Health condition
Coronary microvascular dysfunction
Coronary microvascular dysfunction is disease of the heart’s smallest blood vessels, causing genuine angina despite unobstructed main arteries; specialised functional testing now allows a firm diagnosis and targeted treatment.
Why trust this guide
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Editorial team
Written by our editorial team from the UK sources listed on each page.
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Sourced from guidance
Checked against current NHS and UK specialist society guidance at the time of review.
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Current for 2026
Reviewed on 2026-09-27 with the next review scheduled for 2027-09-27.
Key points
What matters most, at a glance.
The essentials in plain English - symptoms, when to seek help, who to see and what treatment looks like.
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Typical story: exertional chest pain, an abnormal stress test, then a "normal" angiogram - and a patient left without answers
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It disproportionately affects women and often coexists with hypertension and diabetes
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Adenosine-based testing during angiography measures coronary flow reserve and microvascular resistance; acetylcholine testing identifies spasm
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Treatment is stratified by test result: beta-blockers and statins for microvascular disease, calcium channel blockers for spasm
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The condition carries real prognostic weight - it is not "just reassurance" territory
Understanding it
About Coronary microvascular dysfunction, and what to do next.
The microcirculation - vessels too small to see on an angiogram - controls most of the heart’s blood flow. When these vessels cannot dilate properly or spasm inappropriately, the muscle is starved during exertion exactly as with a blocked artery, producing angina that standard imaging cannot explain.
The landmark change in this field is invasive functional testing: a guidewire-based study during angiography that objectively classifies the problem. Trials show that stratified treatment based on these measurements improves symptoms and quality of life. Most people start with their GP, who can refer to a consultant cardiologist with expertise in angina with non-obstructed coronary arteries (ANOCA). In many parts of the UK, routine NHS referrals for this kind of problem currently take 20-45+ weeks, whereas an initial private consultation is typically available within around two weeks.
A quiet reminder
This guide is for information, not medical advice.
Your GP knows your history and can tell you which parts apply to you. If in doubt, see them - and seek urgent care for any emergency symptoms described above.
Frequently asked
Common questions about Coronary microvascular dysfunction.
Quick, plain-English answers to what people ask us most.
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What is coronary microvascular dysfunction?
Coronary microvascular dysfunction (CMD) is disease of the heart's smallest blood vessels, which causes genuine angina even though the main coronary arteries look unobstructed on a standard angiogram. It's a real and treatable cause of chest pain, not simply a diagnosis of exclusion.
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What causes coronary microvascular dysfunction?
CMD occurs when the tiny vessels that supply the heart muscle fail to dilate properly or spasm inappropriately during increased demand. It disproportionately affects women and often coexists with high blood pressure and diabetes.
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What are the symptoms of coronary microvascular dysfunction?
The typical picture is exertional chest pain with an abnormal stress test but a seemingly normal angiogram, which historically left many patients without a clear explanation. Symptoms can otherwise resemble typical angina.
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Is coronary microvascular dysfunction serious?
Yes - despite the normal-looking angiogram, CMD carries real prognostic weight and is not simply reassurance territory. It should be properly investigated and treated rather than dismissed.
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How is coronary microvascular dysfunction diagnosed?
The key advance is invasive functional testing during angiography: adenosine-based measurement of coronary flow reserve and microvascular resistance, plus acetylcholine testing to identify spasm. This gives an objective classification rather than relying on symptoms alone.
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How is coronary microvascular dysfunction treated?
Treatment is guided by the specific test results: beta-blockers and statins are typically used for microvascular disease, while calcium channel blockers are used where spasm is identified. Trials show this stratified approach improves symptoms and quality of life.
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Can coronary microvascular dysfunction be cured?
Ongoing risk-factor control (blood pressure, diabetes) also helps.
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CMD vs classic coronary artery disease - what's the difference?
Classic coronary artery disease involves visible narrowing or blockage of the main coronary arteries on angiogram, while CMD affects vessels too small to see on standard imaging and needs specialised functional testing to diagnose. Both can cause angina, but they need different tests and treatments.
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How long does treatment take to work?
Many people notice improvement in symptoms within weeks of starting the correctly targeted medication, though ongoing follow-up is usually needed to fine-tune treatment and confirm control is being maintained.
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When should I see a specialist about unexplained chest pain?
If you have exertional chest pain with a normal angiogram, ask your GP for referral to a cardiologist with expertise in angina with non-obstructed coronary arteries (ANOCA). NHS routine referrals for this can take 20-45+ weeks, whereas an initial private cardiology consultation is typically available within about two weeks.