Background: Dobutamine stress hemodynamics (DSH) has the potential to stratify operative risk in low-gradient aortic stenosis (AS), but little is known about the relation between left ventricle contractile reserve and postoperative left ventricular ejection fraction (LVEF). We sought to assess the value of DSH to predict postoperative improvement in LVEF.
Methods and results: Sixty-six consecutive patients with symptomatic severe AS (aortic valve area < or =1 cm2), LVEF < or =40%, and mean pressure gradient < or =40 mm Hg prospectively enrolled in the French multicenter study on low-gradient AS and who survived to aortic valvular replacement (AVR) were included. Preoperative contractile reserve was present in 46 patients (group I; 70%) and absent in 20 patients (group II; 30%). In the overall sample, 58% of patients improved by 2 New York Heart Association (NYHA) classes after AVR. Mean LVEF improved from 29+/-6% to 47+/-11% (P<0.0001). LVEF improved by > or =10 EF units in 38 patients (83%) in group I and in 13 patients (65%) in group II. Mean LVEF improvement was similar in the 2 groups (19+/-10% versus 17+/-11%; P=0.54). On multivariable analysis, multivessel coronary artery disease (P=0.05) and baseline mean transaortic pressure gradient (P=0.01) were related to LVEF improvement, whereas contractile reserve was not.
Conclusions: LVEF increases in the majority of patients with low-gradient AS who survive after AVR. Although the absence of contractile reserve on DSH is related to high operative mortality, it does not predict the absence of LVEF recovery in patients surviving to AVR. These data further support the concept that surgery should not be contraindicated on the basis of absence of contractile reserve alone.