anticoagulants basics exam 3 PART 1

Anesthetic Implications
– Preop Considerations

👉 Undetected bleeding → life-threatening intraop
👉 Hx first, then labs: platelets, PT/PTT, fibrinolysis
👉 Meds matter: ASA, NSAIDs, herbals (ginkgo, garlic, ginseng) → ↓ plat

Anticoagulants

• Unfractionated heparin
• Low-molecular-weight heparin
• Coumarin derivatives
• Direct thrombin inhibitors
• Direct factor Xa inhibitors

Nonherbal Dietary

• Vitamin K
• Vitamin E
• Coenzyme O10
• Zinc
• Omega-3 fatty acids

Procoagulants

Vitamin K

Antiplatelets

• NSAIDs

Persantine
• Thienopyridine

Antifibrinolytics

• Aminocaproic acid
• Tranexamic acid

Herbal

• Garlic, Ginger, Ginkgo
• Feverfew, Fish oil and Flaxseed oil
• Black cohosh (KUSH)
• Cranberry

Antiplatelets (platelet problem)

GANG memory trick

• ASA

• NSAIDs

• Clopidogrel / Prasugrel / Ticlopidine (ADP blockers)

• GPIIb/IIIa inhibitors (Abciximab, Eptifibatide, Tirofiban)

Anticoagulants (clotting cascade problem)

Think: “factors blocked”

• Heparin / LMWH

• Warfarin

• DOACs (dabigatran, rivaroxaban, apixaban, etc.)

Fibrinolytics (clot busters)

• tPA

• Streptokinase

ANTIPLATELETS = LONG HOLD (especially ASA & Plavix)

• ASA → stop 7 days (irreversible)

• Clopidogrel → stop 5–7 days

• Prasugrel/Ticlopidine → stop 7–10 days

NSAIDs = SHORT HOLD

Stop 24–48 hrs
👉 reversible = quick recovery

GPIIb/IIIa inhibitors = VERY SHORT

Stop 8–72 hrs

Eptifibatide and Tirofiban: stop 8-24 hrs

Abciximab - stop 48 - 72 hrs

ADP receptor antagonis

Clopidogrel: 5-7 days

Prasugrel: stop 7-10 days

Ticlopidine: stop 7-10 days

ANTICOAGULANTS = THINK HALF-LIFE

Heparins:

• Heparin → stop 6 hrs, reversal = protamine, monitor = aPTT

• LMWH → stop 12–24 hrs, partial protamine, monitor = anti-Xa

Warfarin = SLOW

• Stop 4–5 days

• Reversal:

  • Vitamin K

  • FFP / PCC

• Monitor = PT/INR

DOACs = SHORT + CLEAN

Dabigatran (Factor IIa)

• Stop 1–4 days

• Reversal = idarucizumab

Xa inhibitors (rivaroxaban, apixaban, etc.)

• Stop 1–3 days

• Reversal = andexanet alfa

👉 Monitor = anti-Xa

FIBRINOLYTICS

• tPA → stop 1 hr

• Streptokinase → stop 3 hr

👉 but HIGH bleeding risk

ULTRA-HIGH YIELD MEMORY TRICKS

“7–5–1 Rule”

• 7 days → ASA

• 5 days → Plavix

• 1–3 days → DOACs

Reversal Cheat Sheet

• Heparin → protamine

• Warfarin → Vit K + PCC/FFP

• Dabigatran → idarucizumab

• Xa inhibitors → andexanet alfa

• Antiplatelets → platelets

🔥 Monitoring

• Heparin → aPTT

• Warfarin → PT/INR

• LMWH/DOACs → anti-Xa

What forms the structure of a thrombus?

• Fibrin = framework of thrombus

• Traps blood cells → stabilizes clot

Where do antiplatelets vs anticoagulants act in thrombus formation?

• Antiplatelets → inhibit platelet adhesion/activation/aggregation (early step)

• Anticoagulants → inhibit clotting cascade → ↓ thrombin (IIa), Xa → ↓ fibrin formation

Fibrinolytics vs antifibrinolytics — MOA

• Fibrinolytics (tPA, alteplase, etc.) → ↑ plasmin → break down fibrin (clot busting)

• Antifibrinolytics (TXA) → inhibit plasminogen → plasmin → prevent clot breakdown

Antifibrinolytics (TXA)

inhibit plasminogen → plasmin → prevent clot breakdown

REVERSAL AGENTS (by class)

• Antiplatelets (ASA, NSAIDs, clopidogrel, etc.) → Platelets

• GP IIb/IIIa inhibitors → Platelets

• Heparin (UFH) → Protamine (FULL)

• LMWH → Protamine (PARTIAL)

• Fondaparinux → NONE

• Warfarin → Vitamin K, FFP, PCC

• Direct thrombin inhibitor (Dabigatran) → Idarucizumab

• Factor Xa inhibitors (Rivaroxaban, Apixaban, Edoxaban, Betrixaban) → Andexanet alfa

• Fibrinolytics (tPA, streptokinase) → Antifibrinolytics (TXA, aminocaproic acid)

WHEN TO STOP BEFORE SURGERY

• ASA → 7 days

• NSAIDs → 24–48 hr

• Clopidogrel → 5–7 days

• Prasugrel / Ticlopidine → 7–10 days

GP IIb/IIIa inhibitors:

• Abciximab → 48–72 hr

• Eptifibatide / Tirofiban → 8–24 hr

Anticoags

• Heparin (UFH) → 6 hr

• LMWH → 12–24 hr

• Fondaparinux → 2–4 days

• Warfarin → 4–5 days

DOACs:

• Dabigatran → 1–4 days

• Rivaroxaban → 1–3 days

• Apixaban / Edoxaban → 1–2 days

• Betrixaban → 3–4 days

Anti-PLT

stop for neuroaxial anesthesia

• NSAIDs → ✅ NO contraindication

• Clopidogrel / Prasugrel / Ticlopidine → ❗ STOP 5–10 days

• Ticagrelor → 5–7 days

• Cangrelor → 3 hrs (IV = short)

• GPIIb/IIIa inhibitors → 8–48 hrs

• Cilostazol → 2 days

• Dipyridamole → 24 hr

HEPARIN

• neuroaxial anesthesia

LOW DOSE (5,000 units)

• Do neuraxial: 4–6 hrs after dose

• Remove catheter: 4–6 hrs after last dose

• Restart: wait 1 hr

HIGH DOSE : Wait 12 hrs

FULL THERAPEUTIC: Wait 24 hrs

IV HEPARIN

• Stop infusion → wait 4–6 hrs

• Check normal coagulation

• Remove catheter: 4–6 hrs

• Restart: wait 1 hr

LMWH (ENOXAPARIN)

12 / 24 RULE

• Prophylactic dose → wait 12 hrs

• Therapeutic dose → wait 24 hrs

Catheter:

• Remove ≥12 hrs after last dose

• Restart LMWH → 4 hrs after removal

WARFARIN

• Must have NORMAL INR before neuraxial

• Remove catheter when:

  • INR ≤ 1.5

FONDAPARINUX

• Avoid catheter (⚠ risky)

• Single needle only
  👉 Basically: DON’T MESS WITH IT

DIRECT THROMBIN INHIBITORS (IV)

Argatroban, Bivalirudin
👉 ❌ NO neuraxial anesthesia

DOACs (VERY TESTED) Dabigatran (Factor IIa

• ❌ Contraindicated

• Restart → 6 hrs after

Xa inhibitors (Rivaroxaban, Apixaban, etc.)

• Wait 72 hrs before neuraxial

• Restart → 6 hrs after

HERBALS

• No strict stop rule

• BUT:

  • Ginkgo, Garlic, Ginseng = bleeding ris

ULTRA-HIGH YIELD SUMMARY

⏱ TIME RULES

• 4–6 hr → Heparin (low dose / IV)

• 12 hr → LMWH prophylaxis

• 24 hr → LMWH therapeutic

• 72 hr → Xa inhibitors

• 5–10 days → Clopidogrel group

🚫 HARD NOs

• Direct thrombin inhibitors (IV)

• Dabigatran (neuraxial = avoid)

• Fondaparinux (avoid catheter)

Procedures = SAFE to continue anticoagulation

Eye: Cataracts and Trabeculectomy

Dental (basic work)

• Cleaning

• Fillings/restorations

• Root canals

• Simple extraction

• Skin (superficial): Mohs and Simple excisions

Procedures = SAFE to continue anticoagulation

• GI = ONLY if NO CUTTING

If they add biopsy or sphincterotomy → STOP anticoagulation

• Endoscopy / colonoscopy → ✅ ONLY if NO biopsy

• ERCP → ✅ ONLY if NO sphincterotomy

• Stent placement → ✅ if no cutting

• Endosonography → ✅ no needle

No cutting, no biopsy, no deep tissue = continue anticoagulation

Ortho/Podiatry

» MSK procedures safe with anticoagulation

• Joint injections / aspirations

• Nail removal

• Minor foot procedures

💉 Most commonly ordered:

• Platelets → quantity

• PT (INR) → extrinsic pathway (warfarin)

• aPTT → intrinsic pathway (heparin)

• Bleeding time → platelet function (rarely used now)

Blood availability:

• Type & Screen

  • ABO + Rh + antibodies

  • “Just in case”

Type & Crossmatch

• Fully matched blood ready

• “We expect bleeding”

Platelet - Primary role

Primary role:

• Maintain vascular integrity

• Aggregate when a plug is necessary to stop bleeding

• Help initiate the clotting pathways

Labs – PT

• Efficiency of the extrinsic factors (III & VII) and common coagulation pathway (X, V, II, I) in generating a stable clot

• Monitor oral anticoagulant therapy

• Prolonged: Patient. with abnormalities or deficiency in extrinsic or common pathway factors

• Not a very sensitive test

• Only identifies an existing problem that may or may not cause bleeding

PLT count

• Actual # of platelets present in blood per cubic millimeter

• Used to monitor thrombocytopenia

• Normal count: 150,000–300,000/mm³

• Thrombocytopenia:

  • <100,000/mm³

  • Critical: <20,000/mm³

INR

• Evaluates extrinsic and common pathway

• Normal: 1.5 – 2.5

aPTT

• Monitoring of heparin therapy

• Factor concentration ↓ 30% = prolong PT or aPTT

• Intrinsic coagulation pathway (factors XII, XI, IX, VIII) and common coagulation pathway

• Identify abnormalities in all factors except III and VII

“WHAT TO GIVE”

• Platelet problem? → Platelets

• Factor problem? → FFP

• Fibrinogen low? → Cryo

• Heparin? → Protamine

• vWD? → DDAVP

↑ aPTT ONLY

Heparin / Hemophilia

• Cause: Factors VIII, IX, XI or heparin

• 💉 Treatment:
  👉 Protamine (if heparin)
  👉 FFP (if factor deficiency)

↑ PT ONLY

Issue with Factor VII / Warfarin

💉 Treatment:
👉 FFP

↑ PT + ↑ aPTT

BIG PROBLEM (multiple factors)

• Causes:

  • Liver disease

  • Warfarin overdose

  • Severe deficiency

• 💉 Treatment:
  👉 FFP ± cryo ± protamine

↑ BT (bleeding time)

Platelet PROBLEM

If platelet COUNT ↓ 👉 Thrombocytopenia. » 💉 Give: Platelets

If platelet COUNT normal

👉 Platelet dysfunction (ASA, NSAIDs) » 💉 Give: Platelets

↑ BT + ↑ aPTT

👉 Think: von Willebrand disease

👉 Desmopressin (DDAVP)
👉 ± Cryoprecipitate

LOW FIBRINOGEN

Cryo problem

• 💉 Treatment:
  👉 Cryoprecipitate ± FFP

EVERYTHING ABNORMAL💀💀💀💀

DIC / liver failure

• ↑ PT, ↑ aPTT, ↑ BT, ↓ platelets, ↓ fibrinogen

• 💉 Treatment: FFP + Platelets + Cryo

↑ aPTT only (no bleeding)

Cause: Factor VIII deficiency, heparin, lupus anticoagulant, poor sample
Treatment: No treatment

↑ aPTT only + bleeding

Cause: Factors XI, IX, VIII deficiency or heparin
Treatment: FFP; protamine if heparin

↑ aPTT + ↑ PT

• Factors V, X, II, dysfibrinogenemia, heparin, coumarins

• Tx: FFP, cryoprecipitate, protamine

↑ PT only

• Factor VII

• Tx: FFP

↑ aPTT only due to heparin

Cause: Heparin therapy
Treatment: Protamine

↑ aPTT + ↑ BT

• von Willebrand disease

• Tx: Desmopressin acetate, cryoprecipitate

↑ aPTT + ↑ PT + ↑ BT + ↓ fibrinogen

• Hypofibrinogenemia

• Tx: FFP, cryoprecipitate

↑ BT + ↓ platelet count

• Thrombocytopenia

• Tx: Platelet concentrate (8–10 units)

↑ BT (platelet count normal)

• Thrombocytopathy, aspirin, NSAIDs

• Tx: Platelet concentrate

↑ aPTT + ↑ PT + ↑ BT + ↓ platelets + ↓ fibrinogen

• DIC, severe liver disease, dilutional coagulopathy

• Tx: FFP, cryoprecipitate, platelet concentrate, whole blood

Recognize and efficiently control blood loss

• Hemodynamics
• Surgical site
• Sponges
• Canisters
• OR floor

Most commonly transfused blood components

1. RBCs

2. Platelets

3. FFP

4. Cryoprecipitate