DVT & PE Nursing Guide — GCC Clinical Reference

Virchow's Triad — The Three Pillars of Thrombosis

1. Venous Stasis

Immobility / prolonged bed rest
Long-haul flights (>6 hours)
Varicose veins
Congestive heart failure
Obesity (BMI >30)
Pregnancy — uterine compression of IVC

2. Hypercoagulability

Malignancy (tissue factor expression)
Oral contraceptive pill (OCP)
Pregnancy & puerperium
Inherited thrombophilias
Dehydration / hyperviscosity
Polycythaemia vera, HIT

3. Endothelial Injury

Surgery / trauma
IV cannula insertion (UEDVT)
Central venous catheters
Atherosclerosis
Vasculitis
Prior DVT / post-thrombotic syndrome

Caprini Risk Score — Surgical Patients

Each factor adds points; cumulative score guides prophylaxis intensity.

Points	Risk Factor
1 pt	Age 41–60 yrs; minor surgery; BMI >25; swollen legs; varicose veins; pregnancy or postpartum; history of unexplained or recurrent spontaneous abortion; oral contraceptives / HRT; sepsis; serious lung disease; abnormal pulmonary function; acute MI; CHF; history of IBD; medical patient at bed rest
2 pts	Age 61–74 yrs; arthroscopic surgery; malignancy (present or prior); major surgery >45 min; laparoscopic surgery >45 min; confined to bed (>72 h); immobilising plaster cast; central venous access
3 pts	Age ≥75 yrs; VTE history; family history of VTE; Factor V Leiden; prothrombin 20210A; lupus anticoagulant; anticardiolipin antibodies; elevated homocysteine; HIT; other congenital/acquired thrombophilia
5 pts	Stroke <1 month; elective hip/knee arthroplasty; hip/pelvis/leg fracture; acute SCI/paraplegia; multiple trauma <1 month

        Score Interpretation:

        0–1: Low risk — early ambulation

        2: Moderate risk — pharmacological or mechanical prophylaxis

        3–4: High risk — pharmacological + mechanical

        ≥5: Highest risk — extended prophylaxis (28–35 days post-op)

Padua Score — Medical Inpatients

Points	Criterion
3 pts	Active cancer (mets or chemo ≤6 months)
3 pts	Previous VTE (excluding superficial thrombophlebitis)
3 pts	Reduced mobility ≥3 days
3 pts	Known thrombophilic condition
2 pts	Recent (<1 month) trauma or surgery
1 pt	Age ≥70; Heart/respiratory failure; Acute MI or ischaemic stroke; Acute infection or rheumatological disorder; Obesity (BMI ≥30); Ongoing hormonal treatment

        Score ≥4: High risk — pharmacological prophylaxis recommended (unless contraindicated)

        Score <4: Low risk — mechanical methods; reassess daily

GCC-Specific Risk Factors

Environmental & Lifestyle

Long-haul aviation hubs: Jeddah, Dubai, Doha, Abu Dhabi — millions of travellers annually; >4 h flight doubles VTE risk, >8 h quadruples
Extreme heat & dehydration: Summer temperatures 42–50°C → insensible fluid losses → haemoconcentration → increased blood viscosity
Sedentary lifestyle: High rate of physical inactivity across GCC; WHO data shows Saudi Arabia and UAE among highest globally
High OCP prevalence: Combined OCP increases VTE risk 3–5×; progesterone-only pill minimal risk
Ramadan fasting: Prolonged immobility, altered hydration patterns, medication timing

Inherited Thrombophilias in GCC Populations

Factor V Leiden (FVL): Prevalence ~7–10% in Middle East vs ~5% globally; autosomal dominant; activated protein C resistance; heterozygotes: 5–10× VTE risk; homozygotes: 80×
Prothrombin gene mutation (G20210A): ~2–4% GCC prevalence; elevated prothrombin → 2–3× VTE risk
Antithrombin III (AT-III) deficiency: Rarer but high-risk; AT-III is primary natural anticoagulant; deficiency → 25–50× lifetime VTE risk; consanguinity in GCC increases prevalence of homozygous states
Protein C & S deficiency: Increased frequency in GCC; severe homozygous protein C deficiency causes neonatal purpura fulminans
Antiphospholipid syndrome (APS): Lupus anticoagulant + anticardiolipin/anti-β2-GP1 Ab; arterial and venous thrombosis; pregnancy loss; requires indefinite anticoagulation

Feature	Proximal (Thigh/Popliteal)	Distal (Calf)
Location	Femoral / iliac / popliteal vein	Tibial / peroneal veins
PE risk	High (~50% untreated)	Low (~2%)
Management	Anticoagulate immediately	Serial US vs anticoagulate
Post-thrombotic	Higher risk	Lower risk

Test	Role / Notes
D-dimer (ELISA)	High sensitivity (~95%), low specificity. Elevated in infection, surgery, malignancy, pregnancy. Use with Wells score. Negative D-dimer + low Wells = DVT excluded (no imaging needed)
Compression Duplex US	Gold standard for proximal DVT. Sensitivity 97%, specificity 94% for symptomatic proximal DVT. Less sensitive for calf/pelvic veins
CT Venography	Superior for pelvic and IVC veins; used when US inconclusive or pelvic DVT suspected (pregnancy complications, post-partum, pelvic malignancy)
MRI Venography	No radiation; excellent for pelvic veins; preferred in pregnancy for pelvic/IVC DVT

Clinical Features of PE

Dyspnoea (most common, 73%) — often sudden onset
Pleuritic chest pain (66%) — worse on inspiration
Cough (37%) — may be dry or productive
Haemoptysis (13%) — pulmonary infarction
Tachycardia (HR >100; 26%)
Syncope / presyncope (massive PE → reduced cardiac output)
Signs of DVT (unilateral leg swelling; 15%)
Hypoxaemia (SpO2 <95%)
Hypotension (SBP <90 → massive PE)

PE can be clinically silent: Up to 50% of patients with DVT have asymptomatic PE on imaging. Conversely, PE can mimic pneumonia, pleurisy, ACS, or anxiety.

PE Severity Classification

Category	Haemodynamics	RV Function	Management
Low Risk	Stable (SBP ≥90)	Normal	Anticoagulation; consider outpatient if PESI class I–II
Intermediate (Submassive)	Stable (SBP ≥90)	RV strain on echo or elevated troponin/BNP	Anticoagulate; monitor closely; thrombolysis if deteriorates
Massive	SBP <90 or drop >40 mmHg, shock/arrest	Severe RV failure	Systemic thrombolysis (if no contraindications) or catheter-directed / surgical

Investigations

Test	Findings / Role
CTPA	Gold standard. Sensitivity 83%, specificity 96%. First-line if haemodynamically stable
V/Q scan	Use in: renal failure, contrast allergy, pregnancy (lower radiation dose). Results: normal (excludes PE), high probability, indeterminate
ECG	S1Q3T3 pattern (classic but non-specific, seen in <20%); sinus tachycardia most common; right heart strain; RBBB; AF
Echo (TTE/TOE)	RV dilatation, McConnell's sign (RV free wall akinesia with apical sparing), tricuspid regurgitation, D-sign on parasternal short axis. Useful in haemodynamic instability when CTPA not safe
Troponin	Elevated in RV microinfarction → intermediate/high risk marker; guides monitoring intensity
BNP / NT-proBNP	RV wall stress marker; elevated → worse prognosis; not diagnostic alone
ABG	Hypoxaemia, hypocapnia (hyperventilation), respiratory alkalosis; low PaO2 with wide A-a gradient

Wells PE Score Calculator

Select all applicable criteria. Score guides pre-test probability and diagnostic approach.

Clinical signs and symptoms of DVT (minimum of leg swelling and pain with palpation of deep veins)+3

PE is the #1 diagnosis OR equally likely as alternative diagnosis+3

Heart rate >100 beats/minute+1.5

Immobilisation ≥3 days OR surgery in previous 4 weeks+1.5

Previous objectively diagnosed DVT or PE+1.5

Haemoptysis+1

Active malignancy (treatment within 6 months or palliative)+1

Select criteria above

Tick applicable boxes to see pre-test probability and diagnostic pathway.

Unfractionated Heparin (UFH)

Mechanism & Use

Binds antithrombin III → inhibits thrombin (IIa) and factor Xa
IV infusion for massive PE, haemodynamically unstable patients, high bleeding risk (reversible), renal failure (CrCl <30), pregnancy (does not cross placenta)
Reversal: Protamine sulphate 1 mg per 100 units UFH

Monitoring — aPTT

Target aPTT: 1.5–2.5× control (therapeutic range)
Check aPTT 6 hours after each dose change
Adjust by weight-based nomogram
Check platelets every 2–4 days (HIT surveillance)

Heparin-Induced Thrombocytopenia (HIT):
Paradoxical thrombosis (not bleeding). Suspect if platelets drop ≥50% from baseline or fall <100×10⁹/L at days 5–14 of UFH therapy. Use 4T score. If suspected: STOP all heparin products immediately. Switch to argatroban or fondaparinux. Do NOT use LMWH (cross-reactivity ~90%).

          Weight-Based UFH Dosing (IV):

          Bolus: 80 units/kg (max 10,000 units)

          Infusion: Start at 18 units/kg/h

          Adjust per aPTT every 6 hours until therapeutic × 2 consecutive readings

Low Molecular Weight Heparin (LMWH)

Enoxaparin — Standard Dosing

Treatment (VTE): 1 mg/kg SC twice daily (BD) OR 1.5 mg/kg SC once daily (OD)
Prophylaxis: 40 mg SC OD (standard); 20 mg SC OD (CrCl 15–30)
Preferred over UFH for most VTE (predictable kinetics, less HIT risk)
No routine aPTT monitoring needed

Anti-Xa Monitoring — When to Check

Obesity (BMI >40 or weight >120 kg)
Renal failure (CrCl <30 — consider UFH instead)
Pregnancy (pharmacokinetics change each trimester)
Extremes of weight (<45 kg)
Draw 4 hours post-dose; target 0.5–1.0 IU/mL (BD dosing)

Renal Dosing:
CrCl 15–30: Reduce enoxaparin dose; consider monitoring
CrCl <15 or HD: Use UFH; anti-Xa cannot be reliably used

Reversal: Protamine partially reverses LMWH (~60%); no complete reversal agent (Andexanet alfa reverses anti-Xa activity)

          Cancer-Associated Thrombosis:

          LMWH (e.g., enoxaparin) preferred over warfarin for first 6 months — CLOT trial: 50% relative risk reduction in VTE recurrence.

          Edoxaban and rivaroxaban now non-inferior alternatives (Hokusai-VTE Cancer, SELECT-D trials) but higher GI bleed risk with GI malignancies.

Direct Oral Anticoagulants (DOACs)

Drug	Class	VTE Treatment Dosing	Special Notes
Apixaban (Eliquis)	Factor Xa inhibitor	10 mg BD × 7 days, then 5 mg BD × ≥3 months; extended: 2.5 mg BD	No bridging needed. Least GI bleed risk. Preferred in elderly, GI malignancy. No renal adjustment unless CrCl <25
Rivaroxaban (Xarelto)	Factor Xa inhibitor	15 mg BD × 21 days (with food), then 20 mg OD (with evening meal)	Must be taken with food (bioavailability drops 29% fasted). Higher GI bleed vs apixaban. Avoid CrCl <15
Dabigatran (Pradaxa)	Direct thrombin inhibitor	After 5–10 days of parenteral anticoagulation: 150 mg BD (or 110 mg BD if age ≥80)	Only DOAC requiring parenteral lead-in. Reversed by idarucizumab (Praxbind). Avoid CrCl <30. Dyspepsia common
Edoxaban (Lixiana)	Factor Xa inhibitor	After ≥5 days parenteral: 60 mg OD (30 mg OD if wt ≤60 kg or CrCl 15–50)	Paradoxically less effective if CrCl >95 mL/min — avoid. Good for cancer-associated VTE

DOACs in Pregnancy: ALL DOACs are contraindicated in pregnancy (cross placenta, teratogenic/fetotoxic). Use LMWH throughout pregnancy. Warfarin can be used cautiously in 2nd trimester for mechanical heart valves.

Reversal Agents: Andexanet alfa (AndexXa) — reverses apixaban and rivaroxaban. Idarucizumab (Praxbind) — reverses dabigatran. Four-factor PCC (Beriplex/Octaplex) — off-label option when specific reversal agents unavailable.

Warfarin (Vitamin K Antagonist)

Target INR: 2.0–3.0 for DVT/PE; 2.5–3.5 for mechanical heart valves
Heparin bridging mandatory: Overlap LMWH/UFH with warfarin for minimum 5 days AND until INR ≥2.0 on 2 consecutive readings (warfarin is initially prothrombotic due to protein C/S depletion)
Onset: 3–5 days to therapeutic INR
Reversal: Vitamin K (IV/oral), FFP, 4-factor PCC (immediate reversal)
Extensive drug and food interactions; CYP2C9 polymorphisms affect dose requirement
Warfarin warfarin sensitivity higher in some GCC populations (CYP2C9*2, VKORC1 haplotypes)

          Duration of Anticoagulation:

          Provoked VTE (surgery, trauma, transient risk): 3 months — VTE risk returns to baseline after treatment

          Unprovoked VTE (first episode): ≥3 months; consider indefinite if low bleeding risk; use HERDOO2 / Vienna prediction score

          Unprovoked (second episode): Indefinite anticoagulation recommended

          Cancer-associated: Continue until cancer cured or indefinitely with active cancer

          Antiphospholipid syndrome: Indefinite (warfarin INR 2–3; DOACs inferior for APS)

Massive PE — Recognition & Emergency Management

Definition: SBP <90 mmHg OR drop >40 mmHg from baseline for >15 minutes (not explained by hypovolaemia, sepsis, or arrhythmia) PLUS evidence of RV failure.
Mortality without treatment: 30–50%.

Immediate Actions (ABCDE approach)

High-flow oxygen (15 L/min via non-rebreathe mask); target SpO2 ≥94%
Gain large-bore IV access × 2; cautious fluid resuscitation (250–500 mL bolus — avoid aggressive fluids → RV overdistension)
12-lead ECG, continuous monitoring, ABG, troponin, BNP, CTPA if stable
Vasopressors if persistent hypotension: noradrenaline first-line; vasopressin adjunct
Call senior physician / ICU team immediately

Systemic Thrombolysis

Indications

Massive PE with haemodynamic instability (SBP <90)
Cardiac arrest with suspected PE
Intermediate-risk PE deteriorating despite anticoagulation

Agent & Dose

        Alteplase (rtPA): 100 mg IV over 2 hours (peripheral vein or central line)

        Hold anticoagulation during infusion

        Restart UFH (no bolus) when aPTT <80 seconds after thrombolysis completion

Absolute Contraindications

Any prior intracranial haemorrhage
Ischaemic stroke within 3 months
Structural intracranial lesion (AVM, tumour)
Recent intracranial or spinal surgery within 3 months
Active internal bleeding (not menstrual)
Suspected aortic dissection
Significant closed-head trauma within 3 months

Relative Contraindications

Major surgery / serious non-head trauma within 10 days
Pregnancy or first postpartum week
Non-compressible vascular punctures
Active peptic ulcer disease
Ischaemic stroke >3 months ago
Current anticoagulation use

Advanced Interventional Options

Catheter-Directed Thrombolysis (CDT)

Lower-dose alteplase infused directly into pulmonary artery via catheter
Reduces systemic bleeding risk vs systemic thrombolysis
Indicated: intermediate-high risk PE with relative contraindications to systemic thrombolysis, or failure of systemic therapy
Ultrasound-assisted CDT (EKOS system) — adjunct

Surgical Pulmonary Embolectomy

Last resort for massive PE: absolute contraindication to thrombolysis OR failure of thrombolysis
Cardiopulmonary bypass required
Mortality 20–30% in experienced centres

ECMO (Extracorporeal Membrane Oxygenation)

Bridge to thrombolysis, embolectomy, or recovery
VA-ECMO for cardiogenic shock from massive PE
Used in cardiac arrest or peri-arrest situations

IVC Filter — Indications

Absolute contraindication to anticoagulation with confirmed proximal DVT or PE (active intracranial bleeding, recent surgery)
Recurrent PE despite adequate therapeutic anticoagulation
NOT indicated as routine adjunct to anticoagulation (increases DVT without reducing PE mortality)
Retrievable filters preferred — retrieve when anticoagulation can be resumed

DVT Emergency — Phlegmasia Cerulea Dolens

Definition: Massive proximal DVT occluding virtually all venous drainage of the limb → venous hypertension → arterial insufficiency → limb gangrene if untreated. Medical emergency.

Clinical Features

Severe limb pain, massive swelling
Cyanosis (blue/purple discolouration) — hallmark
Blistering, petechiae, skin necrosis (late)
Loss of peripheral pulses (venous compartment syndrome)
Systemic shock (fluid sequestration into limb)
Contrast: Phlegmasia alba dolens = white leg of pregnancy (femoral vein DVT, arterial spasm, no cyanosis)

Management

Immediate anticoagulation: IV UFH
Limb elevation; IV fluid resuscitation
Urgent catheter-directed thrombolysis (CDT) — alteplase via femoral vein catheter
Surgical thrombectomy if CDT unavailable or ineffective
Fasciotomy if compartment syndrome develops
Amputation as last resort for irreversible ischaemia
ICU monitoring mandatory

Pharmacological Prophylaxis

Agent	Dose	Notes
Enoxaparin	40 mg SC OD (standard)	First-line; reduce to 20 mg if CrCl 15–30; hold 12 h before neuraxial anaesthesia
UFH	5000 units SC TDS (every 8 h)	Preferred in severe renal failure (CrCl <15); no dose adjustment; higher HIT risk; give every 8h (not BD) for surgical patients
Fondaparinux	2.5 mg SC OD	Synthetic anti-Xa; no HIT risk (minimal platelet interaction); avoid CrCl <20; used when UFH/LMWH contraindicated (HIT history)
Apixaban	2.5 mg BD (extended prophylaxis post-THR/TKR)	10–14 days post-TKR; 32–38 days post-THR
Rivaroxaban	10 mg OD post-THR/TKR	35 days post-THR; 14 days post-TKR

Timing of pharmacological prophylaxis:
Initiate within 6–12 hours post-surgery (once haemostasis achieved)
Do NOT give within 4 h of spinal/epidural (neuraxial haematoma risk)
Resume 4 h after epidural catheter removal

Mechanical Prophylaxis

Anti-Embolism Stockings (TED Stockings)

Correct measurement: Measure ankle circumference and length from floor to gluteal fold (for full-length) or floor to knee. Document measurements in patient record
Apply pre-operatively or before ambulation; remove for 30 minutes twice daily for skin inspection
Check hourly for 24 h post-op for signs of ischaemia (pale, cold, painful toes)
Contraindicated if: Peripheral arterial disease (ABI <0.5), diabetic neuropathy, severe oedema, local skin breakdown
Anti-embolism stockings (18 mmHg graduated compression) ≠ therapeutic compression stockings (20–40 mmHg) — do NOT confuse

Intermittent Pneumatic Compression (IPC)

Foot/calf sleeves inflate and deflate cyclically (12-second compression, 48-second release)
Augments venous return; activates endogenous fibrinolysis
Apply intraoperatively and continue postoperatively until fully mobile
Can be used when pharmacological prophylaxis contraindicated (active bleeding)
Remove for patient transfers; document compliance duration (minimum 18 h/24 h for efficacy)
Contraindicated in acute DVT (risk of dislodging thrombus → PE)

Bleeding Risk Assessment — When to Withhold Prophylaxis

IMPROVE Bleeding Risk Score (Medical Patients)

Active gastroduodenal ulcer (+4.5)
Bleeding within 3 months before admission (+4)
Platelet count <50×10⁹/L (+4)
Age ≥85 (+3.5)
Hepatic failure — INR >1.5 (+2.5)
ICU/CCU admission (+2.5)
Central venous catheter (+2)
Rheumatic disease (+2)
Male sex (+1)
Score ≥7: High bleeding risk — use mechanical methods only

General Contraindications to Pharmacological Prophylaxis

Active major bleeding or haemorrhagic stroke
Thrombocytopenia (platelets <50×10⁹/L)
Uncontrolled severe hypertension
Neurosurgery / spinal surgery (first 24–48 h)
HIT (switch to non-heparin agent)
Severe hepatic failure (coagulopathy)
Lumbar puncture / epidural in past 4 h

          Risk-Benefit Discussion:

          Always weigh VTE risk (Padua/Caprini score) against bleeding risk (IMPROVE/HAS-BLED). Document the decision and review daily. Combination mechanical + pharmacological provides synergistic benefit in highest-risk patients.

Non-Pharmacological & GCC Hospital VTE Bundle

Non-Pharmacological Measures

Early mobilisation: Most powerful non-pharmacological intervention; physiotherapy referral within 24 h of admission; ambulate to toilet if safe
Adequate hydration: Critical in GCC — minimum 30 mL/kg/day; monitor fluid balance; particularly important in fasting states and extreme heat
Leg exercises in bed: Ankle pumps 10× hourly; calf flexion/extension; teach patient and family
Avoid constrictive clothing around groin or knee
Elevate foot of bed 10–15° if tolerated

GCC Hospital VTE Compliance Bundle

VTE risk assessment completed within 24 h of admission (Joint Commission International requirement)
Bleeding risk assessment documented concurrently
Prophylaxis order (pharmacological and/or mechanical) entered within 24 h
TED stocking measurement documented; IPC applied within 4 h of surgical admission
Patient/family education completed (discharge)
Reassessment triggered by: transfer to ICU, new diagnosis (malignancy), post-procedure, clinical deterioration

Hospital VTE bundle compliance target: ≥95% (JCI/MOH standard). Non-compliance reportable as quality indicator in KSA, UAE, and Qatar National Health Authority.

Practice MCQs — DVT & PE

10 questions | Click an answer option to check instantly | Score tracked below

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Q1.A 58-year-old man presents with a 3-day history of left calf pain and swelling. He had a right total knee replacement 6 weeks ago. His Wells DVT score is calculated. Which feature, if present, would REDUCE his Wells DVT score?

A. Active cancer diagnosis

B. Entire leg swelling on the affected side

C. An alternative diagnosis (e.g., Baker's cyst) being at least as likely as DVT

D. Previously documented DVT

The "alternative diagnosis equally likely" criterion subtracts 2 points from the Wells DVT score. All other listed features ADD points (+1 each). This feature is critical — it prevents over-investigation when another diagnosis clearly explains the presentation.

Q2.A 34-year-old woman on the combined oral contraceptive pill presents to the Emergency Department with sudden-onset dyspnoea and right-sided pleuritic chest pain. HR 88 bpm, SpO2 98%, no leg swelling, no haemoptysis. Wells PE score is 1.5 (low). Which is the MOST appropriate next step?

A. Proceed directly to CTPA

B. Discharge with safety-netting advice — low probability, no imaging needed

C. Apply PERC rule; she meets all 8 PERC criteria so discharge safely

D. PERC rule cannot exclude PE here (she is on OCP — PERC criterion not met); perform D-dimer

PERC requires ALL 8 criteria to be absent for exclusion. "No exogenous oestrogen" is one criterion — this patient is ON the OCP, so PERC is positive. PERC cannot be used to exclude PE. The next step is D-dimer (Wells PE <2). If D-dimer negative → PE excluded. If elevated → CTPA.

Q3.You receive a patient from theatre following emergency laparotomy for bowel obstruction 6 hours ago. She is 72 years old, BMI 34, with no prior VTE. When is it most appropriate to initiate pharmacological VTE prophylaxis?

A. Immediately on admission to the ward — no delay needed

B. When surgeon confirms haemostasis is adequate and pharmacological prophylaxis is prescribed (typically 6–12 hours post-op)

C. Only after 48 hours to ensure wound healing

D. Not recommended — mechanical prophylaxis only for abdominal surgery patients

Pharmacological prophylaxis should begin 6–12 hours post-surgery once haemostasis is confirmed. Immediate post-op initiation risks haematoma formation. Waiting 48 hours is excessive and increases VTE risk. Mechanical prophylaxis (IPC) should be applied intraoperatively and continued until pharmacological prophylaxis begins.

Q4.A patient on UFH infusion for DVT develops sudden thrombocytopenia on day 8 — platelets drop from 210 to 88 × 10⁹/L. The 4T score is high. What is the MOST important immediate nursing action?

A. Increase the UFH infusion rate to maintain therapeutic aPTT

B. Switch to LMWH enoxaparin and continue anticoagulation

C. Stop all heparin products immediately and notify the physician to switch to a non-heparin anticoagulant (e.g., argatroban)

D. Administer platelet transfusion to raise count above 100

HIT (Heparin-Induced Thrombocytopenia) is a paradoxical THROMBOTIC complication — NOT a bleeding disorder. Immediate cessation of ALL heparin products is mandatory (cross-reactivity ~90% with LMWH). Switch to a non-heparin anticoagulant (argatroban, fondaparinux, or bivalirudin). Platelet transfusion is contraindicated — it "fuels the fire" of HIT thrombosis.

Q5.A 45-year-old Saudi woman is prescribed rivaroxaban for a first unprovoked proximal DVT. She asks "how long will I need this tablet?" According to current guidelines, what is the most appropriate answer?

A. 6 weeks — short course is sufficient for first DVT

B. Exactly 3 months — standard for all DVT patients

C. At least 3 months; indefinite treatment is then considered based on bleeding risk and patient preference

D. 12 months mandatory for proximal DVT regardless of aetiology

Unprovoked proximal DVT carries a recurrence risk of ~30% at 5 years without anticoagulation. Guidelines recommend ≥3 months minimum, followed by shared decision-making about extended (indefinite) treatment. Factors favouring extended therapy: male sex, elevated D-dimer after stopping anticoagulation (Vienna model), no significant bleeding risk. Recurrent unprovoked VTE mandates indefinite anticoagulation.

Q6.A 68-year-old man with stage IV lung cancer presents with confirmed PE. Which anticoagulation regimen is MOST appropriate for initial management?

A. Warfarin, target INR 2–3, after 5-day UFH bridge

B. LMWH (enoxaparin) for first 6 months, then reassess; alternatively edoxaban or rivaroxaban

C. Dabigatran started immediately without parenteral lead-in

D. Aspirin 300 mg daily as antiplatelet therapy for cancer-associated clot

Cancer-associated VTE: LMWH (CLOT trial) reduced recurrence 50% vs warfarin for first 6 months and remains guideline-supported. More recently edoxaban (Hokusai-VTE Cancer) and rivaroxaban (SELECT-D) showed non-inferior efficacy but higher GI bleeding risk — exercise caution with GI malignancies. Warfarin is suboptimal due to drug-food interactions, chemotherapy-related thrombocytopenia, and variable INR. Dabigatran requires a parenteral lead-in and is not first-line for cancer-VTE. Aspirin has no role in VTE treatment.

Q7.A 55-year-old woman is admitted with massive PE confirmed on CTPA. SBP is 76 mmHg. She had a right total hip replacement 10 days ago. What is the MOST appropriate definitive treatment?

A. Systemic thrombolysis with alteplase 100 mg IV over 2 hours — no contraindications apply

B. Major surgery within 10 days is a relative contraindication; multidisciplinary decision needed — consider catheter-directed thrombolysis or surgical embolectomy

C. Start UFH infusion only — thrombolysis never indicated within 3 months of surgery

D. IVC filter insertion is the definitive treatment for massive PE

Surgery within 10 days is a RELATIVE (not absolute) contraindication to systemic thrombolysis. In haemodynamic collapse the risk-benefit often favours thrombolysis. However, this requires urgent senior/MDT decision. Catheter-directed thrombolysis delivers lower-dose lytic agent directly to the clot, reducing systemic bleed risk — preferred here if available. Surgical embolectomy is an option if thrombolysis fails or is contraindicated. IVC filter treats recurrent PE, not acute massive PE.

Q8.You are measuring TED stockings for a post-operative patient. She tells you her previous nurse said to leave them on continuously and never remove them. What is the correct guidance?

A. Correct — anti-embolism stockings should never be removed until the patient is fully mobile

B. Remove them only when the patient showers — daily is unnecessary

C. Remove for 30 minutes at least twice daily to inspect skin for pressure injury, ischaemia, or incorrect fit; reapply promptly

D. Remove overnight and reapply each morning

TED stockings must be removed for at least 30 minutes TWICE DAILY (some guidelines say once daily minimum) to inspect skin for pressure sores, ischaemia, or allergic reactions — particularly at the heel, ankle, and behind the knee. Check toes for capillary refill. Document skin condition. Also verify correct sizing at each shift assessment — stockings that are too tight act as a tourniquet and increase DVT risk.

Q9.A 29-year-old Emirates cabin crew member presents with severe left arm pain and swelling after an unusually heavy week of flying. Duplex US confirms left subclavian vein thrombosis. He is otherwise fit and healthy with no CVC. What is the MOST likely underlying mechanism?

A. Catheter-associated upper limb DVT from recent PICC insertion

B. Paget-Schroetter syndrome (effort thrombosis) — compression of subclavian vein at thoracic outlet

C. Malignancy-related hypercoagulability

D. Antiphospholipid syndrome — routine anticoagulation indefinitely

Paget-Schroetter syndrome (primary UEDVT / effort thrombosis) typically affects young, athletic adults — particularly those performing repetitive arm movements (cabin crew, swimmers, baseball pitchers, construction workers). The subclavian vein is compressed between the first rib and clavicle at the thoracic outlet. Management: anticoagulation, then consider surgical thoracic outlet decompression (first rib resection) to prevent recurrence. This is distinct from secondary catheter-associated UEDVT.

Q10.A 77-year-old woman with CKD stage 4 (CrCl 22 mL/min) is admitted with an acute medical illness. Padua score is 5. Which pharmacological VTE prophylaxis is MOST appropriate?

A. Enoxaparin 40 mg SC once daily — standard Padua high-risk prophylaxis

B. Rivaroxaban 10 mg once daily — preferred DOAC for medical prophylaxis

C. UFH 5000 units SC three times daily — preferred in severe renal failure as it does not accumulate

D. Fondaparinux 2.5 mg SC once daily — safest renal option

In severe renal impairment (CrCl <30 mL/min), enoxaparin accumulates (renally cleared) → risk of haematoma and serious bleeding. UFH is NOT renally cleared — it is metabolised by the reticuloendothelial system and thus safe to use at standard prophylactic doses (5000 units TDS) in renal failure with no dose adjustment needed. Fondaparinux is contraindicated when CrCl <20 mL/min (this patient is borderline at 22). Rivaroxaban has insufficient evidence for medical prophylaxis and is not appropriate here.

Venous Thromboembolism (VTE) — DVT & PE