Coagulation disorders

Diagnosis

• By CBC
  • Thrombocytopenia
• By coagulogram
  • PT prolongation
    • Early vit K deficiency/antagonist
      • Cefoperazone
    • Mild liver dz.
    • Factor VII def./inh.
    • Early DIC
  • aPTT prolongation
    
    

    Bleeding diathesis differentials

    Mixing study/Bleeding	Without bleeding	With bleeding
    Correctable by mixing	Contact factor deficiency	Haemophilia A, B, C, von Willibrand disease
    Not correctable by mixing	Lupus anticoagulation	Factor inhibitors

  • Combined PT and aPTT prolongation
    (PT prolonged > aPTT, normal TT)
    • vit K deficiency/antagonist
    • mod. to severe liver dz.
    • Massive transfusion
    • Common pathway def.
    • DIC (TT may be prolonged if severe hypofibrinogenemia)
  • Prolonged TT
    • Without bleeding
      • Heparin contamination
      • Hyperfibrinogenemia
    • With bleeding
      • Hypo/dysfibrinogenemia
      • Impaired fibrin polymerization
      • Heparin
      • Anti-IIa
• Liver disease
  • Combination of multiple mechanisms
  • Hyperfibrinolysis: bleeding unresponsive to transfusion
    • Cryoprecipitate (CPP) for fibrinogen replacement
      • Fibrinogen, FVIII, vWF, FXIII
      • Dose: 1.5 – 2 g/dL
      • Lower volume than FFP
  • Surgery in cirrhosis with coagulopathy
    • Admit
    • Cryoremoved FFP: keep INR ≤ 1.5
    • Plt transfusion over 80,000
    • Tranexamic acid for a week
• Massive transfusion
  • Dilution of Plts and clotting factor
  • Tranexamic acid in trauma
    • 1 g IV over 10 min then 1 g over the next 8 hrs

Common pre-analytical errors

• Lipemic plasma
• Heparin contamination (Falsely prolonged aPTT, TT)
• High haematocrit (falsely prolonged aPTT, PT)

Indications for antithrombotic treatment

• Indications for antiplatelets (aspirin or P2Y12 inhibitors)
  • Arterial thrombosis (CAD, ischaemic Stroke, PAD)
  • Primary and secondary prevention of arterial thrombosis
• Indications for anticoagulants
  • VTE
  • Cardiogenic embolism
    • AF
    • Valvular heart disease
    • Valve replacement

Haemostatic levels

• Platelet count targets
  • General surgery ≥ 50,000
  • Spinal and epidural anaesthesia ≥ 80,000
  • Neurological or cardiac surgery ≥ 100,000
• PT and aPTT targets (assuming normal platelet count) ≤ 1.5 times control value

Considerations regarding antithrombotic treatments in the perioperative period

• Minor bleeding risk operations: no action required
  • Cataract/glaucoma procedure
  • Dental procedure
  • Superficial surgery
• Moderate - high bleeding risk procedures
  • NSAIDs
    • Stop 1 day prior to surgery
      • Ibuprofen
      • diclofenac
    • Stop 2 days prior to surgery
      • Naproxen
      • Ketorolac
      • Indomethacin
    • Stop 10 days before surgery
      • Piroxicam
  • Antiplatelets
    • Stop 5 days before surgery
      • Clopidogrel
      • Ticagrelor
    • Stop 7 days before surgery
      • Aspirin
      • Prasugrel
    • Stop 14 days before surgery
      • Ticlopidine
  • Dual antiplatelets - DAPT (in non-cardiac surgery)
    • High-thrombotic risk: defer surgery and continue DAPT in the following scenarios
      • PCI less than 1 month ago
      • ACS without PCI less than 3 months ago
      • High-risk stent (as per cardiology advice)
    • If surgery is required in a high-thrombotic-risk patient:
      • Stop DAPT and bridge with cangrelor or GPIIa/IIb inhibitor, e.g., eptifibatide
  • If not high-thrombotic risk
    • continue aspirin
    • hold P2Y₁₂ inhibitor
      • 5 days: ticagrelor, clopidogrel
      • 7 days: prasugrel
• Warfarin
  • High-thrombotic risk patients
    • Stop warfarin 5 days before surgery
    • Start bridging with LMWH on Day 3
    • Restart warfarin post-operation and stop LMWH once INR meets the target
    
    
    High-thrombotic Risk Patients

    ---

    • Recent ischaemic stroke < 3 months ago
    • High VTE risk
      • Anti-thrombin deficiency
      • Protein C/S deficiency
      • LV thrombus
    • AF with high risk features
      • CHADS₂ score 5-6
      • CHA₂DS₂-VASc score ≥ 7
      • Rheumatic valvular heart disease
  
  
  • Low-thrombotic Risk
    • Stop warfarin 5 days before procedure, no bridging required
  • Reversed with fresh frozen plasma and/or vitamin K
  • INR goal
    • General surgery: < 1.5
    • Minor surgery: 1.5 - 2.0
• NOAC, DOAC
  • No bridging needed
  • Interrupt according to the bleeding risk
    • Minimal: surgery day, resume the same day
    • Low: 1-day before, resume post-operative day 1
    • High: 2 days before, resume post-operative day 2-3
• VTE prophylaxis
  • Standard treatments in western countries
  • Rarely used in Thailand (consider in very-high-risk patients)
    • Caucasian
    • Previous VTE
    • Hip and knee surgery
    • Cancer surgery
  • Heparin or intermittent pneumatic compression
• Emergency surgery
  • Antiplatelets - Platelet transfusion
    • Leukocyte pool platelet concentrate (LPPC) 1 unit or platelet concentrate (PC) 6 units
  • Anticoagulants
    • FFP 10-20 ml/kg
    • Vitamin K 1-2 mg IV