Low-Gradient Aortic Stenosis

TLDR

The prognostic value of dobutamine stress hemodynamic data in low‑gradient aortic stenosis has been explored in small, single‑center studies. The study aims to define criteria for selecting low‑gradient aortic stenosis patients who will benefit from valve replacement. Six centers prospectively enrolled 136 patients with low‑gradient aortic stenosis, collecting baseline valve area, gradients, and cardiac index data. Patients with left‑ventricular contractile reserve had markedly lower operative mortality (5% vs 32%) and better long‑term survival, whereas those without reserve had high operative mortality; thus, dobutamine stress Doppler hemodynamics should guide risk‑benefit decisions for valve replacement.

Abstract

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.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 x min(-1) x m(-2) [range, 1.75 to 2.55 L x min(-1) x m(-2)]). 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 (P=0.0002). Predictors for operative mortality were the lack of contractile reserve (odds ratio, 10.9; 95% confidence interval [CI], 2.6 to 43.4; P=0.001) and a mean transaortic gradient < or =20 mm Hg (odds ratio, 4.7; 95% CI, 1.1 to 21.0; P=0.04). Predictors for long-term survival were valve replacement (hazard ratio, 0.30; 95% CI, 0.17 to 0.53; P=0.001) and left ventricular contractile reserve (hazard ratio, 0.40; 95% CI, 0.23 to 0.69; P=0.001).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 analysis for each patient.