Stress native mapping does not distinguish patients with previous myocardial infarction with non-obstructive coronary...

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.

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).

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.