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Coronary Artery Bypass Grafting (CABG)

Also called

Heart Bypass Surgery

ICD-10

02100Z9

Specialty

Cardiology

Onset

For Acute & Chronic Conditions

Reviewed

July 2026
On This Page

Overview

(CABG) is an open-heart surgical procedure that restores blood flow to ischemic myocardium by bypassing obstructed coronary arteries using arterial or venous grafts.

Indications

  • Left main coronary artery disease
  • Complex multivessel coronary artery disease
  • Triple-vessel disease
  • Diabetes mellitus with multivessel CAD
  • Failed or unsuitable PCI
  • Persistent angina despite optimal medical therapy
  • Mechanical complications of MI requiring surgery

Contraindications

-Absolute

  • No absolute contraindication when CABG is lifesaving

 

-Relative

      • Severe frailty
      • End-stage non-cardiac illness
      • Diffuse coronary disease not amenable to grafting
      • Severe irreversible neurological injury
      • Very poor surgical candidate

Pre-Procedure Assessment

    1. General anesthesia
    2. Median sternotomy
    3. Harvest grafts (LIMA, radial artery, or saphenous vein)
    4. Cardiopulmonary bypass (or off-pump CABG)
    5. Distal coronary artery anastomosis
    6. Proximal graft anastomosis to the aorta (if required)
    7. Restore coronary blood flow
    8. Hemostasis and chest closure
Coronary Artery Bypass Grafting (CABG) Overview
Coronary Artery Bypass Grafting (CABG) Overview

CABG Procedure (Step-by-Step)

1. Preoperative Preparation

  • Confirm coronary artery disease with coronary angiography.

  • Review blood tests, ECG, echocardiography, and other investigations.

  • Obtain informed consent.

  • Stop or adjust selected medications as directed.

  • Establish intravenous access and monitoring.

2. General Anesthesia

  • The patient receives general anesthesia.

  • An endotracheal tube is inserted.

  • Mechanical ventilation and continuous cardiovascular monitoring begin.

3. Surgical Access

  • The surgeon usually makes a midline chest incision.

  • The sternum is divided through a median sternotomy to expose the heart.

Some selected procedures may use smaller minimally invasive incisions.

4. Graft Vessel Harvesting

A healthy blood vessel is taken or prepared to bypass the blocked coronary artery.

Common grafts include:

  • Internal mammary artery, usually the left internal mammary artery

  • Great saphenous vein from the leg

  • Radial artery from the arm

The internal mammary artery often remains attached to its original blood supply at one end.

5. Anticoagulation

  • Heparin is administered to prevent blood clotting during surgery.

6. Cardiopulmonary Bypass

In conventional on-pump CABG:

  • Cannulas are inserted into the heart or major vessels.

  • The patient is connected to a heart–lung bypass machine.

  • The machine oxygenates and circulates the blood while the surgeon operates.

CABG may also be performed off-pump, while the heart continues beating.

7. Temporary Cardiac Arrest

In on-pump CABG:

  • The aorta is cross-clamped.

  • Cardioplegia solution is administered.

  • The heart temporarily stops and is protected during graft placement.

8. Graft Anastomosis

The graft is connected so blood can flow around the coronary blockage.

  • The distal end is attached to the coronary artery beyond the obstruction.

  • For a free graft, the proximal end is commonly attached to the aorta.

  • An internal mammary artery graft usually remains attached proximally and is connected distally to the coronary artery.

This creates a new route for oxygenated blood to reach the myocardium.

9. Restore Heart Function

  • The aortic clamp is removed.

  • Blood flow returns to the heart.

  • The heart may restart spontaneously or require electrical stimulation.

  • The surgeon checks graft flow and cardiac function.

10. Weaning From Bypass

    • The heart gradually resumes pumping the circulation.

    • The patient is separated from the heart–lung machine.

    • Heparin is reversed, usually with protamine.

Types of Stents & Devices

Arterial Grafts

  • Left Internal Mammary Artery (LIMA) (gold standard)

  • Right Internal Mammary Artery (RIMA)

  • Radial artery

Venous Grafts

  • Great saphenous vein

Surgical Techniques

    • On-pump CABG

    • Off-pump CABG (OPCAB)

Postoperative Care

    • ICU monitoring
    • Continuous ECG monitoring
    • Pain control
    • Early extubation
    • Early mobilization
    • Aspirin therapy
    • High-intensity statin
    • Cardiac rehabilitation
    • Wound care and infection prevention
    •  
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Related Topics

Complications

    • Bleeding
    • Surgical site infection
    • Atrial fibrillation (most common)
    • Stroke
    • Myocardial infarction
    • Graft occlusion
    • Acute kidney injury
    • Mediastinitis
    • Death

Prognosis

  • Excellent long-term symptom relief.
  • Improves survival in selected high-risk patients.
  • LIMA-to-LAD graft has excellent long-term patency.
  • Long-term success depends on secondary prevention and graft patency.

Key Points / Clinical Pearls

    • CABG is preferred for left main disease and complex multivessel CAD.
    • LIMA to the LAD is the gold-standard graft because of its excellent long-term patency.
    • CABG provides more durable revascularization than PCI in many complex coronary lesions.
    • Secondary prevention (aspirin, statins, BP control, smoking cessation, and cardiac rehabilitation) is essential after surgery.
    • Postoperative atrial fibrillation is the most common complication.