Acute Coronary Syndromes Flashcards
What is meant by an acute coronary syndrome?
What are the 3 ‘conditions’ which are examples of ACS’s?
- Signs and symptoms due to myocardial ischaemia- with or without infarction
- STEMI, NSTEMI, unstable angina
Describe the difference, in terms of pathology, between STEMI, NSTEMI and unstable angina
- STEMI: complete occlusion leading to subendocardial injury/infarction
- NSTEMI: partial occlusion leading to subepicardial injury/infarction
- Angina pectoris: partial occlusion leading to ischaemia but with NO infarction
State some risk factors for ACS
Non-modifiable
- Age
- Sex (male)
- Ethnicity (asian)
- Family history
- Premature menopause
Modifiable
- Smoking
- DM
- Hyperlipidaemia
- Obesity
- Diet
- Physical inactivity
- Hypertension
How may someone with ACS present?
- Cardiac chest pain >20 mins
- Pain may radiate to left jaw, shoulder & arm
- Nausea, vomitting
- Sweating
- SOB
- Palpitations
- Constant pain
- Pain at rest
*NOTE: some patients could present ONLY with less typical symptoms e.g. nausea, sweat, SOB etc… don’t always have ‘central crushing chest pain’
What might you find on examination of someone with ACS?
- Tachycardia
- Tachypnoea
- Sweating
- Hypertension (risk factor)
State some differentials for chest pain
Respiratory
- PE
- Pneumothorax
- Pleuritis
Cardiology
- Aortic dissection
- Pericarditis (usually sharp but may be dull or crushing)
Gastro
- Oesophagitis
- Oesophageal spasm
- Peptic ulcer
- Pancreatitis
- Cholecystitis
MSK
- Rib fracture
- Costochondritis
Other
- Sickle cell crisis
- Panic attack
- Cocaine use
What bedside tests should you do in patients presenting with ACS?
- ECG
- Observations (HR, BP, O2 sats, RR, BMs)
What blood tests do you want if a pt is presenting with ACS?
- Troponin: determine if infarction
- FBC: anaemia, hyperthyroidism, sepsis may precipitte MI
- U&Es: coronary artery disease may be marker for vascular disease in general and this may result in renal impairment which is important to know as contrast is given in angiogram & may be starting ACE inhibitor
- LFT’s
- Coagulation screen: INR needs to be known before taking to cath lab
- Lipid profile: will need statin therapy
- HbA1c: poorly controlled diabetes=risk factor
What imaging might you do for someone with ACS?
- CXR: features of heart failure, alternative diagnosis
- Echocardiogram: assess function of heart
*Don’t delay treatment whilst waiting for these scans in high risk/unstable pt
When determining whether the ACS is a STEMI, NSTEMI or unstable angina, what 3 things do we use/look at?
- Presenting symptom
- ECG
- hs-TnI level (high sensity troponnin I release)
Myocardial infarction can be categorised into type 1 and type 2; explain the difference
*NOTE: there are other types of MI (3, 4a, 4b, 5)
- Type 1: ischaemia due to plaque erosion/rupture which causes thrombus formation in the affected coronary artery
- Type 2: ischaemia due to either increased demand or decreased supply e.g. anaemia, arrhythmia, hyper-/hypotension who has stable coronary artery disease (in summary, ischaemia occured without plaque rupture)
There are different types of MI; we have covered the main types you need to be aware of (type 1 & 2), but what is a:
- Type 3
- Type 4a
- Type 4b
- Type 5
… MI
- Type 3: diagnosed post mortem
- Type 4a: related to PCI (e.g. angioplasty blocked side artery)
- Type 4b: stent thrombosis (if pt stops taking anticoagulants too early or smokes it can occlude the stent)
- Type 5: related to CABG
How do we distinguish between MI and unstable angina?
Rise in hs-TnI
Describe how troponin levels vary over time following myocardial infarction
- Increase within 3-12 hours from onset of chest pain
- Peak at 24-48hr
- Return to baseline in 5-14 days
What value will the hs-TnI frequently be above if the patient has had an MI?
>100ng/L
Alongside hs-TnI, what other biochemical marker should you also test for in a STEMI?
What value is this marker usually above in a STEMI?
- CK-MB (creatine kinase- myocardial band)
- Usually >400ng/L
If hs-TnI is above a certain value there is a high likelihood of myocardial necrosis; state this value for men and for women (it is different)
- Males: > 34ng/L
- Females: >16ng/L
We can use the hs-TnI to predict whether or not the MI was a type 1 myocardial infarction; what levels of hs-TnI have a very high predictive value for a type 1 MI?
- hs-TnI five-fold above the upper limit have very high predictive value for type 1 MI (90%)
- hs-TnI up to three-fold above the upper limit have a limited predited value for a type 1 MI (50-60%) and can be associated with other conditions
When looking at the troponin, we look at the change in cardiac troponin over time to help us differentiate between acute and chronic cardiomyocyte damage. A rise greater than ______ may indicate ACS
Rise greater than 5ng/L may suggest ACS
Discuss how the ECG of someone with a STEMI changes over time
- Hyperacute T wave (minutes)
- ST elevation (minutes-hours)
- T wave inversion (hours)
- Deep Q waves (hours)
- Resolution of ST elevation (days)
- Resolution of T wave inversion
- Persistent Q waves
Where do you place the ECG electrodes in a 12-lead ECG?
Where do you place the ECG electrodes when you are doing a 15-lead ECG/posterior leads?
Place leads V4-V6 on back:
- V4 (recorded as V7)- left posterior axillary line
- V5 (recorded as V8)- tip of left scapula
- V6 (recorded as V9)- left paraspinal region
*Level of normal V6 placement is good indicator of what level to put leads at
Following MONA, what is the management for a STEMI?
Patients with STEMI need coronary reperfusion therapy, two options:
Percutaneous coronary intervention (PCI) = GOLD STANDARD
- Offer if presentation within 12hrs symptom onset AND can be delivered within 120 minutes of the time fibrinolysis could have been given. (NOTE: if still have evidence of ongoing ischaemia but present 12hrs after onset symptoms PCI may still be considered)
- _Prior to PC_I, patients need dual antiplatelet therapy (aspirin + an ADP receptor antagonist):
- If they are not taking an oral anticoagulant: prasugrel
- If they are taking an oral anticoagulant: clopidogrel
-
Drug therapy during PCI varies dependent on access:
- Radial access: unfractionated heparin with bailout glycoprotein IIb/IIIa inhibitor
- Femoral access: bivalirudin with bailout glycoprotein IIb/IIIA inhibitor
Fibrinolysis
- Fibrinolysis (with e.g. alteplase, streptokinase, tenecteplase)
- Antithrombin drug should also be given at same time as fibrinolysis
- ECG should be repeated after 60-90 minutes to see if ECG changes resolved, if NOT resolved then PCI should be considered
- Patient should have ticagrelor as their long term antithrombin drug
NICE summary of STEMI mangement
Following MONA, what is the management of NSTEMI and unstable angina
Following MONA, antithrombin treatment should be given with either:
- Fondaparinux or LMWH: pts who are not high risk of bleeding and who are not having angiography immediately
- Unfractionated heparin: if having immediate angiography or creatinine is >265umol/L
You should risk stratify using the GRACE score to determine if should have PCI (may do this prior to deciding what to give in the above):
- Immediate PCI if pt clinically unstable (e.g. hypotensive)
- PCI within 72hrs if GRACE score >3% (intermediate or above risk)
- Consider PCI if ischaemia experienced after admission/continued ischaemia
Further drug therapy prior to PCI:
- Unfractionated heparin (if not already given?? CHECK). *NOTE: if pts had fondaparinux but then decided to go for PCI still need unfractionated heparin aswell
-
Further antithrombin therapy:
- Not taking oral anticoagulant: prasugrel or ticagrelor
- Taking oral anticoagulant: clopidogrel
If patients not having PCI, will need dual antiplatelet therapy (e.g. aspirin + ) lifelong:
- Not high risk of bleeding: ticagrelor
- High risk of bleeding: clopidogrel
NICE summary of NSTEMI management
What medications should someone be sent home with post MI as secondary prevention?
-
Beta blocker:
- Bisoprolol, starting dose 1.25mg OD
-
ACE inhibitor or ARB:
- ACE-i= amipril, starting dose 2.5mg OD
- ARB= losartan, starting dose 25mg OD
-
Statin
- Atorvastatin, 80mg OD
-
Dual antiplatelet therapy
- Aspirin, 75mg OD
- ADP receptor antagonist if had STEMI or NSTEMI or if high risk unstable angina (e.g. ticagrelor, clopidogrel). **May be discontinued after 12 months but rest of medications lifelong
