At the same time, research was beginning to be published propounding the groundbreaking possibility that, when it came to cardiology, women might need to be treated differently.
"These papers were saying that cardiologists should discriminate between the sexes," says Maas. "Most of my colleagues thought this was a laughable idea and carried on treating women as 'mini-men'. But I remembered my patient, so I started to examine this disparity."
What Maas discovered would profoundly change how she practised cardiology. It would also lead to her new book, A Woman's Heart, currently a best seller in her native Holland, where she lays bare how the disparity between the sexes affects everything from symptoms to diagnoses to outcomes. Still now, she says, too many women are themselves unaware of the danger of heart disease, often considering it to be a "man's condition" even though it is by far the biggest killer of women in the UK, killing twice as many as breast cancer.
"Frankly, cardiology for women and for men are almost two different diseases and they should be treated as such," says Maas, who opened her first female outpatient clinic in 2003.
Thanks to the work of Maas and others, awareness of the "gender heart attack gap" and its impact on health outcomes is improving, but the statistics are still worrying. A 2019 report by the British Heart Foundation found women were 50 per cent more likely to receive an incorrect diagnosis after a heart attack, and significantly less likely to receive the correct aftercare, resulting in 8200 needless deaths over a 10 year period.
Recently, research from Florida has shown that women recovering from a heart attack have fewer complications and a lower risk of dying when they are treated by a female cardiologist.
Maas says the differences start at a basic physiological level. As women age, and particularly as oestrogen levels drop, they tend to develop stiffness and diffuse narrowing of the arteries that supply the heart. In men this arthrosclerosis occurs in one specific place, as a blockage, whereas in women the damage is more widespread. Women are more likely to suffer from cardiac spasms, also known as angina, a short-lived pain or discomfort often described as a heavy ache, in the chest that can spread to the arms, neck, jaw, back or stomach, or a squeezing pressure around the heart.
So while the symptoms of male and female coronary disease can be similar – shortness of breath, spreading pain, nausea, faintness – it is much more challenging to spot in women than men, especially, as Maas drily notes, given the diagnostic process has been developed by and for men.
"Usually if heart disease is suspected the first test will be an exercise test – incidentally, designed to be fitted to a man's flat chest rather than a rounded female one – which because it is a snapshot, will probably not witness a spasm," she explains. "Then, a coronary angiogram will spot a blockage in an instant, but rarely arterial spasm and damage."
Maas believes middle-aged women who complain of upper chest pain should have a completely different initial diagnostic test, such as one to determine calcification in the arteries.
With women under the age of 65 twice as likely to die of a heart attack as men, careful and extensive patient history is also vital.
"With men we look for risk factors such as family history, weight, smoking, high cholesterol, high blood pressure and so on. With women, the doctor must look wider," says Maas.
One risk factor for women that is still poorly recognised is a history of migraines. "It is almost as if the vascular contractions that cause migraines move to the area around the heart, which is of course very dangerous.
"Similarly, a history of early menopause, or high blood pressure, pre-eclampsia and recurrent miscarriages are all warning signals. If the doctor doesn't ask about these things, then the woman should tell them anyway."
Treatments for heart disease work differently in women, too.
"Whilst an arterial blockage can be opened up with a stent or a balloon you can't really do the same with arterial damage that you see [in women]," she says. "Women often react badly to medication such as statins, because of differences in the breakdown of drugs in the female body."
"Instead of just stopping their medication, the doctor could consider putting her on a thrice weekly rather than daily regimen."
Despite everything, she is optimistic - awareness is improving in the medical profession and treatments are being developed for cardiac spasms.
"Women too are learning to help themselves," she adds. "As they have become more economically independent, like my patient from a long time ago, they are more assertive and less likely to accept poor quality answers. Women today often have a higher expectation of good health than their mothers did. They want to live longer and better.
"My profound hope is that my book informs and empowers women to ask the right questions and to demand the best possible treatment. It is their right and we owe it to them."
