Acute Coronary Syndromes (ACS) Flashcards
What is an ACS?
Any sudden cardiac event related to a problem with the coronary arteries (problems arise du to myocardial ischaemia)
How can an atheroma lead to a MI?
- Fibrous cap of plaque injured and thrombus formed
- In more advanced, cap completely ruptures - contents released and thrombus forms
Platelets release serotonin and thromboxane A2 - causes vasoconstriction in the area (ischaemia)
What are the symptoms of ACS?
Chest pain
Nausea
Sweating
Breathless
Describe ischaemic chest pain
Dull retrosternal pain
More of a pressure
May radiate to jaw, neck, arm
What are the signs on clinical examination?
3rd HS (early diastole) Pansystolic murmur (S1 to S2) Pericardial rub Crepitations in lung - Pul. oedema Hypotension Quiet S1 Narrow pulse pressure Raised JVP
How is the diagnosis made?
- History - signs/symptoms
- ECG changes
- Positive cardiac enzyme tests - troponin and creation kinase
What investigations should be carried out?
ECG
FBC U+E LFT TFT Blood glucose (diabetes) Lipid profile Cardiac enzymes ABG
CXR
What is the general management of suspected ACS?
Morphine O2 Nitrates (GTN) Aspirin Clopidogrel
What is given got for STEMI treatment?
Thrombolysis (TNK)
PCI
B blockers
ACEi
What is given for NSTEMI treatment?
CABG Antiplatelet (aspirin, Clopidogrel) Anti-thrombotic (heparin, fonaparinux) BB (bisorolol) - peripheral vasodilation - reduces CO, HR and contractility Statin (simvastin) ACEi (ramipril)
What are the risk factors of ACS?
Male Age Known heart disease High BP High cholesterol Diabetes Smoker FH of premature heart disease
What is the action of antiplatelet agents?
Aspirin inhibits thromboxane A2 production which stimulates platelet aggregation and vasoconstriction, abnormal blood flow (causing atheroma) and vasospasm
What is the action of glycoprotein II/b/IIa receptor inhibitors?
GPIIb/IIa is a complex on platelet, and the receptor for fibrinogen aids in platelet activation
Clopidogrel blocks by inhibiting fibrinogen from binding to GPIIb/IIa receptor.
What is the action of BB?
Competitively inhibit myocardial effects of circulating catecholamines and reduce myocardial O2 consumption by lowering HR, BP and contractility
What is the goal of pharmacotherapy?
Increase myocardial O2 supply through coronary vasodilation
Decrease myocardial O2 demand by decreasing HR, BP, preload or myocardial contractility
What is a major (full blown) MI?
Complete coronary artery occlusion
What is a minor (warning) MI?
Partial (or transient complete) coronary artery occlusion
What does the initial ECG of a complete coronary occlusion show?
ST elevation
What does the ECG of a complete coronary occlusion show after 3 days?
Q waves
What does the initial ECG of a partial coronary occlusion show?
No ST elevation
What does the ECG of a partial coronary occlusion show after 3 days?
No Q waves
Is stable angina an acute coronary syndrome?
No, it is a chronic ischaemic heart disease
Is unstable angina an acute coronary syndrome?
Yes
In a STEMI what thickness of the heart muscle is affected?
Full thickness (transmural MI)
In a NSTEMI what thickness of the heart muscle is affected?
Partial thickness (subendocardial MI)
How is MI diagnosed?
+Ve cardiac biomarkers (myocyte death)
AND one of: Ischaemic symptoms ECG changes Angiogram shows coronary problem Cardiac damage on another test
What protein is used as a biomarker to detect if a major MI has occurred?
Troponin B1
What protein is used as a biomarker to detect if a minor MI has occurred?
Troponin B2
What are some non-cardiac causes of troponin rise?
Pulmonary embolism
Sepsis
Renal failure
Sub-arachnoid haemorrhage
What is a Type I MI?
A spontaneous MI associated with ischaemia and due to primary coronary events such as plaque erosion, rupture, fissuring or dissection
What are some other causes of type 1 MI that are not atherosclerosis?
Coronary vasospasm
Coronary dissecion
Embolism of coronary artery
Inflammation of coronary artery (vasculitis)
Radiotherapy to chest can cause fibrosis and stenosis of coronary arteries
What might the ST segment of the ECG look like in a NSTEMI?
Could be ST depression
Why can posterior MI be easily missed?
A there are no chest lead on the back of the chest
What MI can a problem with the right coronary artery cause?
Inferior MI
What MI can a problem with the LAD coronary artery cause?
Anterior MI
What MI can a problem with the L circumflex coronary artery cause?
Lateral MI
For posterior MI, what precordial chest lead should you look at on an ECG?
V1-V2 as you see opposite changes as they’re opposite the posterior side
How many cases per year of MI are there?
300 000
What can a CXR show in an ACS?
Cardiomegaly
Pul. oedema
Widened mediastinum
What are two treatments that restore reperfusion of occluded artery?
Primary percataneous coronary intervention (PCI)
Pharmacological
What are you looking for in FBC investigation?
Anaemia Inflammation markers (WBC)
What are two cardiac enzymes?
Troponin
Creatine kinase
What is the thrombolysis agent used?
Tenecteplase (TNK)
What do you need to be about with thrombolysis?
Bleeding
Dont give to those if recent stroke or previous intracranial bleed
Caution if recent surgery, on warfarin, severe HPT
Cath lab vs thrombolysis
Cath lab for PCI first choice if you can get to it with 2hrs
Thrombolysis works if given early but likely to cause bleeding
What type of individuals are more likely to get an NSTEMI than STEMI?
Older
Prev MI
Prev CABG/PCI
What is the management given more more chest pain after admission?
GTN - vasodilation of coronary arteries
Opiates (morphine) - relieve anxiety and venodilates
List 2 anti platelet drugs
Aspirin Clopidogrel (or ticagrelor 180mg then 90mg bd)
Both 300mg then 75mg od
List 3 anti-thrombotic drugs
Heparin
LMWH
Fondaparinux (2.5mg od)
What are the risks of coronary stunting?
Bleeding Blood vessel damage MI Coronary perforation Stroke Dye can affect kidneys
What are the complications following an MI?
Arrhythmias
Mechanical: cariogenic shock, myocardial rupture
What are other mechanical problems hat can arise from MI but not cause death?
Valve dysfunction due to papillary muscle dysfunction/rupture
Acute ventricular septal defect
Why are anti platelets required after a stent?
Takes time for stent to become endothelialised into coronary artery wall, so until then it is exposed to blood and can cause thromboses, blocking off the stent unless of antiplatelets
1 to 12 months of dual anti-platelet therapy (DAPT)
