature infants, but right ventricular function increased. Non-invasive cardiac output monitoring is feasible in preterm infants with an increase in left ventricular output driven by an improvement in stroke volume during the transitional period.

Left Ventricular Diastolic Dysfunction and Diastolic Heart Failure in Preterm Infants

Diastolic dysfunction is primarily an echocardiographic diagnosis. Its clinical counterpart is diastolic heart failure, where the heart has difficulty to fill at normal pressure and the patient develops signs of pulmonary edema. Although diastolic dysfunction is common in adults, limited information is available in preterm infants. The aim of this study is to explore left ventricular diastolic dysfunction and diastolic heart failure in preterm infants and describe clinical manifestations in this population. This is a retrospective observational study in preterm infants < 30 weeks' gestation who received an echocardiography in the first 4 weeks after birth. Diastolic dysfunction was graded using a population-specific adapted version of the adult recommendations for the evaluation of left ventricular diastolic function by echocardiography. Left ventricular diastolic dysfunction was absent, indeterminate, and definite in 82%, 14%, and 4% of the 168 echocardiograms analyzed, and is associated with increased respiratory signs and respiratory deterioration at 48 h before echocardiogram. In seven infants, diastolic heart failure was diagnosed with both ultrasound and clinical signs. The cumulative risk of diastolic dysfunction increased with the increasing postnatal age and a patent ductus arteriosus. Evidence of left ventricular diastolic dysfunction on echocardiography is relatively common in preterm infants, while the left ventricular diastolic heart failure is less frequent. Prolonged exposure to volume load was the most common cause.

NT-proBNP as an Early Marker of Diastolic Ventricular Dysfunction in Very-Low-Birth-Weight Infants

The objective is to examine the correlation between plasma levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) and tissue Doppler imaging (TDI) echocardiographic parameters in the first 28 days of life in very-low-birth-weight infants (VLBWI). VLBWI admitted to the Neonatal Intensive Care Unit (NICU) at Hospital Puerta del Mar, Spain, from January 2015 to January 2017 were prospectively enrolled. Weekly determination of plasma NT-proBNP (pg/mL), and echocardiograms were done during the first 28 days of life. 101 preterm infants with a mean GA of 28.85 weeks (± 1.85 SD) and mean birth weight of 1152 g (± 247.4 SD) were included. A total of 483 echocardiograms and 139 NT-proBNP determinations were performed. We found a negative correlation between plasma NT-proBNP levels and diastolic velocities: mitral A' (ρ = - 0.15, p = 0.04), mitral E' (ρ = - 0.17, p = 0.02), tricuspid A' (ρ = - 0.20, p = 0.006), tricuspid E' (ρ = - 0.24, p = 0.0009). In the first 24 h of life, NT-proBNP levels were strongly correlated with mitral A' and E' velocities in patients with no patent ductus arteriosus (PDA) (ρ = - 0.75, p = 0.04). In preterm patients, elevated NT-proBNP levels are related to worse diastolic myocardial function. In the first 24 h, this correlation is much stronger in the absence of PDA.

Reproducibility of the assessment of myocardial function through tissue Doppler imaging in very low birth weight infants

OBJECTIVES

This study aims to analyze the variability between two trained neonatologists when performing consecutive echocardiograms using tissue Doppler imaging (TDI) and conventional methods in very low birth weight infant (VLBWI).

METHODS

Two serial echocardiograms were performed in 30 VLBWI infants. The echocardiographic parameters analyzed were tricuspid annular plane systolic excursion (TAPSE), A', E', and S' waves, and myocardial performance index acquired by TDI (MPI-TDI) of both ventricles and shortening fraction (SF). The intra-observer and inter-observer agreements and the intra-operator agreement were analyzed using quantitative and qualitative statistical methods.

RESULTS

The intra-observer agreement was very good, TAPSE, and TDI-derived parameters had an intra-class correlation (ICC) > 0.8. TDI-derived velocities had a coefficient of variation (COV) < 11%, while MPI-TDI had a COV between 20%-28%. The inter-observer agreement was excellent. There was greater variability when analyzing intra-operator agreement, with the least variable parameter being TAPSE. According to PABAK, the variability presented moderately substantial agreement.

CONCLUSIONS

Tricuspid annular plane systolic excursion is very reproducible between observers and operators. Measurements of TDI wave velocities are more reproducible than MPI-TDI. TDI is sufficiently reproducible in the VLBWI if adequate training is performed, and guidelines are followed to obtain standardized echocardiographic images.

Future perspectives on the use of deformation analysis to identify the underlying pathophysiological basis for cardiovascular compromise in neonates

The assessment of the wellbeing of the cardiovascular status in premature infants has come to the forefront in recent years. There is an increasing realisation that myocardial performance, systemic blood flow and end-organ perfusion (particularly during the transitional period) play an important role in determining short and long-term outcomes in this population. The recent open access series on Neonatologist Performed Echocardiography (NPE) published in this journal outline the necessary techniques for image acquisition and analysis and provide a framework for the potential clinical applications of NPE in neonatal, and specifically preterm care. In this "Future Perspectives" review, we describe the important determinants of adequate cellular metabolism and myocardial performance (e.g. loading conditions, intrinsic contractility and morphological change), we discuss the maladaptive state of the preterm cardiovascular system, and highlight the emerging role that non-invasive echocardiography techniques, such as deformation analysis, serve in identifying the underlying physiological basis for cardiovascular instability.

Postnatal Myocardial Function in Monochorionic Diamniotic Twins with Twin-to-Twin Transfusion Syndrome following Selective Laser Photocoagulation of the Communicating Placental Vessels

BACKGROUND

Monochorionic diamniotic (MCDA) twins are at risk for developing twin-to-twin transfusion syndrome (TTTS) throughout pregnancy. This may lead to myocardial dysfunction in the recipient and/or donor twin that persists beyond delivery. Selective laser photocoagulation of the communicating placental vessels (SLPCV) attempts to mitigate the cardiovascular outcomes. The objective of this study was to characterize early postnatal myocardial performance in MCDA twins with TTTS with and without SLPCV.

METHODS

A prospective study was performed of four MCDA twin groups: (1) uncomplicated MCDA twins, (2) MCDA twins with selective fetal growth restriction, (3) MCDA twins with TTTS following SLPCV (TTTS with SLPCV), and (4) MCDA twins with TTTS who did not undergo SLPCV (TTTS without SLPCV). Fifty-four twin pairs were enrolled: 23 uncomplicated MCDA twin pairs, 15 pairs with selective fetal growth restriction, seven TTTS pairs with SLPCV, and seven TTTS pairs without SLPCV. In each group, twin pairs were divided by birth weight into donor (smaller) and recipient (larger) and compared. Echocardiography was performed on day 1, day 2, and between days 5 and 7 of age, and myocardial performance was characterized by speckle-tracking echocardiography-derived left ventricular and right ventricular longitudinal strain (LS) and systolic strain rate (LSR). Longitudinal strain and longitudinal systolic strain rate are expressed as absolute values.

RESULTS

Compared with all recipient groups, recipient TTTS without SLPCV infants had lower left ventricular LS (16 ± 3% vs 22%-24%, P < .01) and right ventricular LS (15 ± 5% vs 21%-24%, P < .01) on day 1 that persisted throughout the first week of age. Left ventricular LSR (1.7 ± 0.3 vs 2.3 ± 0.3 sec^-1, P < .05) and right ventricular LSR (1.5 ± 0.4 vs 1.7 ± 0.5 sec^-1, P < .05) were both lower in the recipient compared with the donor twin in the TTTS without SLPCV group. LS and LSR measurements were similar among all four donor twin groups.

CONCLUSIONS

Biventricular performance is diminished in recipient MCDA twins with TTTS who are not treated with SLPCV, highlighting the need for close monitoring of their hemodynamic status during the early neonatal period.

Maturational patterns in right ventricular strain mechanics from the fetus to the young infant

AIM

To test the hypothesis that right ventricular (RV) function has age-specific patterns of development, we tracked the evolution of RV strain mechanics by 2D-speckle tracking echocardiography (2DSTE) in healthy subjects from mid-gestation through one year of age.

METHODS

We conducted a prospective longitudinal echocardiography study in 50 healthy subjects at five time periods across gestation (16-20 weeks, 21-25 weeks, 26-30 weeks, 31-35 weeks, and 36-40 weeks) and four time periods following delivery (1 week, 1 month, 6 months, and 1 year of age). We characterized RV function by measuring RV global and free wall longitudinal strain and systolic strain rate, and segmental longitudinal strain at the apical-, mid-, and basal- ventricular levels of the free wall. Possible associations of gestational age, postnatal age, estimated fetal weight, body surface area, gender, and heart rate on strain were investigated.

RESULTS

The magnitudes of RV global and free wall longitudinal strain and global strain rate were decreased throughout gestation (p < 0.05 for all). Following birth, the magnitudes of all measures increased from one week through one year (p < 0.001 for all). RV segmental longitudinal strain maintained a base-to-apex gradient (highest-to-lowest) from mid-gestation through one year (p < 0.001). There was no significant difference in strain patterns based on gender or hear rate.

CONCLUSION

The maturational patterns of RV strain are gestational- and postnatal age- specific. With accepted physiological maturation patterns in healthy subjects, these myocardial deformation parameters can provide a valid basis that allows comparison between health and disease.

Early inotropes use is associated with higher risk of death and/or severe brain injury in extremely premature infants

Introduction: Extremely premature infants are susceptible to fluctuations in cerebral blood flow due to immaturity of cerebral autoregulation. Inotropes may cause rapid changes to systemic blood pressure and consequently cerebral blood flow, especially within the first 72 hours of life. This period is recognized to carry the greatest risk for cerebral hemorrhage. This study evaluates the incidence of death and/or severe brain injury in extremely preterm infants treated with inotropes in the first 72 hours of life.Methods: Prospective cohort study of infants born ≤29⁺⁰ weeks gestational age (GA) between January 2013 and December 2016. Severe brain injury was defined based on head ultrasound as presence of: grade III or IV intraventricular hemorrhage (IVH), moderate to severe post-hemorrhagic ventricular dilatation (PHVD), or cystic periventricular leukomalacia (cPVL). The association between inotrope use and death and/or brain injury was explored via logistic regression controlling for predefined confounding risk factors.Results: Of 497 eligible infants, 97 (19.5%) received inotropes during the first 72 hours. GA at birth, birth weight (BW), and 5-minute Apgar scores were lower among infants who received early inotropes compared to those not treated with inotropes. A stepwise logistic regression of the predefined confounding factors showed GA, exposure for antenatal steroids, and admission hypothermia to be significant confounding factors. Adjusting for those factors, early use of inotropes was associated with increased risk of death and/or severe brain injury (AOR 4.5; 95%CI: 2.4-8.5), severe brain injury (AOR 4.2; 95% CI: 1.9-8.9), and IVH of any grade (AOR 2.9; 95%CI: 1.7-4.9).Conclusion: Early inotropes use was associated with higher risk of death and/or severe brain injury. Strict indications and strategies for minimizing inotrope use while preventing hypotension should be implemented in the early postnatal care of infants at risk for severe brain injury.

Left ventricular diastolic function influences right ventricular - Pulmonary vascular coupling in premature infants

INTRODUCTION

Reduced left ventricular (LV) diastolic function can exert significant load to the right ventricle (RV) that can affect RV-pulmonary vasculature (PV) coupling. RV-PV can be assessed with the RV length-force relationship (tricuspid annular plane systolic excursion [TAPSE] to pulmonary artery acceleration time [PAAT] ratio). We aimed to determine the association between LV diastolic function measured using tissue Doppler imaging (TDI) and TAPSE/PAAT.

METHODS

A study of premature infants <29 weeks gestation. TAPSE/PAAT, LV e' and a' waves were measured on Day 1 following birth. Correlation between diastolic indices and TAPSE/PAAT was performed. The independent effect of LV diastolic function and TAPSE/PAAT was assessed using linear regression.

RESULTS

One hundred and sixty-two infants with a mean ± SD gestation & birthweight of 26.6 ± 1.5 weeks & 938 ± 241 g. There was a significant positive correlation between LV e' (r = 0.44, p < 0.01)/LV a' (r = 0.44, p < 0.01) and TAPSE/PAAT. This relationship remained significant when adjusting for important confounders (all p < 0.01). Infants with LV a' values in the lowest quartile had lower TAPSE values (4.2 ± 1.2 vs. 5.1 ± 1.1 mm, p < 0.01) without a difference in PAAT (41 ± 8 vs. 41 ± 10 ms, p = 0.97).

CONCLUSIONS

We observed a direct correlation between LV diastolic function and RV-PV coupling in the first day of age, highlighting the importance ventricular interdependence in premature infants. TAPSE/PAAT, as the index of the RV-PV interaction may be further explored for its potential to assess RV reserve under stress with preterm infants in health and disease.

Early diastolic dysfunction and respiratory morbidity in premature infants: an observational study

OBJECTIVE

To test if diastolic dysfunction measured on day one of age is associated with the need for invasive ventilation in preterm infants.

STUDY DESIGN

We conducted a retrospective observational tissue Doppler echocardiographic study over the first 12 h of age for infants born <32 weeks who were invasively ventilated, and infants on continuous positive pressure ventilation (CPAP).

RESULTS

One hundred and eighty-three infants were included (27 ± 2 weeks and 999 ± 296 g). Invasively ventilated infants [(n = 96 (53%)] had lower left ventricular (LV) e' (3.4 ± 1.0 vs. 4.1 ± 1.5 cm/s, p < 0.01) and lower LV ea' ratio (0.8 ± 0.2 vs. 1.0 ± 0.4, p < 0.01), even after adjusting for common neonatal confounders (LV e' adjusted OR 0.62, 95% CI 0.45 - 0.87, p < 0.01; LV ea' adjusted OR 0.14, 95% CI 0.03-0.68, p = 0.01).

CONCLUSION

LV diastolic dysfunction is independently associated with a higher risk for invasive ventilation on day one of age.

Chronological Echocardiographic Changes in Healthy Term Neonates within Postnatal 72 Hours Using Doppler Studies

BACKGROUND

This study evaluated echocardiographic changes in full-term healthy neonates during early transitional period from postnatal 0-72 hours at 12-hour intervals by echocardiography.

METHODS

This was a prospective, observational, and longitudinal single-center cohort study. Morphometric, functional, systolic, diastolic, and tissue Doppler imaging (TDI) parameters (patent ductus arteriosus [PDA], aorta, superior vena cava [SVC], stroke volume [SV], cardiac output [CO], cardiac index [CI], early diastolic flow velocity [E], late diastolic flow velocity [A], early filling in TDI [E'], peak systolic annular velocity in TDI [S'], late velocity peak in TDI [A'], and myocardial performance index [MPI]) were evaluated in left ventricle (LV) and right ventricle (RV) with 56 newborns.

RESULTS

Sizes and peak velocities of PDA before postnatal 24 hours were significantly changed than those after postnatal 24 hours. Aortic velocity time integral (VTI), systolic blood pressure (BP), LV SV/kg, LV CO/kg, LV CI, and SVC flow/LV CO before 24 hours showed significantly changes than those after 24 hours. Also, LV and RV MPI before 24 hours were significantly higher than those after 24 hours. LV E/E' was significantly higher than RV E/E'.

CONCLUSION

Postnatal 24 hours is critical time for hemodynamic closure of PDA because aortic VTI, systolic BP, LV SV, LV CO, LV CI, and SVC flow/LV CO showed simultaneously significant changes after 24 hours at the same time as 24 hours of physiological closure of PDA. Chronological and dramatic changes of systolic, diastolic, and TDI parameters during early postnatal period can be used to compile normal baseline data of healthy full-term neonates.

Incidental Findings on Routine Targeted Neonatal Echocardiography Performed in Preterm Neonates Younger Than 29 Weeks' Gestation

OBJECTIVES

The aim of this study was to quantify the rate of incidental findings identified on elective research echocardiography performed on neonates younger than 29 weeks' gestation.

METHODS

We conducted a retrospective study of echocardiographic examinations performed within the first 24 hours of age on neonates younger than 29 weeks' gestation over a 3-year period for research purposes. Incidental echocardiographic findings and pertinent clinical data were recorded.

RESULTS

Echocardiographic examinations performed on 145 neonates were retrospectively reviewed. Forty-three neonates (30%) had a total of 54 unexpected findings (37%). Most comprised malpositioned umbilical venous catheters, where the tip was located in the left atrium. The remainder of the conditions identified included unsuspected congenital heart disease, liver hematomas, and unexpected pulmonary hypertension.

CONCLUSIONS

There is a high rate of incidental findings identified on screening echocardiograms. Routine targeted neonatal echocardiographic screening of preterm neonates may be warranted to identify the considerable likelihood of asymptomatic findings.

Early modifications of cardiac function in preterm neonates using speckle tracking echocardiography

BACKGROUND AND AIMS

Preterm newborns undergo hemodynamic challenges in the postnatal period. The aim of this study was to investigate myocardial mechanics changes in the postnatal period in preterm infants using speckle tracking echocardiography (STE).

MATERIAL AND METHODS

Thirty-nine preterm infants ≤34 weeks' gestation underwent cardiac ultrasound evaluation during the first 96 hours of life. A repeated echocardiogram at 3 weeks of age was performed. Echocardiographic assessment involved left ventricular ejection fraction, mitral E/A ratio, S' and E' velocities, E/E' ratio, tricuspid annular plane systolic excursion (TAPSE), left atrium-to-aorta ratio, ductal diameter and ductal shunt pattern. Left ventricular longitudinal, circumferential and radial strain, apex-basal rotation and twist were measured from the apical 4-chamber and short-axis views using STE.

RESULTS

The mean gestational age was 30 ± 2.7 weeks with a mean birth weight of 1318 ± 485 g. Apical segments demonstrated higher longitudinal strain than basal and mid-ones. In all gestational ages, endocardial longitudinal strain was higher than the epicardial. Epicardial longitudinal strain significantly increased during the first 3 weeks, resulting in the change in basal rotation from counterclockwise to clockwise and thus in the acquisition of twist. Deformation parameters were higher in infants with a hemodynamic significant patents ductus arteriosus.

CONCLUSIONS

Echocardiographic assessment of myocardial deformation parameters is feasible in preterm infants. Our data suggest that the maturational process of the myocardium is due to the development of the epicardial layer after birth, which allows the acquisition of the twist.

The Preterm Heart in Childhood: Left Ventricular Structure, Geometry, and Function Assessed by Echocardiography in 6-Year-Old Survivors of Periviable Births

BACKGROUND

Preterm birth has been associated with increased risk of cardiovascular morbidity in adult life. We evaluated whether preterm birth is associated with deviating cardiac structure and function before school start.

METHODS AND RESULTS

In total, 176 children aged 6 years and born extremely preterm (EXPT; gestational age of 22-26 weeks) and 134 children born at term (control [CTRL]) were studied. We used echocardiography to assess left heart dimensions, geometry, and functions. Recording and off-line analyses of echocardiographic images were performed by operators blinded to group belonging. Body size, blood pressure, and heart rate were also measured. Rates of family history of cardiovascular disease and sex distribution were similar in the EXPT and CTRL groups. Heart rate and systolic blood pressure did not differ, whereas diastolic blood pressure was slightly higher in EXPT than CTRL participants. After adjusting for body surface area, left ventricular length, width, and aortic valve annulus diameter were 3% to 5% smaller in EXPT than CTRL participants. Left ventricular longitudinal shortening and systolic tissue velocity were 7% to 11% lower, and transversal shortening fraction was 6% higher in EXPT than CTRL participants. The EXPT group also exhibited lower atrial emptying velocities than the CTRL group. Sex, fetal growth restriction, or a patent ductus arteriosus in the neonatal period did not contribute to cardiac dimensions or performance.

CONCLUSIONS

Six-year-old children born extremely preterm exhibit a unique cardiac phenotype characterized by smaller left ventricles with altered systolic and diastolic functions than same-aged children born at term.

C.10BreatnachC. R.11BreindahlM12DempseyE13GrovesA. M.14GuptaS15Horsberg EriksenB16LevyP. T.1718McNamaraP. J.19MolnarZ20RogersonS. R.21RoehrC. C.22SavoiaM23SchwarzC. E.24SehgalA25SinghY26SliekerM. G.27TissotC28van der LeeR29van LaereD30van OvermeireB31van WykL32. Tissue Doppler velocity imaging and event timings in neonates: a guide to image acquisition, measurement, interpretation, and reference values

Neonatologists can use echocardiography for real-time assessment of the hemodynamic state of neonates to support clinical decision-making. There is a large body of evidence showing the shortcomings of conventional echocardiographic indices in neonates. Newer imaging modalities have evolved. Tissue Doppler imaging is a new technique that can provide measurements of myocardial movement and timing of myocardial events and may overcome some of the shortcomings of conventional techniques. The high time resolution and its ability to assess left and right cardiac function make tissue Doppler a favorable technique for assessing heart function in neonates. The aim of this review is to provide an up-to-date overview of tissue Doppler techniques for the assessment of cardiac function in the neonatal context, with focus on measurements from the atrioventricular (AV) plane. We discuss basic concepts, protocol for assessment, feasibility, and limitations, and we report reference values and give examples of its use in neonates.

Application of Neonatologist Performed Echocardiography in the Assessment and Management of Neonatal Heart Failure unrelated to Congenital Heart Disease

Neonatal heart failure (HF) is a progressive disease caused by cardiovascular and non-cardiovascular abnormalities. The most common cause of neonatal HF is structural congenital heart disease, while neonatal cardiomyopathy represents the most common cause of HF in infants with a structurally normal heart. Neonatal cardiomyopathy is a group of diseases manifesting with various morphological and functional phenotypes that affect the heart muscle and alter cardiac performance at, or soon after birth. The clinical presentation of neonates with cardiomyopathy is varied, as are the possible causes of the condition and the severity of disease presentation. Echocardiography is the selected method of choice for diagnostic evaluation, follow-up and analysis of treatment results for cardiomyopathies in neonates. Advances in neonatal echocardiography now permit a more comprehensive assessment of cardiac performance that could not be previously achieved with conventional imaging. In this review, we discuss the current and emerging echocardiographic techniques that aid in the correct diagnostic and pathophysiological assessment of some of the most common etiologies of HF that occur in neonates with a structurally normal heart and acquired cardiomyopathy and we provide recommendations for using these techniques to optimize the management of neonate with HF.

C.12BreatnachC. R.13BreindahlM14DempseyE15GrovesA. M.16GuptaS17Horsberg EriksenB18McNamaraP. J.19MolnarZ20RogersonS. R.21RoehrC. C.22SavoiaM23SchwarzC. E.24SehgalA25SinghY26SliekerM. G.27TissotC28van der LeeR29van LaereD30van OvermeireB31van WykL32. Deformation imaging and rotational mechanics in neonates: a guide to image acquisition, measurement, interpretation, and reference values

Advances in neonatal cardiac imaging permit a more comprehensive assessment of myocardial performance in neonates that could not be previously obtained with conventional imaging. Myocardial deformation analysis is an emerging quantitative echocardiographic technique to characterize global and regional ventricular function in neonates. Cardiac strain is a measure of tissue deformation and strain rate is the rate at which deformation occurs. These measurements are obtained in neonates using tissue Doppler imaging (TDI) or two-dimensional speckle tracking echocardiography (STE). There is an expanding body of literature describing longitudinal reference ranges and maturational patterns of strain values in term and preterm infants. A thorough understanding of deformation principles, the technical aspects, and clinical applicability is a prerequisite for its routine clinical use in neonates. This review explains the fundamental concepts of deformation imaging in the term and preterm population, describes in a comparative manner the two major deformation imaging methods, provides a practical guide to the acquisition and interpretation of data, and discusses their recognized and developing clinical applications in neonates.

Controversies in the identification and management of acute pulmonary hypertension in preterm neonates

It is increasingly recognized that the abnormal physiologic consequences of pulmonary hypertension (PH) may contribute to poor cardiopulmonary health in premature babies. Conflicting literature has led to clinical uncertainty, pathological misinterpretation, and variability in treatment approaches among practitioners. There are several disorders with overlapping and interrelated presentations, and other disorders with a similar clinical phenotype but diverse pathophysiological contributors. In this review, we provide a diagnostic approach for acute hypoxemic respiratory failure in the preterm neonate, outline the pathophysiological conditions that may present as acute PH, and discuss the implications of high pulmonary vascular resistance (PVR) on the cardiovascular system. Although PVR and respiratory management are highly interrelated, there may be a population of preterm neonates in whom inhaled nitric oxide may improve illness severity and may relate to outcomes. A management approach based on physiology that considers common clinical conundrums is provided. A more comprehensive understanding of the physiology may help in informed decision-making in clinical situations where conclusive scientific evidence is lacking. Regardless, high-quality research is required, and appropriate definition of the target population is paramount. A thoughtful approach to cardiovascular therapy may also provide an avenue to improve neurodevelopmental outcomes while awaiting more clear answers.

Serial measures of cardiac performance using tissue Doppler imaging velocity in preterm infants <29weeks gestations

INTRODUCTION

Tissue Doppler imaging (TDI) is a useful marker of myocardial performance in preterm infants. We aimed to demonstrate serial changes in TDI velocity in preterm infants <29weeks gestation, to assess the impact of inotropes and a haemodynamically significant patent ductus arteriosus (hsPDA).

METHODS

This was a prospective observational study of preterm infants <29weeks gestation. Echocardiography was performed at days 1, 2, 5-7 and at 36weeks, or before hospital discharge. Infants with hsPDA's on day 5-7 and those who received inotropes in the first week of life were not included in the Reference Cohort. Systolic (s`) and diastolic (e` and a`) velocity waves were assessed at the mitral and tricuspid annulus and basal septum.

RESULTS

One hundred and thirty nine infants with a mean (SD) gestation and birthweight of 26.7 (1.5) weeks and 946 (247) grams were enrolled. The 66 infants (47%) in the Reference Cohort demonstrated an increase in functional parameters with increasing age [LV s`, Septal s`, and RV s`, Day 1-36weeks: 2.8 (0.6) to 4.7 (1.0), 2.4 (0.6) to 4.6 (0.8), 3.6 (0.6) to 6.9 (1.0) cm/s respectively; all p<0.05). The 24 infants who received inotropes had lower LV e` [2.9 vs. 3.6cm/s], Septal e` [2.3 vs. 2.8cm/s] and a` [3.2 vs. 3.9cm/s], and lower RV a` [3.3 vs. 3.9cm/s] on Day 1 (all p<0.05). Fifty five infants had a hsPDA on Day 5-7, demonstrating higher LV [4.7 vs. 4.0cm/s] and Septal e` [3.9 vs. 3.3cm/s], and a higher LV E/e` [13 vs. 10] (all p<0.05).

CONCLUSION

Extremely preterm infants display a gradual increase in tissue Doppler velocities from birth until 36weeks corrected age. The presence of a hsPDA increases diastolic TDI velocities. Infants requiring inotropes have lower diastolic myocardial velocities on Day 1.

Maturational Patterns of Systolic Ventricular Deformation Mechanics by Two-Dimensional Speckle-Tracking Echocardiography in Preterm Infants over the First Year of Age

BACKGROUND

The aim of this study was to determine the maturational changes in systolic ventricular strain mechanics by two-dimensional speckle-tracking echocardiography in extremely preterm neonates from birth to 1 year of age and discern the impact of common cardiopulmonary abnormalities on the deformation measures.

METHODS

In a prospective multicenter study of 239 extremely preterm infants (<29 weeks gestation at birth), left ventricular (LV) global longitudinal strain (GLS) and global longitudinal systolic strain rate (GLSRs), interventricular septal wall (IVS) GLS and GLSRs, right ventricular (RV) free wall longitudinal strain and strain rate, and segmental longitudinal strain in the RV free wall, LV free wall, and IVS were serially measured on days 1, 2, and 5 to 7, at 32 and 36 weeks postmenstrual age, and at 1 year corrected age (CA). Premature infants who developed bronchopulmonary dysplasia or had echocardiographic findings of pulmonary hypertension were analyzed separately.

RESULTS

In uncomplicated preterm infants (n = 103 [48%]), LV GLS and GLSRs remained unchanged from days 5 to 7 to 1 year CA (P = .60 and P = .59). RV free wall longitudinal strain, RV free wall longitudinal strain rate, and IVS GLS and GLSRs significantly increased over the same time period (P < .01 for all measures). A significant base-to-apex (highest to lowest) segmental longitudinal strain gradient (P < .01) was seen in the RV free wall and a reverse apex-to-base gradient (P < .01) in the LV free wall. In infants with bronchopulmonary dysplasia and/or pulmonary hypertension (n = 119 [51%]), RV free wall longitudinal strain and IVS GLS were significantly lower (P < .01), LV GLS and GLSRs were similar (P = .56), and IVS segmental longitudinal strain persisted as an RV-dominant base-to-apex gradient from 32 weeks postmenstrual age to 1 year CA.

CONCLUSIONS

This study tracks the maturational patterns of global and regional deformation by two-dimensional speckle-tracking echocardiography in extremely preterm infants from birth to 1 year CA. The maturational patterns are ventricular specific. Bronchopulmonary dysplasia and pulmonary hypertension leave a negative impact on RV and IVS strain, while LV strain remains stable.

Myocardial Infarction in Neonates: A Review of an Entity with Significant Morbidity and Mortality

Coronary artery disease is a global problem with high mortality rates and significant residual sequelae that affect long-term quality of life. Myocardial infarction (MI) in neonates is a recognized, uncommon entity, but the incidence and broad spectrum of the disease is unknown and likely underestimated due to limited reporting which in the majority is confined to acute ischemic events. The challenges involve clinical diagnosis which masquerades in the early phase as non-specific symptoms and signs that are commonly found in a host of neonatal disorders. Precise diagnostic criteria for neonatal MI are lacking, and management is driven by clinical presentation and hemodynamic stabilization rather than an attempt to rapidly establish the root cause of the condition. We conducted a review of the published reports of neonatal MI from 2000 to 2014, to establish an approach to the diagnosis and management based on the existing evidence. The overall evidence from 32 scientific articles stemmed from case reports and case series which were graded as low-to-very low quality. Neonatal MI resembles childhood and adult MI with features that involve characteristic ECG changes, raised biomarkers, and diagnostic imaging, but with lack of robust, standardized criteria to facilitate prompt diagnosis and timely intervention. The mortality rate of neonatal MI ranges from 40 to 50% based on inclusion criteria, but the short-term data reflect normal quality of life in survivors. An algorithm for the diagnosis and management of neonatal MI may optimize outcomes, but at the present time is based on limited evidence. Well-designed clinical studies focusing on the definition, diagnosis, and management of neonatal MI, backed by international consensus guidelines, are needed to alter the prognosis of this serious condition.

A modified echocardiographic approach improves reliability of superior vena caval flow quantification

OBJECTIVE

To assess accuracy and repeatability of a modified echocardiographic approach to quantify superior vena cava (SVC) flow volume that uses a short-axis view to directly measure SVC area and a suprasternal view to measure flow velocity, both at the level of the right pulmonary artery.

SETTING

Three tertiary-level neonatal intensive care units.

DESIGN

This was a multicentre, prospective, observational study. Accuracy of the traditional and modified approach was first assessed by comparing echo measurements according to both techniques with Phase contrast MRI (PCMRI) assessments, in a cohort of 10 neonates. In a second cohort of 40 neonates, intraobserver scan-rescan repeatability and interobserver analysis-reanalysis repeatability were assessed by repeated SVC flow echo measurements, according to both techniques.

RESULTS

The traditional echocardiographic approach to assessment of SVC flow had a moderate agreement with PCMRI (r² 0.259), a scan-rescan intraobserver repeatability index (RI) of 37% (limits of agreement (LOA) -47/+51 mL/kg/min) and an interobserver analysis-reanalysis RI of 31% (LOA -38/+40 mL/kg/min). The modified approach showed a stronger agreement with PCMRI (r² 0.775), an improved intraobserver scan-rescan repeatability (RI 22%, LOA -24/+18 mL/kg/min) and improved interobserver analysis-reanalysis repeatability (RI 18%, LOA -18/+20 mL/kg/min).

CONCLUSIONS

Echocardiographic assessment of SVC flow volume by tracing area from a short-axis view and measuring velocity-time integral from a suprasternal view offered an improvement in accuracy and repeatability, building on the traditional approach previously described.

Right Heart Function of Fetuses and Infants with Large Ventricular Septal Defect: A Longitudinal Case-Control Study

The objective of this study was to detect the effect of a large ventricular septal defect (VSD) on right ventricular function before and after birth. All consecutive children with large VSD who were born in our hospital between January 2013-February 2016 and followed up throughout early infancy, and who lacked malformations or chromosomal abnormalities, were identified by a retrospective review of the medical records and included in this retrospective longitudinal case-control study (n = 30). Thirty normal control cases with an equivalent gestational age and gender served as controls. Tricuspid annular plane systolic excursion (TAPSE), right ventricle (RV) Tei index, and tricuspid E/E _m were measured in the fetal, neonatal (day 1-28), and infant (day 29-70) periods. In all periods, the VSD and control groups did not differ in TAPSE values, but VSD associated with higher Tei indices and tricuspid E/E _m values (in the fetal period: VSD group RV Tei was 0.48 ± 0.12 and E/E _m was 11.84 ± 1.53, control group RV Tei was 0.42 ± 0.16 and E/E _m was 10.16 ± 1.61; in neonatal period: VSD group RV Tei was 0.41 ± 0.17 and E/E _m was 12.21 ± 1.59, control group RV Tei was 0.30 ± 0.13 and E/E _m was 7.20 ± 1.28; in the infant period: VSD group RV Tei was 0.39 ± 0.09 and E/E _m was 11.89 ± 2.80, control group RV Tei was 0.28 ± 0.12 and E/E _m was 5.26 ± 1.90, all p < 0.05). In the fetal and neonatal periods, TAPSE correlated negatively with Tei index and tricuspid E/E _m in both groups. However, in the infant period, only the control group exhibited correlations between TAPSE and Tei index or tricuspid E/E _m. Tei index correlated positively with tricuspid E/E _m in both groups in all three periods. The VSD group had smaller correlation coefficients than the control group. Large VSD may already start to impair RV diastolic and global function before birth. This impairment continued and increased after birth. These changes did not associate with obvious RV longitudinal systolic function impairment. Large VSD mainly affected RV function by decreasing diastolic function and myocardial performance.

Assessment of myocardial function in preterm infants with chronic lung disease using tissue Doppler imaging

OBJECTIVES

To assess myocardial function and presence of pulmonary hypertension (PH) using both tissue Doppler imaging (TDI) and conventional echocardiography in preterm infants of <32 weeks gestation with chronic lung disease (CLD).

DESIGN

Prospective observational study.

SETTING

Tertiary neonatal intensive care unit.

PATIENTS

Three groups of preterm infants were recruited. Group 1-CLD receiving positive pressure airway support including high-flow humidified nasal cannula oxygen (n=25), group 2-CLD receiving low-flow nasal oxygen (n=25) and group 3-no CLD (n=22).

METHODS

Echocardiography was performed around 36 weeks corrected gestational age. Myocardial function and PH were assessed using both conventional (left ventricular fractional shortening (LVFS) and left ventricular output (LVO), tricuspid regurgitation and ventricular septal flattening) and TDI techniques (myocardial velocities, myocardial performance index (MPI) and right ventricular isovolumetric relaxation time (RV-IVRT)).

RESULTS

The MPI of right ventricle (RV) and left ventricle (LV) was significantly higher in CLD infants: mean RV MPI group 1-0.79, group 2-0.65 and group3-0.52. LV MPI: group 1-0.77, group 2-0.70 and group 3-0.45. There was a trend towards higher MPIs in group 1 compared with group 2. LVFS and LVO were similar across all three groups. RV-IVRT was also significantly higher in infants with CLD infants (group 1-64 milliseconds, group 2-62 milliseconds and group 3-52 milliseconds). PH was not detected by conventional echocardiography.

CONCLUSIONS

Infants with CLD have evidence of relative biventricular dysfunction and higher pulmonary arterial blood pressure as demonstrated by TDI, which were not detected by conventional echocardiography.

Preterm Birth Is Associated with Altered Myocardial Function in Infancy

BACKGROUND

Preterm birth has been associated with myocardial remodeling and accelerated cardiovascular ageing in later life, but the underlying mechanisms are unknown. The investigators used echocardiography to undertake a sequential analysis of myocardial function in preterm infants.

METHODS

This study evaluated the cardiac performance of 25 very preterm infants (born at a gestational age of 26-30 weeks), at birth, 3 months (term-equivalent age), and 6 months later (3 months of corrected age). Speckle-tracking echocardiography was used to determine myocardial function, assessing the magnitude of myocardial deformation as longitudinal strain, deformation rate (strain rate), and velocity in both ventricles during systole and diastole. The results were compared with those in 30 infants born at term investigated at birth and at 3 months of age.

RESULTS

At term-equivalent age, the speckle-tracking estimates were similar in both groups. Three months later, very preterm infants exhibited significantly lower left ventricular mean free wall longitudinal strain (-20.0% vs -22.0%, P = .010) and lower left ventricular early diastolic (median, -7.37 vs -10.9 cm/sec, P = .003) and late diastolic (median, -5.11 vs -6.95 cm/sec, P = .009) myocardial velocities than infants born at term. There were no statistically significant group differences in right ventricular or interventricular septal measurements. Conventional echocardiographic variables did not differ significantly between the two groups at any age.

CONCLUSIONS

Very preterm infants develop altered left ventricular myocardial function 6 months after birth. Follow-up examinations are needed to determine the implications for cardiovascular health in the growing number of children surviving very preterm birth.

Novel Echocardiography Methods in the Functional Assessment of the Newborn Heart

Echocardiography in the neonatal intensive care unit has led to improvements in our ability to assess the neonatal heart in health and disease. Advances in neonatal cardiac imaging have provided the capability to obtain quantitative information that often supersedes the qualitative information provided by conventional methods. Novel quantitative measures of function include the assessment of the velocity of muscle tissue movement during systole and diastole using tissue Doppler velocity imaging, and evaluation of deformation and rotational characteristics of the myocardium utilizing speckle tracking echocardiography or tissue Doppler-derived strain imaging. A comprehensive understanding of these novel functional modalities, their predictive value, and limitations can greatly assist in managing both the normal and maladaptive responses in the newborn period. This article discusses the novel and emerging methods for assessment of left and right heart function in the neonatal population.

Clinical utility of right ventricular fractional area change in preterm infants

INTRODUCTION

Right ventricular fractional area change (RV FAC) is a novel non-invasive quantitative measure of RV function. Reference values of RV FAC and RV end systolic and diastolic areas (RVEDA, RVESA) have recently been established in preterm infants, but their role as marker to assess the efficacy of patient management strategies in the first week of life is largely unknown. The aims of this study were to assess the relationship between RV FAC and gestational age/birthweight, assess the RV FAC on day one of age to predict the later evolution of peri/intraventricular haemorrhage (P/IVH), and assess the influence of a persistent patent ductus arteriosus (PDA) on RV FAC during the first week of age.

METHODS

Preterm infants <29 weeks gestation underwent echocardiography assessments on days 1, 2 and 5-7. RVEDA and RVESA were traced in the RV-focused apical four-chamber view, and RV FAC was calculated using the formula [(RVEDA-RVESA)÷(RVEDA)] × 100. PDA treatment was not carried out during the study period. A cranial ultrasound was carried out on all infants on Days 5-7 of age. P/IVH was defined as IVH grades II to IV.

RESULTS

One hundred and one infants with a mean gestation of 26.5 (1.4) weeks and a birthweight of 983 (240) grams were enrolled in the study. There was no relationship between RV FAC and birthweight (r=-0.02, p=0.86) but there was a negative correlation between RV FAC and echo-measured SVR (r=-0.57, p<0.001). On Day 1, RV FAC was lower in infants who developed P/IVH (24% [18-34] vs. 31% [25-40], p=0.04). On Days 5-7 infants with a PDA had a lower RV FAC compared with those without [42 (7) vs. 49 (9) %, p<0.001].

CONCLUSION

RV FAC may be a useful addition to the haemodynamic assessment of preterm infants during the first week of age.

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.