JC02 (Surgery) - Peripheral Vascular Ischaemia and Acute vascular emergencies Flashcards
(45 cards)
Risk factors for chronic limb ischaemia (5)
□ Smoking**
□ DM
□ Hyperlipidaemia
□ Pre-existing arterial disease: coronary artery disease, stroke/TIA, carotid disease
□ Family history of vascular disease
Typical presentation of non-critical limb ischaemia?
Non-critical ischaemia:
→ Asymptomatic
→ Intermittent claudication:
- Reproducible discomfort of a defined group of muscles
- Induced by exercise and relieved by rest
Typical presentation of critical limb ischaemia?
→ Rest pain: continuous, severe unremitting pain at toes or forefoot
→ Tissue loss: ulcers or gangrene at pressure areas
Describe arterial ulcer:
- Symptom
- Site
- Size
- Edge
- Base
- Discharge
- Depth
□ Symptom: rest pain ± inciting episode of trauma □ Site: over pressure areas □ Size/shape: variable size, often elliptical □ Edge: punched out (if non-healing) or sloping (if healing) □ Base: pale, dry □ Depth: typically very deep ± exposure of bone, ligament, tendon □ Discharge: thin clear serous exudate
Describe dry gangrene:
- Description
- Cause
- Line of demarcation
- Management
→ Hard, dry, dark, crinkled mass
→ Distinct line of demarcation
→ auto-amputate
Describe wet gangrene:
- Description
- Cause
- Line of demarcation
- Management
→ Moist, swollen, often blistered, with discharge
→ Infection spreads proximally, line of demarcation spreads
→ Emergency debridement or amputation to avoid spreading gangrene and sepsis
4 major causes of chronic limb ischemia
□ Atherosclerosis: most common
□ Vasculitis, eg. takayasu arteritis, Behcet’s disease
□ Buerger’s disease (thromboangiitis obliterans)
□ Entrapment syndrome (e.g. Popliteal artery entrapment syndrome (PAES) - abnormally positioned or enlarged calf muscle presses on popliteal artery)
Assessment for entrapment syndrome which may cause chronic limb ischaemia
- test for ↓pulse with foot in passive dorsiflexion or active plantarflexion
- exercise test (i.e. post-exercise ABI)
4 major sites of arterial occlusion in lower limbs
Aortoiliac
Iliac
Femoro-popliteal
Distal
Signs and symptoms for aortoiliac arterial occlusion
Claudication in bilateral buttocks, thighs, calves
Usually no rest pain (unless concomitant distal disease)
Impotence in LeRiche’s syndrome (caused by occlusion at terminal bifurcation of aorta. It is characterized by the tetrad of buttock: claudication, impotence (M), absent femoral pulse and ± aortoiliac bruit.)
Signs and symptoms for iliac arterial occlusion
Claudication in unilateral thigh and calf ± buttocks
Signs and symptoms for Femoro-popliteal arterial occlusion
Claudication in unilateral calf
Rest pain if critical
Tissue loss
Signs and symptoms for Distal Lower limb arterial occlusion
Tissue loss
Outline assessments/ tests for lower limb ischaemia
- Ankle‐Brachial Index (ABI) and exercise testing
- Duplex Ultrasound
- Arteriography (planning for surgery, not for Dx)
Formula for Ankle‐Brachial Index (ABI)
Typical ABI ranges for arterial occlusion
ABI = ipsilateral ankle systolic BP/ higher arm systolic BP
Normal = 0.90 – 1.30
Arterial occlusive disease = ≤0.9 (diagnostic)
0.40 – 0.90 = moderate - claudication
<0.4 = severe - rest pain, tissue loss
Indication for exercise testing for arterial occlusion
ABI normal (0.9-1.3) but symptomatic for arterial occlusion e.g. claudication
Normal waveforms in arterial blood flow in lower limb on Doppler ultrasound
□ Triphasic (normal): forward flow (systole)
+ reverse then forward flow (diastole)
□ Biphasic: forward flow (systole) + reverse flow (diastole) → single-level arterial occlusion
□ Monophasic: forward flow alone → multi-level occlusion
3 modalities of arteriography?
□ Conventional angiography: gold-standard for planning intervention (invasive)
□ CT angiography: initial imaging of choice (non-invasive)
□ MR angiography: non-contrast alternative
Management of intermittent claudication? (5)
Improve survival:
□ Risk factor modification: smoking cessation, DM control, HTN control, lipid control
□ Lifelong antiplatelets: aspirin and/or clopidogrel
Improve symptoms:
□ Supervised exercise training
□ Drugs - platelet-aggregation inhibitors : cilostazol, naftidrofuryl, pentoxifylline
□ Endovascular surgery
Main indications for surgical management of chronic limb ischaemia?
□ Treating disabling claudication in non-critical ischaemia after refractory to conservative treatment
□ Limb salvage in critical ischaemia
4 choices for surgical management of chronic limb ischaemia?
□ Balloon angioplasty + stenting
□ Arterial bypass
□ Endarterectomy
□ Amputation
5 considerations for surgical management of chronic limb ischaemia?
□ Treat inflow before outflow disease, i.e. treat aortoiliac disease first
□ Consider length and degree of occlusion: short stenosis are better treated by endovascular Tx
□ Consider availability of venous grafts: normal, healthy veins are required for arterial bypass
□ Consider life expectancy of pt: those with ≤2y life expectancy are unlikely to benefit
□ Consider presenting symptom of pt: prefer bypass for rest pain
Define the TASC II classification (type A,B,C,D)
TASC II classification: Based on overall success rates of treating different lesions using endovascular/surgical means
□ Type A: short and focal → endovascular therapy
□ Type B: prefer endovascular Tx
□ Type C: prefer open revascularization
□ Type D: prefer surgery as primary Tx for low-to-moderate risk patients
Types of surgical bypass surgery for aortoiliac, above knee and below knee arterial occlusion?
Aortoiliac disease:
Aortofemoral (1st choice)
Axillofemoral (high-risk)
Femorofemoral cross-over (unilateral iliac occlusion)
Above knee:
Femoropopliteal bypass
Below knee:
Femoro-anterior tibial bypass
Femoro-posterior tibial bypass
