VTE Prophylaxis in Medical Inpatients — Bleeding Risk Cut‑offs, Algorithm, and Quick‑Reference (Blood🩸Doctor Pocket Card)

Dr Abdul Mannan FRCPath FCPS I Blood🩸Doctor I [email protected]

Quick cut‑offs before starting LMWH

Platelets
- < 50 ×10⁹/L → high bleeding risk in IMPROVE; usually avoid or individualise pharmacological prophylaxis.[1]
- 50–75 ×10⁹/L → grey zone; weigh VTE risk, trend, cause, and alternatives.[1]
75 ×10⁹/L → generally acceptable if no other risks.[1]
Coagulation/liver
- Liver failure with INR > 1.5 counts toward high bleeding risk; correct reversible causes and individualise.[1]
- Active DIC/uncompensated coagulopathy or ongoing bleeding → do not start pharmacological prophylaxis.[2]
Renal function
- eGFR < 30 mL/min → avoid standard LMWH dosing; consider UFH, or adjusted LMWH with monitoring per local policy.[2][3]
Recent neuraxial anaesthesia or high‑risk procedure → respect timing windows; consider mechanical prophylaxis pending reassessment.[2]

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High‑risk situations to hold pharmacological prophylaxis: active bleeding, critical‑site bleeding, platelets < 50 ×10⁹/L (especially < 20–30), uncontrolled coagulopathy, immediate post‑neuraxial period, or inability to dose safely in severe renal failure. Use mechanical prophylaxis and reassess daily.[4][2]

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Bedside reference table

Parameter	Prefer pharmacological prophylaxis?	Notes
Platelets ≥ 75 ×10⁹/L	Yes (if VTE risk present)	Standard LMWH dose acceptable
Platelets 50–74 ×10⁹/L	Individualise	Consider VTE risk, trend, aetiology; consider mechanical ± haematology input
Platelets < 50 ×10⁹/L	Generally no	Mechanical prophylaxis; escalate only with clear indication and plan
INR > 1.5 (liver failure)	Caution	Address correctable causes; counts in IMPROVE bleed risk
eGFR < 30 mL/min	Caution	UFH preferred or adjusted LMWH with monitoring
Active bleeding/DIC	No	Mechanical only until corrected
Early post‑neuraxial	No	Follow anaesthesia timing guidance

[1][2][3]

Use a validated bleeding risk tool

IMPROVE Bleeding Risk Score for medical inpatients includes: platelets < 50 ×10⁹/L, liver failure (INR > 1.5), severe renal failure (< 30 mL/min), recent bleeding, active ulcer, ICU/CCU, CVC, cancer, age, male sex.[1]
Operationalise: low score → pharmacological prophylaxis; high score → mechanical prophylaxis with daily reassessment.[1]

Decision algorithm

flowchart TD
    A(["Medical inpatient with VTE risk"])
      --> B{"Absolute contraindication for anticoagulant prophylaxis?"}

    B -- Yes --> C(["Use mechanical prophylaxis(IPC/GCS) and reassess daily"])
    B -- No  --> D{"Calculate IMPROVE bleeding risk"}

    D -- Low risk --> E(["Start LMWH prophylaxis (e.g., enoxaparin 40 mg SC daily)"])
    D -- High risk --> F(["Prefer mechanical prophylaxis; correct reversible risks; reassess daily"])

    E --> G{"eGFR < 30 mL/min?"}
    G -- Yes --> H(["Consider UFH or adjusted LMWH with monitoring"])
    G -- No  --> I(["Continue standard dose"])

    E --> J{"Neuraxial procedure planned?"}
    J -- Yes --> K(["Time doses per anaesthesia guidance; consider mechanical until safe"])
    J -- No  --> L(["Proceed"])