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Stem A (claudication)
A 62-year-old male smoker with diabetes and hypertension develops left calf pain after walking 150 m, relieved within minutes of rest. No rest pain. Femoral pulse present; popliteal and foot pulses absent. ABPI 0.55 left, 0.95 right. No tissue loss.
Stem B (acute limb ischaemia — for part d)
Separately, a 70-year-old with atrial fibrillation presents with sudden severe pain in a cold, pale, pulseless right leg with paraesthesia; power reduced in toes.
Questions
a) Define PAD using ABPI and stage Stem A by Fontaine and Rutherford concepts. (3 marks)
PAD: atherosclerotic stenosis/occlusion of lower-limb arteries causing ischaemia. ABPI ≤0.90 diagnostic (normal 1.00–1.40; >1.40 incompressible — use toe pressures/TBI).
Stem A: Fontaine IIb (claudication <200 m) / Rutherford category 2 moderate claudication — not critical limb-threatening ischaemia (no rest pain/tissue loss).
b) Best medical therapy with exact antiplatelet/statin/exercise prescriptions and symptom drug caution. (4 marks)
For ALL symptomatic PAD:
- Smoking cessation (single most important)
- High-intensity statin e.g. atorvastatin 40–80 mg OD
- Antiplatelet: aspirin 75 mg OD or clopidogrel 75 mg OD (CAPRIE favoured clopidogrel slightly over aspirin in PAD subgroup)
- Supervised exercise programme ≥30–45 min, 3×/week, 12 weeks
- BP and glycaemic control; foot care in diabetes
- Cilostazol 100 mg BD for claudication symptoms if no heart failure (PDE3 inhibitor — contraindicated in HF)
- Revascularisation if lifestyle-limiting despite BMT or if CLTI
c) Critical limb-threatening ischaemia features, TcPO2 thresholds, and revascularisation principle. (3 marks)
CLTI: ischaemic rest pain ≥2 weeks and/or ulceration/gangrene attributable to arterial disease (often ABPI <0.4–0.5).
TcPO2: >40 mmHg healing likely; <30 mmHg poor healing without revascularisation.
Urgent vascular MDT: endovascular and/or surgical bypass tailored to anatomy (TASC), vein bypass preferred for extensive infrainguinal disease when good conduit; goal is blood to foot and wound care/antibiotics for infection.
d) Stem B — diagnosis, 6 Ps, immediate drugs/doses, and definitive options with time urgency. (5 marks)
Acute limb ischaemia — likely embolus (AF) vs thrombosis-in-situ.
6 Ps: Pain, Pallor, Pulselessness, Paraesthesia, Paralysis, Perishing cold. Sensory loss/paralysis = immediately threatened.
Immediate: ABC; IV unfractionated heparin e.g. 80 units/kg bolus then infusion per local aPTT protocol (or 5000 IU bolus then infusion); analgesia (morphine 2.5–5 mg IV titrated); keep limb dependent, avoid heating; urgent vascular surgery.
Definitive: catheter embolectomy (Fogarty) for embolus; thrombolysis/thrombectomy for many thrombotic occlusions; bypass if needed. Muscle necrosis risk rises after ~6 hours of profound ischaemia — irreversible injury → amputation. Post-embolectomy: fasciotomy if reperfusion compartment syndrome; long-term anticoagulation for embolic AF.
Additional teaching points
Buerger’s (TAO): young male smokers, distal small-vessel, treat by absolute tobacco cessation.
Leriche: aortoiliac — buttock claudication + erectile dysfunction + absent femorals.
Diabetic foot: mixed neuropathic/ischaemic; ABPI may be falsely high — use TBI/duplex.