Pulmonary valve stenosis cannot be prevented

Pulmonary valve stenosis

Pulmonary stenosis can be life-threatening

I guess you refer to the pulmonary valve stenosis which usually is due to the valve calcification when less blood supply will go from right ventricle of heart to the pulmonary circulation. The right ventricle will be hypertrophied because it's working harder then before.

Patients with the most severe form of pulmonary valve stenosis may die in infancy