Anticoagulation Management — Advanced Nursing Guide

Anticoagulation Mechanisms & Drug Classes

Coagulation Cascade Overview

INTRINSIC PATHWAY
XII→XI→IX→VIII + EXTRINSIC PATHWAY
Tissue Factor + VII → COMMON PATHWAY
X → Xa

Xa + Va
Prothrombinase complex → Prothrombin (II)
→ Thrombin (IIa) → Fibrinogen
→ Fibrin → CLOT
+ XIII crosslink

PT/INR tests extrinsic pathway | APTT tests intrinsic pathway | Both reflect common pathway

Drug Targets on the Cascade

Drug/Class	Mechanism & Targets
UFH	Activates antithrombin III → inhibits Xa + IIa (thrombin). Binds AT in 1:1 ratio. Larger chains also bind IIa.
LMWH	Activates antithrombin → inhibits Xa primarily; weak IIa inhibition. Anti-Xa:anti-IIa ratio ~4:1 (enoxaparin).
Fondaparinux	Synthetic pentasaccharide — activates AT → inhibits Xa only. Too short to bridge to IIa.
Warfarin	Inhibits vitamin K epoxide reductase (VKOR) → impairs carboxylation of factors II, VII, IX, X + protein C, S.
Dabigatran	Direct thrombin (IIa) inhibitor — competitive, reversible. No AT needed.
Rivaroxaban Apixaban Edoxaban	Direct factor Xa inhibitors — competitive binding at active site. No AT needed.
Argatroban Bivalirudin	Parenteral direct thrombin inhibitors. Used in HIT or PCI.

Indications Comparison

Indication	Options
VTE Treatment	LMWH→warfarin \| NOAC (rivaroxaban/apixaban preferred) \| UFH in severe renal failure
VTE Prevention	LMWH \| fondaparinux \| rivaroxaban \| apixaban
Atrial Fibrillation	Warfarin (INR 2-3) \| NOACs (preferred over warfarin in most) \| Aspirin not recommended
Mechanical Heart Valves	Warfarin ONLY — NOACs contraindicated (RE-ALIGN trial: dabigatran inferior)
ACS / PCI	UFH \| LMWH \| bivalirudin; fondaparinux + bailout UFH for PCI
Antiphospholipid Syndrome	Warfarin preferred (INR 2-3); rivaroxaban showed inferiority in RAPS/TRAPS trials
Pregnancy	LMWH only — warfarin teratogenic (T1); NOACs contraindicated

Monitoring Tests — When & Why

Test	Monitors	Target / Normal	Notes
INR (PT ratio)	Warfarin effect (extrinsic pathway, factors II/VII/X)	2.0–3.0 most indications; 2.5–3.5 mechanical mitral valve	Standardised across labs. Not useful for NOACs.
APTT	UFH therapy (intrinsic pathway)	1.5–2.5× control (~60–100 sec)	Also elevated in dabigatran — qualitative only
Anti-Xa level	LMWH in special populations; also UFH by anti-Xa method	LMWH therapeutic: 0.5–1.0 IU/mL (4h post dose BD dosing); prophylactic: 0.2–0.4	Check in obesity, pregnancy, renal impairment, neonates
Thrombin Time (TT)	Dabigatran — very sensitive; elevated even at low levels	Normal TT = dabigatran unlikely to be present	Qualitative screen; ECT more quantitative
Ecarin Clotting Time (ECT)	Dabigatran — quantitative	Correlates with dabigatran concentration	Not widely available in all GCC labs
Anti-Xa (chromogenic)	Rivaroxaban / apixaban levels	Drug-specific calibrators needed	Routine monitoring not required; use in emergencies or renal/hepatic concerns
Platelet count	HIT screening on UFH	Baseline, then every 2-3 days on days 4-14	Fall >50% or absolute <100 × 10⁹/L — investigate HIT

Warfarin Management

Initiation & Loading Dose Protocols

Standard Adult: 5 mg loading dose (days 1-2), then adjust per INR response

Higher Bleeding Risk — Use 5 mg or Less: Age >75, low body weight (<50 kg), liver disease, heart failure, malnutrition, CYP2C9/VKORC1 variants, concurrent interacting drugs, post-cardiac surgery

Some protocols use 10 mg loading (younger, robust patients with VTE needing rapid anticoagulation) — but increased risk of over-anticoagulation in first 3-5 days

Initiation Monitoring Schedule

Day 0: Baseline INR, FBC, LFTs, renal function
Day 3-4: First INR check after loading
Weekly until stable (2 consecutive INRs in range)
Monthly when stable
Any INR check after dose change or new interacting drug

Bridging with LMWH

Continue LMWH therapeutic dose until INR ≥2.0 for 2 consecutive days (usually 5-7 days overlap minimum)

INR Targets by Indication

Indication	INR Target
VTE treatment (DVT/PE)	2.0 – 3.0
VTE prevention (recurrent risk)	2.0 – 3.0
Atrial fibrillation	2.0 – 3.0
Mechanical aortic valve	2.0 – 3.0
Mechanical mitral valve	2.5 – 3.5
Antiphospholipid syndrome (standard)	2.0 – 3.0
High-risk APS (triple positive + thrombosis)	3.0 – 4.0

Time in Therapeutic Range (TTR): >65% is the quality benchmark. TTR <65% indicates poor control — consider switching to NOAC if appropriate indication.

Dose Adjustment Algorithm

INR Result	Action	Recheck Timing
<1.5	Increase weekly dose by 10-20%; consider extra dose if subtherapeutic and high clot risk	1 week
1.5 – 1.9	Increase weekly dose by 5-10%	2 weeks
2.0 – 3.0 (target)	No change	4-6 weeks (stable) or 1-2 weeks (recently adjusted)
3.1 – 3.9	Reduce weekly dose by 5-10%	2 weeks
4.0 – 4.9	Omit 1-2 doses, reduce weekly dose by 10-15%	1 week
5.0 – 8.9 (no bleeding)	Hold warfarin, consider oral vitamin K 1-2.5 mg. Restart at lower dose when INR therapeutic.	24-48 hours
≥9.0 (no serious bleeding)	Hold warfarin, oral vitamin K 5 mg	24 hours
Any INR + active bleeding	See Bleeding & Reversal tab	—

Key Drug Interactions

Drugs That INCREASE Warfarin Effect (INR rises — bleeding risk)

Amiodarone — inhibits CYP2C9 and CYP3A4; reduces warfarin dose by 30-50%; effect delayed 1-4 weeks
Fluconazole — potent CYP2C9 inhibitor; even single doses can raise INR significantly
Ciprofloxacin / metronidazole — reduce vitamin K-producing gut flora; CYP inhibition
Erythromycin / clarithromycin — CYP3A4 inhibition
Omeprazole — mild CYP2C19 effect; monitor
NSAIDs — do NOT raise INR but increase GI bleeding risk significantly
Aspirin — antiplatelet effect + GI bleeding; avoid combination unless mechanical valve

Drugs That DECREASE Warfarin Effect (INR falls — clot risk)

Rifampicin — potent CYP induction; may require 2-3× normal warfarin dose
Carbamazepine / phenytoin — CYP induction
St John's Wort — herbal CYP inducer; common in GCC
Cholestyramine — reduces warfarin absorption

Diet, Lifestyle & Patient Education

Vitamin K & Diet

Consistent vitamin K intake is the key message — NOT vitamin K avoidance. Large sudden changes in vitamin K intake destabilise INR.

High vitamin K: spinach, kale, broccoli, cabbage, brussels sprouts, green tea
Moderate: lettuce, asparagus, cucumber skin
Low: fruit, bread, dairy, meat, eggs

Advice: Eat green vegetables regularly and consistently. Do not suddenly increase or avoid them.

Patient Self-Testing / Self-Management

Point-of-care INR devices (CoaguChek) — validated for self-testing
Patient self-management (PSM): patient adjusts dose based on INR result — evidence shows superior TTR vs clinic management
Requires training, literacy, and regular review
Anticoagulation clinic model: specialist nurse-led, dose algorithms, patient education, TTR tracking — gold standard in GCC hospitals

Other Lifestyle Advice

Avoid contact sports / activities with high injury risk
Carry anticoagulation alert card (Medical ID)
Alcohol: limit to ≤14 units/week; binge drinking unpredictable effect
Report any unusual bleeding, falls, new medications immediately

NOACs — Non-Vitamin K Oral Anticoagulants (Direct Oral Anticoagulants)

General NOAC Advantages: Predictable pharmacokinetics, no routine monitoring, few food interactions, rapid onset (1-4 hours), shorter half-life than warfarin, proven non-inferior or superior to warfarin for most indications.

General Cautions: Renal function monitoring essential (frequency depends on agent), avoid in pregnancy, NOACs CONTRAINDICATED in mechanical heart valves, avoid with strong P-gp/CYP3A4 inducers (rifampicin).

Dabigatran (Pradaxa) — Direct Thrombin Inhibitor

Property	Details
Dosing	Twice daily (BD)
VTE Treatment	150 mg BD (after 5-10 days parenteral anticoagulation)
AF Stroke Prevention	150 mg BD; 110 mg BD if age >80 or high bleed risk
Renal Clearance	80% — most renally cleared of all DOACs
Avoid if eGFR	<30 for VTE; <15 for AF; caution 30-50
Side effects	Dyspepsia (10-15%) — take with food or use PPI
Reversal Agent	Idarucizumab (Praxbind) 5g IV — only DOAC with specific licensed reversal agent
Monitoring	eGFR: 6-monthly if eGFR 30-60; 3-monthly if 15-30. TT screen if toxicity suspected.

Key fact: Dabigatran is dialysable (~60% removed by 2-4h dialysis) — useful in overdose if idarucizumab unavailable.

Rivaroxaban (Xarelto) — Direct Factor Xa Inhibitor

Property	Details
Dosing	Once daily (OD) with evening meal (increases absorption ~39%)
VTE Treatment	15 mg BD with food × 21 days, then 20 mg OD with food
AF	20 mg OD with evening meal (15 mg if eGFR 15-50)
Renal Clearance	~33% unchanged renal; rest hepatic/metabolised
Avoid if eGFR	<15 (all indications); dose adjust for eGFR 15-49 in AF
Renal Monitoring	6-monthly
Reversal	Andexanet alfa (licensed) or 4-factor PCC (unlicensed)

Key fact: Must be taken WITH food — absorption is significantly reduced in fasted state. Most prescribed DOAC globally.

Apixaban (Eliquis) — Direct Factor Xa Inhibitor

Property	Details
Dosing	Twice daily (BD) — can be taken with or without food
VTE Treatment	10 mg BD × 7 days, then 5 mg BD
AF	5 mg BD; 2.5 mg BD if ≥2 of: age ≥80, weight ≤60 kg, creatinine ≥133 µmol/L
Renal Clearance	~25% — LEAST renally cleared → preferred in CKD
Avoid if eGFR	No absolute cut-off in licence but avoid if eGFR <15 (limited data)
Renal Monitoring	6-monthly
Reversal	Andexanet alfa (licensed) or 4-factor PCC

Key fact: Most evidence for reducing bleeding vs warfarin (ARISTOTLE trial — 31% reduction in major bleeding). Preferred DOAC in moderate CKD (eGFR 30-59).

Edoxaban (Lixiana) — Direct Factor Xa Inhibitor

Property	Details
Dosing	Once daily (OD)
VTE Treatment	60 mg OD (after ≥5 days LMWH); 30 mg OD if weight ≤60 kg or eGFR 15-50 or P-gp inhibitor
AF	60 mg OD; 30 mg OD if eGFR 15-50, weight ≤60 kg, P-gp inhibitors
Renal Clearance	~50%
Avoid if eGFR	<15; also caution with high eGFR >95 in AF (reduced efficacy paradox)
Reversal	Andexanet alfa or 4-factor PCC

Note: Edoxaban has a paradoxical reduced efficacy in AF patients with very high renal function (CrCl >95 mL/min) due to rapid clearance — use alternative DOAC.

NOAC Switching Protocols

From Warfarin to NOAC

Check INR
If INR <2.0: start NOAC immediately
If INR 2.0–2.5: start NOAC (some guidance says can start, monitor closely)
If INR >2.5: wait and recheck INR in 1-3 days before starting
No overlap period needed — NOAC onset rapid (1-4 hrs)

From LMWH to NOAC

Start NOAC at time of next scheduled LMWH dose
No overlap needed — do NOT give both simultaneously

From NOAC to Warfarin

Start warfarin immediately (overlapping); continue NOAC for 3-5 days
Check INR when NOAC held for ≥24h (dabigatran) or ≥12h (Xa inhibitors)
Stop NOAC when INR ≥2.0

From NOAC to LMWH

Start LMWH at time next NOAC dose would have been due

Heparin Products

Unfractionated Heparin (UFH)

Route & Uses

IV infusion (continuous) or SC bolus prophylaxis
ACS (NSTEMI/STEMI), massive PE, high bleeding risk patients (reversible rapidly), renal failure (no dose adjustment needed), cardiac surgery/ECMO
Preferred when rapid reversal may be needed

Monitoring — APTT Protocol

APTT Ratio	Action
<1.5× control	Sub-therapeutic — increase infusion rate by 20%; rebolus if clinically indicated
1.5 – 2.5× control	Therapeutic range — no change. Recheck in 6h.
2.5 – 3.0×	Slightly supra-therapeutic — reduce rate by 10%
>3.0×	Stop infusion for 30 min; reduce rate by 15%; recheck in 4h

Note: Some centres use anti-Xa method (target 0.3-0.7 IU/mL) to monitor UFH — avoids APTT variability from lupus anticoagulant or factor deficiencies.

Heparin-Induced Thrombocytopaenia (HIT)

HIT is a life-threatening prothrombotic complication — NOT just thrombocytopaenia!

Pathophysiology

IgG antibodies form against heparin-PF4 complex → platelet activation → thrombosis (arterial + venous) and paradoxical clot risk despite low platelets

4Ts Score (Pre-Test Probability)

Category	2 pts	1 pt	0 pts
Thrombocytopaenia	>50% fall; nadir ≥20	30-50% fall or nadir 10-19	<30% fall or nadir <10
Timing	Days 5-10 or ≤1d if prior heparin 30-100d	Consistent but not clear; >10d	<4d, no prior heparin
Thrombosis	New confirmed thrombosis/skin necrosis	Progressive or recurrent thrombosis	None
Other cause	None apparent	Possible	Definite other cause

Score ≥6 = high probability; 4-5 = intermediate; ≤3 = low

Management if HIT Suspected

STOP ALL heparin immediately (including flushes, LMWH, heparin-coated catheters)
Send HIT antibody (anti-PF4-heparin ELISA + functional assay if positive)
Start non-heparin anticoagulant: argatroban (preferred in renal failure) or danaparoid (preferred in hepatic impairment)
Do NOT give warfarin until platelets recover to >150 (risk of venous limb gangrene)
Monitor platelets daily until recovery

LMWH (Low Molecular Weight Heparin)

Available Agents

Enoxaparin (Clexane) — most widely used in GCC; 1 mg/kg SC BD or 1.5 mg/kg OD therapeutic; 40 mg OD prophylactic
Dalteparin (Fragmin) — 200 IU/kg OD therapeutic; widely used in cancer-associated VTE
Tinzaparin (Innohep) — 175 IU/kg OD therapeutic; some evidence in moderate CKD

When to Monitor Anti-Xa (Routine monitoring NOT required in standard patients)

Renal impairment (eGFR <30) — accumulation risk
Extreme obesity (BMI >40) — underdosing risk
Pregnancy — volume distribution changes
Neonates/paediatrics
Unexplained bleeding or thrombosis on therapy

Timing: Anti-Xa level 4 hours after SC injection (peak level). Therapeutic target BD dosing: 0.5–1.0 IU/mL; OD dosing: 1.0–2.0 IU/mL; Prophylactic: 0.2–0.4 IU/mL.

Patient Teaching — Self-Injection

Inject into abdomen (lateral), alternating sides; avoid 5 cm around navel
Pinch skin fold; inject at 90° (or 45° if thin); release fold after injection
Do NOT rub injection site after (causes bruising)
Store at room temperature (most brands); check leaflet
Dispose in licensed sharps container — never in household waste
Pre-filled syringes available — air bubble at top is normal, do not expel

Fondaparinux (Arixtra)

Mechanism

Synthetic pentasaccharide — selectively activates antithrombin → inhibits factor Xa ONLY. Cannot bridge to IIa (too short chain). Does NOT cause HIT (no PF4 binding).

Dosing

Indication	Dose
VTE prophylaxis (surgical)	2.5 mg SC OD
VTE treatment (<50 kg)	5 mg SC OD
VTE treatment (50-100 kg)	7.5 mg SC OD
VTE treatment (>100 kg)	10 mg SC OD
ACS (NSTEMI)	2.5 mg SC OD (add UFH for PCI)

Renal Adjustment & Contraindications

Contraindicated if eGFR <20 mL/min (renally cleared, accumulation)
Caution eGFR 20-50 (risk of accumulation)
No specific reversal agent (protamine ineffective; recombinant FVIIa in severe haemorrhage)

Advantage in HIT: Fondaparinux does not bind PF4 and does not cause HIT. Can be used as an alternative anticoagulant post-HIT diagnosis (unlicensed but used in practice).

Bleeding Complications & Reversal

HAS-BLED Score — Bleeding Risk Assessment in AF Patients on Anticoagulation

Letter	Risk Factor	Points
H	Hypertension (uncontrolled, systolic >160 mmHg)	1
A	Abnormal renal function (dialysis, transplant, creatinine >200 µmol/L) OR liver function (cirrhosis, bilirubin >2×, ALT/AST/ALP >3×)	1 or 2
S	Stroke history	1
B	Bleeding history or predisposition (anaemia, thrombocytopaenia)	1
L	Labile INR (TTR <60% if on warfarin)	1
E	Elderly (age >65)	1
D	Drugs (antiplatelets, NSAIDs) or alcohol (≥8 drinks/week)	1 or 2

Score ≥3 = high bleeding risk — does NOT mean stop anticoagulation (clot risk often exceeds bleed risk in AF); rather, use score to identify and correct modifiable factors (BP control, review interacting drugs, reduce alcohol, optimise INR control).

Classification & Initial Management of Bleeding

Minor Bleeding

Bruising, epistaxis, gum bleeding, minor wound
Local pressure / wound care
Review dose timing / recent INR
Usually continue anticoagulation with dose review
Epistaxis: nasal packing if persistent; refer ENT if recurrent

Clinically Significant (Non-Major)

Haematuria, prolonged epistaxis, haematoma
Temporarily withhold dose
Investigate source
Consider urgent INR/anti-Xa check
Resume at lower dose or switch drug once controlled

Major Bleeding (ISTH Criteria)

Hb fall ≥20 g/L or transfusion ≥2 units pRBC
Symptomatic in critical area (intracranial, pericardial, retroperitoneal, intraocular, intramuscular with compartment syndrome)
Fatal bleeding
→ FULL REVERSAL PROTOCOL

Reversal Agents — Drug-Specific

Anticoagulant	Reversal Agent	Dose & Notes
Warfarin	IV Vitamin K + 4-factor PCC (Beriplex/Octaplex) ± FFP	Vitamin K 10 mg slow IV (30 min) for urgent reversal (INR normalises in ~6-12h). 4-factor PCC 25-50 IU/kg for immediate urgent reversal (within minutes). FFP 10-15 mL/kg if PCC unavailable (slower, large volume). Check INR 30-60 min post-PCC.
UFH	Protamine sulfate	1 mg per 100 units UFH (given in last 2-3 hours). Max single dose 50 mg. Give SLOWLY (max 5 mg/min) — risk of hypotension/anaphylaxis. Check APTT 15 min after. If UFH stopped >2h ago, reduce protamine dose (heparin half-life ~1.5h).
LMWH	Protamine sulfate (partial)	1 mg protamine per 1 mg enoxaparin (or 100 anti-Xa units dalteparin). Reverses ~60-80% anti-IIa activity; anti-Xa activity only partially reversed. Second dose 0.5 mg per 1 mg enoxaparin if bleeding continues. Given within 8h of LMWH dose.
Dabigatran	Idarucizumab (Praxbind)	5g IV (two 2.5g doses 15 min apart or as single infusion). Humanised antibody fragment binds dabigatran with 350× higher affinity than thrombin. Complete reversal within minutes. Available in most GCC hospitals with anticoagulation clinics.
Rivaroxaban Apixaban	Andexanet alfa (Ondexxya) or 4-factor PCC	Andexanet alfa: recombinant modified Xa decoy — licensed for rivaroxaban and apixaban. Dose depends on agent and timing of last dose (high or low dose). 4-factor PCC 50 IU/kg used when andexanet not available (evidence weaker but widely used).
Fondaparinux	No specific agent	Protamine ineffective. Recombinant activated Factor VII (rFVIIa) 90 µg/kg in life-threatening haemorrhage (unlicensed). Haemodialysis does not clear fondaparinux. Supportive care.

Intracranial Haemorrhage — Most Feared Complication

EMERGENCY: Anticoagulant-related ICH has 30-day mortality ~40-50%. Speed of reversal directly impacts outcome.

Stop anticoagulant immediately
STAT CT head (if not done)
Contact neurosurgery AND haematology urgently
Reverse anticoagulation IMMEDIATELY (do not wait for lab results if clinical suspicion high and recent anticoagulant use confirmed)
Target: INR <1.3 or anti-Xa <0.1 within 4 hours
Blood pressure control: target systolic <140 mmHg
Avoid anticoagulation restart for minimum 4-12 weeks (reassess risk/benefit)
Consider IVC filter if anticoagulation contraindicated long-term + proximal DVT

Peri-Procedure Bridging Anticoagulation

Warfarin — Standard Protocol

Stop warfarin 5 days pre-procedure (INR <1.5 target)
Bridge with therapeutic LMWH from day -3
Last LMWH dose: 24h before procedure (BD) or 24h before (OD)
Resume warfarin evening of or next day post-procedure
Resume LMWH 24-48h post-procedure (haemostasis confirmed)

Who NEEDS bridging? (High thrombotic risk)

Mechanical mitral valve
Recent VTE (<3 months)
AF with prior stroke/TIA or CHADS₂ score ≥5

DOACs — No Bridging (simply hold)

Stop DOAC 1-2 days before (normal renal; minor procedure)
Stop DOAC 2-3 days before (high bleeding risk procedure; dabigatran eGFR 30-50)
Resume 24-48h post-procedure when haemostasis confirmed

GCC Context & Exam Preparation

GCC-Specific Clinical Considerations

Warfarin Use in GCC

Warfarin remains widely used for AF, valve disease (especially mechanical valves), and VTE across GCC — driven by availability, cost, and long-established clinic infrastructure
INR monitoring available in GCC primary care (MOH, DHA, DOH clinics)
Anticoagulation clinics (nurse-led or pharmacist-led) now established in major GCC hospitals

Dietary Interactions — Arabic Diet

Vitamin K content is variable in traditional Arabic diet:

Khobz (Arabic bread), rice, grilled meats — low vitamin K; minimal warfarin effect
Fattoush, tabbouleh, spinach-rich dishes — higher vitamin K; can lower INR
Fresh herbs (parsley, coriander, fenugreek) — high in vitamin K; significant if eaten in large quantities
Olive oil — low vitamin K; generally consistent
Counsel patients on consistent intake of green salads and herbs; seasonal variation in diet common

Mechanical Heart Valves in GCC

Relatively higher rate of rheumatic heart disease and cardiac valve surgery in GCC compared to Western populations → more patients on long-term warfarin with INR target 2.5–3.5 for mitral valve prostheses. Warfarin remains the ONLY anticoagulant for mechanical valves — nurse education on this is critical.

Ramadan & Anticoagulation

Ramadan fasting (approximately 29-30 days of dawn-to-sunset fasting) significantly impacts anticoagulation management

Warfarin During Ramadan

Dietary changes (larger evening meals, altered timing) → INR instability
Dehydration risk → reduced renal clearance → changed pharmacokinetics
Recommend: INR check before and 2 weeks into Ramadan
Advise consistent meal timing and food choices during Ramadan
Some evidence for increased anticoagulation intensity during Ramadan

NOAC Adherence During Ramadan

Once-daily NOACs (rivaroxaban, edoxaban): Take at Iftar (break-fast meal) — rivaroxaban requires food; no major issues with once-daily dosing
Twice-daily NOACs (dabigatran, apixaban): Split between Iftar and Suhoor (pre-dawn meal) — maintains ~12h dosing interval; widely accepted approach
Advise patients not to double-dose if a dose is missed during fasting hours

LMWH During Ramadan

SC injection during fasting hours is permissible (does not break fast — confirmed by Islamic scholars in most schools of thought)
Preferred timing: Iftar (once-daily LMWH) or split Iftar/Suhoor (twice-daily)
Ensure proper sharps disposal in patients managing at home

DHA / DOH / SCFHS Regulatory Standards

DHA & DOH Anticoagulation Clinic Standards

Dedicated anticoagulation clinic with named clinical lead
TTR ≥65% as quality indicator for warfarin clinics
Patient education documentation required at each visit
Adverse event reporting for INR >8 or major bleeding episodes
Competency-based training for nurses managing anticoagulation
DOAC prescribing guidelines aligned with ESC/ACC guidance with local adaptations
Renal function monitoring protocols for DOACs required in electronic records

SCFHS Nursing Exam — High-Yield Topics

INR target ranges for specific indications (especially mechanical valves)
Warfarin drug interactions (amiodarone, rifampicin, fluconazole)
HIT recognition and management (4Ts score, stop heparin, switch to argatroban)
LMWH anti-Xa monitoring indications and timing
Reversal agents: protamine/vitamin K/PCC/idarucizumab
NOAC renal dose adjustments
Contraindications: mechanical valves + NOACs; pregnancy + warfarin
Bridging anticoagulation principles
Signs of major bleeding requiring urgent intervention

Quick Reference — High-Yield Exam Facts

INR Targets — Memorise

Most indications: 2–3
Mechanical mitral valve: 2.5–3.5
Triple-positive APS: 3–4
NOACs: No INR monitoring

Mechanical Valves

Warfarin ONLY — NOACs contraindicated
Dabigatran failed RE-ALIGN trial
Lifelong anticoagulation required

NOAC Renal Cutoffs

Dabigatran VTE: avoid eGFR <30
Dabigatran AF: avoid eGFR <15
Rivaroxaban: avoid eGFR <15
Apixaban: preferred in CKD (25% renal)
Edoxaban: avoid eGFR <15; paradox if >95 in AF

Pregnancy

LMWH: SAFE throughout
Warfarin: avoid T1 (teratogenic), T3 (neonatal bleeding)
NOACs: CONTRAINDICATED

Reversal Agents — Memorise

Warfarin: Vit K + PCC
UFH: Protamine 1mg/100 units
LMWH: Protamine (partial)
Dabigatran: Idarucizumab 5g IV
Rivaroxaban/Apixaban: Andexanet alfa or 4-factor PCC

HIT — Key Points

Thrombotic (not just thrombocytopaenia)
Stop ALL heparin products
Switch to argatroban or danaparoid
Do NOT restart warfarin until platelets >150

Interactive NOAC Dose Checker

Enter patient parameters to calculate appropriate NOAC dose, renal adjustments, and clinical warnings.

Drug

Indication

eGFR (mL/min)

Age (years)

Weight (kg)

High bleeding risk

P-gp/CYP3A4 inhibitor (e.g. dronedarone, ketoconazole)

Mechanical heart valve