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Table 4. European and Canadian recommendations for timing of discontinuation of antiplatelet agents prior to coronary artery
bypass grafting. Class or strength of recommendation are in parentheses
Aspirin Ticagrelor Clopidogrel Prasugrel
European society of cardiology (2017) [56]
No discontinuation 3 days 5 days 7 days
(Class 1) (Class 2a) (Class 2a) (Class 2a)
Canadian cardiovascular society (2018) [57]
No discontinuation Minimum: 48-72 h (Weak) Minimum: 48-72 h (Weak) Minimum: 5 days (Weak)
(Strong) Ideal: 5 days (Strong) Ideal: 5 days (Strong) Ideal: 7 days (Strong)

favorable to decrease bleeding risk, as the use of cardiopulmonary bypass may exacerbate the deleterious
[58]
effect of antiplatelet therapy on hemostasis . Furthermore, the use of platelet function testing, such as
rotational thromboelastometry assays and genotyping, may be used to guide decision-making for
antiplatelet therapy de-escalation and for optimal timing of surgical intervention [59,60] . In addition,
antiplatelet reversal agents are currently being investigated for clinical use. In an experimental study by
Bhatt et al., intravenous administration of the monoclonal antibody PB2452 in healthy volunteers resulted
in immediate and persistent reversal of the antiplatelet effects of ticagrelor . These findings have been
[61]
further supported in a prospective study evaluating the use of this drug in 150 ticagrelor-treated patients
who required urgent surgery or who were suffering from a major hemorrhage. Platelet-function testing
confirmed the rapid reversal of ticagrelor-mediated platelet dysfunction within five to ten min. Hemostasis
[62]
was achieved in over 90% of the patients . This drug is currently not available for routine use but is being
tested in REVERSE-IT, an international multicentre trial (ClinicalTrials.gov ID NCT04286438), in cardiac
surgery patients.

Most in-hospital patients awaiting surgery after a STEMI are treated with parenteral anticoagulation.
Whereas unfractionated heparin (UFH) can be continued up to induction in the operating theatre, most
other forms of anticoagulation should be stopped well in advance as they cannot effectively be reversed with
protamine at the end of cardiopulmonary bypass. It is currently recommended that low molecular weight
heparin (LMWH) be stopped a minimum of 18 h prior to surgery or longer, depending on renal function.
[63]
In patients treated with the synthetic pentasaccharide fondaparinux, the drug should be stopped for at least
[64]
3 full days as anticoagulant activity may persist even in the presence of normal renal function .

SPECIAL CONSIDERATIONS
In certain cases, the presence of an indication for emergent surgery, such as structural complications and
ongoing ischemia with hemodynamic instability, overrides the risks of early surgery in AMI patients [34,37] . In
the 2021 ACC/AHA/SCAI guidelines [Table 2], a class 1 indication is attributed for CABG in patients with
STEMI who have mechanical complications (e.g., ventricular septal rupture, mitral insufficiency secondary
to papillary muscle infarction or rupture, or free wall rupture) . Similarly, emergent revascularization -
[26]
whether with CABG or PCI - is recommended as a class 1 indication in patients with cardiogenic shock and
hemodynamic instability [26,65] .

CONCLUSION
While some studies have shown an association between early CABG and surgical mortality following ACS
treated with primary PCI, the optimal timing of CABG remains to be elucidated. Chen and Liu proposed a
[33]
U-shaped distribution in mortality depending on the timing of surgery from AMI [Figure 1] . This
concept supports the idea that the lowest mortality can be achieved after the hyperacute phase of systemic
inflammation and before the development of irreversible complications from myocardial injury. Ultimately,