Definition of Acute Myocardial Infarction

1. Definition of Acute Myocardial Infarction

2. Changing times, changing definition

3. Diagnosis of MI

4. NECVN – Diagnosis of MI

5. Clinical sub-groups -EMMACE

6. Classification of MI Type 1- due to primary coronary event Type 2 - secondary to spasm, embolism, anaemia, arrhythmia, blood pressure changes Type 3 - sudden death before markers can be measured Type 4a - associated with PCI Type 4b - stent thrombosis (angio or autopsy) Type 5 - associated with CABG

7. Causes of raised TnT in 514 cases with other condition

8. What do we mean by an MI?

9. What do we mean by an MI?

10. What do we mean by an MI?

11. NECVN CAG Jan 2008 Proposal - adopt the universal definition across the network

12. NECVN CAG Jan 2008 Proposal - adopt the universal definition across the network BUT not “type 2 MI”

13. Proposal for Changing Definition of Myocardial Infarction (1) 1. All hospitals in NECVN should switch to using the term “Myocardial Infarction” for any troponin rise associated with clinical presentation consistent with myocardial infarction. Myocardial infarction should ONLY be diagnosed where there is also at least one of the following : Typical symptoms of myocardial ischaemia ECG changes indicative of NEW ischaemia Development of pathological Q waves on ECG Imaging evidence of new loss of viable myocardium or new regional wall motion abnormality

14. NECVN Definition of MI (2) 2. Events without ST segment elevation on the ECG will be classified as NSTEMI (non ST elevation myocardial infarction) and coded as “subendocardial myocardial infarction- I21.4 ” for the purposes of SMR01 reporting

15. NECVN Definition of MI (3) 3. Each hospital should use the level equivalent to the 99th centile of the upper reference range in their centre for the threshold or detectable level to make this diagnosis 4. Where diagnosis of MI is entirely dependant on troponin, a minimum of two levels should be compared to look for typical rise or fall, with minimum 20% increase required. This will not be required where diagnosis clinically obvious or confirmatory information is available from ECG, angiography or other imaging modalities.

16. NECVN Definition of MI (4) 5. STEMI (ST elevation myocardial infarction) should be coded as transmural MI 6. The term unstable angina (I200) should be reserved for ACS without detectable troponin release. 7. NSTEMI associated with coronary intervention or cardiac surgery should be diagnosed using the scheme outlined MI with PCI = Troponin > x 3 99th centile URL MI with CABG = Troponin > x5 99th centile URL current ICD10 coding will not differentiate these from spontaneous MI.

17. NECVN Definition of MI (5) 8. Troponin release associated with events other than acute coronary insufficiency will NOT be coded as myocardial infarction. The putative cause of troponin release should be stated and coded.

18. Recommended terms and Coding for ACS Admissions

19. Implications Consistency in diagnosis of NSTEMI Improved clinical management Most appropriate treatment to those with greatest benefit Ties to ACS management pathway BUT continued education re use of troponin key Patients Driving Employment Insurance Justified by trial data and improved clinical outcomes

20. Implications Potential increased workload for cardiac rehabilitation departments Trust pathology departments Review troponin assay know 99th percentile of upper reference range Ensure troponin assay achieves optimal precision, defined as coefficient of variation at the 99th percentile of <10% Increased throughput : paired results Coding Commissioners

21. Purposes of a diagnosis What to tell the patient How to treat Tells us prognosis Helps us discuss condition Defines research population Enables accurate communication … providing we all use the same language

22. National Issues MINAP : varying prevalence in MI across country purely due to definition/coding Artificial differences in clinical outcomes MI rates and outcomes Complications of PCI and CABG Tariff Consistency in wider management DVLA Insurance industry : critical illness cover etc

23. NECVN 2008 Adopt Universal Definition across the network Approved by Network board July 08 Local “champions” identified Implementation – now !