Coronary artery bypass

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In medicine, coronary artery bypass is a form of myocardial revascularization that is a "surgical therapy of ischemic coronary artery disease achieved by grafting a section of saphenous vein, internal mammary artery, or other substitute between the aorta and the obstructed coronary artery distal to the obstructive lesion.'[1]


Use of the left internal mammary artery for a source improves outcomes.[2] Use of a radial artery for a source may improve outcomes.[3]

Surgery is best done with cardiopulmonary bypass using a heart–lung machine, [4] although there are minimally invasive techniques that do not require cardiopulmonary bypass.


Clinical practice guidelines address management and selection of patients.[5] Patient who have a left ventricular ejection fraction between 35 and 49 percent benefit from coronary artery bypass surgery if they have disease of three coronary arteries.[6].

Coronary artery bypass is more effective for myocardial revascularization of coronary heart disease than percutaneous transluminal coronary angioplasty[7], especially for patients with diabetes who have stenosis of three coronary arteries.[8] Coronary artery bypass is also more effective than percutaneous transluminal coronary angioplasty with drug-eluting stents; however, bypass may increase the rate of stroke.[9] The SYNTAX score may help determine choice of procedure for myocardial revascularization.[10]

Major randomized controlled trials of surgery for chronic stable angina
Trial Patients Results
Veterans Administration cooperative study
686 patients[11]
686 patients
• Males: 100%
• LVEF ≥ 25%
3 year survival was 87% of the medical group and 88% of the surgical group. No significant difference.
Coronary Artery Surgery Study
780 patients
• Males: 90%
• LVEF ≥ 35%
• Mild or no angina
The 5 year survival 92% with medical therapy and 95% with surgery (not significant). "The likelihood of nonfatal Q-wave myocardial infarction was 11 and 14 per cent, respectively (not significant). The five-year probability of remaining alive and free of infarction was 82 per cent in the patients assigned to medical therapy and 83 per cent in the patients assigned to surgery (not significant)."
European Coronary Surgery Study
767 patients
• Males: 100%<
• LVEF ≥ 50%
5 year survival was 92% with surgery and 83% with medical therapy.
Pooled results[13] Patients Surgery fared better except for patients with one or two vessel disease with neither vessel being the LAD or left main.

Adverse effects

Risk can be estimated with the 72 STS (Surgical Thoracic Society) Normal 0 false false false EN-US X-NONE X-NONE 72 Normal 0 false false false EN-US X-NONE X-NONE risk calculator ([14]

Stroke may occur.[15]

Delirium may occur the postoperative period in 46% of patients:[16]

  • Patients without postoperative delirium: cognition may take one yeaer to return to normal. At 6 months, 40% returned to their original cognition
  • Patients with postoperative delirium: cognition returns to normal after one month. At 6 months, 24% returned to their original cognition


  1. Anonymous (2022), Coronary artery bypass (English). Medical Subject Headings. U.S. National Library of Medicine.
  2. Zeff RH, Kongtahworn C, Iannone LA, et al (May 1988). "Internal mammary artery versus saphenous vein graft to the left anterior descending coronary artery: prospective randomized study with 10-year follow-up". Ann. Thorac. Surg. 45 (5): 533–6. PMID 3259128. [e]
  3. Desai, Nimesh D.; Eric A. Cohen, C. David Naylor, Stephen E. Fremes, the Radial Artery Patency Study Investigators (2004-11-25). "A Randomized Comparison of Radial-Artery and Saphenous-Vein Coronary Bypass Grafts". N Engl J Med 351 (22): 2302-2309. DOI:10.1056/NEJMoa040982. PMID 15564545. Retrieved on 2009-04-30. Research Blogging.
  4. Shroyer, A. Laurie; Frederick L. Grover, Brack Hattler, Joseph F. Collins, Gerald O. McDonald, Elizabeth Kozora, John C. Lucke, Janet H. Baltz, Dimitri Novitzky, the Veterans Affairs Randomized On/Off Bypass (ROOBY) Study Group (2009-11-05). "On-Pump versus Off-Pump Coronary-Artery Bypass Surgery". N Engl J Med 361 (19): 1827-1837. DOI:10.1056/NEJMoa0902905. Retrieved on 2009-11-05. Research Blogging.
  5. Hillis LD, Smith PK, Anderson JL, Bittl JA, Bridges CR, Byrne JG et al. (2011). "2011 ACCF/AHA Guideline for Coronary Artery Bypass Graft Surgery: A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines.". Circulation. DOI:10.1161/CIR.0b013e31823c074e. PMID 22064599. Research Blogging.
  6. 6.0 6.1 (March 1984) "Myocardial infarction and mortality in the coronary artery surgery study (CASS) randomized trial". N. Engl. J. Med. 310 (12): 750–8. PMID 6608052. “This is the CASS randomized controlled trial.” [e] Cite error: Invalid <ref> tag; name "pmid6608052" defined multiple times with different content
  7. Bravata DM, Gienger AL, McDonald KM, et al (2007). "Systematic Review: The Comparative Effectiveness of Percutaneous Coronary Interventions and Coronary Artery Bypass Surgery". Ann Intern Med. PMID 17938385. [e]
  8. (July 1996) "Comparison of coronary bypass surgery with angioplasty in patients with multivessel disease. The Bypass Angioplasty Revascularization Investigation (BARI) Investigators". N. Engl. J. Med. 335 (4): 217–25. PMID 8657237. [e]
  9. Serruys PW, Morice MC, Kappetein AP, et al (March 2009). "Percutaneous coronary intervention versus coronary-artery bypass grafting for severe coronary artery disease". N. Engl. J. Med. 360 (10): 961–72. DOI:10.1056/NEJMoa0804626. PMID 19228612. Research Blogging.
  10. Valgimigli M, Serruys PW, Tsuchida K, et al (April 2007). "Cyphering the complexity of coronary artery disease using the syntax score to predict clinical outcome in patients with three-vessel lumen obstruction undergoing percutaneous coronary intervention". Am. J. Cardiol. 99 (8): 1072–81. DOI:10.1016/j.amjcard.2006.11.062. PMID 17437730. Research Blogging.
  11. Murphy ML, Hultgren HN, Detre K, Thomsen J, Takaro T (September 1977). "Treatment of chronic stable angina. A preliminary report of survival data of the randomized Veterans Administration cooperative study". N. Engl. J. Med. 297 (12): 621–7. PMID 331107. [e]
  12. Varnauskas E (August 1988). "Twelve-year follow-up of survival in the randomized European Coronary Surgery Study". N. Engl. J. Med. 319 (6): 332–7. PMID 3260659. [e]
  13. Yusuf S, Zucker D, Peduzzi P, et al (August 1994). "Effect of coronary artery bypass graft surgery on survival: overview of 10-year results from randomised trials by the Coronary Artery Bypass Graft Surgery Trialists Collaboration". Lancet 344 (8922): 563–70. PMID 7914958. [e]
  14. Shahian DM, O'Brien SM, Filardo G, Ferraris VA, Haan CK, Rich JB et al. (2009). "The Society of Thoracic Surgeons 2008 cardiac surgery risk models: part 1--coronary artery bypass grafting surgery.". Ann Thorac Surg 88 (1 Suppl): S2-22. DOI:10.1016/j.athoracsur.2009.05.053. PMID 19559822. Research Blogging.
  15. Farkouh ME, Domanski M, Sleeper LA, Siami FS, Dangas G, Mack M et al. (2012). "Strategies for Multivessel Revascularization in Patients with Diabetes.". N Engl J Med. DOI:10.1056/NEJMoa1211585. PMID 23121323. Research Blogging.
  16. Saczynski JS, Marcantonio ER, Quach L, Fong TG, Gross A, Inouye SK et al. (2012). "Cognitive trajectories after postoperative delirium.". N Engl J Med 367 (1): 30-9. DOI:10.1056/NEJMoa1112923. PMID 22762316. Research Blogging.