1. Consultant Clinical Scientist Royal Wolverhampton NHS Trust UK
High sensitivity cardiac troponin I at presentation enables early safe discharge
Dr Clare Ford
Consultant Clinical Scientist
Royal Wolverhampton NHS Trust UK

2. Where is Wolverhampton?
West Midlands
17 miles north west of Birmingham
14th highest index of multiple deprivation in 2015 in England
V. high ED attendance rate per 100,000 population.

3. Commissioners keen to avoid unnecessary hospital admissions.
ED chest pain pathway 2012
? Cardiac chest pain AMU for 12hr cTn.
Drivers for change
Commissioners keen to avoid unnecessary hospital admissions.
ED excessive workload
Financial penalties as more than 5% patients exceeding 4hr ED wait

4. Where is Wolverhampton?
West Midlands

5. Stafford Hospital Scandal
1st public enquiry report published in Feb 2010
By 2011 ED not longer had acceptable staffing levels for 24/7 service

6. Introduction of POCT cardiac troponin I in late 2012
Low risk patients with cardiac chest pain
POCT cTnI measured on admission and 3 hours later.
Loan analysers introduced on a trial basis post evaluation

7. Introduction of POCT cardiac troponin I in late 2012
Advantages
Disadvantages
Discharge from ED if POCT cTnI at 0 & 3 hr ≤ 99th centile
Poor performance on EQA
Reduction in admissions to AMU
Unacceptable downtime & complex for POCT analyser
In our hands didn’t have ≤ 10% CV at 99th centile

8. New Pathology Lab Apr 2013 New Abbott analysers
All labs in the UK were using the conventional Abbott troponin assay
Abbott were looking to slowly launch hs assay 8

9. Project Group Consultant in Acute Medicine Dr Kate Willmer
Consultant Cardiologist
Dr Mike Cusack
Consultant in Emergency Medicine
Dr Andy Morgan
Company representatives
Dr Agim Beshri; Gareth Stone; Gordon Avery
Lab professionals
Prof Rousseau Gama; Dr Simon Whitehead; Me

10. ARCHITECT STAT hs-cTnI assay
Requirements and Recommendations for hs-cTn Assays
Abbott hs-cTnI
99th centile with ≤ 10% CV* √
Ability to quantitate (i.e. not report as < LOD) at least 50% and ideally 95% of results in healthy individuals**
√ 75% using the lower LOD in pack insert***
Gender specific cut offs*
*3rd Universal definition of . Thygesen et al. Circulation 2012; 126:
** Task force of IFCC on Clinical Applications of cardiac biomarkers
*** Krintus et al Clin Chem Lab Med ; 52:

11. Universal Definition of AMI
At least one cTnT >99th percentile of the values found in a healthy population
Rise and/or fall of cTnT
Evidence of myocardial ischaemia
AMI
Evidence of myocardial ischaemia – symptoms; ECG change; imaging evidence
If one then myocardial damage, if 1 and 2 then acute myocardial injury, if 1,2 and 3 then MI
Can have acute changes in cTn that are not due MI e.g. pulmonary embolism, myocarditis
Thygesen et al. Circulation 2012; 126:

12. Decisions Made Gender specific 99th centiles 34ng/L in males
15ng/L in females
Rule out on presentation sample for low risk patients if hs-cTnI ≤1.9ng/L (LoD) unless sample collected within 1 hour of onset of pain*
0 and 6 hour samples
Significant delta 50%
*Gimenez et al. Int. J. Cardiol. 2013; 168:

13. Recommended use of Abbott hs-cTnI assay for early rule out of AMI using a 0 and 3 hour troponin strategy

14. Risks & Benefits Risks Benefits
Inappropriate early discharge for a few
Appropriate early discharge from ED for many
n=1 on EQA
Reduction in admissions
No IQC at the LoD cut off
Better patient experience
Modest increase in test costs
Address male/female inequalities
Failure to achieve required TRT
Excessive cardiology workload

15. Implementation
Chest pain pathway designed and agreed
hs-cTnI algorithm designed and agreed
Interpretative comments produced and agreed
IT implemented and tested
Communication strategy compiled

16. Chest Pain Pathway Immediate clinical assessment & ECG
If low risk & hs-cTnI ≤1.9 ng/L or ≤99th centile if >12 hr post pain: Discharged
If hs-cTnI >1.9ng/L and patient low risk: CDU
If patient high risk: AMU
Presentation Sample sent to lab for hs-cTnI (if needed)
CDU not classed as an admission

17. CDU Inclusion Criteria
Cardiac sounding chest pain within 24 hr
TIMI-RS score <3
Pain free on admission
Age >16 yrs
Clear hx
Safe for discharge
No suspected or proven alternative diagnosis
No social reason for admission
No evidence of heart failure
No haemodynamic instability
No ECG or hs-TnI elevation
No coronary revascularisation within 6 weeks
ED Consultant sign off for CDU admission
In Oct 2013 audit 51/529 patients to CDU
One subsequently admitted to AMU for ACS unrelated issue
None had discharge diagnosis of ACS

18. hs-cTnI Interpretation
0 and/or 3 hr Tn >99th centile and change >50%
0 hr Tn ≤1.9ng/L or 0 & 3 hr Tn ≤99th centile
0 and /or 3 hr Tn >99th centile and change ≤50%
0 hr Tn >260ng/L
Indicative of cardiac damage, clinical assessment required. Tn change ≤50% makes acute myocardial injury and therefore, MI unlikely in an appropriate clinical context but does not exclude
Indicative of cardiac damage, clinical assessment required. Tn change >50% makes acute myocardial injury and therefore MI likely in an appropriate clinical context
Supports a diagnosis of MI in an appropriate clinical context
Normal, cardiac damage unlikely in an appropriate clinical context

19. Project group members communicated to their teams
Communication
Project group members communicated to their teams
Communication sent out by (more than once) to all hospital staff.
Targeted s to clinical directors
Clinical scientist in ED in the first week of roll out and visited other wards if problems
Algorithm available in ED/wards and on intranet

20. Turnaround Time of samples within the laboratory

21. Impact of New Pathway on Length of Stay and Admissions
Differences between groups
Asprin; B blocker use and ST depression higher in before than after patients
Pulse rate lower in before than after
ST depression

22. Impact of pathway on Cardiology
The cardiology input of all patients presenting to ED with chest pain was assessed for all presentations in October 2013.

23. Study of Patients presenting to ED with Chest pain in Oct 2013
529
ACS possible from hx, exam &ECG? No
257
Yes
272 (51%)

24. Study of Patients presenting to ED with Chest pain in Oct 2013
? ACS
272
ACS possible post hs-cTnI? No
224
Yes
48 (9%)

25. Study of Patients presenting to ED with Chest pain in Oct 2013
?ACS 48
Cardiology input? No 13
Yes
35 (7%)

26. Study of the safety of the pathway
Study Group
Consecutive patients presenting to ED with chest pain for 6 months (Jul 13 – Jan 14)
Exclusions
< 16 yrs
Trauma calls
Self discharge

27. Study of the safety of the pathway
Study Design
Evaluation of NPV of hs-cTnI ≤1.9ng/L for MACE (defined as death; myocardial infarction; symptom driven revascularisation and readmission for ACS)
At 30 days
At 9 months

28. Study of the safety of the pathway
Patients presenting to ED with chest pain
3853
ACS possible from hx, exam &ECG? No
1280 (33%)
Yes
2573 (67%)

29. Study of the safety of the pathway
? ACS at Presentation
2573
Presentation hs-cTn>1.9ng/L? No
849 (32% of ?ACS)
Yes
1724

30. Study of the safety of the pathway
Patients hs-cTn>1.9ng/L
849
Discharged immediately? No
161
Yes
688 (27% of ?ACS)

31. 30 day review of MACE in all 849 patients
2 deaths
1 unrelated malignancy
1 peri-arrest sample
1 PCI
Negative predictive value of hs-cTn ≤1.9ng/L at presentation for MACE at 30 days
99.6% (95% CI )
Cardiac arrest
In ED within 30 min of arrest
Asystole in ED & unsuccessful resuscitation
PM showed heart failure due to three valve disease but no AMI

32. 9 month review of MACE in all 849 patients
11 additional MACE
9 deaths
8 unrelated malignancy
1 pulmonary fibrosis
2 PCI
Negative predictive value of hs-cTn ≤1.9ng/L at presentation for MACE at 9 months
98.4% (95% CI )

33. 9 month review of MACE in all 849 patients
One discharged patient had a MACE; elective PCI following ED referral to cardiology
There were no MI or ACS re-presentations

34. Conclusion
ARCHITECT STAT hs-cTnI at presentation may be used to safely discharge over 25% of low clinical risk patients attending ED with possible ACS
This strategy together with the introduction of a CDU improved patient flow in ED and reduced hospital admissions. Safe earlier discharge has a positive impact on patient care, both for the individuals concerned and by releasing resources for the benefit of other patients.

35. Thank you for Listening!