Pulmonary Hypertension in Down Syndrome Versus Non-syndromic Pediatric Populations With Congenital Heart Disease: A Comparative Study

Background: Down syndrome (DS), or trisomy 21, is the most common chromosomal disorder associated with congenital heart disease (CHD), profoundly affecting disease progression and management. While 4-10% of all CHD cases occur in DS, 40-60% of individuals with DS have CHD. CHD remains the leading cause of mortality in DS within the first two years of life, with atrioventricular septal defect (AVSD), ventricular septal defect (VSD), atrial septal defect (ASD), patent ductus arteriosus (PDA), and tetralogy of Fallot (TOF) being most prevalent. Pulmonary hypertension (PH) frequently complicates these lesions, influencing prognosis and therapeutic decisions. Early detection via echocardiography is crucial for optimising outcomes. This study compares the prevalence and phenotypic patterns of pulmonary hypertension in paediatric patients with syndromic versus non-syndromic congenital heart disease. Materials and methods: A cross-sectional study was conducted over 24 months in the Paediatric Cardiology Department of Bangladesh Medical University (BMU), enrolling 208 children with CHD, including 104 with DS and 104 non-syndromic controls between 2022 and 2024. Karyotyping confirmed DS, while 2D, M-mode, and colour Doppler echocardiography diagnosed CHD and assessed pulmonary artery pressure (PAP). Statistical analysis was performed using SPSS version 26 (IBM Corp., Armonk, New York, USA); categorical variables were compared with χ² tests and continuous variables with unpaired t-tests, with p < 0.05 considered significant. Results: Children with DS presented earlier (2.02 ± 3.77 vs. 3.78 ± 3.8 years; p < 0.001) and had a higher prevalence of PH (97 (88.5%) vs. 55 (52.9%)). Severe PH (>70 mmHg) was more common in DS (18 (17.3%) vs. 7 (6.7%)), while normal PAP was rare (9 (8.7%) vs. 40 (38.5%); p < 0.001). Echocardiography revealed lower tricuspid annular plane systolic excursion (TAPSE) (15.7 ± 3.71 mm vs. 18.3 ± 3.77 mm; p < 0.001) and higher pulmonary artery systolic pressure (PASP) (48.9 ± 16.9 mmHg vs. 35.2 ± 14.4 mmHg; p < 0.001). AVSD predominated in DS (36 (34.6%)), associated with moderate-severe PH, whereas VSD and ASD were common in non-syndromic children, typically with mild or no PH. Combined lesions correlated with higher PH severity in both groups. Conclusion: Children with DS and CHD exhibit earlier onset and greater severity of PH than non-syndromic peers. Prompt diagnosis and tailored management are critical to prevent progression to advanced pulmonary vascular disease in this high-risk population.