There are differences between men and women across different types of coronary artery disease.
Coronary artery disease
Obstructive coronary artery disease generally manifests similarly in women and men, with the most common symptom being central chest pain. In women, there is a greater likelihood of chest pain onset at rest, during sleep or when under mental stress. Women also more frequently present atypically with pain in the upper back, arms, neck and jaw, as well as presenting with dyspnoea, diaphoresis, indigestion, nausea, palpitations, dizziness and weakness.41 Furthermore, the proportion of women aged 55 years and younger presenting with acute coronary syndrome without chest pain is significantly greater than the proportion of men (19% vs 13.7%).42 As a result, they are at a greater risk of being discharged home with evidence of acute coronary syndrome compared to men.43
Women with coronary artery disease also more frequently develop symptomatic heart failure than men. This may be due to the impact of co-existent hypertension, an important risk factor for coronary artery disease, which leads to a greater incidence of left ventricular hypertrophy that is less responsive to antihypertensive therapy in women, resulting in diastolic dysfunction and heart failure with preserved ejection fraction.44
Ischaemia with non-obstructive coronary artery disease
Ischaemia with non-obstructive coronary disease is a condition due to coronary microvascular dysfunction or epicardial vascular spasm. It is more common in women, especially at 45–65 years of age.45 If this condition or coronary stenosis is not diagnosed, many women are mistakenly presumed to not have heart disease and are not treated, which increases their risk of adverse cardiac events. A comprehensive meta-analysis has revealed an overall estimated incidence of all-cause mortality or myocardial infarction of 0.98 per 100 person-years in patients with non-obstructive coronary disease compared with 0.2 per 100 person-years in a similarly matched general population. In addition, 50% of patients with non-obstructive coronary disease will experience repeated episodes of ischaemic chest pain, similar to those with obstructive coronary artery disease, further underscoring the importance of the condition. Functional coronary angiography is needed to evaluate macroscopic resistance, coronary flow reserve and microvascular resistance to confirm the diagnosis that is otherwise missed on routine non- invasive testing.46
Myocardial infarction with non-obstructive coronary artery disease
Myocardial infarction with non-obstructive coronary artery disease (MINOCA) is roughly three times more common in women than in men.47 This is based on a pooled analysis of 10 studies that recruited both patients with MINOCA and myocardial infarction with obstructive coronary artery disease (MI-CAD).48 Furthermore, approximately 25% of patients with MINOCA have ongoing angina, equivalent to the prevalence in patients with MI-CAD.47 The pathophysiology is unknown in approximately a quarter of MINOCA cases. Processes involving the epicardial vessels and coronary microvascular disease, which prevent an increase in myocardial blood flow in response to an increased oxygen demand, may be responsible. There may also be an overlap with mild forms of Takotsubo syndrome.49
Takotsubo syndrome
Takotsubo syndrome accounts for 7.5% of cases of acute myocardial infarction in women, with 90% of cases occurring in postmenopausal women aged 50–75 years.50-52 It is triggered by emotional or physical stress, which is associated with enhanced sympathetic activity. Patients present with chest pain and ECG changes characteristic of acute coronary syndrome but without angiographically obstructive coronary artery disease. These patients have reversible left ventricular ballooning. Cardiac arrest occurs in 5.9% of patients.53
Spontaneous coronary artery dissection
In at least 25% of women aged 60 years or younger, spontaneous coronary artery dissection causes acute myocardial infarction, with conventional risk factors often being absent. It is the most common cause of myocardial infarction associated with pregnancy, primarily occurring in the third trimester or postpartum.54 The risk of recurrence is substantial with a pathological process independent of atherosclerotic disease. While strategies to prevent spontaneous coronary artery dissection include avoiding hormonal therapy and future pregnancies, there is currently a lack of evidence that allows for treatment guidelines to be established.