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Page 2 of 8 Joo et al. Vessel Plus 2018;2:2 I http://dx.doi.org/10.20517/2574-1209.2017.36

by coronary artery bypass grafting (CABG) as well as the overall management of ACS patients have evolved
a great deal over the last 15 to 20 years [4,10] .

INDICATIONS FOR SURGICAL REVASCULARIZATION
For patients with UA or NSTEMI, treatment choices are based on the patient’s level of risk as indicated by
[5]
clinical symptoms, electrocardiogram changes, and cardiac biomarker levels . Based on joint guidelines
from the American College of Cardiology and American Heart Association, CABG is recommended as
primary treatment for patients with significant left main disease or left main equivalent (i.e. significant
proximal left anterior descending and proximal left circumflex stenosis) and for patients unresponsive to
maximal nonsurgical treatment (Class of Recommendation: I & Level of Evidence: A) . Surgery is also
[10]
a reasonable consideration in patients with proximal left anterior descending (LAD) stenosis with 1- or
2-vessel disease, presence of complex coronary lesions, and for patients in whom percutaneous intervention
is not feasible [11-13] .

For patients experiencing NSTEMI and UA, while indications for CABG vs. percutaneous coronary
intervention (PCI) are similar to those for patients with stable angina, studies show that high-risk patients
with left ventricular systolic dysfunction [14,15] , severe 3-vessel disease [16-19] , 2-vessel disease involving the
proximal LAD, or diabetes mellitus [20-22] should be considered for CABG. Existing guidelines affirm the
indications for high-risk patients given the increased chances of long-term survival [23,24] . In contrast, the
survival benefits of CABG are much more modest in lower-risk patients. Thus, these patients should only
be considered for early surgery if they are willing to accept the short-term risks associated with surgical
revascularization in exchange for potentially improved functional status.

The accepted first-line treatment for STEMI is PCI or systemic thrombolysis. However, CABG is performed
in up to 5% of STEMI cases . In particular, surgery is indicated among patients with good surgical targets
[25]
but whose hemodynamic instability results in a complicated or failed angioplasty; after a failed fibrinolysis;
who have persistent, refractory ischemia; who show evidence of mechanical or valvular disease; who are
in cardiogenic shock; or who have life-threatening ventricular arrhythmias and either severe stenosis or
multivessel disease . There is also class II evidence that CABG may be appropriate as primary intervention
[10]
in patients for whom PCI failed, and it can also be considered in patients with evidence of severe left main
or multivessel disease with poor left ventricular function or diabetes.

PROGNOSIS
Despite improvements over time, in-hospital mortality for patients with acute myocardial infarction (AMI)
in the USA remains at 5% and is even higher among STEMI patients who undergo either PCI or emergency
CABG [26-30] . Additionally, NSTEMI patients undergoing surgical intervention have a poorer prognosis than
their non-ACS counterparts , and the hospital level 30-day risk-standardized mortality rates for patients
[31]
[32]
discharged with AMI remains at approximately 16% . Outcomes for CABG are also worse in patients with
ACS than in patients without ACS [4,33] . The preoperative troponin I level has been promoted as the strongest
independent predictor of short-term death [1,31] .

OFF-PUMP CABG
The advent of off-pump CABG (OPCABG) - which avoids cardiopulmonary bypass and its associated risks
- brought the promise of reducing operative risk while producing long-term outcomes that were as good
as or better than those of on-pump surgery [34-36] . Several studies have since shown short-term outcomes
comparable to those of on-pump CABG [37,38] , as well as lower rates of atrial fibrillation, less need for blood
transfusions, less renal and neurocognitive dysfunction, and shorter hospital stays in mixed-risk patient