Preoperative Left Ventricular Global Longitudinal Strain Identifies Aortic Stenosis Patients with Improved Postoperative Recovery of Left Ventricular Geometry: A Prospective Cohort Study

Abstract

Introduction: The left ventricular ejection fraction (LVEF) is commonly used as a marker of aortic stenosis (AS) disease severity and to indicate surgical intervention. However, an LVEF <50% identifies mainly advanced disease. Hence, earlier detection of subclinical LV systolic dysfunction may improve clinical decision-making. The global longitudinal strain (GLS) can identify subclinical systolic dysfunction at earlier stages of AS progression even in the presence of preserved LVEF. To this end, we evaluated the preoperative prognostic significance of the LVGLS to identify patients who will undergo a more extensive postoperative LV reverse remodeling as a surrogate marker for clinical recovery.

Methods: We performed a prospective observational study based on detailed pre- and postoperative 2D transthoracic echocardiographic examinations, including strain analysis with speckle tracking. We screened 60 consecutive patients with severe AS and a preoperative LVEF ≥50% indicated for surgery; 39 patients met the study entry criteria and consented to their participation.

Results: The median age was 67 (range 30-79) years; 56.4% were female. At baseline, the GLS was 61.64±7.22%. Surgery led to an improvement in the GLS; the mean difference was 3.23% [95% CI=1.96 to 4.49%] during a median follow up time of 5 (interquartile range 4-6) months. The preoperative GLS correlated with the postoperative LV mass index (LVMI) r=0.526, P=0.001 and the intraventricular septal thickness in diastole (IVSd) r=0.462, P=0.003. Furthermore, patients with a normal GLS (≤-18.9%) at baseline experienced a better recovery of their LV morphology and systolic function during the postoperative course compared to those with an abnormal GLS (>-18.9%). The effect size, hedges g, was at least >0.75 for the LVMI, IVSd, intraventricular septal thickness in systole (IVSs), left ventricular posterior wall thickness in diastole (LVPWd) and LVEF, suggesting a clinically significant difference between subgroups at follow-up.

Conclusion: A normal preoperative left ventricular global longitudinal strain is associated with an improved left ventricular reverse remodeling and systolic function following surgery to resolve aortic stenosis.

Keywords: Aortic Valve Stenosis; Biomarkers; Clinical Decision-Making; Echocardoography; Heart Ventricules; Severity of Illness Index; Ventricular Remodeling.

Fig. 1

STROBE study flow diagram. Patient eligibility evaluation, inclusion and exclusion criteria and patient eligibility.

Fig. 2

Representative bull’s-eye images of patients presenting with normal versus abnormal preoperative GLS. Panels A and B show preoperative and postoperative bull’s-eye images of a patient with preoperative abnormal GLS who experienced minor, but clinically insufficient, improvement in LV systolic function and myocardial contractility. Panels C and D show perioperative bull’s-eye images of a patient with normal GLS. Panels E and F display images of a patient with impaired subclinical LV systolic function at baseline which improved during the postoperative course.

Fig. 3

Overview of echocardiography correlated with the GLS. Linear regression line represents the correlation between the GLS and A) left ventricular mass index and B) intraventricular thickness at diastole. Correlation coefficients are embedded in the graphs. C) Scatter plots depict preoperative (open symbols) and postoperative (closed symbols) data of the global longitudinal strain based sub-groups, stratified according to a “normal GLS” (≤-18.9%) cohort (n=13) (circles) and “abnormal GLS” (>-18.9%) cohort (n=26) (squares), D) left ventricular mass index and E) intraventricular septal thickness at diastole. F) Scatter plots show the preoperative left ventricular mass index according to the NYHA class. G) Contingency graph presents the percentage of patients who experienced a full recovery of LV geometry within a median follow-up period of 5 (IQR 4-6 months). The odds ratio is embedded in the graphs as a measure of effect size.

Supplemental Fig. 1

Normal vs. abnormal GLS age, BMI and BSA comparative analysis and evaluation of postoperative left ventricular geometry of patients undergoing isolated SAVR versus patients undergoing SAVR and CABG. A) The global longitudinal strain based sub-groups, stratified according to a “normal GLS” (≤-18.9%) cohort (n=13) (circles) and “abnormal GLS” (>-18.9%) cohort (n=26) (squares) compared based on age, BMI and BSA. Evaluation of the preoperative and postoperative B) global longitudinal strain, C) left ventricular mass index and D) intraventricular septal thickness at diastole.

Supplemental Figs. 2 to 3

Overview of echocardiography correlated with the left ventricular global longitudinal strain. Scatter plots depict the preoperative (open symbols) and postoperative (closed symbols) data of the global longitudinal strain based sub-groups, stratified according to a “normal GLS” (≤-18.9%) cohort (n=13) (circles) and “abnormal GLS” (>-18.9%) cohort (n=26) (squares).

Supplemental Figs. 2 to 3

Overview of echocardiography correlated with the left ventricular global longitudinal strain. Scatter plots depict the preoperative (open symbols) and postoperative (closed symbols) data of the global longitudinal strain based sub-groups, stratified according to a “normal GLS” (≤-18.9%) cohort (n=13) (circles) and “abnormal GLS” (>-18.9%) cohort (n=26) (squares).