Study: Women remain at higher risk of dying or developing heart failure after a heart attack

Women face a 20 per cent higher risk than men of dying or having heart failure during the five years following a heart attack, according to a new study from University of Alberta cardiology researchers.

The women were on average a decade older than men at the time of their first heart attack and they more commonly presented with the less severe type of heart attack. But when they were faced with the more severe type of heart attack, they did develop heart failure more often."

Justin Ezekowitz, Lead Author, Professor of Medicine and Co-Director of the Canadian VIGOUR Centre

"We don't know yet why there continue to be these differences in outcomes for men and women, but there is an international interest in looking at heart disease in women," said co-author Padma Kaul, professor of medicine and Sex and Gender Science Chair funded by the Canadian Institutes of Health Research. "Our study shows that there's more work to be done."

The research team examined health records for more than 45,000 Canadians who were hospitalized for a first-time heart attack between 2002 and 2016, linking data on their angiogram results, treatments including medications and bypasses or stents, and clinical outcomes.

About 45 per cent of the patients experienced the more severe type of heart attack, known as STEMI, and 55 per cent the less severe type known as NSTEMI. Both types involve a blockage of the blood supply to the heart muscle and can lead to permanent damage. Heart failure occurs when the heart muscle can no longer pump enough blood and oxygen to sustain life.

The researchers found that the female patients were on average 10 years older than the male patients, had more chronic conditions such as diabetes, high blood pressure or atrial fibrillation and were more likely to die in hospital. The women were also less likely to receive a diagnostic angiogram or see a heart specialist and were prescribed fewer medications.

"We have to be careful not to introduce bias when applying the therapeutic regime," Ezekowitz said. "The basics have to be applied across all patients--that includes men and women of all ages."

"Close is no longer good enough."

Ezekowitz said his advice to men and women is the same: Stop smoking, get more exercise, and control blood pressure and stress levels, especially if you've already had a heart attack.

Both researchers pointed out that some women delay going to the hospital because they don't realize they are having a heart attack, and more needs to be done to help women recognize the signs, which may include chest or upper body pain, sweating, nausea, shortness of breath or light-headedness.

Ezekowitz said all patients presenting with heart attack symptoms should be diagnosed with both electrocardiogram (ECG) and a blood test looking for markers of heart damage, to determine whether the patient is having a STEMI or NSTEMI heart attack. Though the recommended treatments for both types of heart attack are similar, those experiencing the more severe type need treatment faster.

Differences between how men and women are diagnosed and treated for heart attack have been documented in previous studies, but this study showed the gap is narrowing over time.

"It's not all bad news, as we do see the rates of diagnostic and intervention procedures coming together," said Kaul, co-director of the Canadian VIGOUR centre and member of the Women and Children's Health Research Institute.

"It is improving, which shows there is a recognition on the part of clinicians that women are at risk and what kind of treatment they should get," she said.

"One of the things that's been missing from prior descriptions of the differences between men and women is the actual pictures of the arteries of the heart," said Ezekowitz, a 2020 fellow of the Canadian Academy of Health Sciences. "There are known biologic differences between men and women at the time of a heart attack, so having that information really was a big plus."

Kaul said more research is needed to understand and address the multiple factors behind the difference in outcomes between men and women.

"As we get better information to women and the system stops treating the two sexes differently, I think we'll see it come together."

The research was carried out by six members of the Canadian VIGOUR Centre, a cardiac health research organization based in the U of A's Faculty of Medicine & Dentistry.