According to the Australian Government’s Institute of Health and Welfare, cardiovascular disease is one of the major causes of illness and death among Australian women. Over half a million Australian women had one or more heart, stroke and vascular diseases in 2017–18, and more than 22,200 died from cardiovascular disease in 2016. Yet, as Associate Professor Thomas Ford highlighted in his recent interview with Dr Shauna Watts, it’s still under-recognised and under-diagnosed.
Gender bias and stereotypes can delay diagnosis in women, especially younger women, who often experience differences in symptom recognition and less targeted treatment, leaving outcomes lagging behind those of men.
Central Heart’s Associate Cardiologist Dr Lynn Khor is helping to shine a light on conditions that often remain hidden in traditional heart testing. With a particular focus on coronary microvascular dysfunction (CMD) and ANOCA (angina with non-obstructive coronary arteries), Dr Khor combines clinical expertise with research to better understand how these conditions affect women. Her work is centred on improving diagnosis, advancing treatment, and empowering women on the Central Coast with evidence-based, personalised care.
This month, we sat down for an interview with Dr Khor to learn more about the lesser-known condition CMD and how it affects women.
Many people have heard of “blocked arteries”, but not of coronary microvascular dysfunction (CMD). What is CMD?
When people talk about “blocked arteries,” they’re usually referring to a narrowing or blockage in the larger blood vessels that supply blood to the heart muscle. These large arteries branch out into a delicate network of tiny vessels that deliver oxygen and nutrients directly to the heart tissue.
Coronary microvascular dysfunction (CMD) occurs when these small blood vessels don’t function as they should. Instead of relaxing and expanding to let blood flow freely, they may tighten or respond abnormally. This can cause chest discomfort or other symptoms, even when the larger arteries look clear. CMD is sometimes referred to colloquially as “small vessel disease”.
What tests are most helpful in identifying CMD?
To identify CMD, cardiologists focus on how well blood flows through the heart muscle. Because the small vessels are too tiny to see on traditional angiograms or CT scans, doctors use functional coronary angiography — a specialised test that measures how effectively these small vessels are functioning.
This differs from large blockages, which rely on structural coronary angiography, where we use dye to visualise the anatomy of the larger arteries.
What is the new national guidance on coronary function testing?
Together with A/Prof Ford and colleagues from the Cardiac Society of Australia and New Zealand Working Group, we have co-authored a new Heart, Lung & Circulation position statement on coronary function testing.
This testing helps identify causes of angina in patients without obstructive coronary artery disease (CAD) — a group often left without answers after a normal angiogram. These patients are frequently women, whereas obstructive CAD (which has a dedicated Medicare item number) is more common in men. The absence of an equivalent rebate for patients with ANOCA risks creating a gender bias in access to accurate diagnosis and treatment.
As a working group, we’re advocating for better access to testing and fairer reimbursement, recognising that these measures are linked to improved quality of life — as shown in the CorMicA study and others.
At Central Heart, we’re committed to helping close this gap and ensuring that all patients with limiting angina receive the same opportunity for accurate diagnosis and personalised care. You can read the CSANZ position statement here.
Research shows that CMD is more common in women. Why is this?
Yes, studies have shown that CMD tends to occur more often in women, especially around mid-life. One possible reason is related to changes in hormone levels, particularly a natural drop in oestrogen during menopause.
Oestrogen helps support healthy blood vessel function, so when levels decline, it can affect how the small vessels in the heart respond. The positive news is that growing awareness of this link is helping doctors better understand women’s heart health and provide more tailored care.
Are the symptoms of CMD in women different from those of men?
Yes, heart disease, including CMD, can show up differently in women than in men. While both may experience chest tightness or pressure, women are more likely to notice other signs, such as breathlessness, fatigue, nausea, or a feeling of chest discomfort rather than sharp pain. These symptoms can sometimes be subtle, which is why it’s so important to listen to your body and seek medical advice if something doesn’t feel right.
It’s also worth noting that not all women with these symptoms have CMD — some may have blockages in the larger arteries, as the two conditions share similar risk factors.
What should patients look out for?
If you’ve experienced exertional chest tightness or other concerning symptoms, but have been told your coronary angiogram is normal, it may be worth asking your doctor whether microvascular dysfunction could be contributing. This is a recognised cause of angina, especially in women, and is often underdiagnosed.
When is invasive coronary function testing needed?
Not every patient with angina requires invasive testing. Many people respond well to medication and lifestyle changes, and if their angiogram shows no major blockages consistent with a previous stress test result, this can often confirm the diagnosis without further procedures.
Invasive coronary function testing is a specialised assessment performed during a coronary angiogram. It’s essentially a chemical stress test inside the heart, taking a little extra time and care. A/Prof Ford has been performing these tests for over 10 years and helped develop the national protocol now used across Australia.
This testing can assess two key aspects of vessel function:
- Microvascular function — how well the small vessels of the heart deliver blood flow.
- Vasospasm (excitability) — how reactive or “twitchy” the small and larger coronary arteries are. In some patients, these vessels constrict too easily, reducing blood flow and triggering chest pain even without blockages.
Testing for both microvascular dysfunction and coronary spasm provides a much clearer picture of why symptoms occur. It’s particularly helpful when symptoms persist despite treatment or when there is diagnostic uncertainty. Identifying these conditions allows cardiologists to tailor therapy, relieve symptoms, and improve quality of life.
What treatment options are available for people diagnosed with CMD?
Although CMD treatment is still developing, there are many effective medications and management strategies available to help relieve symptoms and improve quality of life. Cardiologists tailor treatment to each individual, often combining medication with lifestyle adjustments to support overall heart health. Encouragingly, research in this area is expanding every year, giving patients access to more targeted and evidence-based care.
Assess your heart health on the Central Coast
If you’ve noticed any changes to your heart health, or simply want peace of mind, book an appointment with your GP or our cardiology team at our North Gosford or Toukley locations. Using advanced imaging and diagnostic tools, we can detect problems early and tailor treatment plans to help you live and feel better.