Why Plavix is Discontinued Before CABG But Not Before PCI
Plavix (clopidogrel) must be discontinued before CABG to prevent life-threatening surgical bleeding complications, whereas it is actively required during PCI to prevent acute stent thrombosis—fundamentally different procedural risks that dictate opposite antiplatelet management strategies. 1
The Core Difference: Bleeding Risk vs. Thrombotic Risk
CABG Requires Discontinuation Due to Surgical Bleeding
For elective CABG, clopidogrel must be stopped at least 5 days before surgery to allow adequate dissipation of its irreversible antiplatelet effect and prevent excessive perioperative bleeding. 1 The evidence is clear:
Major bleeding complications (pericardial tamponade, reoperation) are significantly increased when CABG is performed within 24 hours of clopidogrel discontinuation. 1
No increase in bleeding or transfusions occurs when CABG is performed ≥5 days after stopping clopidogrel, making this the evidence-based threshold for elective surgery. 1
Blood loss is dramatically higher in patients still on clopidogrel at surgery (802 ml) compared to those who discontinued it ≥72 hours prior (554 ml), with the latter group showing blood loss comparable to patients never on clopidogrel. 2
Clopidogrel increases platelet transfusion requirements 11-fold (OR=11.79) in CABG patients. 2
For Urgent CABG: Minimum 24-Hour Window
When CABG cannot be delayed, clopidogrel should be discontinued for at least 24 hours to reduce major bleeding complications, though some increase in blood transfusions remains likely. 1 This represents the minimum acceptable timeframe when surgical urgency outweighs bleeding risk. 1
PCI Requires Continuation to Prevent Stent Thrombosis
Clopidogrel must be continued during and after PCI because abrupt discontinuation dramatically increases the risk of stent thrombosis, myocardial infarction, and death. 3, 4 The procedural context is entirely different:
PCI involves placing a foreign body (stent) that requires intense antiplatelet therapy to prevent acute thrombosis. 4, 5
For bare-metal stents, clopidogrel is required for a minimum of 1 month (ideally 12 months). 1, 4
For drug-eluting stents, clopidogrel must continue for at least 12 months, particularly in acute coronary syndrome patients. 1, 4
The highest thrombotic risk period is within 30 days of stent placement, with ongoing risk of 0.2-0.6% per year thereafter. 3, 4
The Mechanistic Explanation
Why CABG Bleeding Risk is So High
Clopidogrel irreversibly inhibits the P2Y12 receptor on platelets for their entire 7-10 day lifespan. 1 During CABG:
Extensive surgical dissection, multiple anastomoses, and large raw surface areas create massive hemostatic challenges. 1
The body requires fully functional platelets to achieve surgical hemostasis across these extensive wound surfaces.
Even a small percentage of inhibited platelets significantly impairs clot formation in this high-demand surgical context.
Why PCI Thrombotic Risk is So High
During PCI, stent deployment:
Creates endothelial injury and exposes highly thrombogenic surfaces 4, 5
Triggers intense platelet activation and aggregation at the stent site 4
Requires dual antiplatelet therapy (aspirin + clopidogrel) to prevent catastrophic acute stent thrombosis 1, 4
Comparative Data: Ticagrelor vs. Clopidogrel
Recent evidence shows important differences between P2Y12 inhibitors:
Ticagrelor discontinued 3 days before CABG shows no increased bleeding compared to 5+ days, whereas clopidogrel discontinued 3 days before surgery increases bleeding risk (OR 1.71). 6
Overall CABG-related major bleeding is actually lower with ticagrelor (12.9%) than clopidogrel (17.6%), adjusted OR 0.72. 6
When discontinued <2 days before CABG, ticagrelor causes major bleeding in 16.0% vs. 2.7% when stopped ≥3 days prior. 7
Critical Clinical Pitfalls to Avoid
Never discontinue clopidogrel in stent patients without cardiology consultation, as this is the leading cause of stent thrombosis with potentially fatal consequences. 3
For patients requiring both CABG and PCI (hybrid revascularization), always perform CABG first, then PCI, to minimize perioperative bleeding risk from dual antiplatelet therapy. 1
Aspirin should be continued throughout the perioperative period for both CABG and PCI, as it reduces operative morbidity and mortality with only modest bleeding increase. 1