Chest Pain Without a Major Blockage? There May Be More to the Story.
Some patients continue to experience chest pain, shortness of breath, or other symptoms even when testing does not reveal a significant blockage in the major coronary arteries. ANOCA can involve problems with the smaller vessels, abnormal vessel constriction, or other conditions affecting coronary blood flow.
LEARN ABOUT CORONARY FUNCTION TESTINGWhat Is ANOCA?
ANOCA stands for Angina with Nonobstructive Coronary Arteries. It describes angina or angina-like symptoms occurring when testing does not show the type of major coronary artery blockage that would ordinarily explain those symptoms.
In some patients, the problem may involve how the coronary circulation functions rather than a fixed obstruction that can easily be seen on an angiogram.
Specialized evaluation can help physicians investigate other possible causes of persistent symptoms.
Conditions Coronary Function Testing Can Help Identify
Similar symptoms can result from very different problems within the coronary circulation. Understanding the underlying mechanism can provide your cardiovascular team with additional information when developing a treatment plan.
Microvascular Coronary Dysfunction
The heart contains a network of tiny blood vessels known as the coronary microcirculation. When these vessels do not dilate or regulate blood flow normally, the heart may not receive the expected increase in blood flow when demand rises. This can contribute to chest discomfort, shortness of breath, or other symptoms.
Microvascular Spasm
Microvascular spasm occurs when very small coronary vessels constrict abnormally. This temporary narrowing can reduce blood flow to the heart muscle and may produce angina or evidence of ischemia without a major obstructive blockage.
Endothelial Dysfunction
The endothelium is the thin layer of cells lining the inside of blood vessels. It plays an important role in regulating whether vessels dilate or constrict. When this lining does not respond normally, coronary blood-flow regulation may also be affected.
Epicardial Coronary Spasm
Epicardial spasm involves temporary, significant constriction of one of the larger coronary arteries on the surface of the heart. During an episode, blood flow may decrease and cause chest pain or other signs of myocardial ischemia even without a fixed severe blockage.
Myocardial Bridging
Normally, coronary arteries travel along the surface of the heart. With a myocardial bridge, a segment of a coronary artery travels beneath or through heart muscle. The muscle can compress that segment as the heart contracts. Many myocardial bridges do not cause problems, but further evaluation can help determine whether one may be contributing to a patient's symptoms.
Why Standard Heart Tests May Not Tell the Whole Story
Traditional coronary angiography is designed to identify narrowing and blockages in the major coronary arteries. However, the smallest vessels of the coronary circulation cannot simply be evaluated by looking for a visible blockage.
Some coronary disorders involve how blood vessels respond, constrict, dilate, and regulate blood flow. This means a patient may continue to experience symptoms even when conventional testing has not identified severe obstructive coronary artery disease.
Coronary Function Testing Looks at How the Circulation Works
Specialized coronary function testing can provide information about how the coronary circulation responds and functions rather than looking only for a visible obstruction.
Depending on the patient's condition and testing protocol, physicians may evaluate coronary blood flow, vascular resistance, and how the coronary arteries respond during testing. These findings can help distinguish between different mechanisms that may be contributing to symptoms.
EXPLORE CORONARY FUNCTION TESTING
Testing may provide insight into:
- Coronary microvascular function
- Abnormal coronary vessel constriction
- Coronary blood-flow response
- Vascular resistance
- Possible mechanisms behind persistent symptoms
One Symptom. Different Possible Causes.
Chest discomfort may have different underlying mechanisms. Identifying those differences can help your cardiovascular team better understand your symptoms.
Microvascular Dysfunction
Small coronary vessels do not provide the expected increase in blood flow when the heart needs it.
Microvascular Spasm
Tiny coronary vessels temporarily constrict abnormally, reducing blood flow.
Endothelial Dysfunction
The vessel lining does not regulate vascular tone and blood flow normally.
Epicardial Spasm
A larger coronary artery temporarily constricts and reduces blood flow to the heart.
Myocardial Bridging
A coronary artery passes beneath heart muscle and may be compressed as the heart contracts.
Who May Benefit From Further Evaluation?
Further evaluation may be considered when symptoms continue despite previous testing that has not identified a significant obstructive coronary lesion.
Whether coronary function testing is appropriate depends on your symptoms, medical history, previous testing, and your physician's assessment.
Still Experiencing Chest Pain Without Clear Answers?
Coronary function testing can provide additional information about how the coronary circulation is functioning and may help identify conditions that do not appear as a traditional blocked artery. Talk with your cardiologist about whether further evaluation for ANOCA may be appropriate for you.