Vascular Disease in the Lower Limb Flashcards Preview

Year 2 C&M symposia > Vascular Disease in the Lower Limb > Flashcards

Flashcards in Vascular Disease in the Lower Limb Deck (83):
1

What is ischaemia?

Restriction of blood supply >> decreased oxygen and glucose.
-perfusion fails to meet demands
-leads to tissue death

2

What is the most common cause of lower limb disease?

Atherosclerotic plaque.

3

What are other causes of lower leg ischaemia?

-Emboli
-Trauma

4

What are the main classifications of lower limb ischaemia? (2)

-Acute
-Chronic

5

What is acute ischaemia?

Sudden loss of perfusion.

6

What normally cause acute ischaemia? (3)

-Thrombus (atherosclerosis)
-Embolus
-2* to trauma

7

What is chronic ischaemia?

Gradual loss of perfusion.
-caused by atherosclerosis

8

What is the general process of atherosclerosis formation?

Endothelial damage >> lipid plaques in artery walls.

9

What do adhesion molecules released by endothelial damage attract?

-Monocytes
-Platelets

10

What happens to monocytes attracted to endothelial damage?

They infiltrate the endothelium and differentiated into macrophages.

11

What happens to platelets attracted to endothelial damage?

They adhere to endothelium and release pro-inflammatory mediators.

12

What happens to circulating LDL when endothelial damage occurs?

It is oxidised and scavenged by macrophages >> foam cells.

13

What happens to plaque if inflammation resolves?

It remains stable.
-may occlude artery lumen

14

What happens to plaque if inflammation continues?

It becomes unstable.
-liable to rupture

15

What happens when a plaque ruptures?

Platelet aggregation and coagulation cascade >> thrombus.

16

What are the main risk factors for atherosclerosis?

-Smoking
-Hypertension
-Hyperlipidaemia
-Diabetes
-Genetics
-Male

17

What sort of arteries do atheromas tend to form in?

Medium-large conduit arteries, especially at birfurcations (turbulence).

18

What are the main benefits of taking statins for atherosclerosis? (3)

-Decreases lipids
-Antiplatelet activity
-Stabilises plaque

19

Describe the general path of arteries in the leg.

Abdominal aorta >> common iliac >> internal and external iliacs.

External iliac >> femoral artery.

20

What is the Fontaine classfication?

Severity of peripheral vascular disease, based on symptoms.

21

What are the stages of the Fontaine classification? (4)

1 - Asymptomatic
2 - Intermittent claudication
3 - Ischaemic rest pain
4 - Ulceration / gangrene (CRITICAL)

22

Why is acute ischaemia a surgical emergency?

Must be re-vascularised within an hour to preserve limb.
-significant mortality

23

What is the most common cause of acute ischaemia?

Atherosclerotic plaque rupture >> thrombus/embolus causing complete occlusion.

24

Why does acute ischaemia present so suddenly?

Perfusion suddenly decreases, and no time for collateral circulation to develop.
-unlike chronic ischaemia

25

Is acute ischaemia painful?

Yes, can be very painful.

26

How are the signs/symptoms of acute ischaemia remembered?

6P's.

27

What are the 6 P's?

-Pain
-Pulseless
-Perishingly cold
-Pallor
-Paraesthesia
-Paralysis

28

How does the leg normally appear in acute ischaemia?

Markedly abnormal looking and pale.
-NB may appear red if hanging down

29

When may the affected leg not look as abnormal in acute ischaemia?

If the patient already has vascular disease or chronic ischaemia.
-collateral circulation

30

How is acute ischaemia treated?

-Urgent re-vascularisation
-Treat risk factors (e.g. diabetes)

31

What investigations are carried out in acute ischaemia?

Investigation of the cause.
-e.g. blood tests, ECG, echocardiogram

32

What is chronic ischaemia?

Gradual decreased perfusion, 2* to atherosclerotic disease.
-often bilateral

33

How does the limb remain perfused in chronic ischaemia?

Collateral circulation develops.
-limb poorly perfused

34

What happens to a chronic ischaemic limb eventually?

EITHER:
-limb eventually becomes critically ischaemic
-plaque suddenly ruptures >> ACUTE ON CHRONIC ischaemia

35

What is the general development of chronic ischaemia?

Atheroma plaque grows >> increased obstruction.
-initially only painful when active (INTERMITTENT CLAUDICATION)
-eventually painful at rest (CRITICAL ISCHAEMIA; ulceration and gangrene)

36

What is intermittent claudication?

Cramping pain in the leg induced by exercise.
-usually due to arterial occlusion

37

What is critical ischaemia?

Severe artery obstruction progresses >> pain, ulceration and gangrene.

38

When does chronic gangrene present?

EITHER:
-at intermittent claudication (pain when walking)
-at critical ischaemia (resting pain, ulceration, gangrene)

39

How is chronic ischaemia investigated?

-Blood tests
-ECG
-Vascular imaging
-Ankle brachial pressure index

40

How is chronic ischaemia managed?

-Smoking cessation
-Exercise
-Antiplatelet drugs (e.g. aspirin)

41

What type of gangrene normally develops due to chronic ischaemia?

Dry gangrene.
-tissue necrosis without infection
-black, shrunken toes

42

Why does dry gangrene normally develop instead of wet gangrene?

Decreased blood supply >> decreased O2 and glucose to drive bacterial infection.

43

What is usually the 1st sign of decreased blood flow to the leg?

Claudication.
-then resting pain

44

What is a non-invasive procedure?

Doesn't require incision into the body / removal of tissue.

45

What are the main non-invasive techniques used to view lower limb vasculature? (3)

-Duplex scanning
-MR angiography
-CT angiography

46

What is the main invasive techniques used to view lower limb vasculature?

Catheter/contrast angiography.

47

What is duplex scanning?

Vasculature ultrasound.
-no ionising radiation

48

What effect is used in duplex scanning?

Doppler effect.
-change in wave frequency

49

What measurements can be obtained from duplex scanning? (2)

-Volume
-Velocity

50

What does 'operator dependent' mean in terms of duplex scanning?

Only person doing the scan can interpret the results.

51

What is CT angiography?

Combination of cross-sectional x-rays.

52

What is CT angiography useful to assess? (3)

-Aneurysms
-Bleeding
-Peripheral vessels

53

What is MR angiography (MRA)?

Magnetic resonance.
-no ionisation

54

When is MR angioplasty not suitable?

-Pacemaker
-Prostheses
-Claustrophobia

55

What effect does MR angiography have on stenosis?

Overestimates stenosis.

56

Which non-invasive techniques have no ionisation? (2)

-Duplex scanning
-MR angiography

57

Which non-invasive technique has ionisation?

CT angiography.

58

NB. what is angiography?

Imaging technique used to visualize the inside / lumen, of blood vessels and organs.

59

What is the main invasive techniques used to view lower limb vasculature?

Catheter/contrast angiography.

60

What type of procedure is catheter angiography; invasive or non-invasive?

Invasive.
-contrast is injected

61

What is the access point for catheter angiography in the leg?

Femoral artery over the femoral head.
-superficial and compressible

62

What is the access point for catheter angiography for the heart or kidneys?

Radial artery.

63

What are the 2 main types of contrast used?

-Iodine (iodinated)
-CO2

64

What is interventional radiology?

Use of imaging to affect treatment, rather than just diagnosis.
-e.g. x-ray, CT, ultrasound

65

What are the main advantages of interventional radiology?

-Minimally invasive alternative to surgery (imaging guide treatment)
-Allows novel treatment (thermal tumour ablation, chemoembolisation)
-Can be live-saving

66

What is the 1st line procedure for haemoptysis (coughing up blood)?

Endoscopy (camera), then embolisation.

67

What are the main uses of non-haemorrhagic embolisation? (3)

-Chemo-embolisation (tumour)
-Selective internal radiotherapy (SIRT)
-Uterine artery embolisation (fibroids)

68

What is therapeutic embolisation?

Therapeutic introduction of a substance into a vessel.
-prevents haemorrhage / breaks down tumour / decreases blood flow

69

What are the main uses of interventional radiology? (2)

-Vascular radiology (close/open arteries)
-Oncology (chemoembolisation, thermal ablation)

70

What are the main vascular diseases in the legs? (2)

-Peripheral vascular disease (>> ischaemia)
-Aneurysmal disease

71

What are the main causes of ischaemia? (3)

-Thrombus
-Embolus
-Other (e.g. intrinsic clotting abnormality, surgery)

72

What are the main signs of acute ischaemia?

Initially pale leg
>> mottled (patchy) leg; 6-12 hours
>> irreversible (fixed blue) ischaemia

73

What are the main stages of ischaemia?

I - viable
IIa - marginally threatened
IIb - immediately threatened
III - irreversible injury

74

If someone presents with suspected stage I-IIa ischaemia, how is it dealt with?

Imaging.

75

If someone presents with suspected stage IIb-III ischaemia, how is it dealt with?

Immediate treatment.

76

What is CT angiography good for?

Aneurysm and dissection.
-rapid scan times

77

What are the key treatment principles of ischaemia?

-Clear clot
-Treat underlying lesions
-Revascularise

78

What are the main endovascular treatment options? (3)

-Thombolysis
-Aspiration
-Stent

79

What are the main surgical treatment options? (2)

-Thrombectomy
-Bypass

80

What is thrombolysis?

Breakdown of blood clots by pharmacological means.
-infusion of tissue plasminogen activator (tPA) to activate plasminogen to plasmin

81

What is aneurysmal disease?

>50% expansion of an artery.

82

Who is screened for aneurysmal disease?

Males, >60 years.

83

What size aneurysm needs treatment?

>5.5 cm.
-surgery/endovascular
-emergency for rupture