RESUMO
INTRODUCTION: Diagnosis of acute coronary syndrome (ACS) is often challenging especially in presence of initial normal troponins and non-specific electrocardiogram. The index study aimed at determining the diagnostic value of strain echocardiography in patients with suspected ACS but with non-diagnostic electrocardiogram and echocardiography findings. METHODS: The study was conducted on 42 patients with suspected ACS and non-diagnostic electrocardiograms, normal quantitative troponin-T levels, and left ventricular function. All patients underwent conventional and 2D-strain echocardiography followed by coronary angiography, within 24 h of admission. Patients with regional wall motion abnormalities (RWMA), valvular heart disease, suspected myocarditis, and past coronary artery disease (CAD) were excluded. RESULTS: Amongst the global strains, the global circumferential strain (GCS) was significantly reduced (p = .014) amongst those with significant CAD on angiography as opposed to global longitudinal strain (GLS) which was similar in the two groups (p = .33). The GCS/GLS ratio was also significantly reduced in patients with significant CAD compared to those with normal/mild disease on coronary angiography (p = .025). Both the parameters had good accuracy in predicting significant CAD. GCS displayed a sensitivity of 80% and a specificity of 86% at an optimal cut-off 31.5% (AUROC: .93, 95% CI: .601-1.000; p = .03), and likewise GCS/GLS ratio had a sensitivity of 80% and a specificity and 86% at a cut-off of 1.89% (AUROC: .86, 95% CI: .592-1.000; p = .049). GLS and peak atrial longitudinal strain (PALS) did not differ significantly in patients with/without significant CAD (p = .32 and .58, respectively). CONCLUSION: GCS and GCS/GLS ratio provides incremental value in comparison to GLS, PALS, and tissue Doppler indices (E/e') in patients with suspected ACS and non-diagnostic electrocardiogram and troponins. GCS at cut-off of >31.5% and GCS/GLS ratio >1.89 can reliably exclude patients with significant CAD in this setting.
