Acute Coronary Syndrome Flashcards
Define acute coronary syndrome
Spectrum of acute myocardial ischaemia and/or infarction, including:
- STEMI
- NSTEMI
- Unstable angina.
Aetiology of acute coronary syndrome
Coronary artery disease.
Atherosclerosis with plaque fissuring or rupture and thrombus formation
Coronary spasm → reduced myocardial perfusion
Chest trauma or spontaneous coronary or aortic dissection or emboli
- Artery occlusion
- Sudden change of plaque (e.g. rupture) → superimposed platelet activation and aggregation
- vasospasm, coagulation and thrombosis
- Occlusive intracoronary thrombus overlying disrupted plaque - Myocardial infarction
- compromised myocardial supply → ischaemia
- Contractility loss within 60s (HF may precede)
- Necrosis, myocyte death
Ischaemia >20-40mins → irreversible injury and myocyte death
4H’s and 4T’s: hypoxia, hypo/hyperkalaemia/hypoglycaemia, hypothermia, hypovolaemia | thrombosis, tamponade, toxins, tension pneumothorax
Risk factors for acute coronary syndrome
Non-modifiable:
Age
Male gender
Family history of IHD
Modifiable:
Smoking
Hypertension
DM
Hyperlipidaemia
Obesity
Sedentary lifestyle
Cocaine use
Symptoms of acute coronary syndrome
Acute central chest pain
- Lasts >20 minutes
- Radiates to the jaw, arm or neck
- Increasing in severity and frequency
+ nausea
+ sweatiness
+ dyspnoea
+palpitation
ACS without chest pain (30%) -> “silent”, mostly seen in elderly and diabetics (+women). Presents with:
- Syncope
- Pulmonary oedema
- Epigastric pain
- Vomiting
- Post-op hypotension
- Oligouria
- Acute confusional state
- Stroke
- Diabetic hyperglycaemic states
Signs of acute coronary syndrome on examination
Distress
Anxiety
Pallor
Sweatiness
Pulse raised or depressed
BP raised or depressed
4th heart sound
Signs of heart failure (Raised JVP, 3rd heart sound, basal crepitations)
Pansystolic murmur
Low-grade fever
Pericardial
Signs of risk factors:
Tar staining
Acanthosis nigricans
Xanthoma
Investigations for acute coronary syndrome
ECG: diagnose
Troponin/cardiac enzymes: elevated/20% increase in STEMI/NSTEMI (NOT in angina) (if negative and <4-6 hrs since onset, measure again in 4 hrs)
FBC
U&Es
LFTs
Glucose
Lipids
Clotting screen
CXR: pulmonary oedema, cardiomegaly (HF), widened mediastinum (dissection)
echo: assess LV function
Coronary angiography: can show stenosis or presence thrombus in a coronary artery
What is seen on ECG in STEMI
First sign: Hyperacute T waves
ST elevation
New LBBB
ST depression V1-V4 -> posterior STEMI
T wave inversion
What is seen on ECG in NSTEMI
NO ST elevation, may be ST depression
T wave inversion
What is seen on ECG in unstable angina
NO ST elevation
May have ST depression and T wave inversion
How does the location of myocardial infarction relate to the ECG
Anteroseptal (left anterior descending): V1-V4
Anterolateral (left anterior descending/left circumflex): V4-6, aVL
Inferior (right coronary): II, III, aVF
Lateral (left circumflex): I, aVL ± V5-6
Posterior (left circumflex or right coronary): tall R waves V1-2, ST depression
Management for STEMI
- A-E assessment
- ECG and diagnose
- IV access + bloods
- Oxygen supplementation if low - Dual antiplatelet therapy (DAPT)
- Aspirin 300mg
- Ticagrelor 180mg PO (esp. after thrombolysis)
- PCI considered → Prasugrel
- Taking an oral anticoagulant → clopidogrel - Calculate GRACE score
- Plan intervention - PCI?
<12 hours
– PCI in <120 minutes possible → PCI within 12 hours
– PCI in <120 minutes NOT possible → thrombolysis within 12 hours (tissue plasminogen activator (tPA) or tenecteplase AND antithrombin)
→ ECG after 60-90 minutes → if ST-elevation persisting, PCI
>12 hours → specialist advice + anticoagulation (fondaparinux or enoxaparin/heparin) - Anticoagulate
- Angiography ± PCI <24 hours → (1) enoxaparin (LMWH) OR unfractionated heparin OR bivalirudin
- Fibrinolysis → (1) enoxaparin (LMWH) OR unfractionated heparin OR fondaparinux
- No intervention (low GRACE) → (1) fondaparinux (AKA always give in NSTEMI) - Supportive:
- Analgesia: morphine 5-10mg IV + metoclopramide 10mg IV
- Nitrates: GTN spray or sublingual tablet PRN - Beta-blockers (start early; CI: low BP/HR, HF, COPD/asthma, cardiogenic shock, heart block)
Management for NSTEMI
- A-E assessment
- ECG and diagnose
- IV access + bloods
- Oxygen supplementation if low - Dual antiplatelet therapy (DAPT)
- Aspirin 300mg to start
- PCI considered → prasugrel
- no IMMEDIATE PCI → fondaparinux
- if immediate angiography is planned or a patients creatinine is > 265 µmol/L then unfractionated heparin should be given
- Ticagrelor 180mg PO (esp. after thrombolysis) - Calculate GRACE score (6 month mortality)
- Plan intervention - PCI?
- Intermediate/high risk → PCI within 72 hours (immediately if unstable)
- Low risk → conservative - Anticoagulate
- PCI done → unfractionated heparin
- PCI not done → ticagrelor - Supportive:
- Analgesia: morphine 5-10mg IV + metoclopramide 10mg IV
- Nitrates: GTN spray or sublingual tablet PRN - Beta-blockers (start early; CI: low BP/HR, HF, COPD/asthma, cardiogenic shock, heart block)
Criteria for PCI in NSTEMI/unstable angina
immediate: patient who are clinically unstable (e.g. hypotensive)
within 72 hours: patients with a GRACE score > 3% i.e. those at intermediate, high or highest risk
coronary angiography should also be considered for patients if ischaemia is subsequently experienced after admission
What drug therapy is used during PCI
patients undergoing PCI with radial access: unfractionated heparin with bailout glycoprotein IIb/IIIa inhibitor (GPI) - this is the action of using a GPI during the procedure when it was not intended from the outset, e.g. because of worsening or persistent thrombus
patients undergoing PCI with femoral access: bivalirudin with bailout GPI
Long-term management for patients who have had an acute coronary event
ACEis - prevents the heart from remodelling around dead tissue e.g. ramipril 2.5mg orally 2x daily for 3 days, increase according to response
Beta blockers - reduce the work of the heart e.g. bisoprolol 1.25mg orally once daily initially for 1 week, increase according to response
Conservative:
Mediterranean diet
Exercise 20-30 minutes/day until slightly breathless (sex after 4 weeks; no sildenafil until 6m)
Control HTN and DM
Lifestyle: Stop smoking, exercise, weight loss, reduce alcohol intake
Dual antiplatelet e.g. aspirin 75-100mg orally once daily + ticagrelor 90mg orally twice daily
Stop the second antiplatelet after 12 months
Prasugrel OR ticagrelor can be used if there was PCI management
Statins e.g. atorvastatin 40-80mg orally once daily
