Impact of aortic stenosis on longitudinal myocardial deformation during exercise

In aortic stenosis (AS), left ventricular (LV) adaptation to exercise has poorly been examined. Changes in LV ejection fraction may lack accuracy in identifying the presence of intrinsic myocardial impairment.

We sought to determine the impact of aortic stenosis (AS) on left ventricular (LV) longitudinal function at exercise in a series of asymptomatic patients with AS and preserved LV ejection fraction.

Long-axis function was assessed at rest and at exercise by using 2D speckle tracking of myocardial deformation in 207 AS patients (aortic valve area 0.87 ± 0.19 cm²) and 43 aged-matched control subjects. When compared with control subjects, patients with AS have reduced longitudinal myocardial function at rest (-20.2 ± 2.7 vs. -15.4 ± 4.0%) and at peak exercise (-25.0 ± 3.7 vs. -16.5 ± 4.9%) (P < 0.0001 for both). Exercise changes in global longitudinal strain were correlated with changes in LV ejection in controls but not in patients with AS. Changes in LV global longitudinal strain during test were lower in AS patients with an abnormal response to exercise (-0.5 ± 2.7 vs. -1.5 ± 2.8%, P = 0.001). In multivariate analysis, a lower global longitudinal strain at rest (P = 0.04), a higher increase in mean trans-valvular pressure gradient (P < 0.001) at exercise, and smaller exercise-induced changes in global longitudinal strain (P < 0.001) were associated with an abnormal exercise test.

In AS, subnormal LV function can be reliably identified by 2D strain imaging at rest and during a sub-maximal exercise. That sensitive measure of LV systolic function is depressed in AS and even more in patients having the most severe AS.