“…27 However, there are longitudinal data showing progression of pulmonary stenosis over time, particularly in those patients with at least moderate valvar obstruction. 28 In patients with mild pulmonary stenosis, progression of valvar obstruction can occur but rarely to the degree that treatment is required. It is also important to note that progression of stenosis is not invariable and the degree of obstruction will often remain unchanged and indeed in some instances will improve or even spontaneously resolve.…”