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Ischemia with No Obstructive Coronary Arteries (INOCA)

Ischemia with No Obstructive Coronary Arteries (INOCA) is a condition in which a person experiences symptoms of heart ischemia—such as chest pain (angina) and shortness of breath—despite having no significant blockages or narrowing in the large coronary arteries. Ischemia occurs when there is insufficient blood flow to meet the heart muscle’s oxygen demands, but in INOCA, the typical cause (obstructive coronary artery disease) is not present.

Ischemia with No Obstructive Coronary Arteries can be caused by problems in the small blood vessels of the heart (microvascular dysfunction) or other non-obstructive issues affecting coronary artery function such as:

  1. Coronary Microvascular Dysfunction (CMD): Involves abnormalities in the smaller blood vessels (microcirculation) that do not show up in traditional coronary angiography, which is typically used to detect blockages in larger arteries. These small vessels may not dilate properly or may spasm, reducing blood flow to the heart muscle.
  2. Coronary Artery Spasm (Vasospastic Angina): In some cases, the coronary arteries may temporarily constrict or spasm, reducing blood flow. This can happen even without significant plaque buildup, causing ischemia and symptoms similar to those of obstructive coronary artery disease.
  3. Endothelial Dysfunction: The endothelium is the inner lining of blood vessels. If it becomes dysfunctional, it can result in improper regulation of blood vessel tone and reduced blood flow, even without significant blockages.

The symptoms of Ischemia with No Obstructive Coronary Arteries are similar to those of traditional coronary artery disease and include:

  • Chest pain or discomfort (angina): Typically occurring during exertion or stress, but can also occur at rest.
  • Shortness of breath
  • Fatigue: Especially during physical activity.
  • Lightheadedness or dizziness
  • Heart palpitations

Diagnostic options

Comprehensive Coronary Physiology Evaluation

Vasospastic Angina Testing by AcetylCholine Challenge

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