Second natural history study of congenital heart defects. Results of treatment of patients with aortic valvar stenosis.

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.