1. Emergency Department Bypass for ST-Segment Elevation Myocardial Infarction
Akshay Bagai MD, MHS
St. Michael’s Hospital, Toronto, Canada
Good morning. Thanks faculty and organizers. On behalf of my co-investigators, it is my honor to present our work titled “Bypassing the Emergency Department is Associated with Faster Reperfusion in Patients with Pre-Hospital ST-Segment Elevation: A Report From the AHA Mission: Lifeline Program”
Washington Hospital Center Cath Conference
August 28, 2013

2. Background
In STEMI, faster reperfusion is associated with lower morbidity and mortality
National guidelines recommend device activation within 90 minutes of first medical contact
Timely reperfusion still remains suboptimal in the U.S.
In STEMI, faster reperfusion is associated with lower morbidity and mortality
Over the last half of the last decade, implementation of national campaigns including Door to Balloon alliance and Mission Lifeline, and regionalization of STEMI care both at Statewide and grassroots levels, have been associated with significant improvement in reperfusion times
Despite these improvements, timely reperfusion remains suboptimal in the United States

3. Background PCI-hospital Non PCI-hospital
Practice guidelines recommend device activation to occur within 90 minutes of first medical contact. Recommend several strategies to achieve timely reperfusion 1) 12 lead ECG 2) Primary PCI if can be achieved in a timely fashion 3) Bypassing non-PCI hospitals for direct transport to PCI capable hospital
To aid in achieving this 90 minute goal, Henry et al. suggested the rule, with each 30 minute segment being a target for patient interaction with the STEMI care providers, specifically EMS, the ED, and the catheterization lab.
Although much work has been done to optimize systems of pre-hospital care including utilizing pre-hospital ECG’s and bypassing non-PCI hospital to transport patients directly to a PCI center, there are no reports about delays associated with triage and evaluation of patients in the PCI-hospital Emergency department.

4. Background
European guidelines recommend direct transport to the cath lab, thereby bypassing the emergency department

5. Study Objectives Among patients identified pre-hospital with STEMI,
Determine the proportion of patients transported directly to the cath lab (ED bypass) vs. triaged/evaluated in the PCI- hospital ED prior to transport to the cath lab (ED evaluation)
Assess the association between the strategy to bypass the ED and reperfusion times
Examine the association between ED-bypass and in- hospital mortality
Therefore to assess processes of care and outcomes associated with the ED of the PCI hospital, we developed an analysis plan with the following study objectives.
Among patients identified with STEMI pre-hospital brought directly to a PCI center,
to examine the practice of directly transporting patients from the field to the cath lab lab, thereby bypassing the ED vs. triage and evaluation in the ED prior to transport to the cath lab
to determine the magnitude of delay in reperfusion associated with triage and evaluation in the ED
Finally, to investigate the association between the strategy to bypass the ED and in-hospital mortality

6. (N=12,581 from 371 PCI-hospitals)
ACTION Registry® – GWTG™
STEMI patients treated with primary PCI July March 2011
(N = 61,081)
No pre-hospital ECG (n=26,781)
Arrived first at non-PCI hospital (n=17,297)
Pre-hospital ECG and direct EMS transport to PCI hospital
(N = 17,003)
ST-elevation on subsequent ECG (n=1978)
We studied STEMI patients undergoing primary PCI from the ACTION registry – Get with the guidelines between January 2007 and March 2011.
Patients without pre-hospital ECG and transporting themselves to the ED were excluded.
Among the 19,814 patients who had pre-hospital ECG, patients without ST elevation on 1st pre-hospital ECG and those transferred from non-PCI ED were excluded.
Our analysis cohort comprised of 15,092 patients identified with STEMI on 1st pre-hospital ECG transported directly to a PCI-center for primary PCI
Analysis Cohort
Patients identified with STEMI on 1st Pre- hospital ECG transported directly to PCI-center
(N=12,581 from 371 PCI-hospitals)

7. Methods Comparison Groups ED Evaluation vs. ED Bypass Outcomes
Timing of Reperfusion
In-hospital mortality: Crude and adjusted (Hierarchical logistic regression; modified ACTION® – GWTGTM in-hospital mortality model)
Sensitivity Analysis
Exclude high risk patients (heart failure, shock, and non-system reasons for delay in PCI)
Patients who were triaged and evaluated in the ED were compared against patients bypassing the ED directly to the cath lab
Timing of reperfusion and in-hospital mortality was compared between the groups
In-hospital mortality rates were adjusted for differences between the two groups using hierarchical logistic regression using the modified ACTION – GWTG mortality model
As a sensitivity analysis, we repeated the analysis after excluding patients at high risk such as HF, shock, intubation and cardiac arrest.

8. Temporal Trends in Use of EMS, Pre-hospital ECGs, and ED-bypass

9. Frequency of ED Bypass by Time of Day%
ED bypass occurred more frequently during working hours compared with off hours. 18.1% to 4.3%
Off hours:
M-F h, Saturday & Sunday, Holidays

10. Distribution by Hospital ED-bypass Rate

11. Patient Characteristics
ED Evaluation (n=11,265)
ED Bypass (n=1,316)
P-value
Age, median (years)
60 (52, 70)
60 (52, 69)
0.52
Female sex
28.7%
27.1%
0.23
Prior MI
20.3%
16.2%
0.001
Presentation Features
Congestive heart failure
6.7%
4.0%
<0.001
Cardiogenic shock
9.4%
6.9%
0.003
Non-system reasons for delay in PCI
12.3%
5.9%
Cardiac arrest/intubation prior to PCI
4.6%
2.0%
Following are our results
Among the 15,000 patients, 13, 500 (90%) were evaluated in the ED prior to transport to the cath lab, while 1600 (10%) bypassed the ED directly to the cath lab.
There were no differences in age or gender between the two groups.
Patients bypassing the ED had lower prevalence of prior MI, and high risk features on presentation such as CHF, shock and cardiac arrest and/or intubation prior to PCI

12. First Medical Contact to Device Activation
68 (54, 85) mins
88 (73, 106) mins

13. In-Hospital Mortality
ED Evaluation (n=11,265)
ED Bypass (n=1,316)
P- value
Crude in-hospital mortality
4.1%
2.7%
0.01
Adjusted in-hospital mortality*
Reference
OR 0.69
(95%CI 0.45 –1.03)
0.07
The crude unadjusted in-hospital mortality rate is higher among patients evaluated in the ED compared with patients bypassing the ED, likely due to the higher rate of sicker patients in the ED evaluation group.
After adjustment, there is no difference in in-hospital mortality between the two groups, OR 0.78 with confidence interval crossing unity.
*modified ACTION in-hospital mortality model

14. Excluding Higher Risk Patients
ED Evaluation
ED Bypass
P- value
First medical contact to device time, minutes
86 (72, 102)
67 (54, 84)
<0.001
First medical contact to device ≤ 90 minutes, %
59%
82%
In-Hospital Mortality
Adjusted*
Reference
OR (95%CI 0.33 – 1.31)
0.24
After excluding higher risk patients with HF/shock/cardiac arrest/intubation, time spent in the ED among patients evaluated in the ED remained at 29 minutes.
First medical contact to device activation was achieved more frequently among patients bypassing the ED 82.1% vs. 59%.
There was no difference in unadjusted mortality between the two groups.
*modified ACTION in-hospital mortality model

15. Limitations Observational study: unmeasured confounding and bias
Reasons for delays in the ED (eg. cath lab readiness)
Process and timing of cath lab activation
Distance from scene to hospital
Rates of false activation
Rates of missed alternative diagnosis
There are several strengths and limitations of the study
This is the first study to report the magnitude of delay associated with triage/evaluation in the PCI-hospital ED and it’s contribution to the failure to achieve timely reperfusion
However, this is an observation registry based analysis, subject to unmeasured confounding and bias.
There is lack of information on important consideration including reasons for delay in the ED, including cath lab readiness, process and timing of cath lab activation, rates of missed alternative diagnosis, and rates of false activation

16. Conclusions ED bypass occurs infrequently in the U.S.
There is substantial variability in use of ED bypass across hospitals
ED bypass is associated with significant reduction in reperfusion times with no adverse impact on mortality
Widespread evaluation and implementation of this process is warranted in the U.S.
In conclusion
First, among the best scenario patients, ie those with STEMI diagnosed pre-hospital, transported directly to a PCI-center, only 57% achieve device activation within 90 minutes
Second, a median of 31 minutes is spent in the ED contributing significantly to the failure to achieve timely reperfusion
And finally, the strategy to bypass the ED is used infrequently and represents a potential opportunity to improve reperfusion times.

17. Implementation of ED Bypass Protocols
Triage protocols for unstable patients
Cardiac arrest, cardiogenic shock, respiratory failure
Confirm diagnosis/minimize false activation
Paramedic training, computer ECG interpretation, wireless ECG transmission for consultation
Off-hours holding area until cath lab ready
In-house team of CCU nurse, CCU fellow, Cardiologist
Expectation: start case within 30mins of being paged
RThe results call into question the widespread belief that patients with STEMI make a quick pit stop in the ED on their way to the cath lab, and motivate re-evaluation of the advantages and disadvantages of ED based triage and evaluation of pre-hospital diagnosed STEMI patients.
The major arguments for the role of the ED are as follows:
Confirm diagnosis and minimize false activation: it has been shown that with comprehensive paramedic training, use of computer ECG interpretation and wireless transmission of the ECG for consultation, cath lab cancellation rate can be reduced to 5%
Management of unstable patients: Unstable patients with brady or tachycardia, hypotension and signs of respiratory compromise should still go to the ED for evaluation prior to cath lab
Holding area until cath lab readiness: In house team of CCU nurse, fellow and cardiologist to monitor patient in the cath lab until the cath lab team arrives. The cath lab team is expected to start the case within 30 minutes of being paged.

18. Collaborators PCI-hospital Dr. Matthew Roe Dr. Christopher Granger
Dr. Jamie Jollis
Dr. Harold Dauerman
Dr. Ivan Rokos
Dr. Eric Bates
Dr. William French
Andrew Peng
PCI-hospital
Thank you for your attention