Low-gradient aortic stenosis. Operative risk stratification and predictors for long-term outcome: a multicenter study using dobutamine stress hemodynamics

Background—The prognostic value of dobutamine stress hemodynamic data in the setting of low-gradient aortic stenosis has been addressed in small, single-center studies. Larger studies are needed to define the criteria for selecting the patients who will benefit from valve replacement. Methods and Results—Six centers prospectively enrolled 136 patients with aortic stenosis (96 men; median age, 72 years [range, 65 to 77 years]; median aortic valve area, 0.7 cm2 [range, 0.6 to 0.8]; mean transaortic gradient, 29 mm Hg [range, 23 to 34 mm Hg]; cardiac index, 2.11 L · min1 · m2 [range, 1.75 to 2.55 L · min1 · m2]). Left ventricular contractile reserve on the dobutamine stress Doppler study was present in 92 patients (group I) and absent in 44 patients (group II). Operative mortality was 5 % (3 of 64 patients) in group I compared with 32 % (10 of 31 patients) in group II (P0.0002). Predictors for operative mortality were the lack of contractile reserve (odds ratio, 10.9; 95 % confidence interval [CI], 2.6 to 43.4; P0.001) and a mean transaortic gradient 20 mm Hg (odds ratio, 4.7; 95 % CI, 1.1 to 21.0; P0.04). Predictors for long-term survival were valve replacement (hazard ratio, 0.30; 95 % CI, 0.17 to 0.53; P0.001) and left ventricular contractile reserve (hazard ratio, 0.40; 95 % CI, 0.23 to 0.69; P0.001). Conclusions—In the setting of low-gradient aortic stenosis, surgery seems beneficial for most of the patients with left ventricular contractile reserve. In contrast, the postoperative outcome of patients without reserve is compromised by a high operative mortality. Thus, dobutamine stress Doppler hemodynamics may be factored into the risk-benefit analysi