Exercise-induced changes in left ventricular global longitudinal strain in asymptomatic severe aortic stenosis

Abstract

Background: The management of patients with asymptomatic severe aortic stenosis (ASAS) is still under discussion. Therefore, it is advisable to search for the parameters of early damage to left ventricular (LV) function.

Aim: The aim of the study was to assess exercise-induced changes in LV global longitudinal strain (GLS) in ASAS.

Methods: The ASAS group consisted of 50 patients (26 women and 24 men, aged 38.4 ± 18.1 years) meeting the echocardiographic criteria of severe aortic stenosis (AVA < 1 cm², AVAI < 0.6 cm²/m², Vmax > 4 m/s, mean aortic gradient > 40 mm Hg), with normal LV ejection fraction (LVEF ≥ 55%) and sinus rhythm on electrocardiogram, and without significant concomitant valvular heart diseases. The control group consisted of 21 people matched for age and sex. Echocardiographic examinations and echocardiographic stress tests with the assessment of GLS using the speckle tracking imaging were performed.

Results: The ASAS group was characterised by statistically significantly higher LV mass index (LVMI) and higher LVEF. GLS values at rest in both groups were within normal limits but were significantly higher in the control group (–18.9 ± 2.4% vs. –20.7 ± 1.7%, p = 0.006). An increase in GLS at peak exercise in both groups was observed, lower in the ASAS group (the difference was not statistically significant: –0.8 ± 3.0% vs. –2.2 ± 3.1%, p = 0.086). Changes in GLS during exercise (ΔGLS) did not correlate with the parameters of the severity of aortic stenosis. In the multivariate model, LVMI proved to be a factor associated with GLS at rest and during exercise.

Conclusions: In patients with ASAS, GLS is a non-invasive marker of an early stage of LV myocardial damage associated with myocardial hypertrophy. An increase in GLS during exercise in the ASAS group, smaller than in the control group, indicates a preserved functional reserve of the LV myocardium but smaller than in healthy individuals. The assessment of the clinical usefulness of exercise-induced changes in GLS requires further research.