Echocardiographic evaluation of right heart pressure changes in healthy newborns and its follow-up till 12 weeks of life

Avishikta Das; Uttam Kumar Sarkar; Kaushik Ishore

doi:10.4103/heartindia.heartindia_53_22

ORIGINAL ARTICLE

Year : 2023 | Volume : 11 | Issue : 1 | Page : 3-7

Echocardiographic evaluation of right heart pressure changes in healthy newborns and its follow-up till 12 weeks of life

Avishikta Das¹, Uttam Kumar Sarkar¹, Kaushik Ishore²
¹ Department of Paediatrics, North Bengal Medical College and Hospital, Siliguri, West Bengal, India
² Department of Community Medicine, MJN Medical College, Cooch Behar, West Bengal, India

Date of Submission	25-Nov-2022
Date of Acceptance	10-Jan-2023
Date of Web Publication	12-Apr-2023

Correspondence Address:
Kaushik Ishore
Department of Community Medicine, MJN Medical College and Hospital, Cooch Behar, West Bengal
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/heartindia.heartindia_53_22

Abstract

Background: Right ventricular (RV) pressure undergoes a series of changes from foetal to neonatal period on both left and right heart. Pulmonary velocity acceleration time (PVAccT) measured by trans-thoracic echocardiography has been established as a reliable indicator of RV pressure measurement in neonates. This study aims to throw some light into the changes in the RV pressure by serial PVAccT measurements in the initial 12 weeks of life.
Materials and Methods: A cross sectional study was carried out among term new-borns until 12 weeks of age and serial changes in the PVAccT values were recorded, reflecting the mean pulmonary artery pressure (MPAP), and the left ventricular internal diastolic diameter (LVIDD), left atrial diameter (LAD), right ventricular outflow tract (RVOT), right ventricular free wall thickness (RVFWT).
Results: There was gradual increase in the mean value of PVAccT with age from birth i.e., 1-3 days (70.08±18.62ms) to 3 months (86.23±17.31ms) (p=<0.05). Mean value of right ventricular outflow tract proximal diameter was also seen to have an increase from day 1-3 (0.92±0.19cm) to 3 months of age (1.09±0.01cm) (p= <0.001). There was an overall decrease in the mean value of the RVFWT from day 1-3 (0.37±.07 cm) to 3 months (0.27±0.07cm) of age after an increase at 1 month (p=<0.05). Statistically significant increase in mean LAD from 1.18±0.29cm to 1.40±0.35 cm and LVIDD from 1.54±0.31cm to1.96±0.27 was seen from birth to 3 months of age.
Conclusion: Changes in PVAcct and RV pressure with time from birth to 3 months of age will aid in early diagnosis of persistent pulmonary artery hypertension of new-born (PPHN) or pulmonary arterial hypertension (PAH).

Keywords: MPAP, PPHN, LVIDD, RVOT, LAD, RVFWT

How to cite this article:
Das A, Sarkar UK, Ishore K. Echocardiographic evaluation of right heart pressure changes in healthy newborns and its follow-up till 12 weeks of life. Heart India 2023;11:3-7

How to cite this URL:
Das A, Sarkar UK, Ishore K. Echocardiographic evaluation of right heart pressure changes in healthy newborns and its follow-up till 12 weeks of life. Heart India [serial online] 2023 [cited 2023 May 31];11:3-7. Available from: https://www.heartindia.net/text.asp?2023/11/1/3/374102

Introduction

Right ventricular (RV) performance is an important determinant of clinical status and long-term outcome in preterm and term neonates with cardiopulmonary pathology. RV mechanics begin to undergo maturational changes in the early postnatal period that have long-term influence on cardiac function.^[1],[2],[3]

Shortly after birth, a left ventricular (LV) hypertrophy was found as it becomes the systemic ventricle, RV gets remodeled in to the thin-walled cavity that supplies the low-pressure pulmonary circulation. By 3 weeks after birth, the pulmonary pressure falls below the systemic pressure and by 3–6 months of age the classical LV dominant pattern of adulthood is established.^[4]

According to the recent report by the American society of Echocardiography, the most useful parameters for assessing the RV function and pulmonary hypertension (PH) in children and neonates are: estimation of pulmonary arterial pressure (PAP), assessment of ductal and atrial shunts, assessment of interventricular septum or LV shape, pulmonary velocity acceleration time (PVAccT) and tricuspid annular plain systolic excursion (TAPSE). PVAccT is the interval in milliseconds from the onset of ejection to the peak flow velocity and is used for the estimation of pulmonary vascular resistance (PVR) in adults. The World symposia on pulmonary hypertension (WSPH) in 2018 modified the definition as well as the classification for PH.^[5]

The differences in neonatal and fetal physiology makes it mandatory for the neonatal physicians to have a sound knowledge about the differences of the transitional phase. This would help in understanding the deviations from typical physiological changes better. In various previous studies, the ventricular dominance pattern has been studied by taking into account the ventricular pressures along with cardiac dimensions. Therefore, early assessment of RV performance among the neonates is essential for the surveillance in the early neonatal period.^[6],[7],[8]

Materials and Methods

An observational cross-sectional study was carried out among purposively selected 100 neonates (50 of whom were delivered by Lower Uterine segment cesarean section (LUCS) and 50 by SVD) from obstetrics and pediatric indoor department of North Bengal Medical College and Hospital (NBMCH) during a period between May 2020 and April 2021. NBMCH is a tertiary care teaching hospital located in Darjeeling district of West Bengal, which caters populations from difficult and hilly terrains of eastern Himalayas with cases also attending from bordering nations.

Inclusion criteria: Term healthy babies were included in the study. Exclusion criteria: Babies with any congenital cardiopulmonary anomalies, gross anatomical abnormalities, and requiring any postdelivery resuscitative care or admission to special newborn care unit for any reason were excluded from the study.

Informed consent was taken from the parents, guardians, or care givers of the children beforehand. Standard pretested questionnaire was applied to them to collect the basic sociodemographic and clinic-therapeutic data. All participants were thoroughly examined physically before echocardiographic examination. Echocardiography was done maintaining standard protocol and all measurements were based on the criteria of the American Society of Echocardiography.^[5]

Following key parameters were recorded

Pulmonary velocity acceleration time (PVAccT), mean (mPAP) (calculated using the modified Mahan's equation, i.e.,−79 − 0.45 × PVAccT), left ventricular internal diastolic diameter (LVIDD), left atrial diameter, right ventricular outflow tract (RVOT), and right ventricular free wall thickness (RVFWT). The children were again reviewed at 1 month and at 3 months of age for recording of same parameters and find out the changes.

Two-dimensional transthoracic echocardiography, including M mode, colour Doppler, pulse wave and continuous wave Doppler was done. The 2D-echo was performed by a person expert in cardiology using an Agilent image point ultrasound instrument with age-appropriate transducers. For each study participant, the following views were obtained: parasternal long axis, parasternal short axis, apical 2-chamber, and apical 4-chamber. Transmitral flow was assessed in the apical 4-chamber view with the pulsed Doppler sample volume at the leaflet tips. The following variables were measured: cardiac chambers, valves, RVOT, ejection fraction of LV, TAPSE, mPAP, pericardial effusion, and LV systolic function (categorized by EF 40%–50% mild, 30%–40% moderate, and <30% severe form). Features of RV systolic dysfunction is defined as 14–17 mm as mild, 11–13 mm as moderate, and <11 mm as severe. In case any cardiac abnormality was detected, expert consultation was taken from cardiology department for further management.

Collected data were checked for consistency and completeness and entered in Excel date sheet built by Microsoft corporation. Further analysis was done with the help of the software (IBM statistical package for social sciences (SPSS) for windows, version 22, Armonk, NY: IBM Corporation). Data were organized and presented using the principles of descriptive statistics. Relationship between different changes in cardiological parameters over the time were assessed by doing ANOVA tests with 95% confidence interval and P ≤ 0.05 was considered statistically significant.

Results

Findings of the present study revealed, there was a gradual increase in the mean value of PVAccT with age from birth i.e., day 1–3 (70.08 ± 18.62 ms) to 3 months (86.23 ± 17.31 ms) [Figure 1]. A gradual decrease in the mPAP as the age of the child increases from birth, i.e., day 1–3 (47.46 ± 8.37 mmHg) to 3 months of age (40.19 ± 7.78 mmHg) was obtained from the observed PVAccT values [Figure 2]. The mean value of RVOT proximal diameter was seen to have a very small increase from day 1–3 of life (0.92 ± 0.19 cm) to 3 months (1.09 ± 0.01 cm) of age.

Figure 1: Box plot representation of the distribution of median of PVAccT in study participants over time (three groups are denoting the measurements were taken at 0–1 days, 1 month and 3 months of age). PVAccT: Pulmonary velocity acceleration time

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Figure 2: Box plot representation of the distribution of median of mPAP in study participants over time (three groups are denoting the measurements were taken at 0–1 days, 1 month, and 3 months of age). mPAP: Mean pulmonary arterial pressure

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There was an overall decrease in the mean value of the RV free wall diameter from day 1 to 3 (0.37 ± 07 cm) of life up to 3 months (0.27 ± 0.07 cm). A gradual increase in the mean left atrial diameter with age from 1 to 3 days of life (1.18 ± 0.29 cm) to 3 months (1.40 ± 0.35 cm) of age. The mean value of LVIDD increases from 1 to 3 days of life (1.54 ± 0.31 cm) to 3 months (1.96 ± 0.27 cm).

Discussion

Cardiopulmonary disorders are not uncommon in the neonatal period. Therefore, assessment of RV anatomy and function may be a plausible gateway to gain insight into the early diagnosis of RV compromise. Recently pulmonary artery acceleration time (PAAT) has been validated as a reliable, feasible, and reproducible parameter for assessment of pulmonary artery pressure. The present WSPH 2018 definition of pulmonary artery hypertension does not define a cutoff below 3 months due to the lack of adequate studies in the field. In this study, we aim to throw some light into those areas.^[5]

The current study shows there was an increase in the values of PAAT from birth (day1–3) to 3 months of age. The change in these PAAT values is uniform from birth to 1 month to 3 months, when the mean values were compared. There was decreasing trend in the value of the MPAP [Table 1] which suggests, an increase in the RV compliance and a fall in the PVR as expected in postnatal physiological changes. Both these differences were statistically significant (P < 0.05). The values obtained in this study remain well above the previously established cutoff values for PH provided by the European Special Interest group for the “neonatologist performed echocardiography” endorsed by the European Society of Pediatric Research and European Board of Neonatology.^[9] One of the major reasons being that the study producing such cutoffs were done on children ranging in the age group of 1–18 years with a median age of 5.3 years. Specific neonatal cutoffs were not taken into account.^[10] Hence, a cutoff of <25 mmHg at 3 months for diagnosis of pediatric hypertension cannot be applied when diagnosing neonates.

Table 1: Distribution of study participants to mean of right ventricular outflow tract diameter in study participants over time (n=100)

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Mean value of MPAP derived from PAAT at birth (day 1–3) was found to be decreased at 3 months in the present study. In a cohort studied by Koestenberger et al.^[11] involving the pediatric age group of day 1–18 years producing z score values to PAAT in pediatric age groups, 113 neonates were involved the study found the mean PAAT value of the neonates were 51 ms (53–104 ms), which is similar to the findings of the present study.

In the present study, it was also noted that, there was gradual increase in the RVOT proximal diameter from birth to 3 months of age. The mean value of RVOT proximal diameter at birth was found to be increased significantly (P ≤ 0.001) [Table 1]. This can be explained by the increase in body surface area (BSA) with age. However, the increment was compared to be very less when compared to the increase in the BSA found in previous studies.^[12] This phenomenon can be explained by the fact, with the decrease in pulmonary vasculature resistance, the RV pressure falls and the distending pressure of the blood flow fall proportionately. This leads to a minute shrinkage in the diameter of the RVOT compared to the neonatal parameters, this coupled with the increase in BSA with age produces a comparatively lesser increment in the RVOT proximal diameter. Various previous studies have shown good correlation between RVOT diameter and BSA.^[12]

Another important parameter analyzed in this study was RVFWT. Studies have proven that the RVFW thickness correlates well with the RV systolic pressure.^[13] A statistically significant (P < 0.05) decrease in the value of RVFW thickness was noted. This can be explained by the fact that there is a physiological decrease in the RV systolic pressure with progression of age as the PVR decreases. This is an ongoing process in the transition period of the heart when the left ventricle becomes the systemic ventricle, there is a pressure overload causing thickening of the ventricular walls. Meanwhile as the PVR decreases, there is a thinning in the right ventricular wall along with volume shrinkage.

This study found that the LVIDD value to increase gradually with age [Table 1]. Apart from this the current study also found, there was an increase in the left atrial diameter from birth to 3 months of age. There is an increase in the LV wall thickness as well as diameter of the left atrium as the peripheral systemic circulatory resistance increases and the left heart becomes the systemic ventricle while the right ventricles shrink and wall become thinner due to the decrease in the pulmonary resistance.

The present study has several limitations, the number of participants and the duration of the study was short and selected purposively. Establishment of normative data and cutoff values would require a multicentric approach including a larger number of participants are required.

Conclusion

The study concludes that although by 3 months of age, the RV pressure decreases from the values obtained at birth, the values remain well above the cutoff values used for the diagnosis of PH in older infants. Thus, the physiological changes witnessed here can guide us into gaining insight into the pathological changes of the RV pressure in the neonate that might help us while handling the patients in associated pathological conditions for early diagnosis and prompt management.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

Acknowledgement

The authors are grateful to Professor Dr Rakesh Mondal (Dept of Pediatrics, Medical College, Kolkata) for his necessary guidance and continuous motivation throughout the study.

Ethical approval

The study was conducted in accordance with the ethical principles that have their origin in the Declaration of Helsinki. It was carried out with patients verbal and analytical approval before sample was taken. The study protocol and the subject information and consent form were reviewed and approved by a “Institutional Ethics Committee,” NBMCH.

Authors' contributions

The authors confirm sole responsibility for the following: study conception and design, data collection, analysis and interpretation of results, and manuscript preparation.

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