ANGINA AND ACUTE CORONARY SYNDROME Flashcards
What is angina?
pain (or constricting discomfort) in the chest, neck, shoulders, jaw, or arms caused by an insufficient blood supply to the myocardium.
What causes angina?
Mostly caused by coronary artery disease
Less commonly - valvular disease, hypertrophic obstructive cardiomyopathy, hypertensive heart disease
What is coronary artery disease?
When atherosclerotic plaques form in coronary arteries which causes a progressive narrowing of the lumen
What is stable angina?
pain that occurs predictably with physical or emotional exertion and lasts no longer than 10 minutes. It should be relived within minutes of rest or with the use of medication (e.g. GTN spray).
How long dose angina last?
Stable angina lasts no more than 10 minutes (usually less than this!)
What is unstable angina?
new onset angina or abrupt deterioration in previously stable angina, often occurring at rest
Why is stable angina on painful on exertion?
On exertion, there is an increased oxygen demand within cardiomyocytes. However, the narrowing of coronary vessels means blood flow cannot be increased to meet this demand. This results in pain
Whats the epidemiology of angina?
3% of men and 1.8% of women experience angina
Incidence is rising
Whats the most common single cause of death in the UK?
Coronary heart disease (in 2019 it caused 13% of male and 8% of female deaths)
What are complications of angina?
Stroke
MI
Unstable angina
Sudden cardiac death
Others - reduced quality of life, anxiety and depression
Whats the prognosis of angina?
With appropriate lifestyle modification and medical intervention, more than half of people with angina can expect to be symptom free within 1 year. However, some people may experience recurrence or worsening of symptoms due to progression of coronary artery disease
How does typical angina present?
Presents with all 3 of the following…
Precipitated by physical exertion.
Constricting discomfort in the front of the chest, in the neck, shoulders, jaw, or arms.
Relieved by rest or glyceryl trinitrate (GTN) within about 5 minutes.
How does atypical angina present?
Atypical angina presents with two of the following…
Precipitated by physical exertion.
Constricting discomfort in the front of the chest, in the neck, shoulders, jaw, or arms.
Relieved by rest or glyceryl trinitrate (GTN) within about 5 minutes.
In addition, atypical symptoms include gastrointestinal discomfort, and/or breathlessness, and/or nausea.
What are the 2 types of coronary artery disease?
Obstructive - stenosis in >50% of the left main coronary artery or >70% stenosis of 1 or more major coronary artery
Non-obstructive - <50% of the vessel lumen blocked
outline the process of atherosclerosis?
Endothelial dysfunction - endothelial injury causes local inflammatory response. Leads to accumulation of LDL which become oxidised by local waste products creating ROS
Plaque formation - endothelial cells attract monocytes to phagocytosis the LDLs -> Foam cells and fatty streak
Plaque rupture - continued inflammation triggers smooth muscle cell migration which forms a fibrous cap. Together with the fatty streaks this develops into an atheroma. The top of the atheroma forms a hard plaque which may rupture, exposing a collagen-rich cap where platelets can aggregate on to form a thrombus. Alternatively the thrombus may break loose, embolising to infarct a distant vessel
What features are suggestive of non-anginal chest pain?
Continuous or very prolonged pain, and/or
Unrelated to activity, and/or
Bought on by breathing, and/or
Associated with dizziness, palpitations, paraesthesia
What features make chest pain concerning?
Chest pain lasts > 10 minutes
Chest pain not relieved by two doses of GTN taken 5 minutes apart
Significant worsening/deterioration in angina (e.g. increased frequency, severity or occurring at rest)
(These features may be suggestive of ACS and patients need immediate medical attention)
How is the severity of angina graded?
According to the Canadian cardiovascular society
Grade I: angina with strenuous activity
Grade II: angina with moderate activity (e.g. slight limitation if normal activities performed rapidly).
Grade III: angina with mild exertion (e.g. difficulty climbing one flight of stairs at normal pace).
Grade IV: angina at rest
What is a rapid access chest pain clinic?
In the UK, patients with new-onset exertional chest pain suspected to be angina should have access to a rapid access chest pain clinic (RACPC). These clinics provide patients with early access to specialist cardiology assessment including diagnostic testing. It aims to identify new CAD and prevent a major cardiac event by offering earlier intervention.
GPs refer people to the clinic if their symptoms may be related to their heart.
Where should you refer patients with suspected angina?
If new angina suspected then rapid access chest pain clinic
If patients with established CAD and are already known to cardiology services - cardiology clinic
How should you investigate a pt with suspected angina?
Physical examination
Resting 12-lead ECG ASAP after presentation (dont rule out stable angina on the basis of a normal ECG)
Bloods - FBC, U&Es (needed before starting drugs), LFTs (needed before starting statins), lipid profile, HbA1c, TFTs
Diagnostic testing - CT coronary angiography - gold standard!
What are the 4 principles for managing angina?
Refer to cardiology
Advise them about diagnosis, management and when to call an ambulance
Medical treatment
procedures or surgical intervention
(RAMP)
What ECG changes may indicate previous MI?
Pathological Q waves
Left bundle branch block
ST segment and T wave abnormalities
How should you manage a pt with suspected stable angina whilst awaiting specialist referral?
Provide the pt with sublingual glyceryl trinitrate to use for the relief of symptoms
Consider prescribing aspirin until the diagnosis is confirmed
How should you inform a pt with stable angina on managing chest pain?
Stop what they are doing and rest.
Use their glyceryl trinitrate spray or tablets as instructed.
Take a second dose after 5 minutes if the pain has not eased.
Call 999 for an ambulance if the pain has not eased 5 minutes after the second dose, or earlier if the pain is intensifying or the person is unwell.
What is the pre-test probability of CAD?
the probability of presence of CAD in patient. It helps guide what further testing is required, if any, to determine the presence of CAD
Pretest probability for CAD can be estimated from the patient’s age, sex, and chest pain symptoms
Pre-test probability >15%: non-invasive functional testing recommended
Pre-test probability 5-15%: consider further testing based on basic investigations and risk factors.
What diagnostic testing can be done to diagnose CAD?
CT coronary angiography
Stress echocardiography
Coronary angiography
When should you offer anatomical non-invasive diagnostic testing for CAD e.g. CT coronary angiography?
If low clinical likelihood of CAD or no history of CAD
When should you offer non-invasive function testing for CAD e.g. stress echocardiography??
If high clinical likelihood of CAD, revascularisation therapy is likely needed or if established CAD already
When should you offer invasive coronary angiography for CAD e.g. coronary angiography?
If high clinical likelihood of CAD and symptoms unresponsive to medical therapy
Typical angina at low activity level and high risk of cardiac event
LV dysfunction on ECHO suspected secondary to CAD
What is functional testing for CAD?
Functional tests are used to diagnose obstructive CAD by the detection of myocardial ischaemia when the heart is put under stress
Examples include dobutamine stress echocardiography, stress cardiac MRI, SPECT, exercise ECG
What does acute coronary syndrome cover?
STEMI
NSTEMI
Unstable angina
What are the 2 main issues with the atherosclerosis in walls of coronary arteries?
- Gradual narrowing, resulting in less blood and therefore oxygen reaching the myocardium at times of increased demand. This results in angina, i.e. chest pain due to insufficient oxygen reaching the myocardium during exertion
- The risk of sudden plaque rupture. The fatty plaques which have built up in the endothelium may rupture leading to sudden occlusion of the artery. This can result in no blood/oxygen reaching the area of myocardium.
How does acute coronary syndrome present?
Chest pain - central/left sided, may radiate to jaw or left arm, heavy or constricting
Dyspnoea
Sweating
Nausea and vomiting
Pulse, bp, temp, o2 sats are often normal/only mildly altered
Pt may appear pale and clammy
What are the two most important investigations when assessing a patient with chest pain?
ECG
Cardiac markers e.g. troponin
Which leads will you see ECG changes in when the left anterior descending artery is blocked?
V1-V4 (anterior)
Which leads will you see ECG changes in when the left circumflex artery is blocked?
I, V5-V6, aVL (lateral)
Which leads will you see ECG changes in when the right coronary artery is blocked?
II, III, aVF (inferior)
Whats the mnemonic for treatment of acute coronary syndrome?
MONA
Morphine if in severe pain (may be associated with adverse outcomes so not given routinely anymore(
Oxygen if sats <94%
Nitrates (sublingual or IV)
Aspirin 300mg
When should you give oxygen in ACS?
If sats <94%
How do you manage a STEMI?
MONA
Second antiplatelet drug - clopidogrel, praugrel or ticagrelor
Assess eligibility for coronary reperfusion therapy and if possible give PCI within 120 minutes
How do you manage an NSTEMI?
MONA
If high risk or clinically unstable then perform a coronary angiography. Lower risk pt may have a coronary angiogram at a later date
What is secondary prevention?
Patients who’ve had an ACS require lifelong drug therapy to help reduce the risk of a further event. Standard therapy comprises the following as a minimum:
aspirin
a second antiplatelet if appropriate (e.g. clopidogrel/ticagrelor)
a beta-blocker
an ACE inhibitor
a statin
What is the GRACE score?
A scoring system to estimate 6 month mortality for pt with acute coronary syndrome
It takes into account age, HR, systolic BP< creatinine, cardiac arrest at admission, ST segment deviation, abnormal cardiac enzymes, killing class
What are poor prognostic factors for acute coronary syndrome?
Older age
development/history of heart failure
peripheral vascular disease
reduced systolic blood pressure
Killip class
initial serum creatinine concentration
elevated initial cardiac markers
cardiac arrest on admission
ST segment deviation
What is a Killip class?
A system used to stratify risk post myocardial infarction
Class 1 - no clinical signs of HF - 6% 30 day mortality
Class 2 - lung crackles, S3 - 17% 30 day mortality
Class 3 - frank pulmonary oedema - 38% 30 day mortality
Class 4 - cardiogenic shock - 81% 30 day mortality
Which group of people should you be cautious about giving nitrates to and why?
Those with hypotension as it can worsen it
Whats the ECG criteria for a STEMI?
Clinical symptoms generally of 20 minutes or more, consistent with ACD with >20 minutes of ECG features in 2 or more leads of:
2.5 mm ST elevation in leads V2-3 in men under 40 years, or ≥ 2.0 mm ST elevation in leads V2-3 in men over 40 years
1.5 mm ST elevation in V2-3 in women
1 mm ST elevation in other leads
new LBBB
What are the 2 types of coronary reperfusion therapy?
Percutaneous coronary intervention
Fibrinolysis
When should you offer PCI for a STEMI?
If presentation is within 12 hours of onset of symptoms and if PCI can be delivered within 120 minutes of the time when fibrinolysis could have been given. But if pt presents after 12 hours and still have evidence of ongoing ischaemia then consider PCI still
When should fibrinolysis be offered for a confirmed STEMI?
should be offered within 12 hours of the onset of symptoms if primary PCI cannot be delivered within 120 minutes of the time when fibrinolysis could have been given
What further medications should be given before./during a PCI?
Dual antiplatelet therapy prior to PCI - if pt not taking an oral anticoagulant then give prasugrel, if they are taking an oral anticoagulant then offer clopidogrel
If undergoing PCI with radial access - give unfractionated heparin with bailout glycoprotein IIb/IIIa inhibitor
If undergoing PCI with femoral access - give bivalirudin with bailout GPI
Which mode of access is now preferred for PCI?
Radial access
What drugs should be given before/during fibrinolysis for STEMI?
Give an antithrombin at the same time
Following the procedure give ticagrelor
What should you do if a pt has persistent MI following fibrinolysis?
Consider giving PCI
How should you manage an NSTEMI?
Give 300mg aspirin
Give fondaparinux if no immediate PCI is planned
Estimate 6 month mortality i.e. GRACE score
If low risk then conservative management with ticagrelor
If high risk then offer PCU immediately if unstable, otherwise within 72 hours. Give prasugrel or ticagrelor, give unfractionated heparin
What stents are best for PCI?
Drug-eluting stents (coated with a slow release medication to help prevent thrombosis)
What should be given for thrombolysis of an MI?
Tissue plasminogen activator
Tenecteplase or alteplase
How should you monitor a pt after thrombolysis?
ECG after 90 minutes to check there is a >50% resolution in ST elevation
If not then PCI is needed!
What is secondary prevention?
Stop smoking and avoid passive smoking
Cardio protective diet
Physical activity and avoid sedentary behaviour
Weight loss if overweight
Minimal alcohol consumption
Cardiac rehabilitation programme participation (normally initiated in hospital before discharge)
Continue precibing meds
Meds - dual antiplatelet, ACEi, beta blocker, statin
Outline the rules of driving after an MI?
For a car or motorcycle licence holder, following an MI the person does not need to inform the DVLA. However, driving should stop for a time (the length depends on factors such as type of MI and treatments). The person should check with their insurer that they are still covered for driving.
For a bus, coach or lorry licence holder, following an MI the person must stop driving for a set period and inform the DVLA using form VOCH1. Advise people that they can be fined if they continue to drive and do not inform the DVLA, and be prosecuted if involved in an accident.
When can resumption of sexual activity occur after an MI?
Sexual activity can be resumed when comfortable to do so, usually about four weeks after an MI.
Sexual activity presents no greater risk of triggering a subsequent MI in a person than if they had never had an M
How should you manage pt who have had an acute MI and who have symptoms/signs of HF and left ventricular systolic dysfunction?
With an aldosterone antagonist e.g. eplerenone
(Preferably give after ACEi therapy)
Outline ECG changes seen in an acute MI?
hyperacute T waves are often the first sign of MI but often only persists for a few minutes
ST elevation may then develop
the T waves typically become inverted within the first 24 hours. The inversion of the T waves can last for days to months
pathological Q waves develop after several hours to days. This change usually persists indefinitely
Which MI causes ST depression on a 12-lead ECG?
A posterior MI
What are the complications of an MI?
Cardiac arrest
Cardiogenic shock
Chronic HF
Tachyarrhythmias
Bradyarrhythmias
Pericarditis
Left ventricular aneurysm
Left ventricular free wall rupture
Ventricular septal defect
Acute mitral regurgitation
Whats the most common cause of death following an MI?
Cardiac arrest
Why do MI patients commonly go into cardiac arrest?
This most commonly occurs due to patients developing ventricular fibrillation
Why may MI patients develop cardiogenic shock?
If a large part of the ventricular myocardium is damaged in the infarction the ejection fraction of the heart may decrease to the point that the patient develops cardiogenic shock
What arrhythmias are most likely following an MI?
Ventricualr tachyarrythmias e.g. Ventricular fibrillation and ventricular tachycardia
Bradyarrhythmias - atrioventricular block is more common following inferior MI
What proportion of patients will get pericarditis following a transmural MI?
10% of pt
When is pericarditis most common following an MI?
In the first 48 hours
What is Dressler syndrome?
Postmyocardial infarction syndrome - a form of secondary pericarditis
When does dressler syndrome typically occur following an MI?
2-6 weeks after
Whats the pathophysiology of dressler syndrome?
thought to be an autoimmune reaction against antigenic proteins formed as the myocardium recovers.
How is dressler syndrome characterised?
Low grade fever, pleuritic pain, pericardial effusion and a raised ESR
Pericardial rub on auscultation
Rarely it can cause pericardial tamponade
How do you treat dressler syndrome?
NSAIDs
In more severe cases steroids may be needed and they may need pericardiocentesis to remove fluid from around the heart
Why does left ventricular aneurysm occur following an MI?
The ischaemic damage sustained may weaken the myocardium resulting in aneurysm formation.
What features are associated with left ventricular aneurysm?
persistent ST elevation and left ventricular failure
Why are pt with left ventricular aneurysm anticoagulated?
Thrombus may form within the aneurysm increasing the risk of stroke
Following an MI, when is left ventricular free wall rupture most likely to occur?
1-2 weeks after MI
What proportion of pt will get left ventricular free wall rupture following an MI?
3% of pt
How do pt present with left ventricular free wall rupture?
Patients present with acute heart failure secondary to cardiac tamponade (raised JVP, pulsus paradoxus, diminished heart sounds)
How is left ventricular free wall rupture managed?
Urgent pericardiocentesis and thoracotomy are required.
Following an MI, when is ventricular septal defect most likely to occur?
In the first week following an MI