Colm R. Breatnach

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.

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. HighlightsTwo‐dimensional (2D) speckle‐tracking echocardiography (STE)–derived myocardial strain is a feasible and reproducible imaging modality that can be used to characterize systolic ventricular function in premature infants.This study establishes ventricular‐specific systolic strain maturational patterns by 2D STE in a large cohort of extremely preterm infants from birth through 1 year corrected age.Common cardiopulmonary morbidities, such as bronchopulmonary dysplasia and pulmonary hypertension, appear to leave a negative impact on right ventricular strain, while left ventricular strain remains stable through the first year of age.With the establishment of the range of maturational patterns of strain mechanics and associated variations up to 1 year corrected age, deformation imaging by 2D STE may now be implemented in preterm infants as a means to identify cardiovascular compromise earlier, guide therapeutic intervention, monitor treatment response, and improve overall outcome.

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

Noninvasive continuous cardiac output and cerebral perfusion monitoring in term infants with neonatal encephalopathy: assessment of feasibility and reliability

BackgroundNoninvasive hemodynamic monitoring of infants with neonatal encephalopathy (NE) undergoing therapeutic hypothermia (TH) would be a potentially useful clinical tool. We aimed to assess the feasibility and reliability of noninvasive cardiac output monitoring (NICOM) and near-infrared spectroscopy (NIRS) in this cohort.MethodsNICOM and NIRS were commenced to measure cardiac output (CO), systemic vascular resistance (SVR), blood pressure (BP), and cerebral regional oxygen saturations (SctO2) during TH and rewarming. NICOM measures of CO were also compared with simultaneous echocardiography-derived CO (echo-CO).ResultsTwenty infants with a median gestation of 40 weeks were enrolled. There was a strong correlation between NICOM- and echo-CO (r2=0.79, P<0.001). NICOM-CO was systematically lower than echo-CO with a bias of 27% (limits of agreement 3–51%). NICOM illustrated lower CO during TH, which increased during rewarming. SctO2 increased over the first 30 h of TH and stayed high for the remainder of the study. There was a rise in SVR over the first 30 h of TH and a decrease during rewarming (all P<0.05).ConclusionsNoninvasive hemodynamic assessment of infants with NE is feasible and illustrates potentially important changes. Larger studies are needed to assess the clinical applicability of those methods in this cohort.

Infants Born with Down Syndrome: Burden of Disease in the Early Neonatal Period

Objective To evaluate the incidence of direct admission of infants with Down syndrome to the postnatal ward (well newborn nursery) vs the neonatal intensive care unit (NICU), and to describe the incidence of congenital heart disease (CHD) and pulmonary hypertension (PH). Study design This retrospective cohort study of Down syndrome used the maternal/infant database (2011‐2016) at the Rotunda Hospital in Dublin, Ireland. Admission location, early neonatal morbidities, outcomes, and duration of stay were evaluated and regression analyses were conducted to identify risk factors associated with morbidity and mortality. Results Of the 121 infants with Down syndrome, 54 (45%) were initially admitted to the postnatal ward, but 38 (70%) were later admitted to the NICU. Low oxygen saturation profile was the most common cause for the initial and subsequent admission to the NICU. Sixty‐six percent of the infants (80/121) had CHD, 34% (41/121) had PH, and 6% died. Risk factors independently associated with primary NICU admission included antenatal diagnosis of Down syndrome, presence of CHD, PH, and the need for ventilation. Conclusions Infants with Down syndrome initially admitted to the postnatal ward have a high likelihood of requiring NICU admission. Overall, high rates of neonatal morbidity were noted, including rates of PH that were higher than previously reported. Proper screening of all infants with Down syndrome for CHD and PH is recommended to facilitate timely diagnoses and potentially shorten the duration of the hospital stay.

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

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

Left ventricular rotational mechanics in infants with hypoxic ischemic encephalopathy and preterm infants at 36 weeks postmenstrual age: A comparison with healthy term controls.

There is a paucity of data on left ventricle (LV) rotational physiology in neonates. We aimed to assess rotational mechanics in infants with hypoxic ischemic encephalopathy (HIE) and premature infants (<32 weeks) at 36 weeks postmenstrual age (PMA) (preterm group) and compare them with healthy term controls (term controls). We also compared the parameters in preterm infants with and without chronic lung disease (CLD).

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.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.

The impact of a hyperdynamic left ventricle on right ventricular function measurements in preterm infants with a patent ductus arteriosus.

Background and aims Right ventricular (RV) functional assessment in premature infants includes basal longitudinal strain (RV BLS), RV systolic tissue Doppler velocity (RV s′), tricuspid annular plane systolic excursion (TAPSE) and RV fractional area change (FAC). A hyperdynamic left ventricle (LV) may influence RV measures of displacement (TAPSE) and velocity (RV s′) but not measures of relative change of length (RV BLS) or area (FAC). We aimed to explore this hypothesis in preterm infants with a patent ductus arteriosus (PDA). Methods We measured LV function (ejection fraction (LV EF); left ventricular output) and RV function (RV BLS; RV s′; TAPSE; FAC) on days 1, 2 and 5–7 in infants <29 weeks. The cohort was divided based on PDA presence by days 5–7. LV and RV function measurements were compared between the groups using two-way analysis of variance with repeated measures. Results 121 infants with a mean (SD) gestation and birth weight of 26.8 (1.4) weeks and 968 (250) g were enrolled. By days 5–7, the PDA remained open in 83 (69%), with evidence of hyperdynamic LV function. There was no difference in RV s’ (5.3 (0.9) vs 5.1 (1.0) cm/s, p=0.3) or TAPSE (6.2 (1.3) vs 6.1 (1.2) mm, p=0.7) between infants with and without a PDA, but infants in the PDA group had lower RV FAC (41 (8) vs 47 (10) %, p<0.01) and lower RV BLS (−24.2 (5.0) vs −26.2 (4.1) %, p=0.03). Conclusions LV influence on RV functional parameters must be taken into account when interpreting of RV function using those techniques.

The Impact of Maternal Gestational Hypertension and the Use of Anti-Hypertensives on Neonatal Myocardial Performance

Background: Assessment of myocardial performance in neonates using advanced techniques such as deformation imaging and rotational mechanics has gained considerable interest. The applicability of these techniques for elucidating abnormal myocardial performance in various clinical scenarios is becoming established. We hypothesise that term infants born to mothers with gestational hypertension (GH) may experience impaired performance of the left and right ventricles during the early neonatal period. Objectives: We aimed to assess left and right ventricular (LV and RV) function using echocardiography in infants born to mothers with GH and compare them to a control group. Methods: Term infants (>36+6 weeks) born to mothers with GH underwent assessment to measure biventricular function using ejection fraction (EF), deformation imaging, left-ventricle rotational mechanics (apical rotation, basal rotation, twist, twist rate, and untwist rate), and right ventricle-specific functional parameters (tricuspid annular plane systolic excursion and fractional area change) in the first 48 h after birth. A control group comprising infants born to healthy mothers was used for comparison. Results: Fifteen infants with maternal GH and 30 age-matched controls were enrolled. The GH infants exhibited no differences in birthweight or LV or RV length, but they had lower EF (54 vs. 61%; p < 0.01), LV global longitudinal strain (-20 vs. -25%; p < 0.01), and LV twist (11 vs. 16°; p = 0.04). There were no differences in any of the RV functional parameters. Conclusion: Infants born to mothers with GH exhibited lower LV function than healthy controls, while RV function appeared to be preserved. This relationship warrants further exploration in a larger cohort.