Circumflex Artery

What is the circumflex artery?

The circumflex artery is one of two branches of your left main coronary artery. It delivers oxygenated blood to the back and side of your heart’s left pumping chambers. Your healthcare provider may refer to it as the circumflex branch of the left coronary artery, the LCx artery or simply “the circ.”

What does the circumflex artery do?

Your circumflex artery is a type of cardiac blood vessel that’s part of your circulatory system. This network of blood vessels circulates blood to your heart and the rest of your body.

The functions of the circumflex artery vary depending on a person’s unique anatomy. However, it always carries oxygen-rich blood to the left pumping chambers of your heart, including the:

• Left atrium (upper left pumping chamber).
• Left ventricle (lower left pumping chamber).
• Papillary muscles within the left ventricle.

In some people, the circumflex artery also delivers blood to the heart’s sinoatrial (SA) node. (The right main coronary artery does this job in most people.) Your SA node is part of your heart’s electrical conduction system that controls and regulates your heartbeat. Your provider may refer to this node as “the heart’s natural pacemaker.”

Where is the circumflex artery located?

You have a left and right main coronary artery. The left main coronary artery has two smaller branches: the circumflex artery and the left anterior descending (LAD) artery. Healthcare providers use the term “bifurcation” to refer to this type of arterial branching.

The circumflex artery is within your heart’s outer protective layer, the epicardium. It travels in a groove between your heart’s left upper and lower pumping chambers.

What are the circumflex artery branches?

The circumflex artery has smaller (marginal) artery branches. The number of circumflex artery branches varies from person to person. There may be as many as three lateral branches called obtuse marginal branches. These smaller branches typically travel along the outside margin of the left ventricle toward its tip or apex.

A small number of people also have a left posterior ventricular (LPV) artery that branches from the circumflex artery. But in most people, the LPV artery (also known as the posterolateral artery or branch) branches from the right main coronary artery.

What is coronary arterial dominance?

Your posterior descending artery (PDA) supplies blood to your heart’s muscular middle layer or myocardium. The artery branch that supplies blood to the PDA determines your coronary arterial dominance.

The different types of coronary arterial dominance include:

• Right-dominant circulation: Most people (up to 85%) have right-dominant circulation. This means the right coronary artery supplies blood to the PDA.
• Left-dominant circulation: Approximately 1 in 10 people have left-dominant circulation. Either the circumflex artery or the LAD artery supplies blood to the PDA.
• Codominant circulation: Up to 2 in 10 people have codominant circulation. The right coronary artery and either the left circumflex artery or the LAD artery provide blood to the PDA.

What are other circumflex arteries?

Your body also has these circumflex arteries:

• Femoral circumflex arteries: The middle (medial) and side (lateral) femoral circumflex arteries are deep branches of your femoral artery. Your femoral artery is the main blood vessel that carries blood from your abdomen through your lower limbs. Healthcare providers sometimes use a femoral circumflex artery as a replacement blood vessel (graft) for coronary artery bypass surgery.
• Humeral circumflex arteries: The front (anterior) and back (posterior) humeral circumflex arteries branch from your axillary artery. The axillary artery carries blood from your chest through your shoulders and arms. The posterior humeral circumflex is the main supplier of blood to your upper arm bone (humerus).

What conditions and disorders affect the circumflex artery?

Your circumflex artery is at risk for a type of coronary artery disease (CAD). This “blockage” of the artery occurs when fatty deposits called plaque build up in your artery.

Plaque can build up, causing atherosclerosis or “hardening of the arteries.” Untreated CAD increases your risk of heart attack, heart failure and stroke.

What are the signs of a blockage in the circumflex artery?

Lack of blood flow from narrowed, blocked arteries can cause a type of chest pain called angina. This type of angina can lead to a heart attack, which is a medical emergency. You should call 911.

Because a blockage in a circumflex artery is a type of CAD, the symptoms are the same. You may experience:

• Angina (chest pain or pressure).
• Cold sweats or clamminess.
• Dizziness or feeling lightheaded.
• Fatigue and weakness.
• Heart palpitations.
• Nausea.
• Shortness of breath.
• Shoulder or arm pain.
• Neck or jaw pain.

How do healthcare providers check the health of your circumflex artery?

Healthcare providers use imaging tests to assess the health of your coronary arteries, including the circumflex artery. These imaging tests include:

• Cardiac catheterization to check for blockages and coronary artery disease.
• Coronary computed tomography angiogram (CCTA) to produce 3D images of blood as it flows to your heart.
• Intravascular optical coherence tomography (IVOCT) or intravascular ultrasound (IVUS) to obtain high-definition images of plaque inside an artery.
• Fractional flow reserve (FFR) to measure blood pressure changes inside an artery that help determine if a blockage is severe enough to affect the function of your heart.

How do healthcare providers treat conditions that affect the circumflex artery?

To open a blocked circumflex artery, your provider may perform cardiac catheterization and angioplasty and stent (interventional procedures). Angioplasty opens a narrowed artery using balloons and other tools, while a stent (tiny wire mesh tube) keeps the artery open.

How can I protect my circumflex artery?

These steps can keep your arteries and the rest of your circulatory system healthy:

• Be physically active most days of the week and maintain a healthy weight.
• Drink alcohol in moderation and get help for alcohol use disorder.
• Eat a heart-healthy diet to lower cholesterol levels.
• Know your fats and strive to cut back on unhealthy fats.
• Manage diabetes.
• Take steps to manage high blood pressure, including reducing your sodium.
• Seek help to quit smoking.

A note from Cleveland Clinic

As a branch of the left main coronary artery, your circumflex artery is also at risk for atherosclerosis and coronary artery disease. A buildup of plaque in the circumflex artery can slow blood flow to your coronary artery, and therefore, your heart. This is a bifurcation blockage. You may need angioplasty and stenting to open the artery and allow blood to flow more freely. Talk to your healthcare provider about ways to protect your heart and its arteries.