What is the current procedure for Coronary Artery Bypass Grafting (CABG)?

Current Procedure for Coronary Artery Bypass Grafting (CABG)

Coronary artery bypass grafting (CABG) is primarily performed through a median sternotomy with hand-sewn anastomoses using the left internal mammary artery (LIMA) as the primary graft for the left anterior descending (LAD) artery, with additional arterial or venous grafts as needed. 1

Standard Surgical Approach

• Most CABG procedures are performed using extracorporeal circulation (cardiopulmonary bypass or CPB) in approximately 70% of operations worldwide 1
• The standard approach involves a median sternotomy, which provides full access to the heart and great vessels 1
• The left internal mammary artery (LIMA) should be the primary conduit for revascularization of the LAD artery in all patients, as this is associated with improved long-term outcomes 1
• Additional grafts may include other arterial conduits (right internal mammary artery, radial artery) or saphenous vein grafts 1, 2

Technical Aspects of CABG

• Most coronary bypass grafts are constructed with hand-sewn suture techniques for both proximal and distal anastomoses 1
• Continuous polypropylene suture is commonly used, though some surgeons prefer interrupted silk sutures with similar outcomes 1
• Proximal anastomoses are typically created on the ascending aorta, while distal anastomoses are created on the target coronary arteries beyond the stenosis 1
• Aortic cross-clamping is typically used to perform distal anastomoses, with various methods of myocardial protection employed during this period 1
• Epiaortic ultrasonography may be used to visualize atherosclerotic plaques in the aorta to modify the surgical approach, though it has not been shown to definitively reduce cerebral emboli 1

Intraoperative Monitoring

• Transesophageal echocardiography (TEE) is recommended for:
  • Evaluation of acute, persistent, and life-threatening hemodynamic disturbances 1
  • Patients undergoing concomitant valvular surgery 1
  • Monitoring hemodynamic status, ventricular function, regional wall motion, and valvular function during CABG 1
• Epicardial and epiaortic imaging may be used when TEE is contraindicated or inadequate, or to visualize areas not visible with TEE 1

Alternative CABG Techniques

• Off-pump CABG (OPCAB) is performed without cardiopulmonary bypass in approximately 30% of cases worldwide 1
• Minimally invasive direct coronary artery bypass (MIDCAB) can be performed through smaller incisions such as minithoracotomy, subxiphoid, or lateral thoracotomy approaches 3
• Total arterial revascularization using bilateral internal thoracic arteries or combinations with radial arteries is associated with superior outcomes compared to conventional CABG using LIMA and veins 2
• Robotic-assisted CABG and connector devices for anastomoses have been developed to enable grafting without direct suturing, though these are less commonly used 1

Perioperative Management

• If clinical circumstances permit, clopidogrel should be withheld for 5 days before CABG surgery to reduce bleeding risk 1
• Beta-blockers should not be discontinued before surgery to avoid acute ischemia 1
• In patients with diabetes and multivessel CAD, CABG should be recommended as standard therapy regardless of coronary anatomy complexity, given improved long-term survival 4

Outcomes and Risk Factors

• Early clinical outcomes at 3 months after CABG include:
  • 1-2% mortality rate 1
  • 1-2% morbidity rate for each of: stroke, renal failure, pulmonary failure, cardiac failure, bleeding, and wound infection 1
• Hospital mortality is higher for urgent procedures (2.6%) compared to elective procedures (1.1%) 1
• Patients with left main stenosis have higher mortality (2.5%) compared to those without (1.5%) 1
• Patients with diabetes have higher mortality (2.6%) compared to those without (1.6%) 1

Common Pitfalls and Considerations

• In patients with recent myocardial infarction, CABG mortality is elevated for the first 3-7 days after infarction, and the benefit must be balanced against this increased risk 1
• Endoscopic vein graft harvesting is not currently recommended as it has been associated with vein graft failure and adverse clinical outcomes 1
• In patients with diseased ascending aortas, techniques that minimize aortic manipulation may reduce neurological complications 1
• The heart team approach should consider coronary anatomy, patient characteristics, and local expertise when deciding between CABG and percutaneous coronary intervention (PCI) 4