Functional correlates of strain stress echocardiography

Background The assessment of global longitudinal strain (GLS) allows an objective, reproducible assessment of global left ventricular (LV) longitudinal function during stress echocardiography (SE). OBJECTIVES This study aimed to assess the functional correlates of SE-GLS in chronic coronary syndromes (CCS). Methods This prospective, observational, multicenter study initially screened 5779 patients (3454 [60%] male; age 64 ± 12 years; ejection fraction 59 ± 10%) with CCS. All patients underwent rest and SE (exercise, n = 3506, 60.7%; vasodilator, n =1450, 25.1%; dobutamine, n = 823, 14.2%) in 37 accredited laboratories in 16 countries. Three different strain vendors were used. The measurement of GLS (absolute values, %) was attempted at rest and during SE. Multimarker SE included regional wall motion abnormalities with wall motion score index (WMSI) in all, B-lines (4-site scan) in 5328 (92.2%) , LV contractile reserve (based on force) in 5518 (95.5%), coronary flow velocity reserve (CFVR) in 3257 (56.4%) , and heart rate reserve (HRR) in 5683 (98.3%). Results Stress GLS was successfully evaluated in 4630 patients (feasibility = 80%) with significant differences related to stressors: with exercise in 2532 patients (feasibility 72%), with vasodilator in 1404 (feasibility 97%), and with dobutamine in 694 patients (feasibility 84%). In the 4630 patients with rest and SE measurements, the absolute value of GLS increased (rest=16.8 ± 3.9% to SE=17.5 ± 4.6%, p<0.001 vs rest). Based on the SE-GLS response, 2 groups were identified: ∆GLS stress-rest increase ≥ 2 points (Group 1, n=2990) or ∆GLS <2 (n=1640) (figure 1). Patients with reduced GLS reserve also showed during SE higher values of peak WMSI, and B-lines, with higher prevalence of abnormal force-based LV contractile reserve, reduced (≤2.0) CFVR (see Table 1) Conclusions SE-GLS is feasible with all stress modalities, but the success rate decreases with tachycardia associated with exercise and dobutamine stress. A lower GLS during stress is associated with a more severe functional impairment, with multiple functional vulnerabilities during SE, with more inducible ischemia and greater pulmonary congestion, reduced LV contractile and coronary flow velocity reserve.SE-GLS responder vs non-responderTable. Functional correlates of SE-GLS