Diagnostic performance of bedside transthoracic echocardiography in the management of patients with suspected myocardial infarction
Authors: Haller P M , Schock A , Kellner C , Lehmacher J , Toprak B , Hartikainen T S , Westermann D , Zeller T , Blankenberg S , Neumann J T , Soerensen N A 
Published: November 2023

Abstract

Introduction
The diagnostic management of patients with symptoms indicative of acute myocardial infarction (MI) is largely based on the clinical assessment of symptoms, ECG and diagnostic algorithms based on high-sensitivity cardiac troponin (hs-cTn). Additionally, guidelines recommend transthoracic echocardiography (TTE) for patients neither eligible for rule-out nor rule-in.

Purpose
To assess the diagnostic performance of TTE in the diagnostic management of patients with suspected MI.

Methods
We conducted a prospective, observational cohort study enrolling consecutive patients presenting with symptoms suggestive of MI to the emergency department of a tertiary care hospital. Management was at the discretion of the treating physician. The final diagnosis was adjudicated by two independent cardiologists according to the 4th Universal Definition of MI. Evaluation in the emergency department included TTE with an assessment of left-ventricular (LV) function and regional wall motion abnormalities (WMA). We calculated diagnostic performance parameters (sensitivity, specificity, and negative and positive predictive value [NPV, PPV] with 95% confidence intervals) to rule-out or rule-in MI, respectively, for the presence of WMA. Performance was calculated for patients stratified to the observe and rule-in groups after application the ESC 0/1-hour algorithm using hs-cTnI. Patients without available TTE and those with STEMI were excluded. WMA were only reported if the acoustic window allowed a reasonable evaluation. Variables associated with the conduction of coronary angiography were studied using logistic regression.

Results
Overall, 2,163 patients with available TTE were included, of those 1,707 (78.9%) patients had data on WMA available, with 360 (21.1%) having any WMA (hypokinesia or akinesia) detected. Median age was 64 (51, 75) years, 1,383 (63.9%) were males and 383 (17.7%) were diagnosed with MI. Application of the ESC 0/1-hour algorithm resulted in assignment of 729 (42.9%) and 308 (18.6%) patients to the rule-out and -in groups, respectively, with 599 (38.5%) patients remaining in the observe group. Of these, 45 (7.5%) had MI. Performance of the ESC 0/1-hour algorithm was good and is shown in Figure 1. In the observe group, detection of WMA poorly identified patients with MI (PPV 12.7%, Figure 1). Absence of WMA resulted in moderate performance to rule-out MI (NPV 94.0%, Figure 1). Adjusted for age, sex, symptoms, baseline hs-cTnI, presence of ischemic signs on ECG and cardiovascular risk factors, the presence of WMA was significantly associated with the conduction of coronary angiography at index presentation (OR 2.7 [1.8, 4.0], p &lt; 0.001).

Conclusion
The diagnostic value of bedside TTE is limited for the rule-out or -in of MI. Still, patients with prevalent WMA were significantly more likely to undergo coronary angiography.Performance of TTE in ESC 0/1-hour alg.