The world's four leading cardiovascular health groups have agreed the first universal definition of a heart attack, a move that aims to improve treatment for millions of women after decades of being "deprioritised".
Historically, some less common forms of heart attacks, which evidence shows typically affect women far more than men, have been coded as less important, with treatment and care often worse as a result. Until now, experts said women had been getting less effective treatments that did not always target the specific cause of their heart attack and could even make them more unwell.
New guidance upgrades attacks common in women
The landmark agreement was announced in Munich on the opening day of the annual congress of the European Society of Cardiology (ESC), the world's largest heart conference. The new guidance will upgrade three types of attack that are up to 10 times more common in women and often caused by childbirth, exercise and emotional stress.
The most serious cases, previously known as "type 1" and now classed as "primary" heart attacks, had previously prioritised those caused by a clot blocking blood flow to the heart. However, the types of attacks more common in women involve reduced blood flow for other reasons, such as a tear or tightening of arteries, and are more likely to be missed or not treated as urgently, with delays to care.
Lower troponin threshold for women
The new guidelines will also reduce the threshold for any type of heart attack to be diagnosed in women based upon the levels of a protein called troponin in their blood. Until now, women had been expected to reach the same threshold as men for troponin – which is released when the heart is injured and damaged – to get a diagnosis.
Prof Bryan Williams, the chief scientific and medical officer of the British Heart Foundation, Britain's biggest heart charity, said: "This is a landmark moment, a radical shift in how we define and diagnose heart attacks worldwide which will transform people's care.
"For decades, women have missed out on accurate diagnoses and treatment. This focus on finding less common causes of heart attacks, which predominantly affect women, should help to change that. It could be life-changing for huge numbers of women in the UK and worldwide."
Williams said the new streamlined heart attack categories will also help patients to fully understand the cause of their heart attack and what comes next.
Three upgraded attack types
The three types of heart attacks that have been upgraded – and which mostly affect women – are coronary artery spasm, coronary embolism, and spontaneous coronary artery dissection (Scad). The first involves the tightening of the artery, which can deprive the heart muscle of blood and oxygen and cause a heart attack, and can be caused by emotional stress, exercise or extreme cold. The second is where a blood clot or fatty deposit travels to a coronary artery and causes a blockage. The third is caused by a tear in the coronary artery, which occurs in women at least 80% of the time and often happens during or soon after pregnancy.
Prof Nicholas Mills, a cardiologist at Edinburgh University who led the international taskforce of doctors that agreed the new guidelines, said it was "the first time that we've had a truly global approach to aligning how we diagnose what is probably the most important diagnosis there is".
"It kills so many people, and we've never got everyone together around the world to agree how we're going to describe it, classify it, explain it to our patients," he said. "Our job now is to implement this as widely as possible. It's just as relevant for the UK as it is for any other country around the world. It is a revolution. It's going to make care better for patients."
Mills said there had been "unintended systematic bias against women", including by using the key blood test for diagnosing heart attacks at an average level, which picks up all men but misses some women. "This is used for all types of heart attack in every emergency department in the world, and we want to make sure that it's used correctly," he said.
The new guidelines, published in the European Heart Journal, were drawn up by the ESC, the American College of Cardiology, the American Heart Association and the World Heart Federation.
