Angina with no major blockage is often caused by the small heart vessels not working properly, or by spasm of the heart arteries. Your symptoms are real, and special tests during an angiogram can find the cause so treatment can be matched to it.
What ANOCA and INOCA mean
Doctors use two terms. ANOCA means angina with no obstructive coronary arteries. INOCA means ischaemia (not enough blood reaching the heart muscle) with no obstructive coronary arteries. In both, the large heart arteries have no narrowing severe enough to explain the symptoms.
The angiogram only shows the larger arteries. The heart also relies on a network of tiny vessels, and the arteries can tighten at times. Neither problem shows up on a standard angiogram or CT scan.
Had a CT scan that showed little or no plaque? See Reading your CT coronary angiogram report.
The two main causes
Coronary microvascular dysfunction
The tiny vessels in the heart muscle don't widen properly when the heart needs more blood, or they tighten too much. This is called microvascular angina. Pain often comes with exercise or stress and can last a while after you stop.
Vasospastic angina
A larger heart artery suddenly tightens (spasm) and reduces blood flow. Pain often comes at rest, at night or early in the morning, and usually settles quickly with glyceryl trinitrate (GTN) spray.
Spasm can be triggered by smoking, cocaine and amphetamines, triptans (migraine medicines) and some chemotherapy medicines, such as 5-FU and capecitabine. Tell your doctor about any of these.
Some people have both. Other heart and non-heart causes of chest pain are also checked for.
Who it affects
Angina with normal arteries is common, particularly in women. It is often found in people having an angiogram for chest pain who are then told their arteries are clear. High blood pressure, diabetes, smoking and high cholesterol can all affect the small vessels.
How it is diagnosed
The most direct way to find the cause is coronary function testing, done during an angiogram. It takes extra time but uses the same wrist or groin access (ESC 2024, COVADIS criteria). It is available at selected centres, so you may be referred to one.
Check the large arteries
The angiogram confirms there is no major blockage.
Measure the small vessels
A fine pressure wire measures how well blood flow increases and how much resistance the tiny vessels have.
Test for spasm
A medicine called acetylcholine is given into the artery to see whether it triggers spasm and your usual symptoms.
The spasm test can briefly reproduce your symptoms. The team watches closely and reverses spasm straight away with medicine. Some heart scans, such as stress MRI or PET, can also suggest small-vessel problems without an angiogram.
In the CorMicA trial of 151 people with angina and no major blockage, treatment guided by these tests improved angina and quality of life at 6 months compared with usual care (Ford 2018).
Treatment
Treatment is matched to the cause, and it may take a few changes to find the right medicine and dose.
For artery spasm
Calcium-channel blockers and long-acting nitrates relax the arteries. GTN spray treats attacks. Stopping smoking helps reduce spasm.
For small-vessel problems
Beta-blockers, calcium-channel blockers and other medicines can reduce angina. Statins and ACE inhibitors may also help the small vessels.
- Treating blood pressure, cholesterol and diabetes, and not smoking, protect the small and large vessels.
- Regular physical activity, built up gradually, often helps symptoms.
- Tell your doctor if a medicine causes side effects, because there are usually alternatives.
For more on the large-artery form of heart disease, see Understanding coronary artery disease.
When to get urgent help
See Chest pain: when to worry, and when it isn't your heart for more on which symptoms need help straight away.
For referring doctorsClinical notes for GPs
- Refer when: persistent angina or evidence of ischaemia with non-obstructive coronary arteries on CTCA or invasive angiography, rest or nocturnal angina suggestive of vasospasm, or symptoms limiting quality of life despite initial therapy.
- Urgency: rest pain over 10 minutes or suspected ACS: call 000 (non-obstructive arteries on a prior study do not exclude ACS). Stable but limiting symptoms: routine cardiology referral.
- Send: CTCA or angiogram reports and images, stress test results, ECGs (especially any during symptoms), current medicines and risk factor profile.
- Diagnosis: invasive coronary function testing (available at selected centres) assesses CFR and IMR with a pressure-temperature wire, and acetylcholine provocation for epicardial or microvascular spasm (ESC 2024 CCS; COVADIS). Stratified therapy improved angina in CorMicA.
- Medicines: vasospasm: calcium-channel blocker plus long-acting nitrate; avoid beta-blocker monotherapy. Microvascular angina: beta-blocker or calcium-channel blocker first line; statin and ACE inhibitor for risk factors and endothelial function. Ask about PDE-5 inhibitor use before nitrates. Review vasospasm triggers: smoking, cocaine and amphetamines, triptans, and fluoropyrimidine chemotherapy (5-FU, capecitabine).
- PBS/MBS: check current MBS items for invasive coronary function testing and current PBS criteria for anti-anginal medicines.
General information for referring practitioners. Check current MBS and PBS criteria before acting.
Frequently asked questions
If my arteries are clear, why do I still get chest pain?
The angiogram shows the larger arteries but not the tiny vessels, and spasm may not happen during a routine test. Coronary function testing looks for these problems.
Is angina with normal arteries dangerous?
It is usually less serious than angina from a major blockage, but studies suggest it is linked with a higher chance of heart problems later. Treating your symptoms and risk factors is worthwhile.
Do I need a stent?
No, unless a later test shows a significant narrowing. A stent treats a narrowing in a large artery. Angina with normal arteries is treated with medicines and risk factor changes.
Is the coronary function test safe?
It is done during an angiogram and the added risk is small. The spasm test may briefly bring on your symptoms, which the team treats straight away. Your cardiologist will discuss the risks for you.
References
- Vrints C, Andreotti F, Koskinas KC, et al. 2024 ESC Guidelines for the management of chronic coronary syndromes. Eur Heart J. 2024;45(36):3415–3537. doi:10.1093/eurheartj/ehae177
- Kunadian V, Chieffo A, Camici PG, et al. An EAPCI expert consensus document on ischaemia with non-obstructive coronary arteries in collaboration with European Society of Cardiology Working Group on Coronary Pathophysiology & Microcirculation. Eur Heart J. 2020;41(37):3504–3520. doi:10.1093/eurheartj/ehaa503
- Ong P, Camici PG, Beltrame JF, et al. International standardization of diagnostic criteria for microvascular angina. Int J Cardiol. 2018;250:16–20. doi:10.1016/j.ijcard.2017.08.068
- Beltrame JF, Crea F, Kaski JC, et al. International standardization of diagnostic criteria for vasospastic angina. Eur Heart J. 2017;38(33):2565–2568. doi:10.1093/eurheartj/ehv351
- Ford TJ, Stanley B, Good R, et al. Stratified medical therapy using invasive coronary function testing in angina: the CorMicA trial. J Am Coll Cardiol. 2018;72(23 Pt A):2841–2855. doi:10.1016/j.jacc.2018.09.006
- Picard F, Sayah N, Spagnoli V, et al. Vasospastic angina: a literature review of current evidence. Arch Cardiovasc Dis. 2019;112(1):44–55. doi:10.1016/j.acvd.2018.08.002