Pulmonary hypertension in children — formative SAQs

SAQ 1 (10 marks) — The eight-year-old with exertional syncope and a loud second heart sound

Stem: An eight-year-old child is brought in after collapsing while running at school. Examination reveals a loud, palpable pulmonary component of the second heart sound, a right ventricular heave, and a soft pansystolic murmur at the lower left sternal edge. The echocardiogram estimates a raised pulmonary pressure. Outline the definition and classification, the investigation pathway, and the principles of management. [1] [2]

Model answer

Definition and classification (3 marks). Pulmonary hypertension is a mean pulmonary artery pressure above twenty millimetres of mercury confirmed at cardiac catheterisation, and pulmonary arterial hypertension adds a raised pulmonary vascular resistance — above three Wood units per square metre indexed in children — with a normal wedge pressure of fifteen or less. The WHO clinical classification sorts the disease into five groups: group one pulmonary arterial hypertension, group two left heart disease, group three lung disease or hypoxia, group four thromboembolic, and group five multifactorial. The group decides the cause and the therapy. [3] [2]

Investigation (3 marks). Echocardiography estimates the pressure from the tricuspid regurgitation velocity, assesses the right ventricle, and excludes or defines the congenital heart disease. Cardiac catheterisation is the gold standard and is performed in every child before targeted therapy, measuring the mean pulmonary artery pressure, the wedge pressure, the cardiac output, and the indexed resistance, and testing for vasoreactivity with inhaled nitric oxide. The bloods include the N-terminal pro-brain natriuretic peptide, the iron studies, and the genetic panel. [7] [4]

Management (4 marks). The therapy is risk-stratified. The vasoreactive idiopathic subset receives high-dose calcium channel blockers; the non-vasoreactive child receives combination therapy across the three pathways — a phosphodiesterase-5 inhibitor, an endothelin receptor antagonist, and a prostacyclin analogue. The right ventricle decides the prognosis, so a child in right ventricular failure is escalated to parenteral prostacyclin. The refractory child is escalated to atrial septostomy, the Potts shunt, and lung transplantation. [1] [5]

SAQ 2 (10 marks) — The Eisenmenger threshold and the irreversibly paised resistance

Stem: A teenager with a ventricular septal defect that was repaired late now has cyanosis, clubbing, and decreasing exercise tolerance. The catheter shows a raised, fixed pulmonary vascular resistance. Discuss the pathophysiology, the operability threshold, and the management of the Eisenmenger syndrome. [8] [5]

Model answer

Pathophysiology (3 marks). An unrepaired left-to-right shunt raises the pulmonary flow and the pressure, and the resistance rises over time through vasoconstriction, vascular remodelling, and in-situ thrombosis. When the resistance crosses the threshold, the shunt reverses from left-to-right to right-to-left, producing the cyanosis, the clubbing, and the secondary polycythaemia of the Eisenmenger syndrome. The disease is then irreversible. [8] [3]

Operability threshold (3 marks). The decision to repair a shunt rests on the catheter, not the echo. An indexed resistance below the threshold permits repair with an acceptable operative risk, while a resistance above the threshold makes the operative risk prohibitive and the shunt is left alone. Repairing a shunt above the threshold removes the pop-off and worsens the right ventricular failure, so the resistance number is the must-not-miss judgement. [5] [8]

Management (4 marks). The Eisenmenger patient is managed with targeted therapy across the three pathways, with anticoagulation in selected cases, and with the avoidance of pregnancy and the careful management of non-cardiac surgery. The complications include haemoptysis from the hypertrophied bronchial arteries, atrial arrhythmia, and heart failure. The lesson is prevention — repair the shunt before the resistance crosses the threshold. [8] [4]