Since February 2011, 258 patients with AS and left ventricular hypertrophy underwent AVR with the Trifecta (TR) (St Jude Medical, St Paul, Minn) or Perimount Magna Ease (ME) (Edwards LifeSciences, Irvine, Calif) bioprosthesis. There were longer bypass and crossclamp times and the indexed left ventricular outflow tract was smaller in the TR group. For the TR and ME, respectively, peak (14.4 ± 5.1 mm Hg vs 20.9 ± 7.2 mm Hg; P < .001) and mean (7.3 ± 2.7 mm Hg vs 10.9 ± 4.3 mm Hg; P < .001) gradients were significantly smaller postoperatively in the TR group. There was greater total mass regression (44.3 g/m; 95% confidence interval [CI], 36.3-52.3 vs 29.5; 95% CI, 20.4-38.5 g/m; P = .020) and mass regression over time in the TR group compared with the ME group (P = .016). Freedom from readmission, congestive heart failure, and the composite outcome of all-cause mortality, readmission, and congestive heart failure at 2.5 years was significantly improved in the TR group (composite outcome in TR and ME groups, respectively, 90.2; 95% CI, 81.9-94.9 and 78.2; 95% CI, 67.1-86.0; P = .013) CONCLUSIONS: TR use was associated with significantly increased left ventricular mass regression and improved intermediate-term clinical outcome in patients with left ventricular hypertrophy undergoing AVR for AS, compared with use of the ME.