BCC4: Sarah Wesley- To Thin or Not To Thin (The heart and anticoagulation)
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Transcript of BCC4: Sarah Wesley- To Thin or Not To Thin (The heart and anticoagulation)
To thin or not to thin?
Dr Sarah Wesley Cairns 2013
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
64yo CABG x3
• Aspirin at 6h if bleeding not an issue and daily afterwards• 75-150mg optimal dose• Reduction in mortality/CVA/MI/AKI
AspirinAspirin +
Clopidogrel Warfarin
64yo CABG x3
• Are there any indications for dual (aspirin and clopidogrel) antiplatelet therapy?
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
64yo CABG x3
• Clopidogrel acceptable alternative if allergic to aspirin• No data showing superior• Aspirin remains drug of choice in routine on-
pump CABG
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?
Clopidogreliv Heparin +
WarfarinNone
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
Questions ?
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
72yo tissue AVR
• No risk factors for VTE disease -> aspirin alone• Stroke rate of 0.2% for AVR in sinus
Clopidogrel Aspirin Warfarin
72yo tissue AVR
• Risk factors for VTE disease • AF, EF< 30-35%, hypercoagulable or previous
VTE
• Warfarin with INR 2-3
Clopidogrel Aspirin Warfarin
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
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
Mechanical AVR
• Warfarin alone or combination warfarin and anti-platelets?• Balance of thrombosis risk vs bleeding
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%
63yo with mechanical MVR
• Second generation valve inserted• Past history of Atrial Fibrillation• EF 40%
• What anticoagulation therapy should she have and when?
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?
MV repair or tissue MV
• 3 months warfarin or antiplatelets• No evidence either is superior• 20% of all thromboembolic events in first
month
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
Questions?
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
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
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