In patients with significant aortic stenosis (AS), the prognostic effect of the increase in left ventricular mass (LVM) in relation to one's hemodynamic load has been described. Inappropriately high LVM has been shown to predict adverse cardiovascular events. However, little is known about the prognostic impact of inadequately low LVM (i-lowLVM) in patients with significant AS. I-lowLVM was defined as the measured LVM < 73% of the predicted LVM based on sex, stroke work and height from the reference adult population, used in previous established studies. For outcome analysis, the end-point was defined as all-cause mortality, aortic valve replacement and/or admission for congestive heart failure. Kaplan-Meier curves and multivariable Cox regression models were constructed to compare outcomes on follow-up. During the follow-up (4.5 ± 4.1 years), 132 patients (11.1%) had i-lowLVM, 868 (73.1%) had adequate-LVM, 188 (15.8%) had inappropriately high LVM. Outcome analysis only included patients with i-lowLVM and adequate-LVM (N = 1000). An adverse composite event occurred in 41.7% of the i-lowLVM group and 52.4% of the adequate-LVM group (p = 0.021). Event-free survival in patients with i-lowLVM and appropriate-LVM was 76% versus 68% at 2-year, 55% versus 46% at 4-year, 33% versus 27% at 6-year, 20% versus 17% at 8-year, and 17% versus 11% at 10-year follow-up, respectively (p < 0.001). Cox analysis revealed that i-lowLVM was independently associated with lower composite adverse outcome (HR 0.624, 95% CI 0.460-0.846, p = 0.002) after adjusting for sex, age, ejection fraction, ischemic heart disease, diabetes and transaortic valve mean gradient. In the separate Cox subanalyses, the presence of i-lowLVM remained a predictor of lower composite adverse outcome in the severe AS subgroup (HR 0.587, 95% CI 0.396-0.870, p = 0.008), and the LVH subgroup (HR 0.574, 95% CI 0.401-0.824, p = 0.003) after adjusting for confounders. I-lowLVM despite significant AS may represent a distinct group that is associated with improved survival outcomes independent of other prognostic covariates.
Keywords: Aortic stenosis; Left ventricular hypertrophy; Left ventricular mass.