Potential of speckle tracking echocardiography with the assessment of left ventricle myocardial work in predicting coronary artery disease in non-ST-segment elevation acute coronary syndrome

Abstract

Aim. The study aimed at evaluating the role of the left ventricular (LV) longitudinal strain (LS) measurement and the left ventricle myocardial work parameters in predicting coronary artery disease (CAD), and determining the indications for early invasive diagnosis and treatment in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS).Materials and methods. The study included 51 patients aged from 41 to 93 years who were admitted at the Institute clinic with a diagnosis of NSTE-ACS. Upon admission, the risk of hospital mortality was assessed using GRACE risk score; standard echocardiography (EchoCG) and speckle tracking echocardiography (ST EchoCG) were performed to assess the LV longitudinal strain and the LV myocardial work parameters, and coronary angiography (CAG) was performed within 48 hours. The comparison group consisted of 20 volunteers without CAD.Results. According to the risk assessment with the GRACE score, the patients with low and moderate risk made 41 and 47 %, respectively. Local contractility disorders during standard EchoCG were detected in 15 patients (29 %). When analyzing regional parameters of longitudinal strain and myocardial work, the greatest prognostic value in identifying patients with hemodynamically significant changes in the coronary arteries (CAs) was demonstrated by the functional risk area (FRA) of 4 or more adjacent segments with a myocardial work index ≤1400 mmHg x% (sensitivity and specificity 84,2 and 78,1 %, AUC=0,83). In the dysfunctional segments of the risk zone in almost all patients, a paradoxical mechanism of deformation was detected in the form of post-systolic shortening with a post-systolic index (PSI) reaching a value of ≥20 % at least in one of the adjacent segments. The combination of a significant increase in PSI and the detection of FRA limited to 3 segments indicated the acuity of coronary insufficiency, hemodynamically significant stenosis (sensitivity and specificity 84 % and 79 %). When distributing patients, taking into account the data of standard EchoCG and ST EchoCG with the assessment of myocardial work, in the absence of significant disturbances in systolic function, the patients with intact main CAs or insignificant changes in the main CAs prevailed; among patients without visual impairment of contractility, the detected FRA indicated a hemodynamically significant damage of one of the main CAs; a combination of local contractility disorders and additional FRA was associated with multiple CA damage.Conclusion. The use of ST EchoCG with the assessment of myocardial work and identification of the functional risk area in NSTE-ACS patients makes it possible to predict CAD, detect patients at risk of an unfavorable outcome regardless of the GRACE risk level, determine indications for immediate invasive diagnostics, and choose the optimal method of revascularization.