To thin or not to thin? That is a great question which Wesley helps answer with her talk on the heart and anticoagulation. This podcast was recorded at BCC4. Full posts can be found at intensivecarenetwork.com

1. To thin or not to thin?
Dr Sarah Wesley
Cairns 2013

3. 64yo CABG x3
• On pump, LIMA to LAD and SVG to OM1 and Cx
• PMHx: hypertension and hypercholesterolaemia
• What antiplatelet therapy and when?
Aspirin
Aspirin +
Clopidogrel
Warfarin

4. 64yo CABG x3
• Aspirin at 6h if bleeding not an issue and daily
afterwards
• 75-150mg optimal dose
• Reduction in mortality/CVA/MI/AKI
Aspirin
Aspirin +
Clopidogrel
Warfarin

5. 64yo CABG x3
• Are there any indications for dual (aspirin and
clopidogrel) antiplatelet therapy?

6. 64yo CABG x3
• Dual therapy
• CABG post acute coronary syndrome
• Stent in situ not bypassed by graft
• Off-pump CABG
• Not indicated specifically for SVG
• SVG 15% occlude in 1 year and 50% in 10 years
• CASCADE study 2008
• Clopidogrel and aspirin in SVG
• Showed no benefit in addition of clopidogrel

7. 64yo CABG x3
• Clopidogrel acceptable alternative if allergic to
aspirin
• No data showing superior
• Aspirin remains drug of choice in routine on-pump
CABG

8. 64yo CABG x3
• He goes on to develop AF day 2
• 3 days later remains in rate controlled AF on
amiodarone
• Would you start any additional anticoagulation?
Clopidogrel
iv Heparin +
Warfarin
None

9. 64yo CABG x3
• iv heparin and warfarin if remains in AF for > 48h
• Aim INR 2-3
• Double the risk of stroke with no anticoagulation
• If reverts to sinus within 48h
• Evidence equivocal for aspirin alone or adding warfarin
Clopidogrel
iv Heparin +
Warfarin
None

10. Questions ?

11. 72yo tissue AVR
• EF 45% with moderate LVH
• Sinus rhythm
• No previous DVT/PE
• No post-operative complications
• What anticoagulation therapy should he have and
when?
Clopidogrel Aspirin Warfarin

12. 72yo tissue AVR
• No risk factors for VTE disease -> aspirin alone
• Stroke rate of 0.2% for AVR in sinus
Clopidogrel Aspirin Warfarin

13. 72yo tissue AVR
• Risk factors for VTE disease
• AF, EF< 30-35%, hypercoagulable or previous VTE
• Warfarin with INR 2-3
Clopidogrel Aspirin Warfarin

14. 54yo Mechanical AVR
• What if he was 54 and his original operation was a
mechanical AVR?
• Normal coronary arteries
• No risk factors for cardiovascular disease
Clopidogrel +
Aspirin
Aspirin
iv Heparin +
Warfarin

15. 54yo Mechanical AVR
• Warfarin and iv heparin
• Iv heparin continues till INR therapeutic for 2 days
• Intensity of warfarin relates to thrombogenicity of
valve and risk factors for thrombus formation
• INR 2.5 for low risk up to 3.5 for high risk
• Risk relates to
• Type of valve
• Risk factors for VTE disease

16. Mechanical AVR
• Warfarin alone or combination warfarin and anti-
platelets?
• Balance of thrombosis risk vs bleeding

17. Mechanical AVR
• Add aspirin to warfarin if risk factors for
cardiovascular disease, stents, previous PE, high risk
valve
• Many guidelines recommend adding aspirin unless
concerns over bleeding
• Significant reduction in thromboembolism
and all cause mortality 9 -> 4/5%
• Increase in bleeding risk 5 -> 8%

18. 63yo with mechanical MVR
• Second generation valve inserted
• Past history of Atrial Fibrillation
• EF 40%
• What anticoagulation therapy should she have and
when?

19. MV repair or tissue MV
• What if she’d had a mitral valve repair or tissue
valve rather than mechanical valve replacement and
was in sinus rhythm?

20. MV repair or tissue MV
• 3 months warfarin or antiplatelets
• No evidence either is superior
• 20% of all thromboembolic events in first month

21. Thrombosis rates
• Embolism or valve thrombosis with mechanical
valve replacements
• No anticoagulation
• Aortic valve 4-12% per year
• Mitral valve 10-22% per year
• AVR with anticoagulation
• Warfarin 1% per patient per year
• Aspirin 2.2% per patient per year
• MVR and AVR with risk factors for VTE
• 2% and 4.5% respectively

22. Questions?

23. Stopping anti-platelet agents
• Routine CABG stop anti-platelet drug 7 days pre-op
• NSTEMI/MI/Prior to PCI
• Clear benefits for clopidogrel and aspirin
administration shown in many large RCT
• Guidelines recommend stopping clopidogrel 5-7 days
before surgery if clinical condition allows
• 1% increase in risk of MI during this time

24. Stopping Warfarin pre-op
• Low risk of thrombosis
• Bileaflet mechanical AVR with no other risk factors
• Stop warfarin 3-5 days pre-op no heparin required
• High risk of thrombosis
• Mechanical MVR/Mechanical AVR with risk factors
• Stop warfarin and start heparin when
INR < 2
• Restart heparin as early after surgery as as
bleeding allows

25. What about newer oral antithrombotics?
• Direct thrombin inhibitor – Dabigatrin
• RE-ALIGN study
• vs warfarin in mechanical valves
• Stopped early as increased risk of CVA/MI/Thrombosis
• Factor Xa inhibitor - Rivaroxaban
• Not studied and not recommended