Evaluation of Left Ventricular Global Longitudinal Strain as An Adjunct to Standard and ABCDE Stress Echocardiography for Risk Stratification in Ischemic Heart Disease.

Abstract

Aim     In a prospective observational study of risk stratification in patients with ischemic heart disease (IHD) using stress echocardiography (Stress ECHO), to evaluate the significance of left ventricular (LV) global longitudinal strain (GLS) as an independent prognostic marker or as an adjunct to the existing markers.Material and methods            This study included 273 patients (60.4% men, mean age 60.9±9.5 years) with known (n=109; 39.9%) or suspected (n=164; 60.1%; IHD pretest probability (PT): 17 [11-26]% (interquartile ranges: Me [Q1; Q3])) IHD. All patients underwent Stress ECHO with physical exercise (PE) on a recumbent bicycle ergometer (n=165; 60.4%), vasodilator (adenosine triphosphate (ATP), n=74; 27.1%), and other stress tests (n=34; 12.5%). The Stress ECHO protocol included assessment of local contractile disorders (LCD), B-lines, LV contractile reserve (CR), and heart rate reserve. Additionally, LV GLS was assessed at rest and at the test peak, and GLS reserve and GLS change (ΔGLS) were calculated. The prospective follow-up period was 20 [13-25] months. The composite cardiovascular end point (CVE) included death from cardiovascular causes, acute coronary syndrome, revascularization, and stroke/transient ischemic attack, and was calculated until the first event.Results            Prognostic values were obtained for 272 (99.6%) patients. During the follow-up period, 114 cardiovascular complications (CVC) occurred in 87 (31.9%) patients (1 to 3 in each patient). According to the multivariate regression analysis of the Stress ECHO results, the independent predictors for the CVE were the emergence of new LCDs at the peak of stress testing (odds ratio (OR) 2.95; 95% confidence interval (CI): 1.51-5.76; p=0.02) and ΔGLS (OR 0.90; 95% CI: 0.81-0.99; p=0.039). With the use of ATP, the risk of developing CVC was described by a similar model, that had an even higher level of significance (OR for LCD 36.21; 95% CI: 3.09-424.09; p=0.004; OR for ΔGLS 0.48; 95% CI: 0.25-0.94; p=0.032). In PE Stress ECHO, the GLS index added to the LCD did not demonstrate an independent prognostic value. The ROC analysis identified a threshold value for ΔGLS as a predictor of unfavorable prognosis. The threshold absolute value was 1.2 in the entire group and 0.2 in the ATP Stress ECHO subgroup. In case of difficulties in assessing the LCD at the testing peak, an alternative model was used with evaluation of the IHD PT (OR 1.09; 95% CI: 1.04-1.14; p<0.001), emergence of angina at the testing peak (OR 5.07; 95% CI: 1.81-14.26; p=0.002), reduced LV CR (OR 2.18; 95% CI 0.73-6.53; p=0.162), and ΔGLS (OR 0.83; 95% CI 0.72-0.95; p=0.008).Conclusion      In Stress ECHO performed for risk stratification in IHD, the ΔGLS value, regardless of and in addition to LCDs, is a predictor of CVC. The absolute value of ΔGLS <1.2 in the entire group and ΔGLS <0.2 in the ATP subgroup indicates an unfavorable prognosis for the next 1.5 years.