Multichamber Strain Characterization Is a Robust Prognosticator for Both Bicuspid and Tricuspid Aortic Stenosis

Abstract

Background: Cardiac damage (CD) staging is associated with worse survival in aortic stenosis (AS). However, patients with bicuspid aortic valve (BAV) are less likely to develop CD than those with tricuspid aortic valve AS (TAV-AS). The aim of this study was to assess the prognostic value of multichamber strain (MCS) characterization, a sensitive measurement of subclinical CD, in patients with BAV- and TAV-AS.

Methods: Offline two-dimensional echocardiographic strain analysis was performed in 209 consecutive patients with BAV and 369 patients with TAV with more than moderate AS (mean gradient, 47 ± 12 vs 47 ± 14 mm Hg, respectively; >90% severe AS), retrospectively identified from the echocardiography database. The extent of abnormal cardiac mechanics was characterized by the number of chambers with impaired longitudinal strain (left ventricle, left atrium, and right ventricle) as preserved or single-chamber, paired-chamber, or triple-chamber impaired strain. Cutoffs of strain parameters to define impaired versus preserved chamber function were 15% for the left ventricle, 24% for the left atrium, and 25% for the right ventricular free wall. CD was staged using a panel of comprehensive echocardiographic parameters. The primary outcome was all-cause death.

Results: MCS (per chamber increase) modestly correlated with CD staging (per stage increase) in both groups (BAV, r = 0.36; TAV, r = 0.43). After a median follow-up period of 4.9 years (interquartile range, 2.2-4.6 years), 262 patients died (5-year survival 86.8 ± 2.4% [BAV-AS] vs 49.6 ± 2.7% [TAV-AS], P < .001). In multivariable analysis, MCS was strongly associated with all-cause death in BAV-AS and TAV-AS, separately, and independent of CD staging (P < .001 for both). MCS provided incremental prognostic value to CD staging in both BAV-AS and TAV-AS (P for χ² change < .001 for both) and improved risk classification of CD staging in TAV AS (continuous net reclassification index = 0.24, P = .02).

Conclusion: MCS characterization is a robust prognosticator in patients with greater than moderate AS and provides incremental prognostic value to CD staging in both BAV-AS and TAV-AS. Therefore, MCS characterization could represent an alternative or additive method to CD staging.

Keywords: Aortic stenosis; Bicuspid aortic valve; Strain.