Non-invasive myocardial work index identifies acute coronary occlusion in patients with non-STsegment elevation-acute coronary syndrome

Abstract

Aims Acute coronary artery occlusion (ACO)occurs in30% of patients with non-ST-segment elevation-acute coronary syndrome (NSTE-ACS). We investigated the ability of a regional non-invasive myocardial work index (MWI) to identify ACO. Methods and results Segmental strain analysis was performed before coronary angiography in 126 patients with NSTE-ACS. Left ventricular (LV) pressure was estimated non-invasively using a standard waveform fitted to valvular events and scaled to systolic blood pressure.MWIwascalculated as the area of the LVpressure-strain loop. Empirical cut-off valueswere set to identify segmental systolic dysfunction for MWI (<1700 mmHg %) and strain (more than 214%). The number of dysfunctional segments was used in ROC analysis to identify ACO. The presence of.4 adjacent dysfunctional segments assessed by MWIwas significantly better than both global strain and ejection fraction at detecting the occurrence ofACO(P < 0.05). Regional MWI had a higher sensitivity (81 vs. 78%) and especially specificity (82 vs. 65%) compared with regional strain. Logistic regression demonstrated that elevated systolic blood pressure significantly decreased the probability of actual ACO in a patient with an area of impaired regional strain. Conclusion The presence of a region of reducedMWIin patients withNSTE-ACSidentified patients withACOandwas superior to all other parameters. The regional MWI was able to account for the influence of systolic blood pressure on regional contraction. We therefore propose that MWI may serve as an important clinical tool for selecting patients in need of prompt invasive treatment.