Discordant Grading of Aortic Stenosis Severity: Echocardiographic Predictors of Survival Benefit Associated With Aortic Valve Replacement

ObjectivesThis study sought to assess the survival benefit associated with aortic valve replacement (AVR) according to different strata of echocardiographic parameters of aortic stenosis (AS) severity, and especially in patients with an aortic valve area (AVA) comprised between 0.8 cm2 and 1 cm2.BackgroundDiscordant findings between AVA (≤1.0 cm2) and mean gradient (MG) (<40 mm Hg) raise uncertainty regarding the actual severity of AS. Some studies suggested that the AVA threshold value to define severe AS should be decreased to 0.8 cm2 to reconcile these discordances.MethodsA total of 1,710 patients with documented moderate to severe AS by Doppler echocardiography were separated into 4 strata of AS severity based alternatively on AVA, indexed AVA, MG, or peak aortic jet velocity (Vpeak). We compared the survival rates of medically versus surgically treated patients. To eliminate covariate differences that may lead to biased estimates of treatment effect, a propensity matching with a greedy 5-to-1 digit-matching algorithm was used.ResultsMean AVA was 0.9 ± 0.3 cm2, mean MG 33 ± 18 mm Hg, and mean Vpeak 3.6 ± 0.9 m/s. A total of 1,030 (60%) patients underwent AVR within 3 months following echocardiographic evaluation. During a mean follow-up of 4.4 ± 3.0 years there were 469 deaths. Patients with an AVA between 0.8 cm2 and 1.0 cm2 had a significant observed survival benefit with AVR (hazard ratio: 0.37 [95% confidence interval: 0.21 to 0.63]; p = 0.0002). AVR was also associated with improved survival in patients with MG between 25 mm Hg and 40 mm Hg or Vpeak between 3 m/s and 4 m/s, but only in patients with concomitant AVA ≤1 cm2 (p = 0.001 vs. p = 0.46 in patients with AVA >1 cm2).ConclusionsThese results do not support decreasing the AVA threshold value for severity to 0.8 cm2 and they confirm that AVR is associated with improved survival in a substantial number of patients with discordant aortic grading.