Background: From 1958 to 1969, 592 patients (mostly children) with pulmonary stenosis were admitted to the First Natural History Study of Congenital Heart Defects (NHS-1) after cardiac catheterization. Most with gradients < 50 mm Hg were managed medically; most with gradients > or = 80 mm Hg had pulmonary valvotomy. Among these with gradients of 50-79 mm Hg, some were managed medically, and some were managed surgically. Most had a second cardiac catheterization at conclusion of NHS-1. More than 15 years had elapsed since NHS-1, and most of the cohort are adults. This report (Second Natural History Study) addresses the long-term results of medical and surgical management.
Methods and results: Of the original cohort of 592 patients, 580 were alive at completion of NHS-1. New data were obtained on 464 (78.4%) of the original cohort. Probability of 25-year survival was 95.7%. Probability of survival was less (80%) in a subgroup of patients entering NHS-1 > 12 years old with cardiomegaly. Less than 20% of patients managed medically during NHS-1 subsequently required a valvotomy. Only 4% of operated patients required a second operation. Bacterial endocarditis occurred rarely. Ninety-seven percent were in New York Heart Association class I. There was a small but higher-than-normal prevalence of serious arrhythmias. Most patients, whether medically or surgically managed, had low Doppler maximum gradients. Final clinical status was excellent or good in 83%.
Conclusions: Probability of survival is similar to that of the general population, and the vast majority of patients are asymptomatic. If valvotomy or valvuloplasty is required in a child, reoperation is rarely necessary. Patients with gradients < 25 mm Hg do not experience an increase in gradient. Patients with a gradient > or = 50 mm Hg should have valvotomy or valvuloplasty. Choice of management of patients with gradients of 40-49 mm Hg remains debatable.