Diagnostic value of speckle tracking strain analysis in non-st elevation acute coronary syndrome; comparison study with coronary angiography

Background and aims: Early detection of coronary artery disease (CAD) in patients with non-ST elevation acute coronary syndrome (ACS) remains a clinical challenge, especially in the absence of regional wall motion abnormalities by echocardiography on presentation. This study was designed to evaluate the accuracy of Global Longitudinal Strain (GLS) by speckle tracking analysis for the diagnosis of significant CAD in patients with ACS. It also assessed the ability of Territorial Longitudinal Strain (TLS) analysis in localizing the coronary artery lesion, along with coronary angiography (CA), considered the gold standard. Patients and Methods: This study included 133 patients who presented with non-ST elevation acute coronary syndrome (NSTEACS) to the emergency department, Heart Hospital, Hamad Medical Corporation, Doha, Qatar, during the period of January 1, 2014 to May 31, 2015. 85% of the patients were male; they ranged in age from 32 to 65 years (mean ± SD: 49.4 ± 9.5 years). Significant CAD was defined as having at least one epicardial vessel with ≥ 70% or left main > 50% stenosis. All patients enrolled in this study underwent basic echocardiography, speckle tracking analysis, and coronary angiography. Results: The echocardiogram obtained from the patients did not show any wall motion abnormalities at rest, although speckle tracking analysis was abnormal in 97 patients. Average GLS was considered positive for CAD if ≥-18.7%. TLS was also calculated for each major artery, as the average of the strain of the segments supplied by that artery. TLS was considered positive if ≥-16.7%. In other experiments, GLS and TLS were compared with CA results. Here, the patients were further subdivided into those with either multi-vessel disease or left main disease (MV, n = 52, 53.6%), and those with single vessel disease (SV, n = 45, 46.4%). LAD, circumflex and RCA lesions were found in 65, 50 and 39 patients, respectively. A control group of 29 cases was selected from outpatients referred to the echocardiography unit. The results show that in comparison to CA, GLS sensitivity and specificity were 84% and 70%, respectively in all the patients. The sensitivity of GLS was 87% in MV and 80% in SV. Territorial strain sensitivity was 50%, 74% and 84.6% for the left anterior descending artery (LAD), circumflex and right coronary artery (RCA), respectively compared to specificity values of 64%, 65% and 61.7%, respectively. Conclusion: GLS by speckle tracking analysis may be a non-invasive and accurate method in early diagnosis of significant CAD, in patients presenting with non ST-elevation ACS, without regional wall motion abnormalities. Sensitivity was found to be more in patients with multi-vessel heart disease. For localizing CA lesions, TLS was found to be sensitive only for RCA and circumflex lesions with limited specificity.