Importance of global and regional left ventricular myocardial strain values in different outcomes in patients after myocardial infarction and unstable angina
Abstract
Aim . To identify the most significant global and regional left ventricular myocardial strain values as predictors of mortality in patients after unstable angina and myocardial infarction. Material and methods . A total of 264 patients after myocardial infarction and unstable angina were studied. The median follow-up was 32 [28; 38] months. The criterion for an unfavorable outcome was cardiogenic death. Thus, group 1 consisted of 31 patients with fatal coronary artery disease and group 2 consisted of 233 patients with a favorable outcome. History, clinical, and paraclinical data were analyzed. Using two-dimensional speckle tracking, regional strain parameters were determined in 16 segments: longitudinal strain (LS, %), circumferential strain (CS, %), and global longitudinal strain (GLS), global circumferential strain (GCS). Systolic and diastolic, apical and basal rotations, and left ventricular (LV) torsion and twisting values were also determined. All patients underwent coronary angiography. The Gensini score was calculated. Results . Among the global parameters studied, a significant decrease in GLS was found in group 1 (fatal outcome). Patients with fatal outcomes were characterized by a predominant decrease in regional longitudinal strain parameters (LV septal and inferior walls) and, less commonly, regional circumferential strain (LV inferior wall). The study groups of patients were best distinguished using regional strain values: basCSinf (diagnostic threshold 20,9%, AUC=0,65), apexLSsept (diagnostic threshold 10,3%, AUC=0,63), and the average value (apLSsept+basCSinf)/2 (diagnostic threshold 16,4%, AUC=0,72). A decrease in the (apLSsept+basCSinf)/2 value is a consequence not only of myocardial ischemia/necrosis but also of changes in distant segments not involved in ischemia. Conclusion . Regional LV strain indices more accurately differentiate patients with fatal outcomes after myocardial infarction and unstable angina than global ones. The highest discriminatory value was found for the (apLSsept+basCSinf)/2 parameter (diagnostic threshold 16,4%, AUC=0,72), a decrease in which is a consequence not only of myocardial ischemia/necrosis but also of changes in distant, non-involved LV segments.