---
title: Angina with no obstructive coronary arteries
description: What microvascular and vasospastic angina are, why the heart can be short of blood when the coronary arteries are not narrowed by plaques, how this is found, which treatment approaches clinical guidelines describe, and when to call an ambulance.
type: disease
aliases:
  - ANOCA
  - INOCA
  - ischaemia with no obstructive coronary arteries
  - ischemia with no obstructive coronary arteries
  - angina with non-obstructive coronary arteries
  - coronary microvascular dysfunction
  - microvascular dysfunction
  - microvascular angina
  - vasospastic angina
  - variant angina
  - Prinzmetal angina
  - Prinzmetal's angina
  - coronary artery spasm
  - coronary vasospasm
sources:
  - tier: guideline
    org: esc
    title: 2024 ESC Guidelines for the management of chronic coronary syndromes
    year: 2024
    doi: 10.1093/eurheartj/ehae177
    url: https://doi.org/10.1093/eurheartj/ehae177
  - tier: guideline
    org: minzdrav-rf
    title: Стабильная ишемическая болезнь сердца
    year: 2024
    doi: 10.15829/1560-4071-2024-6110
    url: https://cr.minzdrav.gov.ru/view-cr/155_2
  - tier: reference
    org: msd-manuals
    title: Microvascular Angina (MSD Manual Professional Version)
    year: 2026
    url: https://www.msdmanuals.com/professional/cardiovascular-disorders/coronary-artery-disease/microvascular-angina
  - tier: reference
    org: msd-manuals
    title: Vasospastic Angina (MSD Manual Professional Version)
    year: 2026
    url: https://www.msdmanuals.com/professional/cardiovascular-disorders/coronary-artery-disease/vasospastic-angina
  - tier: guideline
    org: esc
    title: 2023 ESC Guidelines for the management of acute coronary syndromes
    year: 2023
    doi: 10.1093/eurheartj/ehad191
    url: https://doi.org/10.1093/eurheartj/ehad191
sources_checked: 2026-10-14
review: null
---

Angina and myocardial ischaemia occur when the heart muscle does not get enough blood for its work.<Cite n={1} /> Many people who have coronary angiography because of angina have no narrowing of the large coronary arteries: this is called angina with no obstructive coronary arteries (ANOCA), and when tests confirm ischaemia, ischaemia with no obstructive coronary arteries (INOCA).<Cite n={1} /> The cause is a problem with how the small blood vessels of the heart work (coronary microvascular dysfunction) and/or spasm of a large coronary artery.<Cite n={1} /> It is more common in women.<Cite n={1} /> These conditions are rarely diagnosed correctly, and without suitable treatment the attacks keep coming back.<Cite n={1} />

<Diagram name="coronary-microvascular-dysfunction">
  <p slot="normal">
    The diagram has two identical halves: on the left we look at the small vessels, on the right at
    the large artery. Small vessels branch off a large coronary artery on the surface of the heart
    into the muscle; with exercise they normally widen, and the muscle gets more
    blood.<Cite n={[1, 3]} />
  </p>
  <p slot="disease">
    The large artery is not narrowed by a plaque.<Cite n={3} /> On the left, microvascular angina:
    the small vessels do not widen with exercise or they constrict, and the muscle gets less blood
    than it needs.<Cite n={[1, 3]} /> On the right, vasospastic angina: a segment of the large artery
    suddenly narrows for a while because of a spasm, then opens up again.<Cite n={[1, 4]} />
  </p>
</Diagram>

## Why it happens

<Patient>

When the large arteries have plaques that narrow them, this is ordinary [coronary heart disease](../coronary-heart-disease/). This article is about something else: the large arteries have no significant narrowing, yet the heart still does not get enough blood.<Cite n={1} />

In microvascular angina the structure or function of the small vessels is changed: they do not widen well with exercise, or they constrict too much.<Cite n={[1, 3]} /> The heart may also be more sensitive to pain.<Cite n={3} /> Smoking, age, diabetes, high blood pressure and abnormal blood fats are linked with small-vessel dysfunction.<Cite n={1} /> See the articles on [hypertension](../hypertension/) and [dyslipidaemia](../dyslipidemia/).

In vasospastic angina a large coronary artery suddenly narrows for a while: this is a spasm.<Cite n={[1, 4]} /> Smoking is a common trigger of spasm; stimulant drugs such as cocaine and methamphetamine can also cause it.<Cite n={4} /> Cold on exposed skin can also bring on attacks.<Cite n={2} />

The two mechanisms can occur together, and then the outlook is worse.<Cite n={1} />

</Patient>

<Student>

ESC 2024: microvascular angina is the clinical manifestation of myocardial ischaemia caused by structural or functional changes in the coronary microvasculature (impaired coronary flow reserve, CFR, and/or reduced microcirculatory conductance) and/or abnormal vasoconstriction of coronary arterioles (dynamic arteriolar obstruction).<Cite n={1} /> Vasospastic angina is the clinical manifestation of myocardial ischaemia caused by abnormal vasoconstriction of one or more epicardial coronary arteries, leading to dynamic coronary obstruction.<Cite n={1} /> In the classification of the Russian Ministry of Health guideline these are separate forms of stable CAD: vasospastic angina (variant angina, Prinzmetal angina) and microvascular angina.<Cite n={2} />

Invasive functional coronary testing with acetylcholine and adenosine distinguishes the endotypes: (i) endothelial dysfunction; (ii) impaired vasodilation (low CFR and/or high microvascular resistance); (iii) epicardial vasospastic angina; (iv) microvascular vasospastic angina; (v) endotype combinations; (vi) equivocal response.<Cite n={1} /> Endotypes frequently overlap.<Cite n={1} />

</Student>

## Symptoms

<Patient>

In vasospastic angina the attack of pain is usually very severe and felt behind the breastbone.<Cite n={2} /> It comes on mainly at rest, often at night and early in the morning, and only rarely with exertion; attacks often recur at the same time of day.<Cite n={[2, 4]} />

In microvascular angina the pain is like ordinary angina, but it comes on some time after exertion or with emotional stress, can also occur at rest, and is less well relieved by nitrates.<Cite n={2} />

The "classic" picture, pain behind the breastbone with exertion or emotional stress that goes away with rest, is rarely complete in these forms.<Cite n={1} /> So before calling chest pain "non-cardiac", doctors check for these causes too.<Cite n={1} />

Angina without narrowed arteries is not harmless: it lowers quality of life, leads to more repeat hospital admissions and is linked with a higher risk of complications.<Cite n={1} /> In microvascular angina the outlook is better than in ordinary coronary heart disease with narrowed arteries, but symptoms may keep coming back for years.<Cite n={3} />

</Patient>

<Student>

Prognosis: ANOCA/INOCA is associated with poor quality of life, a higher risk of disability and a higher incidence of adverse events, including mortality, recurrent hospital readmissions and repeat coronary angiograms.<Cite n={1} /> Coexisting microvascular angina and epicardial vasospastic angina are associated with a worse prognosis.<Cite n={1} /> Vasospasm and coronary microvascular dysfunction are possible causes of type 2 MI, as is non-atherosclerotic coronary dissection.<Cite n={5} /> See [myocardial infarction](../myocardial-infarction/) and [spontaneous coronary artery dissection](../spontaneous-coronary-artery-dissection/).

</Student>

## How it is diagnosed

<Patient>

First, as with any angina, doctors check whether plaques narrow the large arteries, using CT coronary angiography or coronary angiography.<Cite n={[1, 2]} /> If stress tests show that the heart is short of blood but there is no narrowing, the doctor will suspect angina with no obstructive coronary arteries.<Cite n={1} />

An ECG recorded during an attack helps to recognise vasospastic angina: it shows temporary changes, most often ST-segment elevation.<Cite n={[1, 2]} /> Between attacks the ECG may be normal.<Cite n={4} /> If attacks are frequent, a long ECG recording (Holter monitoring) is done.<Cite n={[1, 2]} />

The blood flow reserve of the heart can also be assessed without a catheter, with stress echocardiography, cardiac MRI or PET.<Cite n={1} /> But the small vessels of the heart cannot be seen directly, so only a test during coronary angiography can establish the mechanism with certainty: blood flow is measured through a catheter, and substances are injected that show whether the artery is prone to spasm and whether the small vessels can widen; a spasm caused by the test passes quickly.<Cite n={1} /> This test is recommended when symptoms persist despite treatment and greatly reduce quality of life; the decision takes the patient's choice into account.<Cite n={1} />

</Patient>

<Student>

ESC 2024: myocardial ischaemia on functional imaging without obstructive CAD should always raise the clinical suspicion of ANOCA/INOCA; the diagnosis is based only on invasive functional evaluation.<Cite n={1} /> ESC recommendations (Recommendation Table 25): invasive coronary functional testing in patients with persistent symptoms despite medical treatment, suspected ANOCA/INOCA and poor quality of life (I B); non-invasive assessment of flow reserve by transthoracic Doppler of the LAD, stress echocardiography, CMR or PET (IIb B); a resting 12-lead ECG during angina in suspected vasospastic angina (I C); in repetitive episodes of rest angina with ST-segment changes that resolve with nitrates and/or calcium antagonists, invasive testing to confirm the diagnosis (I C); with frequent symptoms, ambulatory ST-segment monitoring (IIa B).<Cite n={1} />

Thresholds: the CFR threshold is below 2.0–2.5 depending on the method; an IMR of 25 or more indicates microvascular dysfunction.<Cite n={1} /> The acetylcholine test is positive for epicardial spasm if symptoms occur with ischaemic ECG changes and a reduction of the coronary lumen by 90% or more; with a reduction below 90%, microvascular spasm is diagnosed.<Cite n={1} />

</Student>

## How it is treated

<Patient>

Treatment is based on lifestyle and control of risk factors: stopping smoking, healthy eating, physical activity, weight control, coping with stress, and treating high blood pressure, high cholesterol and diabetes.<Cite n={[1, 3]} />

Medicines are chosen according to the mechanism that the tests have shown.<Cite n={1} /> The mechanisms often occur together, and then several medicines are needed at once.<Cite n={1} />

- In microvascular angina, anti-ischaemic medicines such as beta-blockers and calcium channel blockers are used, as well as ACE inhibitors and statins.<Cite n={[1, 2, 3]} />
- In vasospastic angina the main medicines are calcium channel blockers: they reduce symptoms and help prevent dangerous complications; nitrates may be added.<Cite n={[1, 2]} /> A nitrate under the tongue usually relieves an attack quickly.<Cite n={4} /> Beta-blockers can trigger spasm, so they are not used to treat vasospastic angina; the doctor takes this into account.<Cite n={[2, 4]} />

A stent or bypass surgery is not recommended for vasospastic angina.<Cite n={2} /> Which medicines are needed, and in what combination, is decided by the doctor together with the patient.

</Patient>

<Student>

ESC 2024, Recommendation Table 25: medical therapy based on coronary functional test results (IIa A); ACE inhibitors for endothelial dysfunction (IIa B); in microvascular angina with reduced flow reserve, antianginal medications aimed at preventing demand ischaemia (IIa B); in isolated vasospastic angina, calcium channel blockers to control symptoms and prevent ischaemia and potentially fatal complications (I A), and nitrates to prevent recurrent episodes (IIa B); in overlapping endotypes, combinations of nitrates, calcium channel blockers and other vasodilators (IIb B).<Cite n={1} /> Spinal cord stimulation is an option for patients who remain refractory to medical therapy.<Cite n={1} />

Russian Ministry of Health guideline: with CFR below 2.0 or IMR of 25 or more and no signs of vasospasm, beta-blockers, calcium channel blockers, ACE inhibitors and statins together with lifestyle change (I A); with vasomotor disorders of the epicardial arteries or microvessels, calcium channel blockers or long-acting nitrates (I A).<Cite n={2} /> Non-selective beta-blockers are contraindicated in vasospastic angina, and selective ones are allowed only in special clinical situations; revascularisation (PCI or CABG) is not recommended in vasospastic angina.<Cite n={2} />

</Student>

## When to call an ambulance

Spasm of a coronary artery and small-vessel dysfunction can cause a heart attack even when the arteries are not narrowed by plaques.<Cite n={5} /> Vasospastic angina can lead to fainting, a heart attack and sudden cardiac death.<Cite n={1} /> Call your local emergency number (112 in the EU, 911 in the US and Canada, 999 in the UK) straight away if:

- an angina attack at rest or at night is not relieved by the medicine your doctor prescribed for attacks;<Cite n={2} />
- chest pain lasts more than 15 minutes or comes back within an hour;<Cite n={5} />
- you have fainted.<Cite n={1} />

Do not make your own way to a hospital or GP surgery: call an ambulance.<Cite n={5} /> Relief after a nitrate does not prove that it is "just a spasm": a spasm can also come with a heart attack.<Cite n={5} /> For more on the signs, see the article on [myocardial infarction](../myocardial-infarction/).

If attacks become more frequent, new attacks appear at rest and at night, or you need the medicine for attacks more often, see a doctor urgently.<Cite n={2} />

<Quiz />