Clinical Outcome in Asymptomatic Severe Aortic Stenosis

OBJECTIVES: This study examined the clinical course of patients with asymptomatic severe aortic stenosis (AS) according to the new proposed aortic valve stenosis grading classification. BACKGROUND: The management of patients with asymptomatic severe AS remains controversial. Moreover, under the same denomination of severe AS, several entities might be identified according to transvalvular flow rates and pressure gradients, resulting in 4 flow-gradient patterns. METHODS: Transthoracic echocardiography and measurement of B-type natriuretic peptide level from venous blood sample were performed in 150 consecutive patients with asymptomatic severe AS and normal exercise test. Patients were classified in 4 groups, depending on left ventricular flow state (normal flow NF vs. low flow LF: 35 ml/m(2)) and pressure gradient levels (low gradient LG vs. high gradient HG: 40 mm Hg). RESULTS: Patients with NF/LG had significantly lower B-type natriuretic peptide than those with LF/HG and LF/LG. The mean follow-up was 27 ± 12 months. At 2 years, cardiac event-free survival was 83 ± 6%, 44 ± 6%, 30 ± 12%, and 27 ± 13% in NF/LG, NF/HG, LF/HG, and LF/LG groups, respectively (p < 0.0001). On multivariable analysis, LF/LG (hazard ratio HR: 5.26, 95% confidence interval CI: 2.04 to 14.3, p = 0.045) and LF/HG (HR: 2.38, 95% CI: 1.02 to 5.55, p = 0.001) were identified as strong independent determinants of poor prognosis as compared with NF/HG. By limiting the multivariable analysis to patients with LF, LF/LG was an independent predictor of markedly reduced cardiac event-free survival when compared with LF/HG (HR: 5.4, 95% CI: 1.03 to 28.6, p = 0.046). CONCLUSIONS: The use of the new proposed AS grading classification integrating valve area and flow-gradient patterns allows a better characterization of the clinical outcome of patients with asymptomatic severe AS.