Rachel Channon was 27 years old, a keen and fit bushwalker. She thought anxiety was to blame when her hands and face became swollen, and her heart gave a slight murmur that her doctor picked up – but he wasn’t excited by it.
That was in 2009 and Ms Channon, from Wollongong, NSW, describes these symptoms as being “extremely subtle” at the time. The murmur seemed to disappear.
Neither Ms Channon nor her doctor were aware that she had a life-threatening heart complaint – Coronary Microvascular Disease (CMD), a narrowing of the small blood vessels that branch off the arteries
There are uncounted thousands of people just like Rachel Channon going undiagnosed.
The too-hard basket
In 2012, three years after first complaining of feeling unwell, and starting to feel worn out, Ms Channon was referred to a cardiologist, citing chest pains and dizziness.
The cardiologist didn’t think there was much to worry about. She was an active young woman: the implication being that Ms Channon’s issues were more psychological or even imagined.
It wasn’t until 2014 that a cardiologist put Ms Channon through the battery of tests that heart patients are given early in their diagnosis.
These included a stress test, wearing a halter monitor for day-long monitoring, multiple ECGs to examine the electrical signals that keep the heart beating, and an echocardiogram that found her heart muscle and valves were working.
Nothing was shown to be wrong
The tests revealed no issues – and yet she deteriorated.
By 2017, Ms Channon’s symptoms were preventing her from moving around comfortably. The chest pains were severe, so was the dizziness and shortness of breath. She was permanently fatigued and the swelling in her face and hands was no longer subtle.
At this point, she turned to Doctor Google. “I started to do my own research, looking for conditions that might not show up,” she says.
And that’s how she discovered CMD and learnt of the narrowing in the small blood vessels branching off her arteries. She wrote to a researcher who referred her to Sydney interventional cardiologist Professor Martin Ng.
Professor Ng investigated Ms Channon’s heart with an angiography (which ascertains the health of blood vessels) using a pressure wire – a wire four times the width of a strand of hair and fitted with tiny sensors.
The wire is inserted through a catheter in the patient’s wrist and travels up to the heart to record blood pressure and other physiological markers in vessels too tiny to otherwise investigate.
Sure enough, CMD was the culprit – coupled with vasospastic angina.
The standard tests had failed to identify abnormalities in the endothelium, or inner lining, of Ms Channon’s smaller blood vessels. These were cause painful spasms that diminished blood flow to the heart.
Ms Channon had gone undiagnosed for eight years with a condition that significantly increased her risk of dying from a heart attack or stroke.
“It was amazing getting a diagnosis – knowledge is power!” she said.
“So many people have complicated or rare problems that aren’t easily diagnosed and can get pushed to the side in the too-hard basket, and that has a psychological impact.”
She’s now being treated with medications that have improved the chest pains and breathless, but “certain scenarios aggravate the condition”. Lifestyle changes are also advised for patients with this disease.
Shortage of technology and expertise
According to a 2010 report in the New England Journal of Medicine, half of all patients undergoing a coronary angiogram to identify the cause of chest pain or shortness of breath show no blockages of the major arteries and thus could be going undiagnosed for microvascular disorders.
So why don’t doctors, when ruling out an arterial blockage, routinely consider CMD as a possible explanation for symptoms? Well the medical profession appears to be catching up with the disease.
A 2019 review from Harvard Medical School found there were no guideline-directed recommendations for managing these patients.
There was a tendency to see CMD as a secondary problem. The Harvard authors note there were “increased calls for research directed at expanding diagnostic tools” to address the problem.
Twenty years ago, Professor Ng was investigating pressure wires as possible means to identify CMD – but the technology all but disappeared “because of commercial interests”.
Now it’s gradually being used in clinical settings. “There are only 20 (cardiac) units in Australia with this technology,” Professor Ng told The New Daily. “It’s better than nothing. And in the United States, there are only 50 units who have this tool.”
He said there was also a shortage of cardiologists trained to use the technology.
“The issue is trying to make pressure wire technology more available and getting cardiologists familiar with it and comfortable with using it as a technique so that they can provide patients with more definitive answers and better treatment,” said Professor Ng.
There don’t appear to be precise statistics about CMD’s prevalence in Australia, but it’s understood that women are four times more likely to suffer with it than men. It’s said that a third of people with angina also have CMD.
Professor Ng said: “There are many patients who languish at home with the symptoms, without a clear diagnosis, without a clear treatment plan and who remain at risk of further cardiac events.”