Natural history of aortic stenosis

Background: Management of patients with aortic stenosis is challenging since only few data exists indicating the rate of progression and the correlation to relevant determinants. We investigated whether analysis of the long-term progression, etiology and vascular risk factors could help to define optimal control intervals. Methods: We included 77 patients (age 51.1 ± 14.3 years) in one referral centre with an echocardiographyproven aortic stenosis (mean gradient >12 mm Hg) and a long-term follow-up of three echocardiographic examinations. Missing clinical data were supplemented by a questionnaire to the general practitioner. Two retrospective examination time intervals were defined as a second interval of <2 years (1.3 ± 0.4) and a first interval of >2 years (6.0 ± 2.4) dating back to the initial examination (maximum of 10.6 years prior to the last examination). Results: During 6.0 ± 2.4 years, the mean pressure gradient increased from 24.2 ± 13.6 to 38.1 ± 20.4 mm Hg (p <0.0001); respectively 2.1 ± 3.0 mm Hg/year in the first time period and 4.2 ± 8.2 mm Hg/year in the second time period (p = 0.049), for the entire population. According to severity, patients with mild or moderate aortic stenosis showed an increase from 2.0 ± 2.7 to 4.0 ± 6.6 mm Hg/year (p = 0.04) or from 2.2 ± 3.2 to 3.5 ± 10.9 mm Hg/year respectively (p = 0.66). The group with severe aortic stenosis had an increase of 9.6 ± 12.0 mm Hg/year (group too small for statistical analysis). During the total examination period, left ventricular mass index increased from 149 ± 60 g/m2 to 168 ± 63 g/m2 (p <0.0001), which corresponds to an increase of 3.2 to 7.8 g/m2 per annum (p = 0.52), and the relative wall thickness increased from 40.0 ± 8.5 to 43.0 ± 9.8% (p = 0.002). Ejection fraction remained stable and we found no correlation between etiology, vascular risk factors and progression of the disease. Conclusions: Progression of the mean pressure gradient in patients with aortic stenosis went from 2 mm Hg/year for mild stenosis, to 4 mm Hg/year for moderate stenosis. We found no correlation to conventional vascular risk factors. In patients with mild aortic stenosis and preserved left ventricular ejection fraction, echocardiographic follow-up every 3 to 5 years, until a mean transvalvular pressure gradient of 30 mm Hg is reached, might be a safe and cost-effective follow-up strategy. In patients with more severe aortic stenosis, follow-up has to be more frequent.