2011 Guidelines : what’s new in Acute Coronary Syndromes

This is a summary of the new ACS guidelines – hot off the press.

Heart, Lung and Circulation has produced the 2011 Addendum to the National Heart Foundation of Australia/Cardiac Society of Australia and New Zealand Guidelines for the Management of Acute Coronary Syndromes (ACS) 2006.

There are a few new concepts and changes which will effect the way we investigate and manage patients with chest pain and ACS in the ED in smaller hospitals.

Follow the link above to read the full text – it is free at the Heart Foundation website.  I have put together a summary of “practice changing points” from the revised guigelines.

There is a very user-friendly algorithm for the initial investigation of chest pain included – click here

So here are are the parts of the guidelines that I think might change practice in our hospital.

  • The differentiation of the high-sensitivity troponin assays from the older, bedside troponin assays.
    • Essentially you need to know what your lab is using – so that you know which algorithm to follow
    • If your lab turn around on troponin is  > 60 minutes, then you should do a bedside trop
    • If you have access to the highly-sensitive assays then you should use these.
    • A positive can be one of  two things: a level above the 99th centile range OR a change from baseline of > 50%
    • If using the “low-sensitivity” troponin assay, the timing remains – at admission and 8 hours.
  • The timing of repeat troponin has changed if using the high-sensitive assays
    • Do a troponin at presentation – if negative then repeat at the 3 hour mark.
    • The testing interval to ‘rule out’ MI may be reduced to 3 hours, provided that one sample is taken at least 6 hours after symptom onset
    • If both are negative, or the rise is less than 50% above baseline – then an MI is unlikely, and you can go down the lower risk “rule out ACS” pathway – which in small hospitals means an exercise stress test usually.
  • An early positive “high-sensitivity” troponin can mean one of 2 things (as these assays are more likely to pick up ‘non-cardiac’ causes)
    • An early / evolving MI – if suspected – then consult Cardiology ASAP
    • Another diagnosis eg. pericarditis, PE, dissection, sepsis, CCF, cardiac contusion etc.  I assume this is based on the history, exam and clinical scenario.
    • Either way – any positive or rise > 50% stratifies the patient as higher risk – admission would be prudent.
  • Patients presenting at least 6 hours after onset of pain can be investigated with a single “high sensitive” troponin, as long as they do not have ongoing or recurrent pain.
  • The use of routine Oxygen for patients with chest pain has been downgraded / removed following a Cochrane review of this intervention.
    • O2 is recommended for patients with hypoxia (SpO2 < 93%)  or evidence of shock / poor tissue perfusion
  •  Having a robust hospital system to initiate early management of patients with chest pain and optimise early management is a recommendation.
    • For country hospitals this means having systems which minimise door-to-thrombolysis times
    • Maintaining staff competency in recognition of STEMI and the protocols for thrombolysis
    • Having systems which allow rapid access to Cardiologist consultation – this means having a direct telephone link to an on-call Cardioology service and probably having a fax or other means for transmitting ECGs etc to minimise delays in treatment
    • Ambulance diagnosis with ECG can improve outcomes – either by early activation of hospital systems or through the use of pre-hospital thrombolysis.  This can be difficult to achieve as most country towns rely on voluntary Ambos, however the up side of being in a small town is that these patients usually have a ‘zero ED wait time’ and transit to ED is less than 10 minutes in most towns.
  • There are a number of recommendations aimed at minimising bleeding risk for patients undergoing PCI.  Of Course, we don’t do PCI in the country, but some of the recommendations involve the therapies we might be initiating en route to the Cardiologist / angio suite.
    • I think this means we should be consulting closely with the Cardiology team about drugs / agents we might use following either thrombolysis or the diagnosis of NSTEACS.
  • The Guidelines give an A level recommendation to early routine angiography for patients whom have received thrombolysis.  This was irrespective of the clinical response to thrombolytics.
    • For me this means we should try to arrange transfer as early as possible for the STEMI patients.  In the past we have tended to hang on to the patients who do well with thrombolysis – usually going out 24 – 48 hours later.  I think this needs to change based on this recommendation.
Ok, that is my take on the updated ACS guidelines for the smaller hospital (ie. one without access to PCI).  Let me know if you have anything to add.
Casey
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