Background: From 1958 to 1969, 462 patients (mostly children) with aortic 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 aortic valvotomy. Of those with gradients of 50-79 mm Hg, some were managed medically, and some were managed surgically. Most had a second cardiac catheterization at the conclusion of NHS-1. More than 15 years have elapsed since NHS-1, and most of the cohort are adults. This report (the Second Natural History Study [NHS-2]) addresses the long-term results of medical and surgical management.
Methods and results: Of the original cohort of 462 patients, 440 were alive at completion of NHS-1. New data were obtained on 371 (80.3%) of the original cohort. Probability of 25-year survival was 92.4% for those admitted with gradients < 50 mm Hg and 81.0% for those with admission gradients > or = 50 mm Hg. More than half of the cardiac deaths were sudden and unexpected. Forty percent of patients managed medically during NHS-1 subsequently required surgical management. Almost 40% of operated patients required a second operation. Three percent of the original cohort subsequently had bacterial endocarditis. There was a higher-than-normal prevalence of serious arrhythmias. Of NHS-2 full participants, 92.3% were in New York Heart Association functional class I. Most patients had low Doppler mean gradients. Clinically, 46.6% had aortic valve regurgitation. The final clinical status was excellent in 29.9%, good in 22.8%, fair in 28.6%, and poor in 18.7%.
Conclusions: Patients with gradients < 25 mm Hg can be followed medically; however, progressive stenosis can occur, and approximately 20% will require intervention. If the gradient is > or = 50 mm Hg, there is a risk of serious arrhythmias and, possibly, sudden death. If the gradient is > or = 80 mm Hg, intervention is clearly indicated; as techniques improve, delaying intervention in patients with gradients of 50-79 mm Hg may not be advantageous. Patients with gradients of 25-49 mm Hg can be followed medically with annual evaluation.