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Page 8 of 13 Zahrai et al. Vessel Plus 2023;7:32 https://dx.doi.org/10.20517/2574-1209.2023.100

be a clinical benefit in delaying surgery by 24-48 h, whereas this difference in outcomes may not be present
in patients with NSTEMI. A systematic review and meta-analysis of 113,984 AMI patients undergoing
CABG treatment found that early intervention (within 24 or 48 h from AMI occurrence) in the STEMI
group was associated with a higher risk of mortality compared to late intervention, while early versus late
timing of CABG did not significantly impact mortality in NSTEMI patients . Results from registry and
[34]
retrospective cohort studies suggest that in the absence of an absolute need for urgent surgery, delay may be
considered for STEMI patients due to the mortality risk of earlier operations [37-39] . Some studies have
[7]
identified early surgical intervention as a predictor of increased mortality in ACS patients , while others
have demonstrated no association between the time of surgical revascularization and mortality or
periprocedural complications [40,41] .

The transmural infarction seen in STEMI may be a factor resulting in increased inflammatory markers, the
levels of which may be further elevated with early CABG procedures after AMI and potentially impact
myocardial function, and can lead to a profound systemic inflammatory response, a well-known risk factor
for perioperative mortality [34,41-43] . For example, levels of the inflammatory marker C-reactive protein can be
demonstrated to be significantly increased after a transmural MI [43,44] . CABG is also associated with
profound increases in these markers, suggesting that these inflammatory changes may be compounded .
[44]
On the other hand, studies have not found significant differences in postoperative outcomes of NSTEMI
patients who undergo early versus late surgical revascularization; delayed surgery may therefore increase
resource use without considerably improving patient outcomes [45,46] .

Patients with acute STEMI and multivessel CAD who require surgical revascularization are at a higher risk
of death than STEMI patients with an isolated single culprit lesion . These patients may be considered for
[47]
other interventions, for example, primary PCI using balloon angioplasty of the culprit lesion and medical
management of the non-culprit lesions without risk of further angina or MI [48,49] . Other options include
primary PCI and later staged PCIs to treat the non-culprit lesions, or ad-hoc PCI procedures during the
primary PCI. This group of patients, especially if they have cardiogenic shock or ischemia after treating the
[50]
culprit lesion, would require complete revascularization . On the other hand, hemodynamically stable
patients can benefit from primary-staged PCIs and multivessel PCIs [51,52] .

BLEEDING RISK CONSIDERATIONS
Anticoagulation and antiplatelet therapy (and sometimes fibrinolytic agents) are vital in the management of
ACS. While significantly decreasing the risk of ischemic recurrence, these agents increase the surgical risk
due to bleeding [31,53] . Patients with coagulopathy and prolonged bleeding times suffer from longer surgical
time, higher transfusion rate, and higher risk of re-exploration. This is well-known and was one of the
major drawbacks in several large randomized control trials evaluating the use of antiplatelet therapy in ACS,
including the CURE and the TRITON-TIMI 38 CABG substudies.
[54]
[55]
The 2017 European Society of Cardiology focused update on dual antiplatelet therapy in coronary artery
disease and the 2018 Canadian Cardiovascular Society Guidelines for the use of antiplatelet therapy
[57]
[56]
provide specific recommendations for a timeline of discontinuation of antiplatelet therapy prior to CABG,
to minimize this risk [Table 4]. This information must be considered to derive the risk and benefit ratio of
early versus late surgery shortly after the administration of antiplatelet agents to individualize care for each
patient.

In patients with an ACS requiring urgent CABG after administration of antiplatelet agents, certain strategies
exist for clinicians to mitigate the bleeding risk. When possible, performing off-pump surgery may be