Emerging Biomarkers in Acute Coronary Syndromes - A Pathophysiologic Perspective

Role of two-dimensional strain echocardiographic parameters in suspected acute coronary syndrome patients with initial non-diagnostic electrocardiogram and troponins: An observational study

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.

Serum Concentrations of Ischaemia-Modified Albumin in Acute Coronary Syndrome: A Systematic Review and Meta-Analysis

The identification of novel circulating biomarkers of acute coronary syndrome (ACS) may improve diagnosis and management. We conducted a systematic review and meta-analysis of ischaemia-modified albumin (IMA), an emerging biomarker of ischaemia and oxidative stress, in ACS. We searched PubMed, Web of Science, and Scopus from inception to March 2022, and assessed the risk of bias and certainty of evidence with the Joanna Briggs Institute Critical Appraisal Checklist and GRADE, respectively. In 18 studies (1654 ACS patients and 1023 healthy controls), IMA concentrations were significantly higher in ACS (standard mean difference, SMD = 2.38, 95% CI 1.88 to 2.88; p < 0.001; low certainty of evidence). The effect size was not associated with pre-defined study or patient characteristics, barring the country where the study was conducted. There were no significant differences in effect size between acute myocardial infarction (MI) and unstable angina (UA), and between ST-elevation (STEMI) and non-ST-elevation MI (NSTEMI). However, the effect size was progressively larger in UA (SMD = 1.63), NSTEMI (SMD = 1.91), and STEMI (3.26). Our meta-analysis suggests that IMA might be useful to diagnose ACS. Further studies are warranted to compare the diagnostic performance of IMA vs. established markers, e.g., troponin, and to determine its potential utility in discriminating between UA, NSTEMI, and STEMI (PROSPERO registration number: CRD42021324603).