Severe Pulmonary Arterial Hypertension in Healthy Young Infants: Single Center Experience.

Objective: We studied the clinical presentation and management of acute pulmonary arterial hypertension (PAH) in healthy young infants, and the effect of thiamine therapy.

Methods: Review of hospital records was conducted for 56 healthy infants (aged below 6 month) who developed sudden onset of pulmonary arterial hypertension as diagnosed on 2D echocardiography, and were admitted at our institution.

Results: All patients received supportive care and pulmonary vasodilator therapy, whereas those admitted after Sep-tember, 2019 (n=28) received thiamine in addition, as per the institute's protocol. Overall, complete recovery was seen in 80% (n=45). Infants who died had significantly lower mean pH (7.05 vs 7.27; P=0.001) and serum bicarbonate (9.1 vs 14.9; P=0.007), higher arterial lactate (72.7 vs 61.5; P=0.92), ventricular dysfunction (16 vs 10; P=0.01) and shock (7 vs 9; P=0.008) when compared to those who survived. Baseline characteristics, severity of acidosis and pulmonary hypertension, time taken to recover from PAH, presence of ventricular dysfunction were comparable among those who received thiamine and those who did not receive it. Similarly, recovery (89% vs 71%; P=0.17) and mortality (11% vs 29%) were also comparable between the two groups.

Conclusions: A significant proportion of infants with PAH improve with supportive treatment and pulmonary vasodilator therapy. Thiamine supplementation may not give any additional benefit in these patients.