Abstract 15734: Coronary Artery Occlusion in N-STEMI Patients Can Be Identified by Assessing Segmental Work Which Incorporates the Effects of Afterload on Strain Measurements
Introduction: Acute coronary artery occlusion (CAO) occurs in ≈ 30% of patients with N-STEMI. It has been shown that reduced regional segmental peak systolic strain (SPSS), measured by speckle tracking echocardiography (STE), identifies patients in need of immediate coronary intervention. The specificity was however low. We investigated if non-invasive segmental myocardial work (SeW) analysis, which adjusts strain for variations in afterload, could detect CAO.
Methods: STE was performed before coronary angiography in 126 patients with N-STEMI. Longitudinal strain was measured for each of the 18 LV-segments. LV pressure (LVP) was estimated non-invasively using a standard waveform fitted to valvular events and scaled to systolic pressure. SeW was calculated as the area of the LVP-strain loop. Empirical cut-off values were set to identify systolic dysfunction for SeW (<1700%•mmHg) and SPSS (>-14%), and the number of segments were used in ROC analysis (Figure, left).
Results: 27 patients suffered an acute CAO. 4 or more adjacent segments with reduced SeW was significantly better than both global strain and ejection fraction at detecting the occurrence of CAO (Figure). SeW had a higher sensitivity and especially specificity compared to the equivalent region of impaired regional strain (Figure, lower right). Logistic regression analyses demonstrated that systolic blood pressure and SPSS were both independent significant covariates in estimating the occurrence of CAO. This was not true when SeW was substituted for SPSS.
Conclusion: The presence of reduced regional work in patients with N-STEMI identified patients with coronary artery occlusion. This method was superior to regional and global strain parameters. Non-invasive regional work adjusted for the influence of blood pressure and is feasible as a bedside method. It has the potential of becoming an important clinical tool for selecting N-STEMI patients in need of immediate invasive treatment.
- Myocardial infarction, NSTEMI
- Percutaneous coronary intervention
- Blood pressure
- © 2013 by American Heart Association, Inc.