Incidence of aortic stenosis in subjects with normal and slightly elevated aortic gradients and flow

OBJECTIVE: We aimed to describe the progression rate into manifest aortic stenosis (AS) in subjects with normal aortic valves or in an early phase of calcific aortic valve disease. METHODS: Participants were recruited from the Tromsø Study, a population-based health survey. In our prospective cohort study, we performed two echocardiographical examinations (2001 and 2008) of a random sample of 1884 participants. AS was defined as a mean aortic valve gradient ≥15 mm Hg or a peak flow exceeding 2.6 m/s. Those with lesser values were stratified into three groups based on mean gradients (cut-off 5 and 10 mm Hg) and peak aortic flow (cut-off 1.5 and 2 m/s). RESULTS: At baseline, 71 participants had gradients from 10 to 14.9 mm Hg, of whom 32.4% developed AS during follow-up. AS developed in only 3.6% of those with a baseline gradient of 5-9.9 mm Hg and in 0.3% of those with a gradient <5 mm Hg. Almost identical separations were obtained among the three flow velocity groups. Of the 45 subjects who developed incident AS, 56% acquired mild, 33% moderate and 11% severe AS. Their mean gradient progression rate was 2.7 mm Hg/year. CONCLUSIONS: The results support that subjects with a mean aortic valve gradient of 10-15 mm Hg or aortic flow >2.0 m/s should be followed routinely. This group identifies about half of those who develop AS in the following 7 years.