Abstract 16342: Non-invasive Analysis of Regional Myocardial Work Predicts Total Coronary Artery Occlusion in Non-ST-Elevation Myocardial Infarction Patients

Abstract

Introduction: Approximately 30% of patients with non-ST-elevation myocardial infarction (N-STEMI) have acute coronary artery occlusion (CAO), which may lead to reduced regional myocardial function. In the present study we investigated if a previously validated non-invasive method for assessing segmental myocardial work (SW) can identify patients with CAO.

Methods: Echocardiography was performed before coronary angiography (CA) in 52 patients with N-STEMI. Longitudinal strain (LS) curves were assessed by speckle tracking echocardiography for each myocardial segment in a 16-segment LV model. Left ventricular pressure (LVP) was estimated by utilizing a normalized reference curve which was adjusted according to LV isovolumic and ejection phases, as defined by timing of aortic and mitral valvular events. Systolic arterial cuff pressure was used to scale the LVP reference curve. SW was calculated as the area of the LVP-LS loop. To evaluate the ischemic region affected by a CAO, the number of segments with systolic dysfunction judged by empirical cut-off values of <1700%·mmHg for SW and >-14% for segmental peak systolic strain (SPSS) were assessed. CAO was determined by CA. ROC analysis was performed by using the number of segments as the threshold variable. Area under the curve (AUC) (95%CI) for SW and SPSS were compared to ejection fraction (EF).

Results: The AUCs were; SW 0.81(0.68-0.91); SPSS 0.70(0.56-0.82) and EF 0.59(0.44-0.72) (figure 1). 4 or more adjacent segments with reduced SW resulted in 67% sensitivity, 68% specificity, 70% negative predictive value and 64% positive predictive value for identifying CAO.

Conclusion: In the present study assessment of non-invasive myocardial segmental work could predict acute coronary artery occlusion in N-STEMI patients. SW was the only predictor significantly better than EF at identifying CAO, and may therefore be an important clinical tool for selecting N-STEMI patients in need of immediate invasive treatment.