Stable Ischaemic Heart Disease and Angina Presentation and Investigation Flashcards
What is angina?
Discomfort/pain in the chest and/or adjacent areas associated with myocardial ischaemia but without myocardial necrosis
What is angina a result of?
Mismatch between supply of oxygen and metabolites to the myocardium and the myocardial demand for them
What is angina most commonly due to?
Reduction in coronary blood flow to the myocardium caused by;
obstructive coronary atheroma
coronary artery spasm
coronary inflammation/arteritis
What might cause angina, other than reduction in coronary blood flow to the myocardium?
Reduced oxygen transport e.g. anaemia of any cause
Pathologically increased myocardial oxygen demand e.g. left ventricular hypertrophy or thyrotoxicosis
What is the most common cause of angina?
Coronary atheroma
When does myocardial oxygen demand increase?
In situations where heart rate and blood pressure rise e.g. exercise, anxiety, emotional stress etc.
What is necessary in order for ischaemia to occur?
Lumen has to be reduced by more than 70%
What are the non-modifiable risk factors of stable angina?
Age Gender Creed Family history Genetics
What are the modifiable risk factors of stable angina?
Smoking Lifestyle e.g. diet and exercise Diabetes mellitus Hypertension Hyperlipidaemia
Good control of diabetes, hypertension and hyperlipidaemia reduce the risk
What are the typical characteristics of angina?
Retrosternal site
Described as tight band/pressure/heaviness
May radiate to neck, jaw or down arms
Aggravated by exertion and emotional stress
Relieved by GTN and physical rest
Give some characteristics of pain that make the diagnosis of angina less likely
Sharp/stabbing pain Associated with normal body movements or respiration Very localised Superficial No pattern to pain Begins some time after exercise Lasts for hours
What are some cardiovascular differential diagnoses of chest pain?
Angina
Aortic dissection
Pericarditis
What are some respiratory differential diagnoses of chest pain?
Pneumonia
Pleurisy
Peripheral pulmonary emboli
What are some musculoskeletal differential diagnoses of chest pain?
Cervical disease
Costochondritis
Muscle spasm or strain
What are some gastrointestinal differential diagnoses of chest pain?
Gastro-oesophageal reflux Oesophageal spasm Peptic ulceration Biliary colic Cholecystitis Pancreatitis
If myocardial ischaemia occurs without chest pain, what other symptoms might be present on exercise? Who is this more common in?
Breathlessness
Excessive fatigue for the activity undertaken
Near syncope on exertion
More common in the elderly or those with diabetes mellitus
What is the Canadian Classification of Angina Severity (CCS) grading?
I – ordinary physical activity does not cause angina, symptoms only on significant exertion
II – slight limitation of ordinary activity, symptoms on walking 2 blocks or > 1 flight of stairs
III – marked limitation, symptoms on walking only 1-2 blocks or 1 flight of stairs
IV – symptoms on any activity, getting washed/dressed causes symptoms
What signs might be seen on examination of a patient with angina?
Tar staining Obesity (centripetal) Xanthalasma Hypertension Abdominal aortic aneurysm bruits Absent or reduced peripheral pulses Diabetic retinopathy or hypertensive retinopathy
What signs of exacerbating/associated conditions might be seen on examination of a patient with angina?
Pallor of anaemia
Tachycardia, tremor, hyper-reflexia or hyperthyroidism
Ejection systolic murmur, plateau pulse of aortic stenosis
Pansystolic murmur of mitral regurgitation
Signs of heart failure e.g. basal crackles, elevated JVP, peripheral oedema
What blood tests are relevant in the investigation of stable angina?
FBC Lipid profile Fasting glucose Electrolytes Liver function tests Thyroid function tests
What investigations (other than blood tests) are relevant in the investigation of stable angina?
CXR Electrocardiogram Exercise tolerance test Myocardial perfusion imaging Cardiac catheterisation/coronary angiography
In what percentage of cases of angina will the electrocardiogram be normal?
Over 50%
What might an electrocardiogram show evidence of?
Previous MI e.g. pathological Q waves
Left ventricular hypertrophy e.g. high voltages, lateral ST-segment depression
How is an exercise tolerance test useful?
Can often confirm the diagnosis of angina
When is an exercise tolerance test positive?
When patient has typical symptoms and ST-segment depression
What does an exercise tolerance test depend on?
Ability to walk for long enough to produce sufficient cardiovascular stress
What is the prognosis of a negative exercise tolerance test?
Doesn’t exclude significant coronary atheroma but if negative at a high workload the overall prognosis is good
In what ways is myocardial perfusion imaging superior to exercise tolerance testing?
Detection of coronary artery disease
Localisation of ischaemia
Assessing size of area affected
What are the disadvantages of myocardial perfusion imaging?
Expensive
Involves radioactivity
When should myocardial perfusion imaging be used?
Where ETT is not possible or is equivocal
How does myocardial perfusion imaging work?
Exercise or pharmacological agents e.g. adenosine used to produce stress on heart
Radionuclide tracer injected at peak stress on one occasion, images obtained and then this is repeated at rest
Comparison made between stress and rest images
What will happen to the radionuclide tracer in a normal myocardium?
Normal myocardium will take up the tracer
What is indicated if the tracer is seen at rest but not after stress?
Ischaemia
What is indicated if the tracer is seen neither at rest or after stress?
Infarction
When is CT coronary angiography useful?
To show no or severe coronary disease, not useful for distinguishing mild coronary disease
When should invasive angiography be used?
Early or strongly positive ETT which suggests multi-vessel disease
Angina refractory to medical therapy
Diagnosis not clear after non-invasive tests
Young cardiac patients due to work/life effects
Occupation or lifestyle with risk e.g. drivers
What is cardiac catheterisation/coronary angiography useful for?
Definition of coronary anatomy with sites, distribution and nature of atheromatous disease which enables decision over what treatment options are possible
Determining whether medication alone or percutaneous coronary intervention should be given
What is normally the invasive treatment of choice for angina?
Angioplasty and stenting or coronary artery bypass graft surgery
What general measures can be taken in the treatment of angina?
Address risk factors e.g. BP Diabetes mellitus Cholesterol levels Lifestyle
What is the treatment strategy where symptoms can’t be controlled with medical therapy?
Revascularisation with PCI and CABG
What drugs can be used in the medical treatment of angina to influence disease progression?
Statins
ACEIs
Aspirin
How do statins affect angina?
Reduce the LDL-cholesterol deposition in atheroma and also stabilise atheroma, reducing plaque rupture and acute coronary syndrome
How do ACEIs affect angina?
Stabilise the endothelium and reduce plaque rupture
How does aspirin affect angina?
May not directly affect the plaque but does protect the endothelium and reduces platelet activation/aggregation
What drugs can be used in the medical treatment of angina for symptom relief?
Beta blockers CCBs - rate limiting and vasodilating Ik channel blockers Nitrates Potassium channel blockers
How do beta blockers relieve the symptoms of angina?
Help achieve a resting heart rate < 60bpm
Reduce myocardial work and have anti-arrhythmic effects
How do CCBs relieve the symptoms of angina?
Help achieve resting heart rate < 60bpm
Produce vasodilatation
How do Ik channel blockers relieve the symptoms of angina?
Help achieve resting heart rate < 60bpm
Ivabradine reduces sinus node rate
How do nitrates relieve the symptoms of angina?
Produce vasodilatation
PTCA and stenting account for what percentage of procedures done?
95%
What is involved in PTCA and stunting?
Stenotic lesions crossed with guidewire and atheromatous plaque flattened into the lumen wall with a balloon and stent
What drugs are given to the patient if a stent is used?
Aspirin and clopidogrel taken together while the endothelium heals to cover the stent struts until it is no longer seen as a foreign body with associated risk of thrombosis
Is PCI an effective treatment?
Effective for symptom relief but no evidence to show that it improves prognosis in stable disease
What are the risks of procedural complications associated with PCI?
0.1% death
02% MI
0.05% emergency CABG
10-15% risk of re-stenosis with bare metal stents
< 10% risk of re-stenosis with drug-eluting stents
When is coronary artery bypass graft surgery the best treatment option for stable angina?
In diffuse multi-vessel disease
What are the risks of procedural complications associated with CABG?
- 3% death
3. 9% Q-wave MI
What is the benefit of CABG?
Benefit is long-lasting, with 80% being symptom-free 5 years post-operative
What patients derive the most prognostic benefit from CABG?
Over 70% stenosis of left main stem artery
Significant proximal three vessel coronary artery disease
Two vessel coronary artery disease that includes significant stenosis of the proximal left anterior descending coronary artery and those who have ejection fraction < 50%
What vein is most commonly harvested from the leg for CABG?
Long saphenous vein
