Coronary Artery Bypass Grafting

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Contents 1 More Specific Terms 2 Introduction 3 Indications 4 Contraindications 5 Laboratory 6 Complications 7 Management 8 Notes 9 More General Terms 10 Additional Terms 11 References

More Specific Terms

• minimally invasive direct coronary artery bypass (MIDCAB)

Introduction

• Vein or artery grafted surgically to permit blood to travel from the aorta to a branch of the coronary artery at a point past an obstruction.

Indications

• recurrent ischemia ( unstable angina) secondary to coronary artery disease not anatomically appropriate for PTCA ( PCI)
• coronary artery disease with mechanical complications that require surgical repair

• mitral regurgitation
• ventricular septal rupture

• myocardial infarction with impaired left ventricular function

• 2 or more vessels with > 50% stenosis
• viable left ventricular myocardium with abnormal wall motion

• stable angina with normal left ventricular function

• significant left main coronary artery disease
• proximal left anterior descending artery & proximal left circumflex artery disease: >= 70% stenosis
• 3-vessel disease or severe 2-vessel disease

• CABG is indicated for patients with diabetes mellitus who would otherwise be eligible for PTCA (better 5 year survival, 80% vs 65%) [10]
• CABG is superior to PTCA ( PCI) for patients > 65 years of age [10]
  

• CABG improves survival in patients with:

• left main coronary artery disease
• three vessel disease &:

• moderately depressed left ventricular function, or
• ischemia at low workloads

• multivessel disease with involvement of proximal left anterior descending artery ( LAD)

Contraindications

• Caution: (Risk factors)

• age
• female sex
• poor left ventricular function
• left main coronary artery disease
• unstable angina
• diabetes mellitus

• CABG does NOT prevent myocardial infarction
• CABG does NOT reduce incidence of ventricular arrhythmias

Laboratory

• elevation of markers of myocardial infarction after bypass associated with increased mortality at 1 year [13]

• serum creatine kinase MB
• serum troponin I

Complications

• cognitive impairment [4,8]

• short term (53% at hospital discharge)
• long-term (24% at 6 months, 42% at 5 years)
• use of cardiopulmonary bypass pump a factor [6]

• no difference on or off bypass pump [8], 50% at 5 years

• delirium after CABG is associated with increassed mortality [12]
• pulmonary complications common [7]

• pneumonia, atelectasis, pleural effusion, ventilator dependence
• inspiratory muscle training daily for 2 weeks prior to CABG reduces pulmonary complications [7]

• harvesting of veins for coronary artery bypass grafting

• wound infection
• postoperative pain
• vein graft failure

• endoscopic harvesting with higher rate of composite of death, MI, & revascularization (3 year hazard ratio, 1.22) than open harvesting

Management

• aspirin administration during 1st 48 hours after CABG reduces in hospital mortality [5]
• tight glycemic control ( serum glucose 90-120 mg/dL) increases the incidence of hypoglycemic events & does not result in any significant improvement in clinical outcomes relative to moderate glycemic control ( serum glucose 120-180 mg/dL) [14]

Notes

• CABG provides relief from angina
• closure rate on saphenous vein grafts are 20% at 1 year
• CABG superior to PCI for severe coronary artery disease [9]
• no significant advantage of off-pump vs on pump CABG [16]

More General Terms

• cardiac surgery (heart surgery)
• bypass graft; bypass surgery

Additional Terms

• Bypass Angioplasty Revascularization Investivation (BARI)
• coronary stent (PCI) vs CABG
• percutaneous transluminal coronary angioplasty (PTCA, percutaneous coronary intervention, PCI)
• post cardiotomy syndrome
• post perfusion syndrome

References

1. Manual of Medical Therapeutics, 28th ed, Ewald & McKenzie (eds), Little, Brown & Co, Boston, 1995, pg 91
2. Medical Knowledge Self Assessment Program (MKSAP) 11, American College of Physicians, Philadelphia 1998
3. Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 88-89
4. Journal Watch 21(5):38, 2001 Newman et al N Engl J Med 344:395, 2001
5. Journal Watch 22(23):172, 2002 Mangano DT et al, N Engl J Med 347:1309, 2002 Topol EJ et al, N Engl J Med 347:1359, 2002
6. Journal Watch 23(3):23, 2003 Zamvar V et al, BMJ 325:1268, 2002 [1]
7. Hulzebps EHJ et al, Preoperative intensice inspiratory muscle training to prevent postoperative pulmonary complications in high-risk patients undergoing CABG surgery: A randomized clinical trial. JAMA 2006, 296:1851 PMID: [2]
8. van Dijk D et al. for the Octopus Study Group. Cognitive and cardiac outcomes 5 years after off-pump vs on-pump coronary artery bypass graft surgery. JAMA 2007 Feb 21; 297:701-8.
9. Serruys PW et al for the SYNTAX Investigators. Percutaneous Coronary Intervention versus coronary-artery bypass grafting for severe coronary artery disease. N Engl J Med 2009 Feb 18; [e-pub ahead of print]. [3] PMID: &dopt=Abstract
   - Lange RA and Hillis LD. SYNTAX in context. N Engl J Med 2009 Feb 18; [e-pub ahead of print]. [4] PMID: [5]
10. Hlatky MA et al, Coronary artery bypass surgery compared with percutaneous coronary interventions for multivessel disease: a collaborative analysis of individual patient data from ten randomised trials Lancet. 2009 Apr 4;373(9670):1190-7. Epub 2009 Mar 19. <PubMed> PMID: [6] <Internet> [7]
11. Lopes RD et al Endoscopic versus open vein-graft harvesting in coronary-artery bypass surgery. N Engl J Med 2009 Jul 16; 361:235. PMID: [8]
12. Gottesman RF et al. Delirium after coronary artery bypass graft surgery and late mortality. Ann Neurol 2010 Mar; 67:338. PMID: [9]
13. Domanski MJ et al Association of Myocardial Enzyme Elevation and Survival Following Coronary Artery Bypass Graft Surgery JAMA. 2011;305(6):585-591 <PubMed> PMID: [10] <Internet> [11]
14. Lazar HL et al. Effects of aggressive versus moderate glycemic control on clinical outcomes in diabetic coronary artery bypass graft patients. Ann Surg 2011 Sep; 254:458 PMID: [12]
15. Hillis LD et al 2011 ACCF/AHA Guideline for Coronary Artery Bypass Graft Surgery: Executive Summary American College of Cardiology Foundation American Heart Association Task Force on Practice Guidelines American Association for Thoracic Surgery Society of Cardiovascular Anesthesiologists Society of Thoracic Surgeons J Am Coll Cardiol, November 7, 2011 <PubMed> PMID: [13] <Internet> [14]
16. Lamy A et al. for the CORONARY Investigators. Off-pump or on-pump coronary-artery bypass grafting at 30 days. N Engl J Med 2012 Mar 26 <PubMed> PMID: [15] <Internet> [16]
    - Grover FL. Current status of off-pump coronary-artery bypass. N Engl J Med 2012 Mar 26 <PubMed> PMID: [17] <Internet> [18]
17. Heart Bypass Surgery/Angioplasty: NIH Institute and Center Resources [19]
18. National Guideline Clearinghouse
    - Coronary angiography and indications for CABG or angioplasty. (Finnish Medical Society Duodecim) ngc-guideline: [20]
    - Society of Thoracic Surgeons Gender-specific practice guidelines for coronary artery bypass surgery. ngc-guideline: [21]

coronary artery bypass grafting (CABG)