Quantitative perfusion by cardiac magnetic resonance imaging reveals compromised myocardial perfusion in patients with angina with non-obstructive coronary artery disease

Introduction: Stress perfusion cardiac magnetic resonance (CMR) effectively detects myocardial ischemia. In angina with non-obstructive coronary arteries (ANOCA), visually assessed first-pass perfusion often appears normal. Automated quantitative perfusion (QP) might benefit ANOCA diagnosis, offering absolute quantification of myocardial blood flow (MBF) and myocardial perfusion reserve (MPR). Aim: We aimed to evaluate the efficacy of QP in detecting ANOCA. Methods: This study compared fully automated QP CMR in ANOCA patients with age- and sex-matched healthy controls. Participants underwent adenosine stress perfusion CMR, including visual assessment and quantification of MBF and MPR. ANOCA patients underwent coronary function testing to identify vasospasm and/or coronary microvascular dysfunction. Results: Twenty-four ANOCA patients (83% women, 57 ± 9 years) and 25 healthy controls (80% women, 56 ± 7 years) were included. Visual perfusion assessment did not differ between groups (p = 0.54). Additionally, no differences in resting MBF were observed. However, ANOCA patients had significantly lower global MBF during stress (2.43 ± 0.72 vs 2.99 ± 0.65 ml/g/min, p < 0.01) and a significantly lower global MPR (2.24 ± 0.79 vs 2.68 ± 0.64, p = 0.04) compared to healthy controls. MPR was significantly reduced in the RCA territory in ANOCA patients (2.16 ± 0.71 vs 2.69 ± 0.69, p = 0.01), with no significant differences in other coronary territories. MPR did not significantly differ between ANOCA endotypes. Conclusions: ANOCA patients display reduced global MPR, suggesting compromised perfusion. Variation in MPR across coronary territories highlights the importance of assessing perfusion in all teritories. These findings are promising and support the use of QP for non-invasive detection of vasomotor dysfunction in ANOCA patients. Pre-registered clinical trial number: The pre-registered clinical trial number is NL-OMON23861.