ST elevation myocardial infarction coronary artery bypass grafting

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Associate Editors-In-Chief:

Coronary Artery Bypass Surgery


Despite the guidelines, emergency bypass surgery for the treatment of an acute myocardial infarction (MI) is less common then PCI or medical management. In an analysis of patients in the U.S. National Registry of Myocardial Infarction (NRMI) from January 1995 to May 2004, the percentage of patients with cardiogenic shock treated with primary PCI rose from 27.4% to 54.4%, while the increase in CABG treatment was only from 2.1% to 3.2%.

Emergency coronary artery bypass graft surgery (CABG) is usually undertaken to simultaneously treat a mechanical complication, such as a ruptured papillary muscle, or a ventricular septal defect, with ensueing cardiogenic shock. In uncomplicated MI, the mortality rate can be high when the surgery is performed immediately following the infarction. If this option is entertained, the patient should be stabilized prior to surgery, with supportive interventions such as the use of an intra-aortic balloon pump. In patients developing cardiogenic shock after a myocardial infarction, both PCI and CABG are satisfactory treatment options, with similar survival rates.

Coronary artery bypass surgery involves an artery or vein from the patient being implanted to bypass narrowings or occlusions on the coronary arteries. Several arteries and veins can be used, however internal mammary artery grafts have demonstrated significantly better long-term patency rates than great saphenous vein grafts. In patients with two or more coronary arteries affected, bypass surgery is associated with higher long-term survival rates compared to percutaneous interventions. In patients with single vessel disease, surgery is comparably safe and effective, and may be a treatment option in selected cases. Bypass surgery has higher costs initially, but becomes cost-effective in the long term. A surgical bypass graft is more invasive initially but bears less risk of recurrent procedures (but these may be again minimally invasive).

==ACC / AHA Guidelines (DO NOT EDIT) == {{cquote|

Class I
1. Emergency or urgent CABG in patients with STEMI should be undertaken in the following circumstances:
 * a. Failed PCI with persistent pain or hemodynamic instability in patients with coronary anatomy suitable for surgery. (Level of Evidence: B)
 * b. Persistent or recurrent ischemia refractory to medical therapy in patients who have coronary anatomy suitable for surgery, have a significant area of myocardium at risk, and are not candidates for PCI or fibrinolytic therapy. (Level of Evidence: B)
 * c. At the time of surgical repair of post infarction ventricular septal rupture (VSR) or mitral valve insufficiency. (Level of Evidence: B)
 * d. Cardiogenic shock in patients less than 75 years old with ST elevation or LBBB or posterior MI who develop shock within 36 hours of STEMI, have severe multivessel or left main disease, and are suitable for revascularization that can be performed within 18 hours of shock, unless further support is futile because of the patient’s wishes or contraindications/unsuitability for further invasive care. (Level of Evidence: A)
 * e. Life-threatening ventricular arrhythmias in the presence of greater than or equal to 50% left main stenosis and/or triple-vessel disease. (Level of Evidence: B)

Class IIa
1. Emergency CABG can be useful as the primary reperfusion strategy in patients who have suitable anatomy and who are not candidates for fibrinolysis or PCI and who are in the early hours (6 to 12 hours) of an evolving STEMI, especially if severe multivessel or left main disease is present. (Level of Evidence: B)

2. Emergency CABG can be effective in selected patients 75 years or older with ST elevation, LBBB, or posterior MI who develop shock within 36 hours of STEMI, have severe triple-vessel or left main disease, and are suitable for revascularization that can be performed within 18 hours of shock. Patients with good prior functional status who are suitable for revascularization and agree to invasive care may be selected for such an invasive strategy. (Level of Evidence: B)

Class III
1. Emergency CABG should not be performed in patients with persistent angina and a small area of risk who are hemodynamically stable. (Level of Evidence: C)

2. Emergency CABG should not be performed in patients with successful epicardial reperfusion but unsuccessful microvascular reperfusion. (Level of Evidence: C)}}