Aortic Stenosis

The report from Belgium (1) and the accompanying editorial from Sweden (2) complain, rightly, that the published indications for intervention for asymptomatic severe aortic stenosis are in conflict. American guidelines (3) require a valve area 1 cm and a mean gradient 40 mm Hg, whereas Otto et al. (4) required a peak velocity 4 m/s that predicts a gradient of 64 mm Hg. The European guidelines (5) require a mean gradient 50 mm Hg. The recent Belgian study used appropriate measures of outcome, event-free survival and hazard ratio, whereas Otto et al. (4) used aortic valve surgery as an end point in 48 patients and death in only 8. The former is clearly subject to selection bias, reflecting the investigators’ indication for surgery. A 1965 publication from the same hospital (6) on this subject, coauthored by Alvin Merendino, a thoughtful surgeon, emphasized the limitations of what can be accomplished by commissurotomy for congenital aortic stenosis without producing severe aortic regurgitation. That report concluded that young patients with this condition would eventually develop calcification and require valve replacement, with or without early surgery, and that this justified a conservative approach in young patients. Furthermore, the investigators found that the peak systolic gradient was not sufficiently accurate as an indication for surgery, compared with valve area or the mean ejection gradient. (Ejection fraction is primarily of concern when aortic regurgitation is severe.)