Aortic and pulmonary stenosis — branching viva

Opening: classify and grade

The candidate opens by recognising that the murmur at the upper left sternal border with a respiratory-varying ejection click and a widely split second heart sound is the classic presentation of valvar pulmonary stenosis. The click localises the lesion to the valve, its respiratory variation confirms pulmonary rather than aortic origin, and the wide S2 split reflects prolonged right-ventricular ejection. The diagnosis is confirmed by echocardiography, which shows the domed valve with fused commissures and measures the peak systolic gradient. [1] [2]

The candidate classifies the lesion by anatomic level — valvar, subvalvar, or supravalvar — and grades it by peak gradient: mild below 40 mmHg, moderate 40 to 64 mmHg, severe above 64 mmHg. The level predicts the intervention and the syndrome, and the gradient determines the urgency. This dual classification is the framework that earns marks. [1]

Branch 1: balloon valvuloplasty and the evidence

The examiner asks about the management of moderate valvar pulmonary stenosis. The candidate answers that balloon pulmonary valvuloplasty is the first-line and definitive intervention, one of the most successful procedures in congenital interventional cardiology, with long-term outcome data showing sustained gradient reduction and low restenosis rates. The procedure is indicated for moderate and severe gradients and for symptomatic disease. [2]

The examiner probes the complications. The candidate names pulmonary regurgitation as the main late concern, usually well tolerated in childhood but potentially requiring pulmonary valve replacement in adulthood. The candidate contrasts this with aortic valvuloplasty, where aortic regurgitation is the more immediate concern and the VACA Registry data established the predictors of success. [4]

Branch 2: the dysplastic Noonan valve

The examiner branches to the exception. The candidate explains that the dysplastic pulmonary valve of Noonan syndrome — thickened, immobile, myxomatous leaflets without commissural fusion — responds poorly to balloon valvuloplasty and usually needs surgical valvotomy. The syndrome also carries hypertrophic cardiomyopathy, and the phenotype includes short stature, webbed neck, and ptosis. Recognising the syndrome predicts the valve morphology and the intervention, and the candidate names the PTPN11 mutation as the commonest genetic cause. [1]

Branch 3: the critical neonate

The examiner moves to the neonatal emergency. The candidate explains that critical pulmonary stenosis is duct-dependent for pulmonary blood flow, presenting with profound cyanosis as the duct closes. The immediate response is prostaglandin E1 at 0.01 to 0.05 mcg per kg per minute, and the definitive intervention is urgent balloon valvuloplasty. If the right ventricle is too small, a systemic-to-pulmonary shunt may be needed until it grows. The candidate contrasts this with critical aortic stenosis, which is duct-dependent for systemic flow and presents with shock rather than cyanosis. [3]

Closing: the Ross procedure

The examiner closes with the aortic valve that needs replacement. The candidate explains that the Ross procedure — replacing the aortic valve with the patient's own pulmonary autograft and placing a homograft in the pulmonary position — is preferred in growing children because the autograft grows with the child and avoids anticoagulation. Its trade-offs are autograft dilation producing aortic regurgitation and homograft stenosis requiring reoperation every 10 to 15 years. The candidate frames the lifelong trajectory: restenosis, regurgitation, reoperation, and structured transition to adult congenital heart disease services. [1] [4]