Authors: Becky Maxwell, Chris Connolly / Code: A1 / Published: 19/10/2016
In this month’s Guideline Podcast @chrisconnolly83 and @MaxiRebecca discuss the latest SIGN Guidelines on ACS. Below is a summary of the main discussion points and links to any relevant articles.
Why?
Acute coronary syndrome (ACS) is large part of our workload in the Emergency Department, it is a major cause of premature mortality. For this reason it is vital we get the treatment right at the front door.
There has been a large amount of research surrounding clinical decision tools and High Sensitivity Troponin assays in last few years. There is no doubt that how we investigate and manage presentations of ACS has changed considerably over the last decade, and we think this is an area which will continue to develop over the next few years.
Remit of guideline:
This Guideline looks at the recommendations for management of patients with ACS within the first 12 hours and the Emergency Department certainly plays a role in (at least!) four hours of this period of time.
SIGN – Scottish guideline Published April 2016 are the most up to date Guidelines we have on ACS, there are other Guidelines, in particular NICE 2014, ESC 2015, that are worth you reading as well.
Definition of ACS:
Broad definition that includes unstable angina, NSTEMI and STEMI
The Guideline sets out several recommendations, which are split into four categories under the following subtitles:
- Presentation, assessment and diagnosis
- Initial Management
- Reperfusion therapy for ST elevation ACS
- Early pharmacological intervention
Presentation, assessment and diagnosis:
There has been a lot of work on Clinical Decision Rules alongside the use of High Sensitivity Troponin as an early rule out strategy check out this podcast on SGEM about the HEART score (History, ECG, age, risk factors, Tnt).
Recommendations:
- Immediate assessment by HCP and 12 lead ECG
Guidance recommends use of the GRACE score, as clinicians both of us have moved to using the HEART score when deciding when to refer patients. In terms of the immediate assessment, we would suggest this is probably the role of expert triage in the ED, be that nurse or medic. This should be completed within 15 minutes of arrival. We believe the rationale is down to the time critical nature of intervention in ACS – we don’t see a lot of ambulance STEMI anymore but they’re sneaky and sometimes get their wife to drive them in after putting it off for a few hours.
- Troponin – measure at presentation and 3 hours after presentation with a high sensitivity assay, if positive, continue to measure at 12 hours to establish diagnosis.
NICE/ESC recommend the same. There can be a wide scope of practice in this area and it can be difficult to make sweeping statements as lab assays are presumably different depending on where you work and subject to diagnostic accuracy appraisal.
The Guideline mentions sex specific thresholds something that was mentioned in the RCEM Scientific conference last year. We find it interesting that the upper reference range can be twice as high in men than women – are we treating everyone as a woman in our practice and therefore over-diagnosing men?
- If patient has abnormal ECG, give them a copy
A simple thing to do, which can make a massive difference next time an ambulance is called! @chrisconnolly has made a mid-year resolution to improve on this….
Initial Management:
- Patients with Acute Coronary Syndrome should be managed within a specialist cardiology service
This is difficult as cardiology services are often stretched. There is variable practice between different hospitals in the UK. Often patients in the UK are admitted to medicine who sieve the patients to cardiology.
- No evidence that oxygen improves clinical outcome or reduces infarction size.
This shouldn’t come as a surprise to anyone, titrate the oxygen to the saturations. 100% oxygen for all is out!
- In the presence of ischemia on ECG OR elevation of Tnt Rx immediately with Aspirin and ticagrelor.
There is no debate about aspirin. We have been using aspirin for years with excellent evidence that it improves outcome. Is clopidogrel out? There is no doubt that clopidogrel when combined with aspirin is better than aspirin alone (THE CURE TRIAL NEJM 2001)
Prasugrel or ticagrelor – are considered to be more effective P2Y12 receptor antagonists than clopidogrel and evidence suggests that their use as a dual antiplatelet with aspirin is more effective than clopidogrel with Aspirin.
Evidence for Ticagrelor comes from a study in NEJM 2009 Ticagrelor versus Clopidogrel in Patients with Acute Coronary Syndromes (PLATO Trial). The reported results of this trial stated that Ticagrelor, when combined with aspirin, significantly reduces the rate of death from vascular causes, myocardial infarction, or stroke compared with clopidogrel. Of note, however, @chrisconnolly has some concerns about this trial – there was only 82% adherence to the assigned treatment drug. There are no 95% CI reported other than the hazard ratios. Not to mention this trial was also sponsored by the drug company that makes Ticagrelor!
- For patients with acute coronary syndrome that are undergoing for Primary PCI – treatment with Aspirin and Prasugrel may be considered
The evidence for prasugrel comes from the TRILOGY ACS study 2010 and in the TRITON-TIMI 38 study 2007. Careful with those who are older >75 years old and previous history of TIA/CVA
The Guideline does address increased bleeding risk with both these drugs – patients with ACS should be considered for treatment with aspirin and clopidogrel where the risks (of bleeding) outweigh the benefits of ticagrelor or prasugrel.
- In presence of ischaemia on ECG or elevation of TnT, patients should be treated immediately with LMWH or fondaparinux
Of note Fondaparinux is a synthetic pentasaccharide that potentially has reduced harmful effects specifically bleeding in comparison with Enoxaparin. In patients with STEMI it is worth noting that the small benefit offered by fondaparinux was tested where the first dose was given IV rather than SC – we never knew this until reading the Guideline!
- B Blockers In the absence of bradycardia and hypotension patients with ACS and no evidence of heart failure should be considered for immediate B blockcade
Again something we need to consider in our practice this wasn’t routine for either of us until reading the Guideline but Chris has added this to his mid-year resolution list.
- Glycaemic control aim 7.0 to 10.9 in Diabetes or those with hyperglycaemia
In all honesty neither of us can recall the last time we started a sliding scale in an ACS patient in the ED! A blood sugar of 25 would concern us but we freely admit to not worrying (until now!) about a blood sugar of 12. Chris’ resolution list is starting to get a bit long……
Reperfusion Therapy for ST segment elevation acute coronary syndrome:
- Patients with ST segment -elevation ACS should be treated immediately with PCI
This is a no brainer in our opinion. Thought for the day -are specialist Regional Cardiac Centres the way forward, a bit like the Major Trauma Centres?
- When PCI not available within 120 minutes of STEMI being diagnosed the patient should receive immediate thrombolytic therapy
Early Pharmacological intervention:
Patients may re-attend us after the event and it is worth understanding what treatment they should be on..
- Aspirin – no brainer they all should be on this as per the SIGN recommendations and what we have been doing for years
- Dual antiplatelet therapy for 6 months – this varies alongside bleeding risk
- Patients should not be offered DOAC in addition to anti platelet therapy
So that’s a whistle stop tour of the SIGN ACS Guidelines. We certainly learnt a lot from reviewing them and have picked some tips to help improve our management of these patients.