Abnormal Bleeding and Anticoagulant
Aberrant bleeding may be of congenital,
acquired, or technical cause.
Usual workup, e.g:
- bleeding hx, including epistaxis, menstruation
- comorbidities renal, haem disease, liver disease.
- physical exam: bruising, ecchymosis, petechiae, stigmata of liver
If concern, needs Plts, bleeding time, INR, aPTT, haem consult.
1. Stop herbal remedies supplements long enough before surgery to
2. Do not routinely stop aspirin unless risk of bleeding exceeds
3. Stop Clopidogrel 5d prior to elective surgery.
- unless recent coronary stenting; do not stop within 4w of bare
metal stent or 1y after drug-eluding stent
Do not interrupt antiplatelet therapy.
Post-operative bleeding can be treated with DDAVP for aspirin;
clopidogrel would need a platelet transfusion
- stop 4d before surgery
- then rpt INR to ensure <1.5
- if high risk (e.g. AF with stroke or recent VTE or mechanical
heart valve), use clexane or heparin infusion as a bridging
- heparin infusion can be ceased 4h before surgery and restarted
8-12h after surgery for several days until INR therapeutic again.
6. von Willebrands' disease
- vWF stabilizes factor VIII in bld.
- in some vWF types, can have elevated bleeding types but normal
levels of vWF in blood
- mild cases treated with DDAVP which causes release of both factor
VIII and vWF to improve concentrations
- more serious cases treated with factor VIII/VWF concentrates or
- sex-linked recessive disorders; 90% are type A, 10% type B
- mild type A can be treated again by DDAVP (0.3 ug/kg)
- moderate+ disease; need factor VIII or XI for A and B respectively
- maintain at 80% normal for several days pre-op; 100% for 3-4d
after major surgery then 80% for a week+
8. Other congenital factor deficiencies
- FFP, cryo (VIII, vWF, fibrinogen, fibronectin, factor XIII)
- Factor VII deficiency corrected with same.
- malnutrition, hepatic failure, drugs and malabsorption cause
reductions in Vitamin K, hence low factor II, VII, IX, X and
prothrombin, proteins C & S
--> replace with oral / IV vit K
- Vit C deficit can cause troublesome bleeding due to loss of
capillary integrity from improper collagen.
Investigations for patients with ongoing bleeding after
correction of technical factors
- fbc incl. platelets
- INR, aPTT
- bleeding time temp
- arterial blood gas with pH and base deficit.
Normal INR and aPTT?
Consider platelet dysfunction, VWD and vitamin C deficiency
Normal INR; prolonged aPTT?
(aPTT ref range is 30-40s; critical high is >70s)
Commonly drug induced; e.g. heparin or similar
Can reverse by protamine, but not LMWHs; beware hypotension and
reactions in diabetics.
Consider multiple-factor deficiency, e.g. DIC, massive blood loss
and haemodilution, end-stage kidney disease
- DIC confirmed by elevated d-dimer >2000
--> treat underlying problem; sometimes may need heparin
Warfarin targets II, VII, IX and X
Mean half life is 40h; takes 48h to establish and duration of effect
Metabolized in liver via cytochrome p450 pathway
Risk of spontaneous bleeding increases with INR goes above 4
To reverse give Vitamin K 1-2mg orally (5mg if particularly high
INR), 1mg IV; oral preferred unless very rapid reversal required as
rare risk of anaphylaxis IV;
- vit K takes up to 24h to have its full effect
Consider prothrombinex 25-50 IU/kg and FFP (150-300mL),
- prothombinex contains low levels of II, IX and X but only low
leves of VII
- FFP adjunctively provides VII
--> use depends on need for rapid and complete reversal, risk of
bleeding and level of INR
Warfarin / Vit K deficit usually leaves normal aPTT