Pulmonary hypertension in congenital heart disease of children

INTRODUCTION

Congenital heart disease is a cardiovascular malformation that occurs during fetal development. Its incidence ranges from 5 to 14 per 1000 births, with the left-right shunt anomaly being the most frequent in 60% of cases.¹ Mean pulmonary resting pressure (mPAP) ≥25 mmHg with pulmonary vascular resistance (PVR) >3 WU/m².² Cardiac echodoppler is the gold standard for determining the type of heart disease and the presence or absence of pulmonary hypertension. The aim of this study was to determine the epidemio-clinical and evolutionary aspects of pulmonary arterial hypertension (PAH) in congenital heart disease with left-right shunt.

METHODS

This was a multicenter retrospective descriptive study within 03 Antananarivo University Hospitals (Centre Hospitalier Universistaire de Befelatanana, Centre Hospitalier Mère Enfant de Tsaralalana, Centre Hospitalier Mère Enfant d'Ambohimiandra) over a two-year period from 01 January 2020 to 31 December 2021. Patient recruitment was exhaustive.

Inclusion criteria

The study included hospitalized children aged 01 months to 15 years with unoperated congenital left-to-right shunt heart disease(s). Heart disease and PAH were confirmed by cardiac echodoppler.

Exclusion criteria

Incomplete medical records and children with previously operated heart disease were excluded. Heart disease with right-to-left shunts and primary PAH without associated heart disease were not included.

Statistical analysis

The variables studied were socio-demographic profile, heart disease characteristics (type, size of shunt, cardiac decompensation), PAH characteristics (age of onset, severity, Eisenmenger syndrome) and evolutionary mode. Data were processed and analyzed using Epi info software version 7.2.5. The anonymity of patients was respected.

RESULTS

At the end of data collection, we counted 74 congenital heart diseases with left-right shunt, 66.2% (N=50) with PAH and 33.8% (N=24) without PAH (Figure 1).

Socio-demographic profile

The average age of the children was 10.9±18.2 months. The median age of the children was 6 months (minimum: 1 month; maximum: 120 months). The median age of discovery of heart disease was 4 months (minimum: 1 month; maximum: 84 months). The sex ratio was 0.7. Types of heart disease and pulmonary hypertension ventricular septal defect (VSD) was the most common type of heart disease, and also the most likely to develop into pulmonary arterial hypertension (Table 1). PAH was more frequent (58.6%) in VICs larger than 5 mm (Table 2). After IVC, PAH was more frequent (57.1%) in PCAs between 3 and 5mm in size (Table 3). PAH occurred in 71.4% of patients under 1 year of age (Figure 2). PAH was severe in 39.6% of cases. Eisenmenger's syndrome accounted for 4%. The death rate was not negligible at 20.3%.

DISCUSSION

PAH was present very early, following the discovery of congenital heart disease, in our study population. In the literature, the mean age of the children was 8.9±5.4 years.³ In their study, they included all causes of pulmonary hypertension in children. In the present study, the frequency of PAH was 66.2%, which is very high compared with the literature figures of 13% and 24%.^2,3 This difference can be explained by the delayed diagnosis of heart disease. Heart disease is often diagnosed at an advanced stage. Ventricular septal defect was most likely to progress to PAH in 76.3% of patients in this study, which is well over 50% according to Mulder.⁴ IVC is the most common heart disease to progress to PAH, and is the most frequent left-right shunt heart disease.⁵ PAH is severe in large IVC.⁶

After IVC, PCA was the most frequently encountered cardiopathy in this study. In the literature, CIA follows IVC in congenital heart disease evolving towards PAH.⁷ PCA is managed very early in developed countries. Children under 12 months of age were the most affected by PAH, with a frequency of 71.4% in the present study. Diagnosis of heart disease was made at a late stage. Heart disease rapidly evolves into PAH. There is also a delay in treatment due to the difficulty of access to surgery in our country. The major improvement in mortality and morbidity in children with severe PAH of cardiac malformations is early surgical management.⁸

In this study, Eisenmeinger's syndrome accounted for 4% of cases, well below the literature figure of 58%.⁵ Our study population was almost all children under 2 years of age, but that of Duffels was adults with congenital heart disease. Ngouala et al found a value of 12.5% of Eisenmeinger cases.⁹ These cases are often outdated, as they too do not have the technical resources for early surgery, as in the present study.

In this study, the death rate was 20.3%, in line with the literature figure of 27.3%. The children died of PAH during a mean follow-up of 5.6±4.7 years. Survival at one, three, five and ten years was 83.1%, 77.1%, 70.7% and 65.2% respectively.¹⁰ Eight percent of children with PAH associated with congenital heart disease died in the study by Fraisse et al.³ This low rate can be explained by the fact that Fraisse et al carried out their study in children who had already received specific treatment for PAH, and these children were followed up over the long term.

Limitations

This is a retrospective study which has the disadvantage of not providing all the necessary data. Diagnosis of PAH in the present study was based solely on cardiac Doppler ultrasound, as MRI and cardiac catheterization were not available.

CONCLUSION

Congenital heart disease with PAH is common. Early surgical correction limits progression to PAH. In order to be able to treat children with congenital heart disease at an early stage, it is essential to set up technical platforms for cardiac surgery.

Funding: No funding sources

Conflict of interest: None declared

Ethical approval: The study was approved by the Institutional Ethics Committee

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