• myocardial infarction
• epidemiology

The clinical differentiation between type 1 myocardial infarction (MI) and type 2 MI is challenging yet vitally important with implications for diagnosis, treatment and prognosis. While sex differences in treatment and survival among patients with type 1 MI have been well documented, we are still learning about sex differences in type 2 MI. Men are more likely to have a type 1 MI, while women with type 1 MI are less likely to receive reperfusion and revascularisation, are less likely to be prescribed guideline-indicated medical therapy and have higher excess mortality.1 2 Whether there are real sex differences in type 2 MI treatment and outcomes is less clear. Patients with type 1 MI have a relatively homogenous aetiology of an acute thrombotic event, but patients with type 2 MI are much more heterogeneous. Considering that many of the aetiologies of type 2 MI, including spontaneous coronary artery dissection and vasospasm, affect women at much higher rates than men, one might expect type 2 MI to have even more pronounced sex differences in treatment and outcomes. With the increasing incidence of type 2 MI and its higher overall mortality compared with type 1 MI, understanding these differences is critical.1 3

However, taking a step back, even differentiating between type 1 and type 2 MI is difficult. Much of our clinical work on both the cardiology inpatient and consult services centres on these challenging diagnoses. We use our best clinical judgement incorporating labs, imaging, history and physical exam in an attempt to discern which patients would benefit from the more aggressive anticoagulation and invasive approach that is generally more helpful in patients with acute thrombotic type 1 MI events compared with those with type 2 MIs. Yet, even after coronary angiography, the diagnosis is not always clear. The available clinical …