Angina Flashcards
1
Q
What type of cardiovascular disease is angina pectoralis?
What is the underlying pathology involved?
A
- It is a form of atherosclerotic cardiovascular disease
- This involves the build up of fatty plaques on arterial walls
- Stable angina is a common presentation of coronary heart disease, which develops when the coronary arteries cannot supply enough oxygen-rich blood to the heart (due to atherosclerosis)
2
Q
When is chest pain present in stable angina?
A
- chest pain is present on exertion / exercise
- it is relieved by rest or nitrates
3
Q
Why is angina referred to as a clinical syndrome rather than a disease?
Why does this occur?
A
- it represents a clinical manifestation of underlying coronary artery disease
- it occurs when there is insufficient oxygen supply to the heart to meet demand
- i.e. there is myocardial ischaemia without infarct
- the inability to supply the heart occurs as a result of narrowing of the coronary arteries
- this can be due to atherosclerosis or arterial spasm
4
Q
What is the difference between stable angina and unstable angina?
Why is it important to distinguish these from each other?
A
- unstable angina is a form of acute coronary syndrome (ACS) where there is an acute narrowing or complete occlusion of the coronary artery due to a blood clot
- ACS results in infarction of the myocardial tissue, and not just ischaemia
- the presenting chest pain can feel identical but the treatments are very different
5
Q
What is the typical pattern of chest pain that angina presents with?
A
- chest pain is typically central or left-sided
- there may be radiation to the neck, arm or jaw
- it is described as a “tight” or “crushing” sensation
- chest pain is transient and brought on by exertion, but can also be triggered by emotion
6
Q
What are the risk factors for stable angina?
A
The risk factors are the same as for all manifestations of cardiovascular disease:
- hypertension
-
dyslipidaemia (abnormal level of lipids in the blood)
- high LDL and low HDL level
- diabetes
- obesity
-
family history of arterial disease
- this is significant when a first degree relative has had an MI before the age of 55
- smoking
- advancing age
- male gender
7
Q
Other than chest pain, what other symptoms may angina present with?
How long do symptoms usually last for?
A
- dyspnoea may or may not be present alongside chest pain
- symptoms typically last for several minutes and are relieved by rest
- shorter acting symptoms are unlikely to be related to ischaemia
8
Q
How frequently do patients tend to get angina-like symptoms?
A
- patients may get frequent symptoms (several times daily)
- or they may rarely get symptoms (months between episodes)
- this does not necessarily correspond to the severity of the disease
9
Q
What is crescendo angina?
What risk is associated with this and why is it important to monitor changes in patient’s angina symptoms?
A
- crescendo angina occurs when attacks are increasing in frequency and / or severity
- it is correlated with a high risk of ACS
- any changes to a patient’s usual pattern of symptoms should be considered a significant risk for ACS and investigated as such
10
Q
How is angina differentiated from ACS?
What factor in the history will increase suspicion of ACS?
A
- it should be treated as ACS when the pain does not resolve within 5 minutes of cessation of activity** and/or with the use of **GTN spray
- angina is typically exertional
- suspicion of ACS is increased if symptoms have occurred at rest
11
Q
What is the difference in the way that MI and angina damage the heart muscle?
How should any diagnosis of sudden onset chest pain be treated?
A
- MI causes permanent damage to the heart muscle (infarction)
- stable angina causes ischaemia, but not infarction (no permanent damage)
- they present with very similar symptoms so any sudden onset chest pain should be treated as ACS until proven otherwise
12
Q
What are the 3 possible underlying causes for angina-like symptoms?
A
-
atheroma seen in coronary artery disease
- this accounts for the vast majority of cases
- aortic valve disease
-
hypertrophic cardiomyopathy
- involves thickening of the myocardium, which makes the heart muscle stiff and less effective at pumping blood
13
Q
Other than exertion, what are some other precipitating factors for angina?
A
- cold weather
- heavy meals
- intense emotion
14
Q
What is silent ischaemia?
A
- this is myocardial ischaemia that presents as shortness of breath or without symptoms
- it can sometimes be confused for angina
15
Q
What are the different modalities involved in diagnosing stable angina?
A
- It is diagnosed with a combination of history, ECG and myocardial imaging (typically an angiogram)
- need to rule out other causes of chest pain - particularly ACS
- the history should be “typical” of angina, with an ECG
- diagnosis is then confirmed with imaging
16
Q
What changes might be present on an ECG for stable angina?
A
- the ECG can be normal, but changes can include:
- pathological Q waves
- ST depression
- LBBB
- T-wave flattening or inversion
17
Q
What is the first line imaging investigation for stable angina?
A
CT coronary angiogram
- this is performed to confirm the diagnosis
- if there is very high clinical suspicion, you can refer to cardiology without imaging and start treatment first
18
Q
What are the key factors that a patient will mention in a typical history of stable angina?
A
-
chest pain that is “tight”, “heavy” or “gripping”
- it is typically felt behind the sternum
- can radiate to the neck, jaws, arms and sometimes back
- shortness of breath
- BOTH pain and SOB are brought on by exertion and relieved by rest
- symptoms typically last several minutes after the precipitating event has stopped
- classically relieved by GTN
19
Q
What main risk factors increase the likelihood of a diagnosis of angina?
A
- smoking
- hypertension
- diabetes
- FHx of cardiovascular disease < 55
- raised cholesterol
20
Q
When should an ECG be performed in someone with angina and why?
A
- the ECG will often be normal
a normal ECG does not exclude diagnosis of angina or ACS
- if performed during an episode of angina (e.g. during an exercise tolerance test) then changes might be seen:
- ST depression
- ventricular ectopic beats
- bundle branch abnormalities - mainly LBBB
21
Q
Why might a CXR be performed in suspected angina?
A
- used to look for other causes of chest pain
- e.g. pneumonia, pneumothorax
- may show signs of heart failure, which is associated with severe coronary artery disease
22
Q
Why might an exercise tolerance test be performed?
Can it be used to diagnose stable angina?
A
- can be used to assess for symptoms and ECG changes when the heart is stressed
- exercise increases the cardiac load and can provoke myocardial ischaemia
- this manifests as chest pain, dyspnoea and ECG changes
- ECG based ETT cannot diagnose stable angina, but it can be used to rule out coronary artery disease after a single acute episode of chest pain
23
Q
What is involved in a CT coronary angiogram?
Why is this recommended as the primary diagnostic investigation?
A
- contrast is injected through a peripheral cannula
- scan is conducted while the patient holds their breath and takes about 10 - 15 seconds
- contrast fills the coronary arteries and can indicate where they are narrowed
- this is a non-invasive test
24
Q
What is a myocardial perfusion scan (MPS)?
What is the main drawback of this test?
A
- it is a type of stress test that shows blood flow to different areas of the heart during exercise
- reduced blood flow to any given area can indicate vessel blockage in the vessel associated with that particular area of the heart
- it is an alternative to CTCA by does NOT directly visualise the arteries
25
Why is an angiogram not used to diagnose angina despite being the most accurate diagnostic test?
How does this work?
* it is expensive and carries risk
* it is invasive and involves inserting a cardiac catheter
* it gives exact information on the level of narrowing of the coronary arteries and which vessels are affected
26
When is coronary artery narrowing considered significant?
* when the **luminal diameter** is **_reduced by \>70%_**
* proximal narrowing of the **_left main coronary artery_** and **_left anterior descending artery_** is associated with a poor prognosis
* angiogram can be used to assess the extent of coronary artery lesions when revascularisation therapies are being considered
27
What are the 4 different stages in the Canadian Cardiovascular Society Angina Classification?
***_Class I:_***
* ordinary activity (e.g. walking / climbing stairs) does not precipitate angina
***_Class II:_***
* angina is precipitated by walking upstairs, cold weather or meals
***_Class III:_***
* marked limitation of normal physical activity
***_Class IV:_***
* symptoms present at rest
* unable to carry out many normal physical activities
28
Once the presence of stable angina is confirmed, what is the next step involved in risk stratification?
* the presence of angina indicates **underlying coronary artery disease**
* the **severity** of this underlying cardiac disease needs to be evaluated to assess **_future risk of MI_** and whether or not **_revascularisation_** is indicated
* this involves **_coronary artery stenting_** or **_coronary artery bypass graft (CABG)_**
29
What are the prognostic indicators for determining whether revascularisation is indicated?
* left ventricular function
* stress testing
* coronary artery disease extent as seen on angiogram
* age
* diabetes
* hypertension
* hypercholesterolaemia
* heart failure
30
What is the annual mortality for angina?
What risk factors greatly increase annual mortality?
* stable angina (without history of MI and with normal resting ECG and normal BP) has an annual mortality of 1.5%
* presence of an abnormal ECG - 8.4%
* hypertension - 7.5%
* both - 12%
* T2DM doubles the above risks
31
What are the 2 main mechanisms used to relieve the symptoms of angina?
* **_increasing blood flow_** to the heart muscle by **dilating coronary arteries** with **_glyceryltrinitrate (GTN) spray_**
* **_decreasing the workload_** on the heart
* e.g. with a beta-blocker or calcium channel blocker
32
What are the 4 medications considered to be the first-line treatment for stable angina?
* **beta-blocker**
* **calcium channel blocker**
* reserved for patients who are unable to tolerate beta-blockers or whose symptoms are incompletely controlled with beta-blockers
* **nitrates**
* to provide quick relief during acute episodes
* **aspirin** (or other anti-platelet drug)
33
What are examples of beta-blockers that might be prescribed?
How do they work?
* e.g. **_atenolol_** or **_metoprolol_**
* they decrease heart rate, contractility and cardiac output, which **reduces cardiac O2 demand**
* proven to reduce MI and sudden death risk
34
What are examples of calcium channel blockers?
**_verapamil_** or **_diltiazem_**
35
How do nitrates work?
What is typically prescribed and what warning should be given to the patient?
* **_GTN sublingual spray / tablets_** should be carried at all times to relieve acute episodes
* they work by causing **vasodilation**
* they provide quick relief (within a few minutes) that lasts for up to 30 minutes
* they can cause **hypotension**
36
What other anti-platelet drugs might be prescribed?
Why are these prescribed?
**_clopidogrel_** or **ticagrelor**
these reduce the risk of **thrombus formation** and thus ACS
37
What is involved in the second-line treatment for stable angina?
* consider adding a **long-acting nitrate**
* e.g. **_isosorbide mononitrate_**
* the effects of this typically last 4 - 6 hours
38
What is involved in third-line treatment of stable angina?
***_PCI - cardiac stent / balloon angioplasty:_***
* these procedures are performed simultaneously to reduce symptoms of stable angina
* no evidence that this improves survival or reduces risk of ACS
***_Coronary artery bypass graft (CABG):_***
* completely eliminates symptoms in most patients
* modest improvement in survival for those with left main coronary artery disease or triple vessel disease (but not class I or II)
* better outcomes in diabetics than PCI
