Abstract
Background
Speckle tracking echocardiography (STE) is a novel technology that measures regional
wall-motion abnormalities that may speed diagnosis and intervention of acute coronary
occlusion in Emergency Department (ED) patients with non-ST elevation ACS (NSTE-ACS).
STE provides an objective measurement of myocardial strain that is superior to visual
assessment of wall motion when performed as part of a point-of-care (POC) echocardiogram.
We determined the feasibility and preliminary accuracy of POC STE operated by emergency
providers when compared to comprehensive echocardiography or final diagnosis of ACS.
Methods
We retrospectively reviewed 187 emergency provider POC echocardiograms with STE from
7/2014–5/2016 for suspected ACS at a large academic trauma center. Feasibility of
POC STE was determined by calculating the percentage of complete exams (adequate apical
4-chamber and parasternal short axis views) out of all STE exams. We then used two
different criterion standards for calculating diagnostic accuracy of STE: comprehensive
echocardiograms with wall motion abnormalities or formal diagnosis of ACS based on
elevated cardiac troponins, unstable angina, percutaneous coronary intervention, or
coronary artery stenosis >70% on catheterization.
Results
Of 187 STE studies performed, 75 (40%) were considered complete. Ultrasound-experienced
providers had higher rates of complete exams (65% vs. 35%, P = 0.01). 16 of 75 exams (21%) were positive for myocardial strain, and of these 16
(100%) were admitted, 12 (75%) had positive troponins, 6 (46%) had positive comprehensive
echocardiograms, and 3 (19%) had PCI or >70% stenotic lesion on catheterization. Compared
with comprehensive echocardiography, POC STE had 35% sensitivity, 70% specificity,
46% positive predictive value (PPV), and 59% negative predictive value (NPV). Compared
with formal diagnosis of ACS, POC STE had 29% sensitivity, 88% specificity, 75% positive
predictive value (PPV), and 51% negative predictive value (NPV).
Conclusion
STE is a potentially feasible adjunct to standard bedside echocardiography in ED patients
with suspected ACS when operated by experienced ultrasound-trained physicians in the
ED. This data shows STE performed by emergency providers is not yet sensitive enough
alone to diagnose ACS, and has low accuracy when compared to comprehensive echocardiography.
However, the PPV and specificity improve when performed by expert ultrasound-trained
providers. STE should be considered for inclusion in the Emergency Ultrasound Fellowship
curriculum.
Keywords
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Article Info
Publication History
Published online: September 04, 2018
Accepted:
August 28,
2018
Received in revised form:
August 28,
2018
Received:
May 9,
2018
Footnotes
☆Sources of support: There were no funding sources for this study.
☆☆LR, WJS, AJS and RFR report no conflicts of interest and have no disclosures.
★Presentations: SAEM18, Indianapolis, May 17, 2018.
Identification
Copyright
Published by Elsevier Inc.
