Patients with angina and non-obstructive CAD are common within clinical practice, but remain a challenge with regard to diagnosis and treatment. When these patients undergo a comprehensive evaluation at the time of invasive coronary angiography, occult coronary abnormalities are frequently found. We hope to learn the overall prevalence and presentation of these occult coronary abnormalities and its long term outcome in this patient population.

This is a prospective registry of patients with chest pain, chest discomfort, breathlessness who do not have a blockage in their heart artery. This condition is known as angina/ischemia and non-obstructive coronary arteries (ANOCA/INOCA). The purpose of this registry is to help us understand the prevalence, causes of these conditions, identify effective diagnostic strategy, and long term outcome in this patient population.

Patients will undergo comprehensive invasive evaluation including coronary angiography, intravascular imaging, and physiologic measurements as a standard of care. Details regarding the participant's angiogram, endothelial function testing, microvascular testing, intravascular ultrasound, and myocardial bridge testing, if performed, will be entered into a research database.

Participants may be contacted by email or phone periodically for follow-up information, such as surveys, an update on medical history, and/or a check on their medical status or symptoms. We anticipate gathering these data at 6 months, 1 year, 3 years, 5 years, and 10 years, and every 5 years thereafter following their enrollment.

The overall objective of this registry study is to identify specific endotypes of ANOCA by invasive evaluation and study long term outcome.

Specific goals include:

1. Describe the prevalence of the following ANOCA endotypes: endothelial dysfunction, microvascular dysfunction, vasospastic angina, myocardial bridging (MB), and other disorders of coronary physiology, and non-cardiac chest pain;
2. Characterize the natural history and outcomes of patients with ANOCA and determine variables associated with major adverse cardiovascular events

Inclusion Criteria:

1. Patient referred for elective coronary angiography because of a reasonable clinical suspicion of coronary ischemia.
2. Presence of angina or an anginal equivalent (including chest, back, shoulder, arm, neck, jaw discomfort, or shortness of breath brought on by physical exertion, emotional stress, or certain times of day/month).

Exclusion Criteria:

1. Asymptomatic (such as a pre-op cath)
2. Status-post heart transplant
3. Age <18
4. Renal insufficiency (creatinine >1.5)
5. Presence of an acute coronary syndrome (STEMI or NSTEMI), Tako-tsubo, an abnormal ejection fraction (EF<55%), cardiogenic shock, or recent VT/VF
6. Presence of another likely explanation of chest pain, such as pulmonary hypertension or aortic stenosis
7. History of adverse reaction to any of the medications being used (acetylcholine, nitroglycerin, adenosine, or heparin)
8. Currently taking vasoactive medication (such as nitroglycerin)
9. Inability to provide an informed consent, including an inability to speak, read, or understand English, Spanish, Chinese, Farsi, Japanese, Korean, Russian, or Vietnamese
10. A hearing impairment that won't allow for a typical verbal conversation or a visual impairment that won't allow for reading of the written consent
11. Participation in another study (with the exception of the Stanford Gene-PAD study)
12. A potentially vulnerable subject (including minors, pregnant women, economically and educationally disadvantaged, decisionally impaired, and homeless people)

Adult women and men with angina who have been referred for an elective coronary angiogram because of a reasonable clinical suspicion of coronary ischemia.