Vascular Surgery Question Bank

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1. Which structure in the femoral triangle lies outside the femoral sheath?

The femoral sheath is a funnel-shaped extension of the transversalis fascia (in front) and iliac fascia (behind) below the inguinal ligament. It has three compartments: lateral (femoral artery and the femoral branch of the genitofemoral nerve), intermediate (femoral vein) and medial (femoral canal, containing lymphatics and the lymph node of Cloquet). The femoral nerve lies lateral to the artery, outside the sheath, beneath the iliacus fascia. The sheath lets the vessels glide during hip movement, and the canal is the site of femoral hernia. Pearl: the order from lateral to medial is nerve, artery, vein, canal (NAVY); the nerve is at risk from lateral retraction and haematoma after femoral access.

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2. A 70-year-old man with weight loss after meals has aortography. The superior mesenteric artery is occluded at its origin. A large, tortuous vessel near the root of the mesentery fills SMA branches from a hypertrophied inferior mesenteric artery. Which vessels does this collateral connect?

The arc of Riolan, also called the meandering mesenteric artery, is a central collateral between the middle colic (SMA) and left colic (IMA) arteries. It runs closer to the mesenteric root than the marginal artery of Drummond. It enlarges when either the SMA or IMA is occluded. The direction of flow tells you which vessel is diseased. If it is ligated during a colectomy or AAA repair (IMA ligation), bowel ischaemia can follow. The gastroduodenal–pancreaticoduodenal arcade links the coeliac and SMA. The superior–middle rectal anastomosis links the IMA and internal iliac. Pearl: a large meandering artery warns against IMA ligation without assessing SMA patency.

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3. During dissection of the carotid bifurcation in a right carotid endarterectomy under general anaesthesia, the patient's heart rate falls from 72 to 38 beats/min and blood pressure from 140/80 to 80/45 mmHg. What is the most appropriate immediate action?

Manipulation of the carotid sinus baroreceptors at the bifurcation can trigger a vagally mediated reflex bradycardia and hypotension. The immediate steps are to stop manipulation and infiltrate the tissue between ICA and ECA (the carotid sinus nerve region) with plain lidocaine; intravenous atropine or glycopyrrolate is given if bradycardia persists. Clamping does not abolish the reflex, and beta-blockade worsens bradycardia. A shunt addresses clamp ischaemia, not reflex hypotension. Pearl: postoperative hypotension or hypertension can follow CEA because of baroreceptor dysfunction.

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4. A 31-year-old man sustained a low-velocity gunshot wound to the left calf. There is no active bleeding or expanding haematoma, and the foot is warm with normal capillary refill. Pedal pulses are diminished compared with the right side. The arterial pressure index of the injured limb is 0.78. What is the most appropriate next step?

In penetrating extremity trauma without hard signs, an arterial pressure index (injured limb systolic pressure divided by brachial pressure of an uninjured arm) below 0.9 has high sensitivity (about 95%) for a significant arterial injury and mandates further imaging; CT angiography is the preferred modality (EAST guideline). An index of 0.9 or above allows observation with serial examination. Immediate exploration is reserved for hard signs, and discharge or observation alone would miss injuries such as tibial artery occlusion, pseudoaneurysm or AV fistula. Pearl: API <0.9 is the trigger for imaging.

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5. Compared with woven polyester (Dacron) grafts, which property characterises knitted polyester grafts?

Polyester (Dacron) grafts are made by weaving or knitting. Knitted grafts have looser, looped fibres: they are more porous, softer, more compliant, handle and suture more easily and resist fraying, but they dilate more over time (often 10–20%). Their porosity originally required preclotting with the patient's blood; modern grafts are sealed with collagen, gelatin or albumin. Woven grafts have tightly interlaced fibres, low porosity and little dilatation, but are stiffer and fray at cut edges, so they are favoured in the thoracic aorta and when anticoagulation is heavy. In humans, prosthetic grafts endothelialise only a short distance (1–2 cm) from each anastomosis, not along their full length. Pearl: dilated knitted grafts can develop late anastomotic pseudoaneurysm.

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6. A 71-year-old man with a known chronic occlusion of the left internal carotid artery has a surveillance duplex of the right side showing an ICA peak systolic velocity of 260 cm/s and end-diastolic velocity of 95 cm/s. CT angiography measures the right ICA stenosis at 55% (NASCET). Which is the most likely explanation for the discrepancy?

When the contralateral ICA is occluded, the patent ICA carries increased collateral flow to both hemispheres, raising PSV and EDV so that duplex overestimates the true diameter reduction; diameter measurement on CTA or MRA is therefore used to confirm severity. Conversely, low cardiac output, proximal CCA stenosis and aortic stenosis reduce inflow velocities and cause underestimation of stenosis rather than overestimation. Pearl: the ICA/CCA ratio is less affected by systemic haemodynamic factors and helps in such situations, and a second imaging modality should be obtained before any treatment decision.

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7. A 30-year-old woman has a symptomatic high-flow arteriovenous malformation of the right thigh with pain and skin breakdown. Angiography shows multiple feeding branches of the profunda femoris converging on a nidus with early venous drainage. A trainee proposes ligation of the main feeding artery. What is the most appropriate treatment strategy?

Effective treatment of an arteriovenous malformation requires obliteration or complete resection of the nidus, the network of abnormal arteriovenous connections. Embolisation with liquid agents such as ethanol, n-butyl cyanoacrylate or ethylene vinyl alcohol copolymer, delivered transarterially, by direct puncture or transvenously, is the mainstay, with surgical resection after embolisation for selected lesions. Proximal ligation or proximal coiling of feeding arteries is contraindicated: the nidus rapidly recruits collaterals, symptoms recur, and endovascular access to the nidus is lost. Ablating the draining vein alone leaves the nidus untreated and can increase pressure and bleeding. Pearl: ethanol embolisation risks skin necrosis and nerve injury and needs careful dosing.

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8. A day after revascularisation and fasciotomy for prolonged ALI, a 62-year-old man has dark brown urine. Dipstick is strongly positive for blood, but microscopy shows no red cells. Creatine kinase is 85,000 U/L and creatinine has risen from 90 to 160 µmol/L (1.0 to 1.8 mg/dL). What is the most important management step?

Positive haem on dipstick without red cells on microscopy means myoglobinuria from rhabdomyolysis. Myoglobin causes AKI by tubular obstruction (cast formation), direct tubular toxicity and renal vasoconstriction, especially with acidic urine and low volume. Early, aggressive isotonic crystalloid resuscitation, aiming for urine output of about 200–300 mL/h (around 3 mL/kg/h), is the cornerstone. Urinary alkalinisation and mannitol have no proven benefit over fluids alone. Loop diuretics and fluid restriction worsen tubular precipitation. Dialysis is for refractory hyperkalaemia, acidosis or fluid overload; it clears myoglobin poorly.

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9. In the Mangled Extremity Severity Score (MESS), which variable has its assigned points doubled when present for more than 6 hours?

MESS comprises four components: skeletal/soft-tissue injury (1–4 points), limb ischaemia (1–3 points, doubled if ischaemia lasts more than 6 hours), shock (0–2 points) and age (0–2 points). A score of 7 or more was originally associated with amputation. However, subsequent studies, including the LEAP study, showed that MESS and similar scores have poor sensitivity and predictive value, and they should not be used as the sole basis for primary amputation. Decisions should incorporate clinical judgement, nerve integrity, soft-tissue coverage, patient physiology and expected function. Pearl: insensate plantar sole at presentation is not a reliable predictor of eventual function.

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10. An 81-year-old frail woman has ischaemic rest pain in the right foot with no tissue loss. Angiography shows a long SFA and popliteal occlusion with no reconstitution of a usable distal target, and a 75% stenosis at the origin of the profunda femoris. The profunda has large geniculate collaterals. Which procedure is most appropriate?

The profunda femoris is the key collateral pathway around an occluded SFA and popliteal artery. Clearing a stenosis at its origin by endarterectomy and patch profundaplasty can raise distal perfusion enough to relieve rest pain. It is useful when there is no distal target, when the patient is too frail for a long bypass, or to improve healing of an amputation stump. Profundaplasty alone is less likely to heal extensive tissue loss. Bypass needs a usable outflow target, and a prosthetic tibial bypass would have very poor patency. Amputation is premature when a low-risk option could relieve rest pain. Lumbar sympathectomy has no proven benefit in CLTI.