18. Macrovascular Complications of Diabetes Flashcards
Development of atheroma
- A long life issue
- Small accumulations of extracellular lipid leads to atheroma which then leads to FIBROATHEROMA
- It could then lead to complicated lesions which can then ulcerate, exposing the fat underneath and causing thrombosis or embolism.
- Initially involves lipid accumulation, but can progress to smooth muscle.
- Leads to smooth muscle hypertrophy, fibrosis and calcification
Relative risk of cardiovascular events in women with diabetes
Tends to increase because women are protected from atheroma in their reproductive years- with diabetes, this relative benefit is lost.
Risk of microvascular disease without diabetes
The risk of microvascular disease is related to sugar, so without diabetes there is virtually no risk
Risk of macrovascular disease without diabetes
The risk associated with HbA1c and macrovascular disease is more linear - the higher the HbA1c, the greater the risk of macrovascular disease
- Even people without diabetes have a relatively high risk of macrovascular disease
Microvascular/ macrovascuar disease morbidity vs mortality
- Microvascular disease causes morbidity
- Macrovascular disease causes morbidity AND mortality
Changes to percentage cause of death in diabetic population
- In diabetes, the age adjusted mortality from ischaemic heart disease is much higher (around 60%)
- Malignancy appears to be decreased, but this is due to the fact that diabetic patients are likely to die before the age at which you tend to get cancer
Diabetes mortality over time compared to those with known coronary artery disease
- If people have one heart attack they are more likely to have another
- People with diabetes who have NOT had a heart attack have the same mortality as someone without it who has had a heart attack
- Even someone with diabetes who appears well is likely to have ischaemic disease
Arterial beds where macrovascular disease is present (i.e associated diseases)
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Ischaemic heart disease
- Major cuase of morbidity and mortality in diabetes
- Mechanisms are similari with or without diabetes
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Cerebrovascular disease
- Earlier than without diabetes
- More widespread
- Uncommon in people younger than 60
-
Peripheral vascular disease
- Contributes to diabetic foot problems with neuropathy
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Renal artery stenosis
- May contribute to hypertension
General basis for diabetic cardiovascular disease treatment
- Intense glucose control does improve CHD risk
- But it DOES NOT translate to a change in mortality
- Prevention requires aggressive management of multiple risk factors
Management of risk factors in microvascular disease associated with diabetes
- blood pressure and cholesterol need to be managed in the treatment of diabetes and the prevention of macrovascular complications
- It was found that taking a statin had a significant reduction in macrovascular disease risk
- The patients were less likely to have a stroke/heart attack by nearly a half
- So if we treat cholesterol AND blood pressure, you can achieve a dramatic reduction in macrovascular disease risk
- GLYCATED HAEMOGLOBIN is also associated with risk
Complications of diabetes predisposing to foot disease
- Neuropathy
- Peripheral vascular disease
Epidemiology of Diabetic Foot
This is the MOST COMMON CAUSE OF FOOT AMPUTATION in the UK
Monofilament test for diabetic foot
- When the filament bends you have applied 10g of pressure
- This will be felt in a normal individual- but not if there is neuropathy
- The ball of the foot is checked because this is the most common site of ulceration
Pathway to foot ulceration
- Motor neuropathy
- Limited joint mobility- HbA1c makes tendons less flexible
- Autonomic neuropathy
- Trauma (repeated minor/discrete episodes)
- Sensory neuropathy
- peripheral vascular disease
- Reduced resistence to infection
Peripheral sensory neuropathy is important but so is motor neuropathy:
- Causes imbalance between extensory and plantar flexors- gives abnormal shape in the foot
- Increases pressure on the ball of the foot
Autonomic neuropathy can lead to abnormal blood flow in the foot
It also reduces the sweating in the foot which normally protects it from minor disease
Types of foot ulceration
- The neuropathic foot- numb, warm, dry, palpable foor pulses, ulcers at points of high loading
- The ischaemic foot- cold, pulseless ulcers at the foot margin
- The neuro ischaemic foot- numb, cold, dry, pulseless, ulcers at the point of high pressure loading and at foot margins
