1. Intensive Observation Unit Careggi University Hospital, Firenze Italy
Stress Echo in the Emergency Department: diagnostic accuracy in subjects with known or suspected CAD
Francesca Innocenti, Sonia Vicidomini, Alberto Conti, Maurizio Zanobetti, Aurelia Guzzo, Riccardo Pini
Intensive Observation Unit
Careggi University Hospital, Firenze Italy

2. Background
Among patients presenting to the Emergency Department (ED) with spontaneous chest pain, coronary artery disease (CAD) remains undetected in about 4-5% subjects, with significant burden in terms of morbidity and mortality.
Anamnestic data, especially pain characteristics, are not useful in recognizing CAD.
EKG and cardiac necrosis markers are often normal, even in presence of CAD.

3. Stress EKG First Choice test
Suboptimal feasibility for possible physical decontitioning or baseline EKG modifications
Few information about localization and extension of ischemic area
Stress EKG remains the first choice test in patients with normal rest EKG, but has some undeniable limits, like as
Very low sensitivity in patients with established CAD, especially if treated with coronary revascularization

4. Stress echocardiography
Opportunity to choose the most appropriate stressor
Information about baseline left ventricular global and segmental systolic function
Evaluation of ischemic area extension
Unfeasible in patients with poor acoustic window
Subjective interpretation
Stress echo can be an alternative opportunity with some relevant advantages, like as….. We must mention also existing limits, that are mainly presence of a poor acoustic windows and subjective interpretation.

5. Aim
To compare feasibility and diagnostic accuracy of stress echocardiography, performed within 24 hours from presentation, in two groups of patients with suspected (CAD-) or known (CAD+) CAD, with a spontaneous chest pain, normal EKG and negative cardiac necrosis marker.

6. Methods Stress echo 95 subjects in group CAD-
36 patients in group CAD+
Stress echo
Physical stress or dobutamine
All patients, 95 with suspected CAD and 36 with known CAD, were evaluated twice with EKG and cardiac necrosis markers, the second time at least 12 hours after the index symptom. They then underwent stress echo during physical stress whenever possible, otherwise with pharmacological stress with dobutamine, both conducted according to standard protocol. Patients who developed inducible ischemia were asked to undergo coronary angiography; all the other patients were discharged, according to treating physician opinion; at least one month later, they were contacted by telephone to ascertain possible recurrence of symptoms or need for a new hospital admission.
Evidence of inducible ischemia
Coronary angiography
Absence of inducible ischemia
Follow-up

7. Clinical characteristics
CAD -
(n=95)
CAD + (n=36) p
Age (years)
70±13
69±9 NS
Sex (male), n (%)
46 (49)
26 (72)
0.015
Hypertension, n (%)
68 (72)
23 (64)
Diabetes, n (%)
19 (20)
8 (22)
Dyslipidaemia, n (%)
32 (34)
22 (61)
0.004
Smoking habitus, n (%)
43 (46)
25 (70)
0.020
β-Blockers’ therapy, n (%)
9 (10)
7 (19)
Peripheral arterial dis., n (%)
22 (23)
19 (53)
0.010
These are, in summary, clinical characteristics of our study groups: people with established CAD were more frequently male, dyslipidemic, smokers and affected by peripheral arterial disease.

8. Rest and stress echo data
CAD -
CAD +
 LV EF 60±9%  LV EF 46±16%*
 Dobutamine 57%  Dobutamine 75%
 METs 6.2±1.7  METs 6.7±1.0
 %MPHR 96±13  %MPHR 91±15
Inducible ischemia 38 (43%)
Regarding rest echocardiographic data, global left ventricular systolic function, expressed as LV EF, was lower in patients with established CAD. The percentage of patients who underwent dobutamine stress echo was similar in the two groups and patients who performed physical exercise reached a comparable %maximal predicted heart rate and work load, expressed in terms of metabolic equivalents. Inducible ischemia developed in a similar percentage of patients and no severe side effect occurred.
Inducible ischemia 13 (41%)
*p<0.05
No severe side effect

9. Coronary angiography CAD - CAD + 31 coronary angiography
21 patients with significant coronary stenosis (>50%)
8 patients with significant coronary stenosis (>50%)
Coronary angiography was performed in 31 patients with suspected and 10 patients with established CAD: in 21 and 8 patients, respectively, a critical coronary stenosis was diagnosed. In the groups without inducible myocardial ischemia, respectively 1 and 2 patients reported symptoms recurrence.
1 subject with symptoms’ recurrence
2 subjects with symptoms’ recurrence

10. Stress echo diagnostic performance
CAD +
CAD - p
Sensitivity
80%
95% NS
Specificity
89%
83%
Positive Predictive Value
68%
Negative Predictive Value
98%
Accuracy
78%
Analysing stress echo diagnostic performance according to presence of an established CAD, we didn’t find any significant difference between the two groups.

11. Conclusions
Stress Echo showed an excellent feasibility for early evaluation of patients presenting to ED with spontaneous chest pain
Stress Echo accuracy was comparable in patients with known or suspected CAD.