Stress native mapping does not distinguish patients with previous myocardial infarction with non‐obstructive coronary arteries from healthy volunteers

Abstract Aims Patients with myocardial infarction with non‐obstructive coronary arteries (MINOCA) may be affected by coronary microvascular dysfunction with reduced stress perfusion. Changes in native T1 and T2 reflect changes in myocardial perfusion; therefore, the aim of our study was to investigate whether non‐contrast, adenosine stress native T1 and T2 are affected in patients with previous suspected MINOCA. Methods and Results Patients with MINOCA and a normal CMR (n = 15, 59 ± 7 years, 60% female) underwent 1.5T CMR together with age‐ and sex‐matched volunteers. The protocol included native T1, native T2 and quantitative perfusion mapping, at rest and during adenosine stress. Myocardial stress perfusion was globally reduced, both transmurally (2.9 ± 0.9 vs. 3.6 ± 0.7 mL/min/g, p = 0.02) and in the subendocardium (2.64 ± 0.81 vs. 3.47 ± 0.78 ml/min/g, p = 0.008) in patients with MINOCA, with a reduced global ratio of subendocardial‐to‐transmural stress perfusion (0.921 ± 0.042 vs 0.957 ± 0.039, p = 0.021). However, there were no differences in global transmural rest native T1 or T2, stress native T1 or T2, or ΔT1‐ or ΔT2 values between patients and volunteers. Overall, transmural myocardial perfusion correlated with native T1 (R2 = 0.27, p < 0.001) and T2 (R2 = 0.48, p < 0.001) globally, and ΔT1 correlated with the MPR globally (R2 = 0.15, p < 0.05). Conclusions Native T1‐ and T2‐mapping during adenosine stress, although correlated with quantitative myocardial perfusion, are not alone sufficiently sensitive methods for distinguishing patients with MINOCA and reduced stress perfusion from healthy volunteers.