Cardiology: Venous Thromboembolism and Pulmonary Vascular Disease

🩸 Venous thromboembolism and pulmonary vascular disease — mapped to the GMC MLA content map applying from September 2026. VTE is common, often preventable and easily missed: the skill is using clinical probability to decide who needs a D-dimer, who needs imaging and who needs anticoagulation now. Emergencies here are taught as recognition and escalation — follow local protocols and specialist advice.
Your four questions for every suspected VTE: How likely is it (Wells score)? Is the patient stable — or is this high-risk PE? Which test answers the question (D-dimer or imaging)? Should anticoagulation start now — and what is the bleeding risk?

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Deep Vein Thrombosis — Presentation and Risk

• Virchow's triad — venous stasis, endothelial injury and hypercoagulability.
• Risk factors:
  • Recent surgery (especially orthopaedic and pelvic), immobilisation, long-haul travel.
  • Active cancer and chemotherapy.
  • Previous VTE.
  • Oestrogen — combined pill, HRT; pregnancy and the postpartum period.
  • Inherited thrombophilia (factor V Leiden, prothrombin gene mutation, protein C, S and antithrombin deficiency), antiphospholipid syndrome.
  • Obesity, older age, heart failure, inflammatory disease, nephrotic syndrome.
• Presentation — unilateral leg swelling, calf or thigh tenderness, warmth, erythema, distended superficial veins; measure calf circumference 10 cm below the tibial tuberosity (difference of 3 cm or more is significant).
• Signs are non-specific — mimics include cellulitis, ruptured Baker's cyst, muscle injury, superficial thrombophlebitis, lymphoedema and venous insufficiency.
• Examine for — limb circulation (phlegmasia cerulea dolens — massive iliofemoral DVT with a blue, painful, swollen leg threatening the limb) and symptoms of coexisting PE.

DVT — Wells Score and Diagnostic Pathway

• Two-level DVT Wells score (NICE NG158):

  Clinical feature	Points
  Active cancer (treatment within 6 months or palliative)	1
  Paralysis, paresis or recent plaster immobilisation of the leg	1
  Recently bedridden 3 days or more, or major surgery within 12 weeks	1
  Localised tenderness along the deep venous system	1
  Entire leg swollen	1
  Calf swelling 3 cm or more than the other side	1
  Pitting oedema confined to the symptomatic leg	1
  Collateral superficial veins (non-varicose)	1
  Previous DVT	1
  Alternative diagnosis at least as likely	–2

• DVT likely (2 or more):
  • Proximal leg vein ultrasound within 4 hours.
  • If the scan can't be done within 4 hours — D-dimer, interim therapeutic anticoagulation (if suitable) and scan within 24 hours.
  • Scan negative but D-dimer positive — repeat proximal scan in 6–8 days.
• DVT unlikely (1 or less) — D-dimer; if positive, ultrasound (as above); if negative, DVT is excluded — consider other diagnoses.

💡 MLA trap: D-dimer is for excluding VTE in a low-probability patient — not for diagnosing it. It is raised by infection, cancer, pregnancy, surgery, trauma and older age, so a positive result means "image", not "VTE".

Pulmonary Embolism — Presentation and Severity

• Pathophysiology — clot (usually from leg or pelvic veins) obstructs pulmonary arteries → V/Q mismatch, hypoxaemia, raised pulmonary vascular resistance → acute right ventricular strain or failure.
• Typical features — sudden breathlessness, pleuritic chest pain, tachycardia, tachypnoea, haemoptysis, syncope; low-grade fever; signs of DVT.
• Massive PE — obstructive shock, raised JVP, hypotension, cardiac arrest (often PEA).
• Investigations:
  • ECG — usually sinus tachycardia; RV strain (right bundle branch block, right axis, T-wave inversion V1–V4, S1Q3T3 — uncommon); a normal ECG doesn't exclude PE.
  • Chest X-ray — often normal; helps exclude other causes.
  • ABG — hypoxaemia and low CO₂ (may be normal).
  • Troponin and BNP — RV strain and prognosis.
  • Echo — RV dilatation (bedside echo helps in unstable patients).
• Assess — severity (oxygenation, BP, RV strain), and alternatives — ACS, pneumonia, pneumothorax, aortic dissection, pericarditis.
• Risk stratification (ESC) — high risk (haemodynamic instability), intermediate (RV strain or raised troponin, or sPESI 1 or more), low (sPESI 0 — may be suitable for outpatient treatment).

PE — Wells Score, PERC, D-dimer and Imaging

• Two-level PE Wells score:

  Clinical feature	Points
  Clinical signs and symptoms of DVT	3
  An alternative diagnosis is less likely than PE	3
  Heart rate over 100	1.5
  Immobilisation 3 days or more, or surgery in the previous 4 weeks	1.5
  Previous DVT or PE	1.5
  Haemoptysis	1
  Malignancy (treatment within 6 months or palliative)	1

• PE likely (over 4) — CT pulmonary angiography (CTPA) immediately; V/Q scan if contrast allergy, renal impairment or to reduce radiation (e.g. pregnancy, young women).
• PE unlikely (4 or less) — D-dimer; CTPA if positive; if negative, PE is excluded.
• Age-adjusted D-dimer (age × 10 µg/L in people over 50) — may be used with a validated assay and pathway.
• PERC rule (Pulmonary Embolism Rule-out Criteria) — only when clinical suspicion is genuinely low (under 15%): if all 8 criteria are met (age under 50, HR under 100, SpO₂ 94% or more, no haemoptysis, no oestrogen use, no previous VTE, no unilateral leg swelling, no surgery or trauma needing hospital in the last 4 weeks), no further testing is needed.
• Imaging delayed — give interim therapeutic anticoagulation after assessing bleeding risk.
• Pregnancy — leg ultrasound first if leg symptoms; CTPA or V/Q (discuss risks); D-dimer is unhelpful; LMWH.

Anticoagulation and Duration

• First line (NICE NG158) for confirmed proximal DVT or PE — apixaban or rivaroxaban (no LMWH lead-in needed).
• Alternatives — LMWH for at least 5 days then dabigatran or edoxaban; or LMWH with warfarin (INR 2–3) until the INR is 2 or more for 2 days.
• Special situations:
  • Pregnancy — LMWH (DOACs and warfarin are avoided).
  • Severe renal impairment (CrCl under 15) — LMWH or unfractionated heparin, then warfarin.
  • Triple-positive antiphospholipid syndrome — warfarin (not DOACs).
  • Active cancer — DOAC or LMWH depending on cancer type, bleeding risk and interactions.
  • Extremes of body weight, drug interactions (enzyme inducers, some antiretrovirals and antiepileptics).
• Duration:
  • At least 3 months for all.
  • Provoked (transient risk factor — surgery, trauma) — usually stop at 3 months.
  • Unprovoked — consider long-term anticoagulation (typically 6 months then review) if bleeding risk is acceptable; use a validated bleeding score (e.g. ORBIT).
  • Active cancer — 3–6 months then review.
• Unprovoked VTE — history, examination and basic tests for cancer (don't routinely scan if normal); thrombophilia testing only in selected cases (not while on anticoagulation for most tests).
• Document and counsel — renal function, weight, interactions; bleeding warning signs; missed doses; alert card.
• Distal (calf) DVT — management varies (anticoagulation or repeat scanning) — follow local policy.

High-risk PE and Thrombolysis

• High-risk (massive) PE — defined by haemodynamic instability (persistent hypotension — systolic under 90 mmHg, obstructive shock, cardiac arrest), not by clot size.
• Management:
  • ABCDE, oxygen, cautious fluids (RV overload — small boluses only), vasopressors (noradrenaline).
  • Unfractionated heparin (if thrombolysis may follow).
  • Systemic thrombolysis (alteplase) — unless contraindicated.
  • Urgent senior, critical care and PE response team (PERT) input.
  • Catheter-directed therapy or surgical embolectomy if thrombolysis is contraindicated or fails; VA-ECMO in selected cases.
  • Cardiac arrest from PE — give thrombolysis and continue CPR for 60–90 minutes.
• Intermediate-risk PE (RV strain, stable) — anticoagulate and monitor closely; no routine thrombolysis (bleeding risk outweighs benefit — PEITHO); rescue thrombolysis if deterioration.
• Contraindications to thrombolysis — previous intracranial haemorrhage, recent stroke, recent major surgery or trauma, active bleeding, CNS tumour — specialist decision; pregnancy needs specialist input.

⚠️ Safety Pearl: In a hypotensive patient with suspected PE, don't send them to CT if they are too unstable to travel. A bedside echo showing a dilated, struggling right ventricle can justify thrombolysis.

Hospital and Perioperative VTE Prevention

• Assess VTE and bleeding risk on admission and when circumstances change (NICE NG89).
• General measures — early mobilisation, hydration.
• Pharmacological prophylaxis — LMWH (or fondaparinux; DOACs after hip and knee replacement); adjust for renal function and weight; unfractionated heparin in severe renal impairment.
• Mechanical prophylaxis — anti-embolism stockings or intermittent pneumatic compression when anticoagulants are contraindicated; avoid stockings in peripheral arterial disease, peripheral neuropathy, severe leg oedema and fragile skin; not for acute stroke (IPC instead).
• Extended prophylaxis — after major abdominal or pelvic cancer surgery (28 days), hip replacement (28–35 days), knee replacement (14 days), hip fracture.
• Lower limb immobilisation in a cast — assess and consider LMWH.
• Pregnancy and postpartum — RCOG risk assessment; LMWH for higher risk.
• Discharge — document prophylaxis duration, teach injections, explain DVT and PE warning symptoms.

Chronic Venous Insufficiency and Varicose Veins

• Mechanism — valvular reflux and calf-pump failure → ambulatory venous hypertension.
• Features — ankle oedema, aching and heaviness, varicose veins, haemosiderin pigmentation, venous eczema, lipodermatosclerosis, atrophie blanche, shallow exudative ulcers in the gaiter area (above the medial malleolus).
• Examination — standing if possible; check pedal pulses and ABPI before compression (arterial disease — compression can cause necrosis).
• Duplex ultrasound — identifies reflux and guides treatment.
• Treatment (NICE CG168) — refer symptomatic varicose veins, skin changes, ulcers, superficial thrombophlebitis or bleeding varicosities; endothermal ablation first line, then foam sclerotherapy, then surgery; compression for venous ulcers (if ABPI acceptable).
• Venous vs arterial ulcers:

  	Venous	Arterial
  Site	Gaiter area — medial malleolus	Distal — toes, heel, pressure points
  Appearance	Shallow, large, sloping edges, exudative	Small, deep, "punched out", pale base
  Pain	Mild; better with elevation	Painful; worse with elevation, at night
  Surrounding skin	Pigmentation, eczema, lipodermatosclerosis	Cool, hairless, shiny; absent pulses
  Treatment	Compression	Revascularisation — no compression

Post-thrombotic Syndrome and CTEPH

• Post-thrombotic syndrome — after DVT (in up to a third), from damaged valves and residual obstruction — chronic swelling, heaviness, pain, pigmentation, venous ulceration; compression and elevation; prevent by effective anticoagulation.
• Chronic thromboembolic pulmonary hypertension (CTEPH):
  • Develops in a small minority (about 2–4%) after PE — unresolved clot organises in the pulmonary arteries.
  • Persistent breathlessness, exercise intolerance and RV strain despite 3 months of anticoagulation.
  • Don't label persistent symptoms after PE as deconditioning — assess (echo; V/Q scan is the screening test of choice — more sensitive than CTPA for chronic disease).
  • Treatment — lifelong anticoagulation; pulmonary endarterectomy (potentially curative — specialist centre: Royal Papworth in the UK); balloon pulmonary angioplasty; riociguat for inoperable disease.

Pulmonary Hypertension

• Definition — mean pulmonary arterial pressure over 20 mmHg at rest measured by right heart catheterisation (ESC/ERS 2022).
• Classification:

  Group	Type	Examples
  1	Pulmonary arterial hypertension (PAH)	Idiopathic, heritable (BMPR2), drugs, connective tissue disease (systemic sclerosis), HIV, portal hypertension, congenital heart disease
  2	Left heart disease (commonest)	Heart failure, mitral and aortic valve disease
  3	Lung disease and hypoxia	COPD, interstitial lung disease, OSA, altitude
  4	Pulmonary artery obstruction	CTEPH
  5	Unclear or multifactorial	Sarcoidosis, haematological, metabolic disorders

• Symptoms — progressive breathlessness, fatigue, exertional chest pain, syncope (poor prognosis), peripheral oedema.
• Signs — loud P2, RV heave, raised JVP (giant v waves — tricuspid regurgitation), peripheral oedema, hepatomegaly.
• Investigations — ECG (RV hypertrophy, right axis), CXR (enlarged pulmonary arteries), BNP, echocardiography (estimates probability and RV function — but can't confirm the type), lung function and CT, V/Q scan (CTEPH), right heart catheterisation (diagnosis and classification).
• Management — treat the underlying cause (groups 2 and 3); oxygen if hypoxic; diuretics; refer suspected PAH or CTEPH to a specialist centre; PAH-specific drugs (endothelin receptor antagonists, PDE5 inhibitors, prostanoids, riociguat; calcium channel blockers only for vasoreactive patients) — not interchangeable with treatment for left-heart PH.

Superior Vena Cava Obstruction

• Causes — extrinsic compression or thrombosis — intrathoracic malignancy (lung cancer — especially small cell; lymphoma), central venous devices (lines, pacing wires), mediastinal fibrosis.
• Features — swelling of the face, neck and arms; distended neck and chest wall veins; cough, breathlessness; symptoms worse on bending forward or lying down; headache; Pemberton's sign.
• Emergency features — stridor, laryngeal oedema, confusion or reduced consciousness (cerebral oedema).
• Immediate management — sit up, assess airway and oxygenation, oxygen.
• Investigations — urgent CT chest with contrast; tissue diagnosis if no known cancer (before steroids where possible — lymphoma).
• Treatment (by cause) — endovascular stenting (rapid relief), chemotherapy or radiotherapy (sensitive tumours), dexamethasone (selected cases), anticoagulation for thrombotic obstruction (remove or treat the line); acute oncology, respiratory or vascular advice.

VTE and Pulmonary Vascular Disease at a Glance

Topic	Key facts
DVT Wells	2 or more likely — ultrasound in 4 hours; 1 or less — D-dimer first
Negative scan, positive D-dimer	Repeat proximal scan at 6–8 days
PE Wells	Over 4 likely — CTPA; 4 or less — D-dimer first
PERC	Only if suspicion genuinely low; all 8 criteria met — no test
Delayed imaging	Interim therapeutic anticoagulation
First-line treatment	Apixaban or rivaroxaban
Pregnancy	LMWH
Antiphospholipid (triple-positive)	Warfarin, not DOACs
Duration	3 months minimum; consider long-term if unprovoked
High-risk PE	Instability — thrombolysis
Intermediate-risk PE	Anticoagulate and monitor; no routine thrombolysis
Stockings	Avoid in PAD and acute stroke
Venous ulcer	Gaiter area; check ABPI before compression
CTEPH	Breathless after PE — V/Q scan; pulmonary endarterectomy
Pulmonary hypertension	mPAP over 20 on right heart catheter; group 2 commonest
SVCO	Lung cancer or lines — CT, stenting

Spot the Diagnosis

Clue	Diagnosis
Swollen, tender left calf 10 days after a hip replacement	DVT
Sudden calf pain and swelling in a man with knee osteoarthritis; crescent of bruising at the ankle	Ruptured Baker's cyst
Massively swollen, blue, painful leg	Phlegmasia cerulea dolens (iliofemoral DVT)
Pleuritic pain, haemoptysis and tachycardia on the combined pill	Pulmonary embolism
PEA arrest on day 5 after major surgery	Massive PE — consider thrombolysis
Stable PE with dilated RV on echo and raised troponin	Intermediate-risk PE — monitor, no routine thrombolysis
Recurrent VTE with positive lupus anticoagulant, anticardiolipin and anti-β2GP1	Triple-positive antiphospholipid syndrome — warfarin
Shallow ulcer above the medial malleolus with brown pigmentation	Venous ulcer
Painful punched-out ulcer on the toe with absent pulses	Arterial ulcer
Still breathless 6 months after a PE; V/Q shows multiple defects	CTEPH
Young woman with exertional syncope, loud P2 and RV heave	Pulmonary arterial hypertension
Breathlessness and pulmonary hypertension in a patient with systemic sclerosis	Group 1 PAH (connective tissue disease)
Facial swelling and dilated chest wall veins in a smoker	SVC obstruction — lung cancer

Exam-style Scenarios

1. A 45-year-old man has a swollen right calf after a long-haul flight. The whole leg is swollen and he has pitting oedema in that leg only. Ultrasound isn't available until tomorrow.
Answer: DVT likely (Wells 2) with delayed imaging.

• Take a D-dimer and start interim therapeutic anticoagulation (e.g. apixaban) after checking bleeding risk, renal function and weight.
• Proximal leg vein ultrasound within 24 hours.
• If the scan is negative but D-dimer positive — repeat at 6–8 days.

2. A 32-year-old woman on the combined pill has pleuritic chest pain. HR 88, SpO₂ 98%, no leg signs; an alternative diagnosis seems more likely.
Answer: PE unlikely (Wells under 4) — but PERC can't be applied (oestrogen use).

• Request a D-dimer.
• If negative — PE excluded; look for another cause.
• If positive — CTPA (or V/Q scan).

3. A 70-year-old woman on day 4 after a laparotomy collapses. BP 70/40, HR 130, SpO₂ 85%, JVP raised. Bedside echo shows a dilated, hypokinetic right ventricle.
Answer: High-risk (massive) PE.

• Call for senior and critical care help; oxygen; cautious fluids; vasopressors.
• Recent major surgery is a relative contraindication to thrombolysis — discuss urgently with the PE response team.
• Options — systemic thrombolysis, catheter-directed therapy or surgical embolectomy; unfractionated heparin.

4. A 58-year-old man had an unprovoked PE 3 months ago, treated with rivaroxaban. He has no bleeding risk factors.
Answer: Unprovoked VTE — consider long-term anticoagulation.

• Discuss benefits and bleeding risks (use a bleeding score); patient preference.
• If continuing, review at least annually.
• Ask about persistent breathlessness — echo and V/Q scan for CTEPH if present.

5. A 66-year-old smoker has 2 weeks of facial swelling and breathlessness, worse lying down. Neck veins are distended and non-pulsatile.
Answer: SVC obstruction — probable lung cancer.

• Sit up, oxygen; check for stridor (emergency).
• Urgent CT chest with contrast; tissue diagnosis.
• Acute oncology referral — stenting, chemotherapy or radiotherapy; steroids in selected cases.

Key Points

• Use the two-level Wells score to decide between D-dimer and imaging.
• D-dimer excludes VTE in low-probability patients — it doesn't diagnose it.
• Give interim anticoagulation if imaging is delayed.
• Apixaban or rivaroxaban first line; LMWH in pregnancy; warfarin in triple-positive APS.
• Anticoagulate for at least 3 months; consider long-term for unprovoked VTE.
• High-risk PE is defined by instability — thrombolyse; don't thrombolyse stable RV strain routinely.
• Assess VTE and bleeding risk on admission; avoid stockings in PAD.
• Check ABPI before compressing venous ulcers.
• Persistent breathlessness after PE — think CTEPH; V/Q scan.
• Pulmonary hypertension needs right heart catheterisation; left heart disease is the commonest cause.
• SVCO — sit up, CT, tissue diagnosis, stenting.

Guidelines and Further Reading

• NICE NG158: Venous thromboembolic diseases — diagnosis, management and thrombophilia testing
• NICE NG89: Venous thromboembolism in over 16s — reducing the risk of hospital-acquired DVT or PE
• ESC 2019: Guidelines for the diagnosis and management of acute pulmonary embolism
• ESC/ERS 2022: Guidelines for the diagnosis and treatment of pulmonary hypertension
• NICE CG168: Varicose veins — diagnosis and management
• RCOG Green-top Guidelines 37a and 37b: Thromboembolic disease in pregnancy
• GMC: MLA content map (applying from September 2026)
• BNF — for current doses