Presentation
Chest pain. Central, crushing, radiation to arm, neck or jaw. Lasting >20 mins
Dyspnoea and palpitations also common
Beware abnormal presentations, especially in the elderly or diabetics with 'silent' infarct - epigastric pain, pulmonary oedema, acute confusion
Symptoms of NSTEMI overlap with STEMI. NSTEMI patients tend to be older and have more co-morbidities
History
Features of pain - SOCRATES - sight, onset, character, radiation, associated features (autonomic features), time course, exacerbating/relieving factors (breathing, position, exertion, eating) and severity (0-10)
Recent trauma?
Does the patient have a GTN spray and has it helped their symptoms? - relief may occur unlike STEMI
Does the patient have any risk factors for developing vascular disease - Hypertension, hypercholesterolaemia, obesity, diabetes, previous acute coronary event/stroke, smoker, lifestyle/occupation, family history of ischaemic heart disease?
PMHx - consider other causes for the presenting symptoms, such as gastric, respiratory problems, MSK
Medications - cardiac or respiratory medications, antacids, anticoagulants
Vital signs / observations
Tachycardia/Bradycardia
Tachypnoeic
Hypotensive/ hypertensive
Examination
'clammy' - cool and sweaty, pallor
Signs of heart failure? - raised JVP, basal crepitations, 3rd heart sound
Added heart sounds - pan systolic murmer may suggest rupture/dysfunction of papillary muscle/VSD
Bedside tests
ECG - ST depression, inverted or flat T waves; subsequent evolution of changes + T wave inversion. Non-specific changes. ECG may be normal
Laboratory investigations
FBC, U&E, LFT, lipids, glucose, lactate
Cardiac Markers - various cardiac markers so check locally which you should send at what time-points after the onset of chest pain. Troponin I or T will show an increase 6 hour post-pain and remain raised for up to 14 days. Typically blood test taken on presentation and 12h after worst pain.
cardiac markers useful for NSTEMI as will help differentiate from unstable angina
Treatment should Not be withheld waiting on results as ECG findings and history alone are sufficient to make the diagnosis
Consider ABG if patient acutely unwell
Radiological investigations
CXR - cardiomegaly, signs of LV failure (pulmonary oedema)
Urgent echo/CT if suspect other pathologies such as PE, Aortic dissection etc
Management
Immediate management
Continually monitor pulse oximeter, BP and ECG
Morphine - eg IV Diamorphine 2.5-5mg + Antiemetic
Oxygen - only if SpO2 shows evidence of hypoxaemia
Nitratrates - GTN 400micrograms SL, 2 puffs SL every 5 minutes until pain free
Aspirin 300mg PO STAT
+
Clopidogrel 300mg PO
Anticoagulate with LMWH (Fondaparinux)
Beta Blockers Bisoprolol 10mg STAT, Metoprolol 50-100mg/8 hours but beware in patients with COPD, hypotension and LVF
IV Nitrate if pain continues
Risk Stratification
| High Risk Patients | Low Risk Patients | |
| Clinical Features | Persistent or recurrent ischaemia, ST depression, diabetes, raised troponin | No further pain, flat or inverted T waves or normal ECG and negative troponin |
| Management | CCU bed, consider for Glycoprotein IIb/IIIa inhibitors (e.g. Tirofiban) and urgent catheterisation | Ensure pain free and arrange further tests such as exercise ECG, angiogram. Discharge home |
Prior to discharge
Wean of GTN infusion when established on oral medication
Stop heparin when pain free for 24 hours, but give at least 3-5 days of therapy
Aim to reduce modifiable risk factors such as smoking, obesity, control of diabetes, blood pressure and cholesterol.
Non-pharmacological
Smoking cessation and referral to cardiac rehabilitation to provide support for lifestyle modifications such as diet and re-introduction of physical activity following MI
Pharmacological
ACE inhibitor - eg ramipril. Start on low dose for example Ramipril 2.5mg daily, then increase to either 5mg then maximally 10mg
Statin, eg atorvastatin 10-80mg PO ON
Beta blocker, eg bisoprolol 5mg PO OD (this can be uptitrated as BP allows)
Aspirin - 75mg OD for life
Clopidogrel - 75mg OD for 12 months for patients who have had an NSTEMI regardless of treatment
Symptomatic treatment with nitrates (GTN) and possible addition of calcium channel blockers etc
Wean of GTN infusion when established on oral medication
Stop heparin when pain free for 24 hours, but give at least 3-5 days of therapy
Follow up
Review in out-patient clinic and through cardiac rehabilitation
Complications
Complications are less common for NSTEMI than STEMI
Early
Dysrhythmias
Cardiac Arrest
Pericarditis
Systemic Embolism
Valvular Pathology
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Late
Late malignant ventricular arrhythmias
Dreslers Syndrome (Recurrent pericarditis, pleural effusion, fever)
Left Ventricular Aneurysm
Prognosis
Overall risk of Death 1-3% but 15% for refractory angina despite medical therapy. Risk Stratification will help predict mortality. Factors increasing mortality include:
- History of unstable angina
- ST depression or widespread T-wave inversion
- Raised troponin
- Age >70 years
- General comorbidity
