Module 7 Flashcards
What is the treatment of choice for catheter related thrombosis?
anticoagulation for at least 3 months, regardless of whether the catheter is removed
What is the mechanism of action of heparins?
How is fondaparinux different?
Potentiates antithrombin inhibition of thrombin and factor Xa
Fondaparinux only targets Xa and is completely synthetic
What are the target anti-Xa levels for UFH vs LMWH?
UFH 0.3-0.7
LMWH 0.5-1.1
Under what circumstances do we monitor the anti-xa activity for LMWH?
renal insufficiency
extremes of weight
pregnancy
non-compliance
What are the half lifes of UFH, LMWH and dalteparin?
1 hour
4 hours
17 hours
What clinical circumstances favour warfarin over DOAC for long term anticoagulation?
triple positive APLS mechanical valves Cr Cl <30 heart failure non-compliance (longer half life)
Which agent preferentially prolongs the PT vs the APTT?
Which agent preferentially prolongs the APTT vs the PT?
PT over APTT: rivaroxaban, less so apixaban
APTT over PT: dabigatran
How do we manage bleeding in setting of DOACs?
- withhold agent
- supportive measures
- local haemostasis
- FFP as plasma expander
- platelets to normalise
- idracizumab for dabigatran
- prothrombinex but minimal evidence for this
How long to w/h apixaban/dabigatran/rivaroxabanpre-op?
When do we restart?
“PAUSE study”
HIGH RISK
- w/h for 2 days prior to OT
- restart on post-op D2
LOW RISK
- w/h for 1 day prior to OT
- restart on post-op D1
What are the 8 A’s that interact with warfarin?
- Antibiotics
- Antifungals
- Anti-depressants
- Antiplatelets
- Amiodarone
- Anti-inflammatories
- Acetaminophen
- Alternative remedies
What are the factors in prothrombin complex concentrates?
II, IX and X
or
II, VII, IX and X
What is the management plan for patients with
- INR >1.5 with critical bleeding
- INR >2 with non-critical bleeding
- any INR with minor bleed
FIRST 2 CASES Cease warfarin therapy Vit K 5-10mg IV and Prothrombinex 50 IU/KG IV and FFP 150-300ml IV If PTX unavailable, FFP 15ml/kg
ANY INR, MINOR BLEED
Omit therapy, repeat INR next day
Consider Vit K 1-2mg orally or 0.5-1mg IV if INR >4.5 or high risk
What are the elimination routes for
- argatroban
- bivalrudin
- danaparoid
argatroban: hepatic
Bivalrudin and danaparoid: renal
What are the mechanisms of action and monitoring for
- argatroban
- bivalrudin
- danaparoid
Argatroban: direct, selective thrombin inhibitor
Bivalrudin: direct thrombin inhibitor
Monitor both with aPTT
Danaparoid: FXa and Thrombin inhibitor by binding to antithrombin
Monitor anti-Xa if clinically indicated
What are the considerations when using warfarin with respect to HITTS?
avoid prior to platelet count recovery due to risk of warfarin-induced skin necrosis
if receiving warfarin at time of diagnosis of HITTS, reverse wth Vit K
Which are the cancer subtypes with the highest prevalence of cancer thromboses?
breast, prostate, lung, Colorectal, pancreatic, clear cell ovarian, glioblastoma multiforme
What are the treatments advised for cancer-related thromboses?
LMWH for 4 weeks
Alternatively, can use DOAC (rivaroxaban or apixaban) , however increased bleeding with GI and GU cancers
note we don’t treat INCIDENTAL thromboses
Which of the antiphospholipid antibodies are associated with the highest and lowest risk of thrombosis ?
Highest: LAC
Lowest: anti-cardiolipin
What is the management of a patient who is triple positive APLS presenting with first thrombosis?
IV Heparin or LMWH Bridge to warfarin aim INR 2-3 Always bridge if temporary cessation If arterial thrombosis, consider adding aspirin CVD risk modification Can add hydroxychloroquine if SLE
What is the management for patients with no thromboses but persistent anti-phospholipid positivitiy on 12 week testing?
NO EVIDENCE for primary prophylaxis
- Aspirin if CV risk high, hydroxychlorophine with SLE
- Address reversible risk factors
- Consider short term anticoagulation during high risk situations eg. surg
What are the diagnostic features of catastrophic APLS and how do we treat?
FEATURES
- thrombosis in 3 or more organs
- rapidly progressive
- common precipitants: subtherapeutic anticoagulation, infection malignancy
- MOFS
- SIRS
TREATMENT
- early high dose steroids
- plasma exchange
- continue anticoagulation
- IVIg
- if refractory, rituximab/complement inhibition
What are the actions of α2 antiplasmin?
Crosslinked into clot by XIIIa, makes thrombi resistant to plasmin
Inactivates plasmin in circulation
How do thrombolytics work eg. streptokinase/urokinase/alteplase/tenecteplase?
Bind to fibrinogen forming complex that leads to plasminogen conversion into plasmin
What are the broad indications for thrombolysis?
STEMI: where primary PCI cannot be offered
Acute PE: for those with catastrophic RHF
Acute ischaemic/thrombobtic stroke
Acute iliofemoral venous thrombosis
What differentiates tenecteplase from the other thrombolytics?
Same as alteplase, is genetically engineered plasminogen activator
More fibrin-specific
Has a longer half life, can be given as single bolus
What are the assessment components of the Pulmonary Embolism Severity Index? (11)
How do the scores reflect risk/mortality?
Age (years) Male sex +10 Cancer +30 Heart failure +10 COPD +10 HR >110 +20 BP <100 +30 RR >30 +20 Temp <36 +20 Delirium +60 Sats <90 +20
Low risk <65 1.9% mortality
Intermediate risk 86-105 18.5% mortality
High risk >125
25% mortality
How does the PESI score help determine management?
PESI low risk : anticoagulation, consider discharge home
PESI intermediate and above: anticoagulate and hospitalise
PESI intermediate or high with RV dysfunction, consider rescue reperfusion
What are the absolute indications for IVC filter insertion?
- contraindication to anticoagulation
- complication of anticoagulation
- failure of anticoagulation eg. recurrent PE or inability to achieve adequate anticoagulation
Describe some rescue therapies used in PE?
IV thrombolysis
- increased bleeding complications and intracranial haemorrhage
Catheter directed therapy
- no increased bleeding events
Pulmonary embolectomy/surgical thrombectomy
What would be the indication for thrombectomy with DVT?
for iliofemoral DVT with contraindication to thrombolysis
What would be an indication for persistent anticoagulation for VTE post the 6 month mark?
- UNPROVOKED Proximal DVT or PE
- APLS
- active cancer
can persist with DOAC at reduced dose in unprovoked proximal DVT or PE eg. apixaban 5mg or rivaroxaban 10
Under what circumstances would you only anticoagulate for 6 weeks?
provoked distal DVT with resolved major risk factors, no persistent risk factors
