Coronary Computed Tomographic Angiography With Fractional Flow Reserve in Patients With Type 2 Myocardial Infarction

Background Type 2 myocardial infarction (T2MI) related to a supply/demand imbalance of coronary blood flow is common and associated with poor prognosis. Coronary artery disease (CAD) may predispose some individuals to T2MI and contribute to its high rate of recurrent cardiovascular events. Little is known about the presence and extent of CAD in this population. Objectives The goal of this study was to evaluate the presence and characteristics of CAD among patients with T2MI. Methods In this prospective study, consecutive eligible individuals with Fourth Universal Definition of Myocardial Infarction criteria for T2MI were enrolled. Participants underwent coronary computed tomography angiography (CTA), fractional flow reserve derived with coronary CTA (FFRCT), and plaque volume analyses. Results Among 50 participants, 25 (50%) were female, and the mean age was 68.0 ± 11.4 years. Atherosclerotic risk factors were common. Coronary CTA revealed coronary plaque in 46 participants (92%). A moderate or greater stenosis (≥50%) was identified in 42% of participants, and obstructive disease (≥50% left main stenosis or ≥70% stenosis in any other epicardial coronary artery) was present in 26%. Prevalence of obstructive CAD did not differ according to T2MI cause (P = 0.54). A hemodynamically significant focal stenosis identified by FFRCT was present in 13 participants (26%). Among participants with a stenosis ≥50% (n = 21), FFRCT excluded lesion-specific hemodynamically significant stenosis in 8 cases (38%). Conclusions Among individuals with adjudicated T2MI, CAD was prevalent, but the majority of patients had nonobstructive CAD. Mediators of ischemia are likely multifactorial in this population. (Defining the Prevalence and Characteristics of Coronary Artery Disease Among Patients with Type 2 Myocardial Infarction using CT-FFR [DEFINE TYPE 2 MI]; NCT04864119).