Unstable angina / non ST elevation myocardial infarction recommendations for CABG


 * Associate Editor-In-Chief: Smita Kohli, M.D.

Overview of Recommendations for CABG in Unstable angina/NSTEMI
For patients with UA/NSTEMI, when revascularization is required, the choice is between PCI and CABG. In general, the indications for PCI and CABG in UA/NSTEMI are similar to those for stable angina.

Based on the results of multiple randomized trials, CABG is recommended for patients with disease of the left main coronary artery and multivessel disease and impaired left ventricular function. However, recent advance in techniques and less complications with PCI have led to use of PCI for isolated left main disease.

PCI versus CABG-Clinical trial data
More than nine trials have compared PCI and CABG in patients with ischemic heart disease, many of whom had UA/NSTEMI. The BARI and CABRI trials were two large major trials with head to head comparison of PCI versus CABG.

In both BARI and EAST trials, the biggest differences in late outcomes were the need for repeat revascularization procedures and symptom status with 54% of PTCA patients undergoing subsequent revascularization procedures during the five-year follow-up versus 8% of the BARI CABG group and 13% of the EAST CABG group.
 * The BARI trial, the largest randomized comparison of CABG and PTCA, was performed in 1,829 patients with 2- or 3-vessel CAD. Unstable angina was the admitting diagnosis in 64% of these patients, and 19% had treated diabetes mellitus. A majority of patients had two- rather than three-vessel disease (37% of patients had a proximal LAD lesion) and normal LV function. The subgroup of patients with treated diabetes had a significantly better survival rate with CABG. That survival advantage for CABG was focused in the group of diabetic patients with multiple severe lesions.
 * The EAST trial, which was another trial in the US studying PCI versus CABG showed that patients with diabetes had an equivalent survival rate with CABG or PTCA at five years, after which the curves began to diverge but failed to reach a statistically significant difference at eight years (surgical survival 75.5%, PTCA 60.1%; p = 0.23).


 * The CABRI investigators also showed a survival benefit for CABG in patients with diabetes mellitus with multivessel.


 * The SYNTAX trial, failed to show PCI to be noninferior to CABG in left main and triple-vessel disease. SYNTAX trial was an unblinded, randomized clinical trial that assigned patients with 3-vessel and/or left main CAD to an initial treatment strategy of CABG or PCI.The primary prespecified end point for the 1800 enrolled patients was the composite of death, stroke, and myocardial revascularization determined at 12 months. In SYNTAX, for the subgroup with left main CAD, there were no significant differences in the incidence of the composite end point (death, MI, stroke, or repeat revascularization) between the 2 groups, although rates of repeat revascularization were higher and rates of stroke were lower in the PCI group. Left main stented patients with limited CAD (lower SYNTAX score) displayed a trend toward fewer adverse events at 12 months than did similar patients assigned to CABG. This has led to change of recommendation for PCI as an alternative to CABG for left main disease from Class III in 2005 PCI guidelines to Class IIb in 2009 PCI guidelines. However, it should be kept in mind that the number of patients with left main disease in this study was relatively small and the follow up was of 1 year and longer follow up is needed before a decision is made to routinely recommend PCI for patients with isolated left main disease. The writing committee for the 2009 PCI updates clarifies that the Class IIb indication is intended to apply only to those left main lesions that are suitable for PCI. A follow up angiography after PCI of left main disease is no longer recommended.

Indications

 * High-risk patients with LV systolic dysfunction, patients with diabetes mellitus, and those with 2-vessel disease with severe proximal LAD involvement or severe 3-vessel or left main disease should be considered for CABG.
 * Low-risk patients will have negligibly increased chances of long-term survival with CABG (or PCI) and therefore should be managed medically. However, in low-risk patients, quality of life and patient preferences may be considered in addition to strict clinical outcomes in the selection of a treatment strategy.

==ACC / AHA Guidelines-Recommendations for CABG in patients with UA/NSTEMI (DO NOT EDIT) ==

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Class I
1. Coronary artery bypass graft surgery is recommended for UA / NSTEMI patients with significant left main CAD (>50% stenosis). (Level of Evidence: A)

2. Coronary artery bypass graft surgery is recommended for UA / NSTEMI patients with 3-vessel disease; the survival benefit is greater in patients with abnormal LV function (LVEF<50%). (Level of Evidence: A)

3. Coronary artery bypass graft surgery is recommended for UA / NSTEMI patients with 2 vessel disease with significant proximal LAD disease and either abnormal LV function (LVEF <50%) or ischemia on non invasive testing. (Level of Evidence: A)

4. Coronary artery bypass graft surgery is recommended for UA / NSTEMI patients in whom percutaneous coronary revascularization is not optimal or possible and who have ongoing ischemia not responsive to maximal nonsurgical therapy. (Level of Evidence: B)

5. Coronary artery bypass graft surgery (or PCI) is recommended for UA / NSTEMI patients with 1 or 2 vessel CAD with or without significant proximal left anterior descending CAD but with a large area of viable myocardium and high risk criteria on noninvasive testing. (Level of Evidence: B)

6. Coronary artery bypass graft surgery (or PCI) is recommended for UA / NSTEMI patients with multivessel coronary disease with suitable coronary anatomy, with normal LV function, and without diabetes mellitus. (Level of Evidence: A)

Class IIa
1. For patients with UA / NSTEMI and multi vessel disease, CABG with use of the internal mammary arteries can be beneficial over PCI in patients being treated for diabetes. (Level of Evidence: B)

2. It is reasonable to perform CABG with the internal mammary artery for UA / NSTEMI patients with multi vessel disease and treated diabetes mellitus. (Level of Evidence: B)

3. Repeat CABG is reasonable for UA / NSTEMI patients with multiple SVG stenoses, especially when there is significant stenosis of a graft that supplies the LAD. (Level of Evidence: C)

4. Coronary artery bypass graft surgery (or PCI) is reasonable for UA / NSTEMI patients with 1 or 2 vessel CAD with or without significant proximal left anterior descending CAD but with a moderate area of viable myocardium and ischemia on non invasive testing. (Level of Evidence: B)

5. Coronary artery bypass graft surgery (or PCI) can be beneficial compared with medical therapy for UA / NSTEMI patients with 1 vessel disease with significant proximal left anterior descending CAD. (Level of Evidence: B)

6. Coronary artery bypass surgery (or PCI with stenting) is reasonable for patients with multi vessel disease and symptomatic myocardial ischemia. (Level of Evidence: B)

Class IIb
1. Coronary artery bypass graft surgery may be considered in patients with UA / NSTEMI who have 1 or 2 vessel disease not involving the proximal LAD with a modest area of ischemic myocardium when percutaneous revascularization is not optimal or possible. (If there is a large area of viable myocardium and high-risk criteria on non invasive testing, this recommendation becomes a Class I recommendation.) (Level of Evidence: B)

Class III
1. Coronary artery bypass graft surgery (or PCI) is not recommended for patients with 1- or 2-vessel CAD without significant proximal left anterior descending CAD without current symptoms or symptoms that are unlikely to be due to myocardial ischemia and who have no ischemia on non invasive testing. (Level of Evidence: C)}}