Venous thromboembolism is the preventable post-operative death, and the CST clinical station tests it from both ends: the prophylaxis you should have prescribed under NICE NG89, and the swollen leg or breathless patient you now assess under NICE NG158. NG89 asks for a risk assessment on admission, mechanical prophylaxis from admission for abdominal surgery and pharmacological prophylaxis for at least 7 days. NG158 asks for a two-level Wells score and a proximal leg vein ultrasound within 4 hours when DVT is likely.

Key takeaways

  • NICE NG89: assess VTE and bleeding risk as soon as possible after admission or by the first consultant review, and start pharmacological prophylaxis within 14 hours of the decision to admit where indicated
  • Abdominal surgery under NG89: mechanical prophylaxis (anti-embolism stockings or intermittent pneumatic compression) from admission until mobility returns, plus LMWH or fondaparinux for a minimum of 7 days if VTE risk outweighs bleeding risk
  • Consider extending pharmacological prophylaxis to 28 days after major abdominal cancer surgery
  • Do not use anti-embolism stockings in suspected or proven peripheral arterial disease, bypass grafting, neuropathy or fragile skin
  • NICE NG158: DVT Wells score of 2 or more is DVT likely, needing a proximal leg vein ultrasound within 4 hours, or a D-dimer, interim anticoagulation and a scan within 24 hours
  • Apixaban or rivaroxaban first line for confirmed DVT or PE; treatment for 3 months after a provoked event, with surgery within the previous 3 months counting as provoked

How does VTE present on a surgical ward?

Venous thromboembolism presents on a surgical ward as a unilateral swollen, tender leg, or as a pulmonary embolism with breathlessness, pleuritic pain, tachycardia and hypoxia that has no chest source, and sometimes as an unexplained collapse. The provoking factor is the surgery itself: NICE NG158 counts surgery within the previous 3 months as a transient major risk factor.

In practice, the question the panel asks first is what prophylaxis the patient was on. Read the chart: was a risk assessment done, were stockings fitted and measured, was the LMWH prescribed and given every day, and was the dose adjusted for renal function.

What is the immediate management of a suspected VTE, A to E?

Immediate management of a suspected VTE is an ABCDE assessment that separates the swollen leg, which is a same-day investigation, from the suspected pulmonary embolism, which can be a resuscitation.

Airway and breathing

Respiratory rate and saturations first. Oxygen to a target range. A raised respiratory rate with clear lungs in a post-operative patient is a pulmonary embolism until shown otherwise.

Circulation

Pulse, blood pressure and capillary refill. Hypotension with a suspected PE is a massive PE and an emergency call. Intravenous access, a full blood count, renal function, clotting and a group and save, because the treatment is anticoagulation and NG158 asks for baseline bloods to be reviewed within 24 hours of starting it. An ECG for right heart strain or an alternative diagnosis.

Disability and exposure

Conscious level, then examine both legs: measure the calf circumference, look for pitting oedema confined to one leg, collateral superficial veins and tenderness along the deep veins. These are Wells items; examining for them is how you score.

What investigations does a swollen leg or suspected PE need?

A swollen leg needs a two-level DVT Wells score first, and NICE NG158 then sets the pathway by the score. With 2 points or more, DVT is likely: offer a proximal leg vein ultrasound with the result within 4 hours, and a D-dimer if the scan is negative. If the scan cannot be done within 4 hours, take a D-dimer, start interim therapeutic anticoagulation and get the scan within 24 hours.

With 1 point or less, DVT is unlikely: a D-dimer with the result within 4 hours, or interim anticoagulation while waiting if it cannot be. A positive D-dimer then earns the scan within 4 hours, or anticoagulation and a scan within 24 hours. A negative scan with a positive D-dimer is repeated at 6 to 8 days.

For suspected PE the two-level PE Wells score applies: more than 4 points is PE likely, and NG158 recommends a CT pulmonary angiogram immediately if possible, with interim anticoagulation if it cannot be done immediately. Four points or less is PE unlikely and goes to D-dimer. Patients with contrast allergy, a creatinine clearance under 30 ml/min or a high radiation risk are assessed for a V/Q SPECT scan instead.

What is the definitive management of VTE, and the prophylaxis that prevents it?

Definitive management of a confirmed proximal DVT or PE under NICE NG158 is anticoagulation with apixaban or rivaroxaban first line, continued for 3 months after a provoked event if the provoking factor has gone and the course was uncomplicated, and considered beyond 3 months after an unprovoked event. People with active cancer are treated for 3 to 6 months.

That said, in a patient two days after a laparotomy the bleeding risk is the conversation, and the anticoagulant is chosen with the operating consultant and, where needed, haematology. If anticoagulation is contraindicated, NG158 offers a mechanical intervention, which is where an inferior vena cava filter is discussed at senior level.

Prophylaxis under NICE NG89

  • Assess VTE and bleeding risk on admission or by the first consultant review, and reassess when the condition changes
  • Abdominal surgery: start mechanical prophylaxis on admission, either anti-embolism stockings or intermittent pneumatic compression, and continue until mobility is back to normal or anticipated
  • Add LMWH or fondaparinux for a minimum of 7 days where VTE risk outweighs bleeding risk; consider 28 days after major abdominal cancer surgery
  • Start pharmacological prophylaxis as soon as possible and within 14 hours of the decision to admit unless a population-specific rule says otherwise
  • Renal impairment: LMWH or unfractionated heparin, with dose reduction on senior or local protocol advice
  • Stockings: measure the legs, fit correctly, remove daily to inspect skin, and never use them in peripheral arterial disease, bypass grafting, neuropathy or fragile skin

When do I escalate a suspected VTE, and to whom?

Escalate a suspected pulmonary embolism to the registrar at once and to critical care and the medical emergency team if the patient is hypotensive or hypoxic despite oxygen, because thrombolysis for a massive PE is a senior, time-critical decision. A swollen leg with a stable patient is escalated to the registrar the same day for the scan and the anticoagulation decision.

The other escalation is upstream. If the patient was not on the prophylaxis NG89 required, that is a safety incident to report and a conversation with the consultant, not something to bury. Involve the pharmacist for the anticoagulant choice and haematology if there is a bleeding disorder or the patient is on another anticoagulant.

What is the interviewer listening for in a VTE scenario?

  • The prophylaxis checked before the diagnosis is chased: risk assessment, stockings, LMWH, and the 7-day minimum for abdominal surgery
  • The Wells score calculated and its threshold stated: 2 or more for DVT, more than 4 for PE
  • The 4-hour scan window and the 24-hour fallback with interim anticoagulation, quoted from NG158
  • Bleeding risk weighed openly in a fresh post-operative patient, with the consultant involved in the anticoagulant choice
  • Massive PE recognised as an emergency with critical care called, not a CTPA request

What are the common mistakes with VTE?

The commonest mistake in a VTE scenario is to send a D-dimer to a post-operative patient and be reassured or misled by it, when the Wells score should have set the pathway and post-operative D-dimers are often raised. The second is to fit stockings on a patient with peripheral arterial disease.

  • Not knowing whether the patient actually received each LMWH dose
  • Waiting for a scan tomorrow with no interim anticoagulation, against NG158
  • Choosing the anticoagulant without checking renal function or the bleeding risk from the operation
  • Stopping prophylaxis at discharge after major abdominal cancer surgery when 28 days should have been considered
  • Treating breathlessness on day 3 as atelectasis because the chest radiograph is normal

How this comes up at the CST interview

The CST management and clinical station sets VTE as a swollen calf on day 5 after a colectomy or a breathless patient with a normal chest film, and the panel wants NG89 for what should have happened and NG158 for what you do now, with the Wells threshold, the scan window and the anticoagulant named. coresurgeryinterview includes this among its 299 questions with AI-marked spoken practice, at /Question-Bank/Sample-Questions.