# Dynamic assessment of global longitudinal strain after isometric exercise to predict functionally significant coronary lesion

## TL;DR

This study shows that measuring heart muscle strain during isometric exercise can help identify significant coronary artery blockages in patients with chronic heart disease.

## Contribution

The study introduces dynamic global longitudinal strain during isometric hand-grip exercise as a novel non-invasive method for coronary lesion assessment.

## Key findings

- ΔGLS showed strong correlation with FFR (r = 0.660, P < 0.001).
- A ΔGLS threshold of 0.35 had high sensitivity (92%) and specificity (85%) for significant lesions.
- 44% of patients had functionally significant coronary lesions based on FFR.

## Abstract

There is still a wide debate regarding the management of patients with chronic coronary syndrome, the choice of optimal non-invasive stress test, and the decision for coronary revascularization. Evidence has accumulated demonstrating the utility of global longitudinal strain (GLS) as a predictor of significant coronary disease. To evaluate the application of speckle tracking during resting echocardiography and after isometric loading with the hand-grip test, and to compare GLS parameters with fractional flow reserve (FFR).

Patients with known CCS who underwent angiography with evidence of coronary stenosis >40%<90% and were referred for functional assessment were enrolled in this study. Patients with previous MI, depressed LV systolic function, and poor acoustic window were excluded. Patients underwent a standard echocardiography with recordings suitable for LV speckle tracking. Subsequently, a dynamic hand-grip test was performed for 3 min, then the same images were captured. Global longitudinal strain was calculated at rest (rGLS), under stress conditions (sGLS), as well as the absolute difference between the two measurements – ΔGLS. Then, patients underwent invasive functional assessment with measurement of the FFR of the coronary lesion. Correlation analysis of myocardial strain parameters and FFR was performed. A total of 106 patients were included in the study. The mean rGLS was −18.5 ± 1.8, sGLS: −19.1 ± 2.0 and ΔGLS: 0.62 ± 1.4. In total, 44% of patients had a functionally significant coronary lesion when assessed with FFR. There was a statistically significant correlation between ΔGLS and FFR values, r = 0.660, P < 0.001. ΔGLS of 0.35 showed good diagnostic performance capacity (AUC 0.896, 95% CI: 0.83–0.96, specificity 85%, sensitivity 92%) for a functionally significant coronary lesion.

Dynamic GLS during isometric hand-grip exercise is a feasible method for functional assessment in patients with chronic coronary syndrome.