Heart disease is thought of as a man's disease, but it is also a factor in one in every four deaths of Australian women
Heart disease is thought of as a man’s disease, but it is also a factor in one in every four deaths of Australian women, killing three times more women than breast cancer1.
However, awareness of this risk remains low in the community, leading to delays in diagnosis and treatment. Women often don’t perceive themselves to be at risk, are less likely to have health check-ups, can be slower to act on worrying symptoms, and are more likely to delay calling an ambulance when they have chest pain or related symptoms.
Women have not been specifically targeted in clinical trials of the prevention and management of heart disease. However, we know that one in four women over 35 years has high blood pressure, one in three has high cholesterol, and nine in ten women with high cholesterol are not aware of their condition2.
Furthermore, half of all heart attack deaths in 2013 occurred in women3, who were also much more likely to die from a repeat heart attack than men (21% and 14% respectively)4.
Heart disease plays out differently for men and women throughout the lifespan, with differences in prevalence, underlying physiology, risk factors, presenting symptoms
and outcomes.
The uniquely female experience of menopause adds to the complexity of clinical presentations, management options and outcomes for heart disease, and the increasing number of women with pre-existing heart disease reaching childbearing age has led to a greater focus on the cardiovascular risks specific to pregnancy and childbirth.
This complex interplay between pregnancy and heart disease was one of the main themes of the recent IAMAZ / SOMANZ Conference in Alice Springs, where it was noted that the incidence of maternal cardiovascular disease is increasing in developed countries, with the trend attributed to increased risk factors among women, increasing maternal age and the increasing numbers of women with pre-existing heart conditions now reaching childbearing age.
The need for preconception counselling and multidisciplinary pregnancy management was therefore highlighted as essential for managing the risk of maternal complications and the potential impact on
the fetus.
WARNING SIGNS
The Heart Foundation is currently running a campaign, called Making the Invisible Visible, to raise community awareness of heart disease in women.
The annual Heart Foundation survey highlights the low awareness among women of heart disease as a significant health risk, with only 35% of respondents being aware that heart disease is the leading cause of death in women.
In a scientific statement published this year, The American Heart Association has for the first time formally acknowledged there are often differences in how women experience heart attacks, and their response to treatment and medication following a heart attack5. Specifically, the organisation highlighted the non-chest pain warning symptoms of a heart attack in women.
Public awareness that women having a heart attack can present with non-chest pain symptoms is low, with only 26% knowing these symptoms can signal a heart attack in women6:
• Only one in four women is aware of at least one of the non-chest pain symptoms, including jaw, shoulder, neck pain, fatigue and nausea
• Women are less likely to see these symptoms as potentially life-threatening7
• Men were more likely to act within five minutes of experiencing symptoms and more likely to ring for
an ambulance8
Delay in seeking treatment for a heart attack is a critical factor and may contribute to the poorer outcomes experienced by women.
RISK FACTORS
• Risk factors for heart disease are common in young Australian women in their 20s, and tend to be compounded with advancing age
• Heart disease is not limited to post-menopausal women, and is the cause in 6.4% of deaths of women under the age of 54
• More than 90% of Australian women have at least one modifiable risk factor for heart disease, and 50% have
two or three modifiable risk factors
• The average weight of an adult Australian woman has increased from 67kg in 1995 to 74.1 kg in 2011/12. Average BMI is 27.2, above the recommended BMI of <25.
While family history of heart disease is not modifiable, most of the other risk factors are, and should therefore be addressed when aiming for risk reduction:
• Smoking is the greatest risk factor for Australian women under the age of 30
• Lack of physical activity is the greatest risk factor for Australian women over the age of 30
• Among Australian women aged 35 to 44 years, 28% are overweight and 31% obese; obesity may affect fertility and can limit contraceptive options, both of which are significant issues for women of reproductive age
DIAGNOSIS AND TREATMENT
Each year 36,000 men and 19,000 women are admitted to hospital after a heart attack in Australia, demonstrating the higher incidence among men. However annual deaths are similar at 4541 and 4070 respectively9. Women have higher in-hospital death rates, and if they survive, they are more likely than men to die of a second
heart attack10.
Evidence is growing that standard diagnostic procedures may not demonstrate the same sensitivity when diagnosing heart disease in women, with single diagnostic tests potentially leading to under-diagnosis in women. Australian data reveals that women admitted to hospital with heart disease were less likely than men to have a number of heart-related procedures per 100 hospitalisations including:
• Coronary angiography [24 and 30 respectively]
• Percutaneous coronary intervention [26 and 74 respectively]
• Bypass surgery [5 and 9 respectively]11
Women are also less likely to be referred for cardiac rehabilitation while in hospital, and less likely to complete the program if they do enrol12 than men.
UK research has demonstrated that establishing sex-specific at least one modifiable risk factor for heart disease, and 50% have two or three modifiable risk factors
• The average weight of an adult Australian woman has increased from 67kg in 1995 to 74.1 kg in 2011/12. Average BMI is 27.2, above the recommended BMI of <25.
While family history of heart disease is not modifiable, most of the other risk factors are, and should therefore be addressed when aiming for risk reduction:
• Smoking is the greatest risk factor for Australian women under the age of 30
• Lack of physical activity is the greatest risk factor for Australian women over the age of 30
• Among Australian women aged 35 to 44 years, 28% are overweight and 31% obese; obesity may affect fertility and can limit contraceptive options, both of which are significant issues
for women of reproductive age
DIAGNOSIS AND TREATMENT
Each year 36,000 men and 19,000 women are admitted to hospital after a heart attack in Australia, demonstrating the higher incidence among men. However annual deaths are similar at 4541 and 4070 respectively9. Women have higher in-hospital death rates, and if they survive, they are more likely than men to die of a second  heart attack10.
Evidence is growing that standard diagnostic procedures may not demonstrate the same sensitivity when diagnosing heart disease in women, with single diagnostic tests potentially leading to under-diagnosis in women. Australian data reveals that women admitted to hospital with heart disease were less likely than men to have a number of heart-related procedures per 100 hospitalisations including:
• Coronary angiography [24 and 30 respectively]
• Percutaneous coronary intervention [26 and 74 respectively]
• Bypass surgery [5 and 9 respectively]11
Women are also less likely to be referred for cardiac rehabilitation while in hospital, and less likely to complete the program if they do enrol12 than men.
UK research has demonstrated that establishing sex-specific diagnostic thresholds of cardiac troponin may double the diagnosis of myocardial infarction in women, and aid in identifying women at risk of re-infarction and death13.
PRE-ECLAMPSIA AND FUTURE RISK
New research has also focussed on the long-term outcomes for women who have experienced pre-eclampsia during pregnancy, highlighting the role of angiogenic factors in the pathogenesis of pre-eclampsia.
Research may lead to the use of these factors as predictors or diagnostic tools, but a clinical approach to the diagnosis of pre-eclampsia remains best practice.
It is based on the assessment of blood pressure, clinical features, liver and renal function, haemolysis (rare in Australia), thrombocytopenia and proteinuria.
Pre-eclampsia is now recognised as a significant cardiovascular event and a signpost for future increased cardiovascular risk.
Recurrent pre-eclampsia has been shown to be associated with a higher risk of future cardiovascular hospitalisation, along with a shorter time to first cardiovascular event, when compared to women with no history of pre-eclampsia.
The mechanisms involved in this process, such as pre-existing cardiovascular profile, exaggerated response in pregnancy or an irreversible vascular event, are yet to be clarified, as is the feasibility of targeting the risk factors involved.
Annual blood pressure checks post-childbirth and regular assessment of cardiovascular risks every five years are currently recommended for these women.
RHEUMATIC HEART DISEASE AND PREGANCY
According to the data collected by the Australasian Maternity Outcomes Surveillance System, rheumatic heart disease accounts for serious obstetric complications in Australia and New Zealand, with 79% of Australian cases among Aboriginal people and the highest prevalence in New Zealand among  the Maori and Pacific populations.
Researchers have concluded that clinical symptoms alone are not helpful in identifying women who will require high-risk care, and recommended echocardiographic assessment for the high-risk populations to avoid and manage cardiac complications in pregnancy.
Visit the Heart Foundation website for evidence-based summary guidelines, risk calculators, GP tools, patient resources and up-to-date publications, including the Making Invisible Visible campaign materials www.heartfoundation.org.au
References:
 1. Abs. Causes of Death 2014 (3303.0) March 2016
 2. ABS. Australian health Survey 2014/15.
 3. Deloitte Access Economics, ACS in Perspective: The Importance of Secondary Prevention.
 4. ibid
 5.  http://circ.ahajournals.org/content/early/2016/01/25 CIR.0000000000000351
6. Heart Foundation (2015) HeartWatch Survey
 7. Heart Foundation (2015) HeartWatch Survey
8. Heart Foundation (2015) Heart Attack Survivors Survey. Gender Comparison.
9. Â ABS. Cause of death 2013 (3303.0). Released march 2016
10. Deloitte Access Economics, ACS in Perspective: The importance of secondary prevention. 2011.
11. AIHW. National Hospital Morbidity Database 2012/13.
12. Â Heart Foundation (2015) Heart Attack Survivors Survey. Gender Comparison.
13. Shah et al. High sensitivity cardiac troponin and the under-diagnosis of myocardial infarction in women: prospective cohort study. BMJ 2015;
