Purpose of Triple Bypass Surgery

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Triple bypass surgery, also known as coronary artery bypass grafting (CABG), is an open-heart surgical procedure performed when a person has three blocked or partially blocked coronary arteries in the heart. Each vessel needs to be bypassed in order to deliver oxygen and nutrients to the heart muscle.

This surgery is needed when a person has atherosclerosis or coronary artery disease and a buildup of plaque does not allow the blood to flow freely to and from the heart muscle.

Triple bypass surgery does not cure the underlying heart disease that is caused by plaque buildup, but it does relieve symptoms such as chest pain and shortness of breath. Furthermore, it can improve overall heart function, improve quality of life, and reduce the risk of death.

Blood vessels can be taken from your leg (saphenous vein), inside your chest (internal mammary artery), or your arm (radial artery). The specific vessel used will be determined by the surgeon. Bypassing three major blood vessels increases the risks of morbidity and mortality; therefore, this surgery carries more risk than other cardiac procedures.

Heart surgeons during a heart operation - stock photo

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Diagnosis Related to Triple Bypass Surgery

Atherosclerosis resulting in coronary artery disease is the main cause of needing triple bypass surgery. Atherosclerosis, also known as “hardening of the arteries,” occurs when cholesterol and other lipids begin to accumulate on the inner walls of damaged blood vessels. This buildup leads to the formation of a waxy thickening in the vessel, known as a plaque.

This hardening can occur anywhere in the body but when it occurs near the heart, the patient is at an increased risk for a heart attack and possibly death.

The AMA Journal of Ethics considers angina pectoris as the main indication for triple bypass surgery. However, there are other indications for having triple bypass surgery. The American Heart Association identifies the following benefits for bypass surgery:

  • Manage blockage of blood to the heart muscle
  • Improve the supply of blood and oxygen to the heart
  • Reduce the risk of heart attack
  • Improve ability for physical activity that has been limited by angina or ischemia

How Common Is Bypass Surgery?

Bypass surgery is the most common cardiothoracic surgery. A 2020 market report places the number at 340,000 CABG surgeries per year in the U.S. While there is no specific data on the percentage of patients that require triple bypass surgery, the sheer number of CABG procedures is alarming.


The American Heart Association (AHA) in conjunction with the American College of Cardiology developed criteria for bypass surgery. These criteria were last updated in 2011.

The AHA provides recommendations for individuals that fall within specific categories for surgery. These groups include but are not limited to:

More specifically, patients requiring bypass surgery with an acute MI (heart attack) include:

  • Emergency CABG is recommended in patients with acute MI in whom 1) primary PCI has failed or cannot be performed, 2) coronary anatomy is suitable for CABG, and 3) persistent ischemia of a significant area of myocardium at rest and/or hemodynamic instability refractory to nonsurgical therapy is present.
  • Emergency CABG is recommended in patients undergoing surgical repair of a postinfarction mechanical complication of MI, such as ventricular septal rupture, mitral valve insufficiency because of papillary muscle infarction and/or rupture, or free wall rupture.
  • Emergency CABG is recommended in patients with cardiogenic shock and who are suitable for CABG irrespective of the time interval from MI to onset of shock and time from MI to CABG.
  • Emergency CABG is recommended in patients with life-threatening ventricular arrhythmias (believed to be ischemic in origin) in the presence of left main stenosis greater than or equal to 50% and/or three-vessel coronary artery disease (CAD).
  • The use of CABG is reasonable as a revascularization strategy in patients with multivessel CAD with recurrent angina or MI within the first 48 hours of ST-elevation myocardial infarction (STEMI) presentation as an alternative to a more delayed strategy.
  • Early revascularization with PCI or CABG is reasonable for selected patients greater than 75 years of age with ST-segment elevation or left bundle branch block who are suitable for revascularization irrespective of the time interval from MI to onset of shock.

The guidelines also list times when emergency CABG is not indicated:

  • Emergency CABG should not be performed in patients with persistent angina and a small area of viable myocardium who are stable thermodynamically.
  • Emergency CABG should not be performed in patients with no-reflow (successful epicardial reperfusion with unsuccessful microvascular reperfusion).

Tests and Labs

Prior to having triple bypass surgery, a patient must undergo a series of tests and procedures to determine if this type of surgery is the best option. These include,

  • Stress test: This is a cardiac perfusion scan which measures the amount of blood in your heart muscle at rest and during exercise. Patients usually walk and/or run on a treadmill for this test.
  • Echocardiogram: This uses wave technology to create a picture of the heart while it is moving and to assess the blood flow in and out of the heart.
  • Electrocardiogram (ECG or EKG): This study measures the electrical activity of the heart.
  • Coronary angiography: This uses dye and special X-rays to show the insides of the coronary arteries.
  • Cardiac catheterization: This is the most invasive test performed and looks for the specific blockages to the heart in the surrounding blood vessels.
  • Pulmonary function test: This test is performed by a respiratory therapist and measures how well the lungs take in and release air and how well they move gases such as oxygen.
  • Blood work: Your doctor will have you complete a set of blood work to check your overall health and nutrition levels before surgery. These labs may include complete blood count, chemistry, and coagulation studies.
  • Chest X-ray: This will look at the chest, lungs, heart, large arteries, ribs, and diaphragm.
  • Cardiac magnetic resonance imaging (MRI): This provides the most detailed picture of the heart including chambers and surrounding blood vessels
  • Carotid Doppler/ultrasound study: The purpose of a carotid ultrasound is to screen for blockage or narrowing of the carotid arteries, which may increase the risk of having a stroke.
  • Transesophageal echocardiogram (TEE): This is an invasive test that looks at the heart valves, chambers and how optimal the heart is functioning.
  • Computed tomography scan (CT): This test assesses the aorta while also looking at the lungs and surrounding organs.
  • Ankle-brachial index: This test determines if there are any blockages or narrowing of the arteries in the arms and legs.
  • Vein mapping: This is a non-invasive test that examines the blood vessels in the legs.

Not all of the aforementioned studies will be needed or required. Each surgeon will require different pre-surgical studies depending on the patient's condition. Depending on the severity of the heart disease or pain, these tests can all happen within a matter of days.

Furthermore, if it is determined that the bypass surgery is emergent, the surgeon will choose the most conclusive tests in order to decrease surgical wait time.

A Word From Verywell

Triple bypass surgery is a very serious surgery that should not be taken lightly. Because this procedure requires the bypassing of three major blood vessels the risks are more considerable than other cardiac procedures. Thoughtful consideration and consultation with a skilled surgeon is required. Patients should be aware of the benefits as well as the risk associated with the procedure.

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  1. Reenan J. Indications for bypass surgery. AMA Journal of Ethics.

  2. American Heart Association. Cardiac procedures and surgeries. Updated October 5, 2020.

  3. iData Research. New study shows approximately 340,000 CABG procedures per year in the United States. December 15, 2020.

  4. Hillis LD, Smith PK, Anderson JL, et. al. 2011 ACCF/AHA guideline for coronary artery bypass graft surgery: Executive summary: A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Circulation. 2011 Dec 6;124(23):2610-42. doi:10.1161/CIR.0b013e31823b5fee. Erratum in: Circulation. 2011 Dec 20;124(25):e956. Erratum in: Circulation. 2012 Aug 14;126(7):e105