Acute Coronary Syndromes have a significant impact on Australian's morbidity and mortality.
Rural Australians have increased rates per capita of cardiovascular disease and poor outcomes post-Myocardial Infarction compared to their Metropolitan counterparts.
Early recognition followed by access to appropriate reperfusion strategies, plays a key role in improving the outcomes for these patients.
This is part of the Rural Emergency Module series (designed in particular for ACRRM Trainees).
Consider the diagnosis: Women, the elderly, or Aboriginal/Torres Strait Islander, and patients with diabetes may have atypical presentations.
Recognition
Airway:
Analgesia + Antiemetics
Early Interventions to consider
Signs/symptoms
Meds
Events
Rural Australians have increased rates per capita of cardiovascular disease and poor outcomes post-Myocardial Infarction compared to their Metropolitan counterparts.
Early recognition followed by access to appropriate reperfusion strategies, plays a key role in improving the outcomes for these patients.
This is part of the Rural Emergency Module series (designed in particular for ACRRM Trainees).
Initial Assessment
and Management
|
- STEMI: ST segment elevations of 1 mm (0.1 mV) in 2 anatomically contiguous leads or 2 mm (0.2 mV) in 2 contiguous precordial leads, OR new left bundle branch block and presentation consistent with ACS. If ECG suspicious but not diagnostic, consult cardiology early.
- Non-STEMI or unstable angina: ST segment depressions or deep T wave inversions without Q waves or possibly no ECG changes
Recognition
- Recognise, send for help, gather resources and appropriate equipment.
- Move to resuscitation bay
- Monitoring – telemetry, SpO2
- Early risk-stratification
- Rapid ECG and assessment
- Contact Cardiologist and retrievals if applicable early.
Airway:
- Check airway
- If breathing is inadequate, assist with BVM + high flow oxygen
- Avoid routine use of oxygen therapy among patients with SaO2 > 93 %
- COPD patients target SaO2 88-92%, and use oxygen in shocked patients
- Assess Pulse, BP (measure both arms -> DDx Aortic Dissection), Cap refill.
- Insert PIVC x2
- Continuous cardiac monitoring
- Give Aspirin 300mg
- Control Blood Pressure; GTN infusion for HTN. B-Blocker (e.g. Metoprolol)
- Assess for and treat left heart failure if present.
- Determine baseline neurologic function (particularly if fibrinolytic therapy is to be given)
- Altered mental state => evidence of cardiogenic shock
- Maintain Normothermia.
- Check bedside Glucose
Analgesia + Antiemetics
- Opioid analgesia is preferred to nitrates for the initial control of pain in the setting of STEMI.
- IV morphine boluses titrated to clinical effect.
- If morphine is contraindicated, consider fentanyl at 25 to 50 micrograms IV as initial equivalent dose.
Early Interventions to consider
- M orphine / Fentanyl
- O xygen
- N itrates
- A spirin
- R eperfusion (thrombolysis or PCI)
- C lopidegrol / Ticagrelor
- H eparin
History
|
- Use SOCRATES/PQRRST or preferred assessment of Pain
- Associated symptoms: nausea/vomiting, sweating, shortness of breath, palpitations, lethargy/fatigue
Meds
- Anticoagulants, antiplatelets, anti-hyperglycaemics
- Phosphodiesterase 5 inhibitors e.g. Sildenafil (GTN may have an excessive effect if used)
- Ischaemic Heart Disease, HTN, Diabetes, Smoker, Dyslipidaemia, LV Hypertrophy
- Renal Function or known impairment
- Aboriginal & Torres Strait Islander
- Family Hx
- Obesity
Events
- Syncope, collapse, cardiac arrest
Investigations
|
- FBC, Cardiac Enzymes (Troponin), U&Es, Glu, Coags
- Serial ECGs (see Quick Guide to ECG)
- CXR (signs of LV Dysfunction & differential diagnoses)
- Echocardiography (not routine) / A quick Bedside may provide some further clarification on level of cardiogenic shock, if present
Management
|
Risk Stratification:
Risk stratification will guide urgency for transfer in the context of the patient pre-existing function and location. Note risk stratification here is referring to stratifying severity of suspected/diagnosed ACS, rather than risk stratifying chest pain.Queensland Health uses the following general recommendations around timeframes to Angiography.
Antiplatelet Therapy
- Aspirin 300mg load, 100 – 150 mg daily thereafter.
- P2Y12 inhibitors
- Careful assessment of bleeding risk should be undertaken before using these agents.
- Avoid if emergency coronary artery bypass grafting may be required, (e.g. ongoing ischaemia, extensive ECG changes, hemodynamic instability).
- Ticagrelor 180 mg loading dose -> 90mg bd. For moderate to high risk NSTEACS treated conservatively or invasively, and STEMI planned for primary PCI. Avoid if emergency coronary artery bypass grafting is likely. Greater proportional benefit in renal impairment (CrCl < 60mL/min)
- Clopidogrel 300mg loading dose if thrombolysis planned, 600mg if PCI planned and patient < 75yrs. 75mg daily after loading.
- Prasugrel 60mg - may be used in place of clopidogrel in patients with STEMI of less than 12 hours where PCI is planned, or NTEACS after angiography and before PCI.
Anticoagulants
Consider availability and appropriateness of agent. Do not switch between agents due increased risk of bleeding.
- Heparin
- With PCI: Heparin (i.e. “unfractionated”) bolus dose of 5000 units should be given in cases of patients who are to receive PCI for their STEMI.
- With fibrin-specific fibrinolysis: Heparin bolus loading dose with the first fibrinolytic dose and then commence heparin infusion
- Enoxaparin, 1 mg/kg SC (or a reduced dose, 0.75 mg/kg SC in the elderly or those with renal impairment) 12 hourly
Glycoprotein IIb/IIIa inhibitors
- Not routinely available in rural hospitals. If available should only be used in consultation with Cardiologist.
Reperfusion
Indications- All patients who present within 12 hours of symptom onset of STEMI should be considered for a reperfusion strategy, unless they have severe co-morbidities.
Choice
Reperfusion strategy depends upon;
- Duration of symptoms and time to first medical contact
- Locally available resources and geography
- Time to commence reperfusion strategy
- Location of MI
- Patient related factors
- Age
- Comorbidities & Risk status
- Contraindications to Fibrinolytics
Fibrinolysis/Thrombolysis
Typically, the only reasonable option available in rural hospitals/medical practices/prehospital. Fibrinolysis typically does not lead to improve outcomes if administered beyond 12hrs, however could be administered in consultation with a Cardiologist.
Agents
There are 3 fibrin-specific fibrinolytic agents available in Australia:
- tPA (Trade name Alteplase) – Infusion
- Tenecteplase (Trade name Metalyse) – Single bolus dose
- Reteplase (Trade name Rapilysin) -Two standard bolus doses 30 minutes apart
- Streptokinase is no longer used.
Tenecteplase + Enoxaparin is the lysis of combination of choice. Equivalent if not slightly more effective, similar cost and easiest to use.
Taken from Queensland Health Thrombolysis for STEMI Clinical Pathway (2016). Please review local protocols.
Adjunctive Treatment / Supportive Cares
Initiate adjunctive and supportive treatments unless contraindications present.
B-Blockers
- In a large selection of patients, B-Blockers reduce short-term complications and improve long-term survival.
- Recommended orally for both STEMI, and non-STEMI, particularly for hypertension or persistent tachycardia in absence of contraindications, irrespective of other treatment.
- If significantly hypertensive, may initiate beta blocker IV instead.
- Drug examples; Metoprolol 25 mg orally, Bisoprolol 5-10 mg
ACEi / ARBs
- Postulated to reduce myocardial infarct expansion, ventricular remodeling, and ventricular dilatation
- Shown to reduce the risk of death, reinfarction, and hospitalization for congestive heart failure (CHF) post‐acute myocardial infarction
- Drug Examples; Catopril, Enalapril, Lisinopril, Rampril
- ARBs (e.g. Valsartan) are believed to be a noninferior alternative in ACEI‐intolerant patients.
- In Heart Failure with reduced Ejection Fraction (HFrEF) there are newer combination agents (Sacubitril/Valsartan ) which may provide additional benefit, but should ideally be started by a Cardiologist or other appropriate specialist.
Statins
- Initiate cholesterol lowering therapy post-MI, unless contraindicated or there is a history of intolerance.
- E.g. 80 mg of atorvastatin (best-evidence)
Supportive – FAST HUGS IN BED Please
- Fluid therapy and feeding: Mg >1 , K+ >4
- Analgesia, antiemetics: Opioids, Nitrates, Paracetamol. Avoid NSAIDS
- Sedation; not routinely indicated
- Thromboprophylaxis / Anticoagulation; see above
- Head up position (30 degrees) if intubated
- Ulcer prophylaxis: Recommended for patients taking DAPT, high-bleeding risk and previous GIT Bleeds. Not required for all patients.
- Glucose control: Maintain Normoglycaemia.
- Skin/eye care and suctioning
- Indwelling catheter; not routinely indicated
- Nasogastric tube; not routinely indicated
- Bowel cares
- Environment: Maintain Normothermia, remain in monitored environment, transfer to nearest CCU/ICU as applicable.
- De-escalation (e.g. end of life issues, treatments no longer needed)
- Psychosocial support (for patient, family and staff)
Life-threatening complications of Acute MI:
- F ailure (heart failure)
- E ffusion and tamponade
- Therapy: pericardiocentesis
- A rrhythmia (AV block, VT)
- Therapy: correct hypoxia, acidosis, hypovolaemia, K+ >4, Mg2+ >1
- R upture
- Therapy: pericardiocentesis and repair
- A neurysm (ventricular)
- MI (Re-infarction)
Complications of therapy, e.g. haemorrhage, coronary artery dissection, stent thrombosis, surgical complications.
Overall treatment in Post-MI patients: ABCDE
- A ntiplatelets (Aspirin), ACE inhibitors, Antianginals
- B -blocker and Blood pressure control
- C holesterol lowering / Cigarette stopping / Cardiac Rehab
- D iet and Diabetes control
- E ducation and Exercise
References and Further Resources
- https://www.ecrjournal.com/articles/evaluation-and-management-st-elevation-myocardial-infarction-and-shock
- https://www.ncbi.nlm.nih.gov/pubmed/23913604
- http://circres.ahajournals.org/content/114/12/1918
- https://www.nature.com/articles/s41598-018-20651-3
- http://www.acc.org/latest-in-cardiology/journal-scans/2018/03/08/15/26/mortality-after-coronary-artery-bypass-grafting
- anzcor-guideline-14-3-jan16.pdf
- http://jaha.ahajournals.org/content/6/3/e005165
- https://lifeinthefastlane.com/ccc/stemi-management/
- https://lifeinthefastlane.com/collections/ebm-lecture-notes/chest-pain-adjunctive-therapies/
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