Chronic stable angina revascularization coronary artery bypass grafting
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Chronic stable angina Microchapters | ||
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Classification | ||
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Differentiating Chronic Stable Angina from Acute Coronary Syndromes | ||
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Diagnosis | ||
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Alternative Therapies for Refractory Angina | ||
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Discharge Care | ||
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Guidelines for Asymptomatic Patients | ||
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Case Studies | ||
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Chronic stable angina revascularization coronary artery bypass grafting On the Web | ||
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FDA on Chronic stable angina revascularization coronary artery bypass grafting | ||
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Chronic stable angina revascularization coronary artery bypass grafting in the news | ||
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to Hospitals Treating Chronic stable angina revascularization coronary artery bypass grafting | ||
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]; John Fani Srour, M.D.; Smita Kohli, M.D.; Lakshmi Gopalakrishnan, M.B.B.S.;Aysha Anwar, M.B.B.S[3]
Overview
Coronary artery bypass surgery, also coronary artery bypass graft (CABG, pronounced "cabbage") surgery, and colloquially heart bypass or bypass surgery is a surgical procedure performed to relieve angina and reduce the risk of death from coronary artery disease. Arteries or veins from elsewhere in the patient's body are grafted to the coronary arteries to bypass atherosclerotic narrowings and improve the blood supply to the coronary circulation supplying the myocardium (heart muscle). This surgery is usually performed with the heart stopped, necessitating the usage of cardiopulmonary bypass; techniques are available to perform CABG on a beating heart, so-called "off-pump" surgery.
CABG
Coronary Artery Bypass Grafting (CABG) is carried out to prolong life expectancy and improve overall quality of life.
- Prolongation of life has been shown in patients with more than 50% luminal diameter stenosis of the left main coronary artery and in those with impaired left ventricular function (left ventricular ejection fraction less than 40%) and critical, greater than 70% stenosis in all three major coronary arteries or in two arteries, one of which is the proximal left anterior descending artery. The presence of a high-risk result on a noninvasive test also increases the benefit of surgery. Patients with severe left ventricular dysfunction obtain a survival benefit from CABG if the myocardium with impaired contractile function is viable (hibernating myocardium) rather than necrotic.
- The stenotic arteries are bypassed with an internal mammary (arterial) or saphenous vein graft.
- Arterial grafts have excellent long-term patency rates (90% at 10 years), whereas saphenous vein grafts show accelerated atherosclerosis with approximately 50% patency at 10 years.
- The use of internal mammary artery grafts is associated with a 27% reduction in 15-year mortality compared with saphenous vein grafts.
- The left internal mammary artery is most favorable to a graft to the left anterior descending coronary artery and the right internal mammary artery is most applicable to graft to the right coronary artery.
- Patients who require more than two grafts generally receive a combination of arterial and venous grafts.
- Minimally invasive CABG via a smaller thoractomy incision or a thorascopic approach reduces the morbidity and hospital length-of-stay.
- The operative mortality of CABG is about 2%. The steady improvements in perioperative care have been offset by the progressively sicker patients who are referred for this procedure.
- Angina pectoris is relieved in more than 90% of patients who undergo CABG. The recurrence of angina is due to graft stenosis or progression of disease in nongrafted vessels.
Indications
Trials conducted in the 1970s offered no signficant evidence that CABG offered mortality benefits compared to medical therapy. However, in recent years, several trials have established the survival benefits in selected patients.
- Patients with left main coronary artery stenosis or left main equivalent disease (defined as severe (≥70 percent) proximal left anterior descending and proximal left circumflex disease):
- The Veterans Administration Cooperative Study compared a strategy of initial CABG versus deferred CABG. Researchers observed a substantial survival advantage in pateints assigned to initial CABG at two years (93 versus 71 percent) and at 11 year, but not at 18 years out. The benefit was greatest in high-risk patients with >75 percent left main stenosis and/or left ventricular dysfunction.
- The CASS registry demonstrated similar results. In an overview of 10-year results from randomized trials by the Coronary Artery Bypass Graft Surgery Trialists Collaboration, researchers found that the relative risk reduction for death provided by CABG over medical therapy alone was greater at five years for left main disease than for three vessel or one or two vessel disease (odds ratio 0.32 versus 0.58 and 0.77); the absolute survival benefit from CABG among those with left main disease was 19.3 months.[1]
- Researchers have also evaluated the usage of PCI for left main coronary artery stenosis. PCI has been performed in patients with angina and left main disease who are considered inoperable, at high risk for CABG, or with prior CABG and one patent graft to either the left anterior descending or circumflex artery ("protected" left main).
- Patients with multivessel coronary disease and left ventricular dysfunction:
- Reduced left ventricular function is an important determinant of prognosis in patients with stable angina and is an indication for revascularization.
- CABG may improve survival in patients with left ventricular dysfunction and hibernating myocardium; therefore, myocardial viability should be assessed prior to recommending CABG in patients with multivessel coronary disease and left ventricular dysfunction.
- CASS registry showed that survival at seven years was improved with CABG compared to medical treatment (88 versus 65 percent) in patients with an LVEF between 35 and 49 percent and had three vessel disease. No benefit from CABG could be identified in patients with one or two vessel disease.[1]
Clinical Trial Data: CABG versus Medical therapy in the Management of Stable Angina Pectoris
2012 ACC/AHA/ACP–ASIM Guidelines for the Management of Patients With Chronic Stable Angina (DO NOT EDIT)[2][3]
Revascularization With CABG in Patients With Stable Angina (DO NOT EDIT)[2][3]
Revascularization to Improve Survival
Left Main CAD Revascularization
| Class I |
| "1. CABG to improve survival is recommended for patients with significant (greater than or equal to 50% diameter stenosis) left main coronary artery stenosis. (Level of Evidence: B)" |
Non–Left Main CAD Revascularization
| Class I |
| "1. CABG to improve survival is beneficial in patients with significant (greater than or equal to 70% diameter) stenoses in 3 major coronary arteries (with or without involvement of the proximal LAD artery) or in the proximal LAD artery plus 1 other major coronary artery. (Level of Evidence: B)" |
| "2. CABG or PCI to improve survival is beneficial in survivors of sudden cardiac death with presumed ischemia-mediated ventricular tachycardia caused by significant (greater than or equal to 70% diameter) stenosis in a major coronary artery (Level of Evidence: A)" |
| Class IIa |
| "1. CABG to improve survival is reasonable in patients with significant (�70% diameter) stenoses in 2 major coronary arteries with severe or extensive myocardial ischemia (e.g., high-risk criteria on stress testing, abnormal intracoronary hemodynamic evaluation,
or �20% perfusion defect by myocardial perfusion stress imaging) or target vessels supplying a large area of viable myocardium ( (Level of Evidence: B)" |
| "2. CABG to improve survival is reasonable in patients with mild–moderate LV systolic dysfunction (ejection fraction 35% to 50%) and significant (�70% diameter stenosis) multivessel CAD or proximal LAD coronary artery stenosis, when viable myocardium is present in the region of intended revascularization(Level of Evidence: B)" |
| "3. CABG with a left internal mammary artery graft to improve survival is reasonable in patients with significant (�70% diameter) stenosis in the proximal LAD artery and evidence of extensive ischemia (Level of Evidence: B)" |
| "4. It is reasonable to choose CABG over PCI to improve survival in patients with complex 3-vessel CAD (e.g., SYNTAX score �22), with or without involvement of the proximal LAD artery who are good candidates for CABG (Level of Evidence: B)" |
| "5. CABG is probably recommended in preference to PCI to improve survival in patients with multivessel CAD and diabetes mellitus, particularly if a left internal mammary artery graft can be anastomosed to the LAD artery (Level of Evidence: B)" |
| Class IIb | ||||||||||||||||||||||||||||||
| "1. The usefulness of CABG to improve survival is uncertain in patients with significant (�70%) diameter stenoses in 2 major coronary arteries not involving the proximal LAD artery and without extensive ischemia(Level of Evidence: C)" | ||||||||||||||||||||||||||||||
| "2. The usefulness of PCI to improve survival is uncertain in patients with 2- or 3-vessel CAD (with or without involvement of the proximal LAD artery) or 1-vessel proximal LAD disease(Level of Evidence: B)" | ||||||||||||||||||||||||||||||
| "3. CABG might be considered with the primary or sole intent of improving survival in patients with SIHD with severe LV systolic dysfunction (ejection fraction �35%) whether or not viable myocardium is present (Level of Evidence: B)" | ||||||||||||||||||||||||||||||
"4. The usefulness of CABG or PCI to improve survival is uncertain in patients with previous CABG and extensive anterior wall ischemia on noninvasive testing. (Level of Evidence: B)"
Revascularization to Improve Symptoms
ESC Guidelines- Revascularization to Improve Prognosis (DO NOT EDIT)[4]
ESC Guidelines- Revascularization to Improve Symptoms (DO NOT EDIT)[4]
References
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