Global longitudinal strain as a potential marker for earlier treatment referral for severe aortic stenosis
Authors: Zafirovska P , Georgievska-Ismail L , Andova V , Idoski E , Mitrev Z 
Published: October 2022

Abstract

Background
Aortic stenosis (AS) is the most prevalent valvular disease in the developed countries. The disease progression is long and It is of greatest importance to choose the optimal intervention timing and to secure best long term prognosis.

Purpose
To establish left ventricular strain as independent predictor for left ventricular function improvement after AVR which could be used for treatment decision making.

Methods
In this prospective, crossectional study 76 patients were included that fulfilled the criteria for severe aortic stenosis according to the guidelines from professional associations. In all patients before the AVR detailed clinical, functional, angiographic examination was performed as well as transthoracic echocardiography using Philips Epique 7. With 2D TTE the left ventricular systolic and diastolic function was assessed and with speckle tracking echocardiography global longitudinal strain (GLS %) was evaluated. Same TTE evaluation was performed 4 months after AVR. Measurements were analyzed using QLAB 7.1. Statistical analysis was performed using SPSS 25.0.

Results
Surgical treatment of the aortic valve significantly reduced aortic stenosis severity in all patients. Age didn't have any impact on change of left ventricular function after AVR. In both genders there was significant reduction in disease severity as well as improvement in systolic and diastolic function of the left ventricle (Figure 1) with greater improvement of GLS values in the female gender.
Analysis of GLS changes after AVR in patients divided by EF showed significant improvement of GLS in patients no matter the value of preoperative EF (Figure 2). For EF improvement after AVR independent predictors were: left ventricular systolic dimension and GLS. Analysis of our cohort before AVR showed significant correlation of impaired GLS with male gender, obesity, more severe AS, larger LVD dimension and wall thickness, as well as LV systolic and diastolic volumes, higher LVMI, lower EF and lower stroke index, reduced MAPSE and s'TDI, higher wall motion score index, higher Zva and lower left atrial EF. After AVR there was significant improvement of GLS in all patient, however patients with reduced preoperative EF had significantly worse GLS after AVR. In the patients with preserved EF ≥50%, GLS before AVR was independent predictor for postoperative improvement of EF and number of segment with LS less than 13% was independent predictor for positive remodeling only in patients with low flow.

Conclusions
Impairment of LV GLS is of particular significance in the wide variety of patients with preserved EF that vary in ratio between flow and gradient were worse values of GLS imply worse prognosis. The results from our study support promotion of LV GLS as a marker for decision on AVR timing in respect of its prognostic implications. It is our expectation that GLS evaluation would find its place in future guidelines for diagnosis and treatment of patients with AS.

Funding Acknowledgement
Type of funding sources: None.