Parameters of the contractile reserve of the left and right ventricles during dobutamine stress echocardiography and three-year survival in patients with coronary artery disease and left ventricular systolic dysfunction

Abstract

Background. The role of revascularization in patients with severe ischemic left ventricular (LV) dysfunction remains a matter of debate, particularly with regard to patient selection and prognostic stratification. Conventional assessment of myocardial viability does not always reliably predict clinical outcomes. The prognostic value of quantitative assessment of biventricular reserve during dobutamine stress echocardiography (DSE) remains insufficiently studied. Aim: To evaluate the prognostic value of conventional and additional DSE parameters for predicting 3-year all-cause mortality in patients with coronary artery disease (CAD) and severe LV systolic dysfunction referred for treatment strategy selection. Methods. This single-center retrospective observational study included 75 patients with ischemic LV systolic dysfunction and available 3-year vital status data: mean age 60,6 ± 7,1 years, 70 (93.3%) were men, LV end-systolic volume index 77,0 (69,6; 90,7) mL/m², and LV ejection fraction (LVEF) 30,1 ± 5,6%. All patients underwent DSE with assessment of conventional markers of myocardial viability and LV contractile reserve, including LVEF and regional wall motion abnormalities (RWMA), as well as global longitudinal strain (GLS), LV pump function, and right ventricular (RV) longitudinal systolic function assessed by tricuspid annular plane systolic excursion (TAPSE) and peak systolic velocity of the basal segment of the RV free wall (RV S′). Surgical revascularization was performed in 62 (82,7%) patients. The primary endpoint was all-cause mortality within 3 years. The prognostic value of the parameters was assessed using Cox regression and Kaplan–Meier analysis. Results. Three-year survival was 70,7%. Myocardial viability according to conventional criteria was identified in 51 (68,0%) patients; however, the presence of viable myocardium, type of stress response, increase in LVEF, and change in wall motion score index were not significantly associated with 3-year survival. Patients with adverse outcomes had lower stress-induced LVEF, LV pump function parameters (LVOT VTI), worse GLS, and more pronounced RV dysfunction at rest and during DSE. In univariable Cox models, significant associations with 3-year all-cause mortality were found for stress-induced LVEF, GLS, LVOT VTI, LV stroke index, TAPSE, and RV S′. In limited two-variable models adjusted for LV functional parameters, the maximal stress-induced RV S′ remained significantly associated with 3-year all-cause mortality. Kaplan–Meier analysis demonstrated significant separation of survival curves according to RV S′, TAPSE, and LVOT VTI. Conclusion. In patients with CAD and severe LV systolic dysfunction, conventional markers of myocardial viability and LV contractile reserve during DSE had limited prognostic value. A stronger association with 3-year all-cause mortality was observed for parameters of RV systolic function, particularly stress-induced RV S′, and LV pump function.