Three dimensional echocardiography in non ST elevation acute coronary syndrome in North India (3D-EINSTEIN) - A single centre prospective study

Background: In non ST elevated acute coronary syndrome (NSTEACS) significant coronary artery disease cannot be predicted by biological markers, electrocardiogram (ECG) or formal two dimensional echocardiography (2DE). Recent studies have demonstrated role of strain 2DE in determination of significant coronary artery disease but no studies on three dimensional echocardiography (3DE) is available in literature. Our objective was to evaluate role of 3DE in predicting SCAD among NSTEACS patients and compare 3DE viz-a-viz 2DE. Methods and Materials: Three dimensional echocardiography in non ST elevation acute coronary syndrome in North India (3D-EINSTEIN) study is a hospital based prospective study where 324 NSTEACS patients were evaluated by Troponin I levels, ECG, laboratory parameters. Global Registry of Acute Coronary Events (GRACE) risk score were calculated. 2DE and 3DE (4 beat full volume) loop were recorded in Philips iE33 xMATRIX, global ejection fraction (EF) and parametric images were analysed using QLAB9 3DQAdv software. Coronoary angiograms were undertaken and significant coronary artery disease was defined as luminal narrowing >70% in any epicardial coronary artery. Results: Unstable angina comprises only 15% of NSTEACS and clinical profile of them are similar to NSTEMI. Two third of NSTEACS patients had >70% stenosis in at least one coronary artery. 70% of them have single vessel disease (SVD). One third of NSTEACS patients had no significant ECG changes and 50% of them had lesions in left circumflex artery (LCX). Severe MR was present in 10% of total NSTEACS patients. Half of them had concomitant lesion in right coronary artery (RCA). Elevated Troponin I & 3DE changes are significantly more to be associated with significant coronary artery disease whereas ECG changes, 2DE changes & GRACE risk scores are not. Conclusion: In NSTEACS patients, 3DE is found to have more sensitivity and specificity than 2DE in predicting significant coronary artery disease and localising culprit arteries, which can be missed by 2DE in 23% cases. Large multi-centric studies exploring the role of 3DE in assessment of NSTEACS patients are needed.