Right drug · Right dose · Right duration · Right monitoring. A complete concept-building reference for clinicians at every level.
Anticoagulation stewardship is the systematic, ongoing process of ensuring every patient is on the right drug, right dose, right indication, right duration — with continuous monitoring and review at every clinical contact.
Think of it exactly like antibiotic stewardship — but for anticoagulants. Prevent both under-treatment and over-treatment, reduce avoidable harm, and build a system around the prescription rather than stopping at the drug chart.
Anticoagulants are consistently in the top five drug classes causing preventable hospital harm. Getting it wrong causes thrombosis or bleeding — both can be fatal.
Over 1 million UK patients are on anticoagulation at any time. DOACs have overtaken warfarin but introduce new risks — fixed dosing, less monitoring, more room for clinical error.
Prescribing is starting a drug. Stewardship asks: Does this patient still need it? Is the dose right for today's renal function? Has the risk balance shifted?
Haematologists, anticoagulation nurses, clinical pharmacists, thrombosis leads. It needs team governance, not individual heroics.
Too much: Major bleeding, intracranial haemorrhage, GI bleed, haematoma. Especially dangerous in the elderly, renally impaired, post-surgical, and patients on interacting medications.
Too little: Recurrent VTE, stroke in AF, valve thrombosis, cancer clotting events. Subtherapeutic anticoagulation in AF carries stroke rates approaching no treatment at all.
Keep every patient within the therapeutic window. For warfarin: TTR >65%. For DOACs: correct dose for renal function and indication — reviewed regularly, not set and forgotten.
| Clinical Scenario | The Failure | Consequence | Risk |
|---|---|---|---|
| AF patient on apixaban 5mg BD — creatinine now 180 | Dose not adjusted despite worsening renal function | Drug accumulation → major bleeding | High |
| DVT treated 3 months — no review scheduled | Anticoagulant continued indefinitely by default | Unnecessary bleeding risk | Medium |
| Elderly patient, warfarin, INR 4.8 — no action taken | No sick-day rule. No dose reduction protocol. | Intracranial haemorrhage | High |
| Post-op — LMWH omitted beyond recommended window | VTE prophylaxis withheld for perceived safety | DVT / PE | Medium |
| DOAC started for AF — no CHA₂DS₂-VASc calculated | Indication not formally assessed before prescribing | Over- or under-prescribing | Variable |
| Cancer VTE on LMWH — switched to DOAC without review | Indication-specific evidence not considered | Recurrent VTE or bleeding | High |
Validated, documented reason to anticoagulate?
Cancer-VTE → LMWH/DOAC. AF → DOAC. Valve → Warfarin.
Renal function, weight, age, drug interactions. Not one size fits all.
3 months for provoked VTE. Lifelong for AF. Set a review date.
INR for warfarin. eGFR for DOACs. Bleeding scores. Education.
Right Indication · Right Drug · Right Dose · Right Duration · Right Monitoring. If any one of the five is absent, you do not have safe anticoagulation — you have a risk waiting to manifest.
| Indication | Minimum Duration | Extended? | Review Point |
|---|---|---|---|
| Provoked DVT/PE (transient risk) | 3 months | Stop and review | 3-month clinic |
| Unprovoked DVT/PE | 3–6 months | Consider indefinite | 6-month HERDOO2 / HAS-BLED |
| AF (CHA₂DS₂-VASc ≥2M / ≥3F) | Indefinite | Usually lifelong | Annual renal + bleeding review |
| Cancer-associated VTE | Min 6 months | While cancer active | Oncology review each cycle |
| Mechanical heart valve | Lifelong | Warfarin — no DOAC switch | Monthly INR |
| Post-surgical VTE prophylaxis | 7–35 days | No (standard ortho) | Discharge planning |
| APS (triple positive) | Lifelong | Warfarin — avoid DOACs | Annual thrombophilia review |
1. Mechanical heart valves — warfarin only (RE-ALIGN trial: dabigatran caused more events). 2. APS with triple positivity — warfarin preferred (TRAPS trial: higher event rate with rivaroxaban). 3. Severe renal failure (CrCl <15–30) — all DOACs accumulate; warfarin or LMWH required.
| Agent | CrCl >50 | CrCl 30–50 | CrCl 15–29 | CrCl <15 |
|---|---|---|---|---|
| Apixaban (AF) | 5mg BD | 5mg BD (reduce if criteria) | 2.5mg BD | Not recommended |
| Rivaroxaban (AF) | 20mg OD | 15mg OD | 15mg OD (caution) | Avoid |
| Dabigatran (AF) | 150mg BD | 150mg BD (110mg if ≥80) | Avoid | Avoid |
| Edoxaban (VTE) | 60mg OD (reduce if >100) | 30mg OD | 30mg OD (caution) | Avoid |
Check eGFR at least annually for all DOAC patients. Elderly, frail, or acutely unwell — every 3–6 months. Use CKD-EPI, not MDRD. Dabigatran is 80% renally excreted — most sensitive to renal decline.
Every anticoagulation decision weighs thrombotic against haemorrhagic risk. Neither score alone drives the decision — clinical judgement integrates both. But you need the numbers to anchor your reasoning.
| Risk Factor | Score |
|---|---|
| Cardiac failure / LVEF <40% | 1 |
| Hypertension | 1 |
| Age ≥75 years | 2 |
| Diabetes mellitus | 1 |
| Stroke / TIA / thromboembolism | 2 |
| Vascular disease (MI, PAD) | 1 |
| Age 65–74 years | 1 |
| Female sex | 1 |
Score ≥2 (men) / ≥3 (women) → anticoagulate.
Score 1 (men) / 2 (women) → consider anticoagulation.
| Risk Factor | Score |
|---|---|
| Hypertension (SBP >160) | 1 |
| Renal dysfunction (dialysis / Cr >200) | 1 |
| Liver dysfunction (cirrhosis / bilirubin >2×) | 1 |
| Stroke history | 1 |
| Bleeding history or predisposition | 1 |
| Labile INR (TTR <60%) | 1 |
| Elderly (>65 years) | 1 |
| Drugs (antiplatelets / NSAIDs) | 1 |
| Alcohol (≥8 drinks/week) | 1 |
Score ≥3 → high bleeding risk. Not a reason to withhold — it flags modifiable factors to address.
A high HAS-BLED score is not a reason to stop anticoagulation in AF — it is a reason to modify reversible bleeding risk factors. Uncontrolled BP? Treat it. NSAIDs? Stop them. Labile INR? Switch to a DOAC. In AF with CHA₂DS₂-VASc ≥2, the stroke risk almost always outweighs bleeding risk.
| Risk Factor | Score |
|---|---|
| High-risk cancer site (gastric, pancreatic) | 2 |
| Lung, lymphoma, gynaecological, bladder, testicular | 1 |
| Pre-chemo platelet count ≥350 × 10⁹/L | 1 |
| Haemoglobin <100 g/L or ESA use | 1 |
| Pre-chemo WBC >11 × 10⁹/L | 1 |
| BMI ≥35 | 1 |
Score ≥2 = high VTE risk during chemotherapy. Consider primary thromboprophylaxis with apixaban or rivaroxaban (AVERT/CASSINI trial evidence) or LMWH.
Bridging is NOT needed for most AF patients on warfarin having elective procedures (BRIDGE trial 2015: no reduction in thrombosis, significant increase in bleeding). Bridging IS considered for: mechanical mitral valve, VTE within 3 months, very high stroke risk AF. DOACs require no bridging — stop based on procedural bleeding risk, then restart.
Check INR 2–3 days pre-op. Target INR <1.5 for most; <1.2 for neurosurgery/ophthalmology.
Once INR <2.0. Last dose 24 hours before procedure.
Hold LMWH. Restart warfarin same evening if haemostasis achieved.
Continue until INR 2.0–3.0 on two consecutive readings, then stop LMWH.
| Agent | Low Bleed Risk — Stop | High Bleed Risk — Stop | Restart Post-Op |
|---|---|---|---|
| Apixaban / Rivaroxaban | 24h before | 48h before | 24–48h after |
| Dabigatran (CrCl >50) | 24h before | 48h before | 24–48h after |
| Dabigatran (CrCl 30–50) | 36h before | 72–96h before | 48–72h after |
Major or life-threatening bleeding (intracranial, haemodynamic compromise, organ-threatening), or urgent surgery that cannot be delayed. For non-major bleeding or elective procedures — hold the drug and wait. Specific reversal is not always required or available.
Stop anticoagulant. Direct pressure. Transfuse if haemodynamically compromised. Tranexamic acid 1g IV for mucosal / wound bleeding. PCC as a holding measure for Xa inhibitors. Activated charcoal within 2–4h of DOAC ingestion if no contraindication. Haemodialysis removes dabigatran — not Xa inhibitors.
| Agent | What to Monitor | Frequency | Action Trigger | Lab Test |
|---|---|---|---|---|
| Warfarin | INR — target 2.0–3.0 (valve: 2.5–3.5) | Weekly until stable → monthly | INR <1.5 or >5.0 → urgent review. TTR <65% → optimise or switch | INR (PT ratio) |
| Apixaban | eGFR, weight, dose criteria | Annually; 3–6 monthly if CrCl <60 / frail | CrCl <25–30 → review dose; <15 → haematology advice | Anti-Xa (drug-specific) |
| Rivaroxaban | eGFR, dose appropriateness | Annually; more if declining renal function | CrCl <30 (AF) → reduce; <15 → avoid | Anti-Xa (drug-specific) |
| Dabigatran | eGFR — CrCl ÷ 10 = months between checks | Calculated from renal function | CrCl <30 → avoid; consider switch to warfarin or apixaban | dTT or ECT if needed |
| LMWH (cancer-VTE) | Platelets (HIT surveillance), renal function | Weekly ×4 weeks → monthly | Platelet drop >50% → suspect HIT → anti-PF4, stop LMWH | Anti-Xa (4h post dose) |
CrCl (mL/min) ÷ 10 = monitoring interval in months. CrCl 60 → every 6 months. CrCl 30 → every 3 months. This prevents drug accumulation and harm before it occurs.
| Test | Measures | Useful For | Key Limitation |
|---|---|---|---|
| INR / PT | Extrinsic + common pathway | Warfarin monitoring | Unreliable for DOACs — can be misleading |
| APTT | Intrinsic + common pathway | UFH, dabigatran (rough guide) | Not linear with dabigatran at therapeutic doses |
| Anti-Xa (drug-specific) | Plasma DOAC level (Xa inhibitors) | Overdose, surgery timing, renal failure | Must specify which drug — not all labs calibrated for all agents |
| dTT (dilute thrombin time) | Dabigatran concentration | Dabigatran monitoring / reversal decision | Not widely available; ECT is an alternative |
| ECT (Ecarin Clotting Time) | Meizothrombin generation / Direct Thrombin Inhibitor activity | Dabigatran monitoring; argatroban, bivalirudin, HIT transition; confirming idarucizumab reversal | Not widely available; clot-based ECT affected by low fibrinogen / low prothrombin; not useful for FXa inhibitors |
| TEG / ROTEM | Global clot formation dynamics | Perioperative / massive haemorrhage | Not specific for individual DOAC levels |
A patient on apixaban can have a completely normal INR and APTT yet have full anticoagulant effect. Only a calibrated anti-Xa assay detects apixaban or rivaroxaban. Always ask about DOAC use in emergency surgery even when standard coagulation tests are normal.
If asked "What does anticoagulation stewardship mean in your practice?" — the answer goes beyond the drug chart. It includes: structured indication review at every contact, renal function monitoring at fixed intervals, patient education on sick day rules, systematic deprescribing when duration is met, and pharmacist-led anticoagulation clinics with clear governance.
AF: ESC 2023, NICE NG196. VTE: BSH 2023, NICE NG158. Cancer-VTE: ISTH 2019, BSH 2022. Reversal: BSH 2022. Peri-procedural: ACC/AHA 2022. APS: EULAR 2019.