Left Ventricular Contractility and Wall Stress in Patients With Aortic Stenosis With Preserved or Reduced Ejection Fraction.

OBJECTIVES

This study sought to determine the prevalence of reduced contractility and uncompensated wall stress in patients with aortic stenosis (AS) with preserved or reduced left ventricular ejection fraction (LVEF) and their impact on survival.

BACKGROUND

LVEF in AS is determined not only by contractility but also by loading conditions.

METHODS

Patients with first diagnosis (time 0) of severe AS (aortic valve area [AVA]≤1 cm) with prior echo study (-3±1 years) were identified. Contractility was evaluated by plotting midwall fractional shortening (mFS) against circumferential end-systolic wall stress (cESS), stratified by LVEF of 60% at time 0. The temporal changes (from -3 years to time 0) and prognostic value of LVEF, contractility, and wall stress were assessed.

RESULTS

Of 445 patients, 290 (65%) had LVEF ≥60% (median: 66% [interquartile range {IQR}: 63% to 69%]) and 155 patients (35%) had LVEF <60% (median: 47% [IQR: 34% to 55%]). Median AVA was 1.27 cm (IQR: 1.13 to 1.43 cm) at -3 years and 0.90 cm (IQR: 0.83 to 0.96 cm) at time 0. Decreased contractility was already present at -3 years (49 [17%] vs. 59 [38%]; LVEF ≥60% vs. <60%; p < 0.001) and became more prevalent at time 0 (69 [24%] vs. 106 [68%]; p < 0.001). Overall, wall stress was well controlled in both groups at -3 years (1 [0%] vs. 12 [8%]; p < 0.001) but deteriorated over time in patients with LVEF <60% (time 0: 0 [0%] vs. 26 [17%]; p < 0.001). During a median follow-up of 3.4 years, LVEF <60%, decreased contractility and high wall stress were associated with worse survival (p < 0.01 for all). Decreased contractility remained incremental to LVEF in patients with LVEF ≥60% (p < 0.01), but less so when LVEF was <60% (p = 0.11).

CONCLUSIONS

In patients with severe AS, LVEF <60% is associated with a poor prognosis, being linked with decreased contractility and/or high wall stress. Decreased contractility is also present in a subset of patients with LVEF ≥60% and provides incremental prognostic value. These abnormalities already exist before AVA reaches 1.0 cm.