Stable angina Flashcards
define angina
a discomfort/pain in the chest and/or adjacent areas associated with myocardial ischaemia (lack of O2 to the heart) but without myocardial necrosis
describe the pathophysiology of myocardial ischaemia and resultant anginal symptoms
the supply of O2 and metabolites to myocardium (muscular tissue of the heart) doesn’t meet/match the myocardial demand for them
what is the most common cause of angina?
obstructive coronary atheroma (fatty deposits/plaque building up in arterial walls)
what is an uncommon cause of reduced coronary blood flow to the myocardium?
coronary artery spasm - sudden tightening of the muscles within the arteries of your heart.
When this occurs, your arteries narrow and prevent blood from flowing to your heart
what is a very rare cause of reduced coronary blood flow to the myocardium?
coronary inflammation/arteritis (inflammation of arterial walls as a result of infection or autoimmune response)
In what situations does myocardial oxygen demand increase?
when HR and BP rise so during exercise, anxiety/emotional stress, cold weather or after a large meal
what happens when there is an increased demand for O2 by the heart but there is obstructed coronary blood flow?
myocardial ischaemia occurs and then the symptoms of angina
at what point does an obstructive plaque cause stable angina?
if it obstructs >70% of the lumen
acute coronary syndromes occur when what has happened with the lumen of a vessel?
spontaneous plaque rupture and local thrombosis, with degrees of occlusion
why is taking a history important in the diagnosis of stable angina
Essential to establish the characteristics of patients pain and to differentiate it from other causes of chest pain:
What things can you find about patient’s chest pain from taking a history? (5)
Site of pain - retrosternal (retro- behind)
Character of pain: often tight band/pressure/heaviness.
Radiation sites: neck and/or into jaw, down arms.
Aggravating e.g. with exertion, emotional stress
& relieving factors e.g. rapid improvement with GTN or physical rest.
what features make the diagnosis less likely to be angina? (7)
Sharp/‘stabbing’ pain; pleuritic or pericardial.
Associated with body movements or respiration.
Very localised; pinpoint site.
Superficial with/or without tenderness.
No pattern to pain, particularly if often occurring at rest.
Begins some time after exercise.
Lasting for hours.
Comes on consistently at rest
what other cardiovascular causes could there be for chest pain that aren’t angina?
aortic dissection - tear in the aorta
pericarditis
what respiratory causes could there be for chest pain? (3)
pneumonia
pleurisy
peripheral pulmonary emboli (pleuritic)
what musculoskeletal causes could there be for chest pain? (3)
cervical disease
costochondritis (inflammation of cartilage attaching ribs to sternum)
muscle spasm or strain
what GI causes could there be for chest pain? (3)
Gastro-oesophageal reflux oesophageal spasm peptic ulceration biliary coli cholecystitis pancreatitis
when myocardial ischaemia occurs with no chest pain what other symptoms should you look for on exertion?
breathlessness
excessive fatigue for activity undertaken
near syncope
who is most likely to present with myocardial ischaemia without chest pain?
the elderly or those with diabetes probably due to reduced pain sensation
risk factors of stable angina? (10)
smoking hypertension hyperlipidaemia age diabetes gender - male> female family history genetic factors exercise diet
How does stable Angina almost always come on?
stable angina almost always comes on exertion ie walking up a hill NOT lying down or walking around the supermarket
if chest pain comes on at rest constantly then what is it not likely to be
angina
stable angina is more common in people with what?
high cardiovascular risk
what is treatment for Angina based on?
symptoms
Describe the nature of pain experienced by a person with angina?
heaviness in the front of chest
chest tightness or pressure
pain can radiate down the arms, up the neck or into their jaw
can be exacerbating - get worse in cold weather, after a meal, due to emotional stress or exercise
Glyceryl trinitrate (GTN) treatment
can improve a number of chest problems
however if your symptoms improve consistently with GTN this can further prove diagnosis of stable Angina
general definition of ischaemia?
supply and demand mismatch - reduced blood flow
what is stable angina almost always caused by?
arterial stenosis - narrowing of the coronary arteries
What can an exercise test be used for?
to reproduce symptoms and demonstrate ischaemia
Problems with exercise treadmill test?
most people with stable angina are elderly so they may not have the capacity to actually exercise to produce sufficient CV stress - could do bike test instead however as this is non weight baring
it’s not very sensitive or specific
high false positive rate
Why might someone have trouble exercising?
osteoarthritis
peripheral vascular disease
Describe test done to demonstrate myocardial ischaemia?
stress MRI scan or stress myocardial perfusion test
what is the ischaemic cascade?
series of biochemical reactions that are initiated in the brain and other aerobic tissues after seconds to minutes of ischemia (inadequate blood supply).
This is typically secondary to stroke, injury, or cardiac arrest due to heart attack.
e.g occlusion Myocardial O2 consumption increases O2 demand exceeds supply ATP production decreases, lactic acid increases contractility diminishes over time abnormal wall motions ECG changes - ST segment Angina
what investigations can be done for stable angina?
blood- full blood count, lipid profile and fasting glucose
CXR
ECG - normal result in >50% of cases
Pros and cons of myocardial perfusion imaging
PROS:- better than exercise test in detection of Coronary Artery disease CRD
- Can localise ischaemia and assess size of area affected
CONS:- expensive, involves radioactivity
difference between stable and unstable angina?
If the pain happens during certain activities and goes away with rest, it’s called stable angina. However, if the chest pain becomes more severe or frequent, lasts longer, or occurs while resting it’s called unstable angina.
what happens during myocardial perfusion imaging?
Radionuclide tracer injected (iv) at peak stress on one occasion, images obtained; and at rest on another.
Comparison between stress and rest images.
Normal myocardium takes up tracer as blood is flowing through it - ischaemic part wouldn’t as no blood flow
what does it mean if you see the tracer at rest but not after stress?
ischaemia
what does it mean if you can’t see the tracer at rest or after stress?
infarction
how is CT coronary angiography invasive
invasive due to radiodye injected into arteries
what is CT coronary angiography used for?
Definition of coronary anatomy with sites, distribution and nature of atheromatous disease enables decision over what treatment options are possible.
Medical treatment for stable angina: Statins
Reduce LDL-cholesterol deposition in atheroma and also stabilise atheroma reducing plaque rupture and ACS.
don’t make CHD go backwards or arrest the disease but just cause slow progression and reduce stress
modify the disease
Medical treatment for stable angina: ace inhibitors
not commonly used
but used if increased CV risk and atheroma to stabilise endothelium and reduce plaque rupture
Medical treatment for stable angina: aspirin
aspirin is primary preventative
reduce chance of primary spontaneous event - may have upset GI though
what do you do if a patient is still symptomatic despite treatment?
Angioplasty
a minimally invasive, endovascular procedure to widen narrowed or obstructed arteries or veins, typically to treat arterial atherosclerosis.
what is a bypass used for
redirects artery/veins within the heart to coronary arteries or aorta to maintain atrial bloodflow to atrial myocardium
Medical treatment for stable angina: beta blockers
for supply and demand issues
reduced myocardial work and have anti-arrhythmic effects
Coronary artery bypass graft surgery CABG
to restore normal blood flow to an obstructed coronary artery
CABG often best option for stable angina
more risky than PCI - Angioplasty
80% symptom free 5 years later
Percutaneous coronary intervention/ angioplasty «_space;same thing
non-surgical procedure that uses a catheter to place a small structure called a stent to open up blood vessels in the heart that have been narrowed by plaque buildup, a condition known as atherosclerosis.
signs of stable angina (8)
GTN relief tar staining xanthalasma/corneal arcus high blood pressure tachycardia murmurs HF signs AAA - abdominal aortic aneurysm
symptoms of stable angina? (5)
constricting discomfort in front of chest, arms, neck and jaw
brought on by exertion in stable angina - after meals, cold air or exercise
SOB
Syncope
excess fatigue
diagnosis / investigation of stable angina (7)
ECG - exclude ACS acute coronary syndrome Cardiac catheterisation CT angiography stress echo/ MRI / ETT bloods CXR myocardial perfusion imaging
