Stable Angina Flashcards
What is angina pectoris?
Chest pain
What is myocardial ischaemia?
A mismatch in the supply of O2 and metabolite to the myocardium and the demand of for them
What are the two general causes for myocardial ischaemia?
Interruption of blood flow
Inadequate blood flow
What is a common cause of angina?
Obstructive coronary atheroma
What are two uncommon causes?
Coronary artery spasm Coronary inflammation (arteritis)
How can anaemia cause angina?
Reduces the transport, so not as much O2 delivered to myocardium
In what pathological conditions would O2 demand be increase, and so have the capacity to cause angina?
Left ventricular hypertrophy (LVH)
Thyrotoxis (hyperthyroidism)
What can cause LVH?
Persistent hypertension
Significant aortic stenosis
Hypertrophic cardiomyopathy
What is stable angina?
Angina pectoris, a predictable pattern of chest pain
What situations does stable angina arise?
Where HR and BP rise as there is greater myocardial oxygen demand
I.e. exercise, anxiety, cold weather, emotional stress, after a large meal
What are the characteristic of chest pain in stable angina?
Restrosternal pain Tight band/pressure Radiation into neck, jaw, down arms Aggravating: with exertion, emotional stress Improved by GTN or rest
If chest pain is associated with body movements, i.e. leaning forward improves pain and leaning back makes it worse, is it likely to be stable angina?
No
If chest pain is stabbing/sharp, is it likely to be angina?
No - pleuritic or pericardial
If chest pain is localised, is it likely to be angina?
No
If there is no pattern to chest pain, is it likely to be angina?
No
If chest pain begins some time after exercise, is it likely to be angina?
No
If chest pain lasts for hours, is it likely to be angina?
No
List differential diagnoses for chest pain: CVD causes
Aortic dissection
Pericarditis
List differential diagnoses for chest pain: respiratory causes
Pneumonia
Pleurisy
Peripheral pulmonary emboli
List differential diagnoses for chest pain: musculoskeletal
Cervical disease
Costochondritis
Muscle spasm
Strain
List differential diagnoses for chest pain: GI causes
Gastro-oesophageal reflux Oesophageal spasm Peptic ulceration Biliary colic Cholecystitis Pancreatitis
What are other symptoms of myocardial ischaemia on exertion other than chest pain?
Breathlessness
Excessive fatigue
Near syncope
What classification can be used to determine severity of angina?
Canadian classification of angina severity (CCS)
Define the classification of severity in the CCS
I - symptoms only on exertion
II - symptoms walking > 1 flight of stairs
III - symptoms walking 1 flight of stairs
IV - symptoms on any activity
Name modifiable risk factors
Smoking Lifestyle - exercise & diet Diabetes mellitus Hypertension Hyperlipidaemia
Non-modifiable risk factors
Age Gender Race - south asians (high diabetes rate) FH Genetic factors
Signs of stable angina
Tar staining on fingers Obesity Corneal scrubs Xanthalasma Hypertension Abdominal aortic aneurysm arterial bruits Absent or reduced peripheral pulses Diabetic retinopathy, hypertensive retinopathy
Signs of exacerbating conditions:
Pallor of anaemia
Tachycardia
Tremor
Ejection systolic murmur
Plateau pulse of aortic stenosis
Pansystolic murmur of mitral regurgitation
HF: basal crackles, elevated JVP, peripheral oedema
What is a plateau pulse
The time taken to reach the peak is prolonged and the entire wave is flattened and of small amplitude
In aortic stenosis, the rate of ejection of blood into the aorta is decreased so that the duration of the ejection is prolonged. The amplitude of the pulse is diminished as a consequence
List the investigations used
FBC Lipid profile Fasting glucose U+E LFT TFT CXR ECG Exercise Tolerance test Myocardial Perfusion Imaging
Why use CXR to investigate?
Can show other causes of chest pain and show pulmonary oedema
Why use ECG to investigate?
Evidence of:
Prior MI (pathological Q waves)
LVH - ST segment depression
What test can confirm diagnosis of angina?
Exercise tolerance test
Shows typical symptoms and ST-segment depression
Why use myocardial perfusion imaging?
Better than ETT in showing coronary artery disease, localisation of ischameia and assessing size of area affected
Involves radiotherapy, use when ETT not available
How is the ischaemia induced in myocardial perfusion imaging?
Exercise
Pharmacological stress: adenosine, dipyridamole or dobutamine
Radionuclide tracer injected at peak stress
How to determine if ischaemia is present?
Take to imagine: one at rest and at peak stress and compare
Tracer seen at rest but not at stress = ischaemia
Tracer not seen at all = infarction
What investigation can be used to diagnose stable angina?
CT coronary angiography
When to carry out a CT coronary angiography
Strongly positive ETT Angina with no benefit from therapy Diagnosis unclear after non-invasive tests Young cardiac patients Occupation or lifestyle risks
Benefit of using CT coronary angiography/cardiac catheterisation?
Defines coronary anatomy, nature of atheromatous disease and helps decision over what treatment is possible:
Just meds or PCI or CABG
Features of CT angiography
Under local anaesthetic
Cannula inserted to femoral or radial artery
Coronary catheter passes to aortic root then coronary aa.
Radio-opaque contrast injected down aa. and seen on Xray
General measure taken for treatment of stable angina
Adress risk factors: BP Diabetes mellitus Cholesterol Lifestyle
What revascularisation treatment is there and when to use them?
Percutaneous coronary intervention (PCI)
Coronary artery bypass (CABG)
What drugs are used to stop the disease progression in stable angina?
Statins
ACEi
Aspirin
Effect of statins
If total cholesterol > 3.5mmol/L
Reduce LDL deposition in atheroma and stabilise atheroma by reducing risk of plaque rupture and ACS
Effect of ACEi
Stabilise endothelium and reduce risk of plaque rupture
Effect of aspirin
75mg or clopidogrel if intolerant
Protect endothelium and reduces risk of platelet aggregation
What drugs are used for relief of symptoms in stable angina?
B blockers
Ca channel blockers
Ik channel blockers
Nitrates
Trying to achieve HR < 60 ppm
Effect of B blockers
Reduce myocardial work and have anti-arhythmic effects
Effect of CCB drugs
Produces vasodilation
Diltiazem
Amlodipine
Effect of Ik channel blockers
Reduces SA node rate (control HR)
I.e. ivabridine
Effect of nitrates
Rapidly acting GTN spray for immediate use
Mechanism of percutaneous coronary intervention used to treat angina
Similar approach to cardiac catheter, but insert a wguidewire into the stenotic lesion to squash the atheromatous plaque into walls with balloon and stent
What drugs are taken after PCI and why?
Aspirin and clopidogrel
To allow endothelium to cover stent so that it is no longer seen are a foreign body with risk of thrombosis
What type of patient will receive a prognostic benefit from CABG?
> 70% stenosis of L main stem artery
Proximal three-vessel coronary artery disease
Two vessel coronary artery disease with stenosis of LAD and ejection fraction < 50%
Mechanism of CABG
Long saphenous vein harvested then reversed and used as coronary artery bypass graft
