AHA Releases First Scientific Statement on Acute MI in Women

Deborah Brauser

January 29, 2016

WASHINGTON, DC — "A woman's heart is a deep ocean of secrets," states a famous movie quote[1], but the American Heart Association (AHA) wants to remedy that—at least in the case of acute MI.

In its first scientific statement on MIs in women, the AHA notes that underlying causes and symptoms of these events often differ greatly between the sexes, leading to missed diagnosis and significant undertreatment[2].

"CVD is an equal-opportunity killer," report writing group chair Dr Laxmi S Mehta (Ohio State University) and colleagues. "Coronary angiography is used less often in women, largely because their risk is underestimated, yet women have significantly higher mortality rates than men regardless of age."

"I think everyone—patients, nonpatients, and healthcare providers—need to change their thinking," AHA chief science officer Dr Rose Marie Robertson added to heartwire from Medscape.

"Clinicians are used to carrying in their minds the image of a middle-aged or elderly man dramatically clutching his chest and falling to his knees. They're not thinking about a younger woman complaining of chest discomfort or perhaps shortness of breath," she said.

"But since this is a lethal problem, we want healthcare providers from the beginning to think, 'Could this woman be having a heart attack?' so they'll be more likely to offer the needed treatment."

The scientific statement was published online January 25, 2015 in Circulation.

Grim Statistics

Although CV deaths have decreased significantly across the board in the US as public awareness of heart disease has increased, women still fare far worse than men, note the investigators. CHD affects 6.6 million American women each year, but the disease "remains understudied, underdiagnosed, and undertreated" in this group.

More than 53,000 women die each year from an MI and approximately 262,000 are hospitalized for acute MI and/or unstable angina. In addition, 26% of women vs 19% of men die within the year following their first MI; 47% vs 36%, respectively, die within the 5 years after the event.

For its new scientific statement, the AHA sought to provide "a comprehensive review of the current evidence" on MIs in women, including presentation, pathophysiology, treatment, and outcomes.

According to the investigators, literature shows that women are more likely than men to have diabetes mellitus, heart failure (HF), hypertension, depression, and renal dysfunction and more commonly present with non-ST-segment elevation MI (NSTEMI) or coronary artery spasm. They also have more bleeding complications, longer hospitalizations, and higher in-hospital mortality after undergoing coronary revascularization.

A first acute MI occurs at an average age of 71.8 years in women vs 65 years in men. However, more than 30,000 women in the US who are younger than 55 are hospitalized with an acute MI each year. And although annual CHD-related deaths fell for all women in the 1980s, 1990s, and early 2000s, it stopped its decrease for those between the ages of 35 and 54 and actually increased by 1.5% from 2000 to 2002.

"We do well with diagnosing patients with chest pain in the emergency departments in our hospitals across the country. But we don't do as well in women, particularly those under the age of 50, for whom healthcare providers continue to have a bias against in thinking a heart attack can occur," said Robertson.

The mechanisms for risk in young women "remain unclear," note the investigators. For older women, it's been suggested that increased endothelial dysfunction and lipid deposition caused by menopausal estrogen depletion could influence CHD risk. However, "studies evaluating exogenous estrogen hormone therapy for the primary prevention of CHD in postmenopausal women have been convincingly negative."

Atypical Symptoms

Although chest pain or discomfort is the typical symptom of MI for men and women, women are more likely to have atypical symptoms that include nausea/vomiting; pain in the upper back, neck, or jaw; shortness of breath; unusual fatigue; and anxiousness. In addition, shoulder and arm pain "are twice as predictive of an ACS diagnosis" for women vs men.

In other words, all MIs don't look like "that dramatic, Hollywood heart attack," pointed out Robertson.

In fact, she said that when asked when their chest pain started, many patients will answer "never" and instead describe a tightness, pressure, or squeezing. "That's true for both sexes, but more likely to be true for women and likely to be truer as you get older. It's also particularly true in patients with diabetes."

Compared with men, women also have different plaque characteristics. A world survey showed that 76% of fatal AMIs in men were caused by plaque rupture vs 55% of the events in women, note the researchers. On the other hand, autopsy studies have shown that plaque erosion is more common in women.

The researchers note that women often present with less severe artery blockages than men, leading to misdiagnosis and effective treatments not being prescribed.

However, "medical therapies are similar regardless of the cause of the heart attack or the severity of the blockages," noted Robertson. "These medicines are effective even though the way the artery looks might be different."

Low Adherence

As with medications, cardiac rehab (CR) is prescribed less frequently for women than for men. But, as reported by heartwire, even when prescribed, CR adherence is low.

Robertson noted that possible reasons for this could include concerns about transportation to the rehab center, including whether they are too shaky to drive themselves or not wanting to be a burden by asking someone else to make a special trip up to three times per week.

"We know that women don't want to put people out. And transportation might not be easy, especially if there's only one car in a family. Women often don't put their own interests first so may not ask for that extra level of help."

Robertson suggested that, especially with women who didn't grow up in a culture that emphasized the importance of exercise, clinicians should take time to educate their patients about their heart trauma and should stress the importance of following through with treatment adherence. "They may not intuitively understand to do this."

Racial, Ethnic Differences

The investigators also reported on racial and ethnic disparities among women with acute MI. Although ethnically diverse women as a group were significantly younger than white women at the time of their first MI, the group with the highest MI prevalence was black women. After an out-of-hospital cardiac arrest, the survival rate for this group was only one-third of that for white women.

More black and Hispanic women had diabetes, hypertension, HF, and obesity at time of MI presentation vs white women. However, the Hispanic women had fewer sudden cardiac deaths vs non-Hispanic women.

Between 54% and 60% of the black women had at least three comorbid risk factors, as did more than 33% of American Indian women. "A staggering" 78% of CV events in the latter group occurred in those who also had diabetes, report the authors.

"At a time when other groups are experiencing a decline, the rate of coronary events in American Indian women is increasing to levels that are almost twofold higher than in the US population," they add.

Finally, although all women were less likely to undergo PCI or CABG vs men, black women were less likely to be referred for coronary angiography and reperfusion vs white women.

Mehta and Robertson report no relevant financial relationships. Disclosures for the coauthors are listed in the article.

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