Sex disparities continue to characterise the management of non‐ST‐elevation acute coronary syndrome

Women with non‐ST‐elevation acute coronary syndromes remain understudied and undertreated

Ischaemic heart disease is the leading cause of death for women worldwide, and sex‐related disparities continue to characterise its management.1 Despite initiatives addressing this problem, cardiovascular risk in women is still underestimated and guideline recommendations have failed to develop sex‐specific strategies, primarily because women are underrepresented in clinical trials.1,2,3 In particular, sex‐specific pathophysiological mechanisms of ischaemic heart disease have not been fully elucidated; for example, acute coronary syndromes (ACS) are more frequently associated with non‐obstructive coronary artery disease and spontaneous coronary dissection in women than in men.4,5 Further, the symptoms of myocardial infarction may be different in women, and this contributes to its under‐recognition and, ultimately, to delays in appropriate treatment.6

In this issue of the MJA,7 Bachelet and her colleagues report their analysis of data from the Cooperative National Registry of Acute Coronary Care, Guideline Adherence and Clinical Events (CONCORDANCE) registry for 7783 people (including 2422 women, 31%) who had presented with non‐ST‐segment elevation ACS (NSTE‐ACS) to forty‐three Australian hospitals between 2009 and 2018.

The authors found important differences in baseline characteristics by sex. The mean age of the women was higher than for men (68 v 65 years), as was their median GRACE risk score (106 v 101), and larger proportions of women presented with atrial fibrillation, hypertension, and lung disease. Conversely, the proportions of men with prior myocardial infarction, coronary revascularisation, or diagnosis of peripheral artery disease were larger. In keeping with the literature, non‐obstructive coronary artery disease was more frequent in women than men, identified in more than one‐third of those undergoing catheterisation (35% v 14% in men). Overall rates of catheterisation, revascularisation, and subsequent cardiac rehabilitation were all lower in women. Similarly, women were less frequently prescribed antithrombotic therapies. Sex‐related differences in in‐hospital medical therapy were smaller in analyses restricted to patients with documented coronary artery disease, but women were still less likely to receive statin therapy or to be referred for cardiac rehabilitation.

The goal for treatment of patients with ST‐segment elevation myocardial infarction is immediate reperfusion, but the optimal management of NSTE‐ACS depends on more nuanced clinical evaluation and risk assessment. Comparing the treatment of women and men in the study by Bachelet and colleagues7 is difficult, as sex‐related differences in age, comorbidity, and clinical presentation play important roles. Their study found significant differences in the baseline characteristics of women and men with NSTE‐ACS, and the authors’ findings suggest that treating physicians struggle with uncertainty about the safety and efficacy of various treatments in women because of the lack of evidence from clinical studies.

The report by Bachelet and colleagues also confirms that a substantial number of women with ischaemic heart disease do not have obstructive coronary artery disease.7 Ischaemia with non‐obstructive coronary arteries is not a benign condition, and gaps in knowledge about its diagnosis, treatment, and prognosis persist.8 Further research is urgently needed to improve the management of women with ischaemic heart disease without obstructive coronary artery disease.

Even in patients with documented coronary artery disease, secondary prevention therapies were less frequently prescribed for women than for men. Further, women were less likely to be referred for cardiac rehabilitation, irrespective of whether revascularisation was surgical or percutaneous. Bachelet and her colleagues found that outcomes were similar for women and men, but the relatively short follow‐up in their study should be acknowledged as a limitation.7

The findings of Bachelet and her co‐authors add to the body of evidence that differences in treatment constitute a problem that is not adequately managed even in high income countries.9,10 The authors have provided further evidence for sex‐based disparities in the management and treatment of people with NSTE‐ACS. Their findings indicate the importance of the further investigation of sex‐specific pathophysiological mechanisms and the urgent need for evidence‐based sex‐specific strategies and recommendations for the diagnosis and treatment of ischaemic heart disease. Women with NSTE‐ACS are both understudied and undertreated, and the report by Bachelet and colleagues is a valuable contribution to increasing global awareness of differences between men and women in the characteristics of heart disease, and to promoting cardiovascular health in women.