Coronary microvascular dysfunction as assessed by angiography-derived index of microvascular resistance co-localizes with and may explain the presence of ischemia in stress-cardiac magnetic resonance imaging in the absence of coronary artery disease

Andrea Milzi; Rosalia Dettori; Richard Karl Lubberich; Kathrin Burgmaier; Nikolaus Marx; Sebastian Reith; Mathias Burgmaier

doi:10.3389/fcvm.2022.1060764

Coronary microvascular dysfunction as assessed by angiography-derived index of microvascular resistance co-localizes with and may explain the presence of ischemia in stress-cardiac magnetic resonance imaging in the absence of coronary artery disease

Front Cardiovasc Med. 2022 Nov 24:9:1060764. doi: 10.3389/fcvm.2022.1060764. eCollection 2022.

Authors

Andrea Milzi¹, Rosalia Dettori¹, Richard Karl Lubberich¹, Kathrin Burgmaier^{2

3}, Nikolaus Marx¹, Sebastian Reith^{1

4}, Mathias Burgmaier^{1

3}

Affiliations

¹ Department of Internal Medicine I, University Hospital RWTH Aachen, Aachen, Germany.
² Department of Pediatrics, University Hospital of Cologne, Cologne, Germany.
³ Faculty of Applied Healthcare Science, Deggendorf Institute of Technology, Deggendorf, Germany.
⁴ Department of Cardiology, Angiology and Electrophysiology, St. Franziskus-Hospital, Münster, Germany.

Abstract

Introduction: Ischemia with no obstructive coronary disease (INOCA) is a frequent phenomenon in the cath lab. A possible cause is coronary microvascular dysfunction (CMD), which may be assessed by invasive testing with possible complications; therefore, less invasive approaches have emerged, such as the angiography-derived index of microvascular resistance (aIMR). The aim of our study was to investigate the association of single-vessel aIMR as a measure of CMD with areas of INOCA in stress testing.

Methods: We measured aIMR in 286 vessels from 102 patients undergoing both stress cMRI and coronary angiography. Groups were (a) INOCA group (93 vessels, 32 patients); (b) coronary artery disease (CAD) control group (116 vessels, 42 patients) with ischemia due to relevant stenosis; and (c) control group (77 vessels, 28 patients) without ischemia or relevant stenosis.

Results: INOCA patients presented higher mean aIMR (28.3 ± 5.7) compared to both CAD patients (17.4 ± 5.7, p < 0.001) and controls (22.1 ± 5.9, p < 0.001). Furthermore, in INOCA patients aIMR was significantly increased (33.0 ± 8.1 vs. 25.8 ± 6.3, p = 0.021) in vessels with vs. without ischemia. Single vessel aIMR presented a very good diagnostic efficiency in detecting INOCA [AUC 0.865 (0.804-0.925), optimal cut-off 27.1, p < 0.001].

Conclusion: CMD, as assessed by 3-vessel aIMR, co-localizes with and may explain the presence of ischemia in stress-cMRI in INOCA.

Keywords: INOCA; coronary angiography; coronary artery disease; coronary physiology; index of microvascular resistance (IMR); myocardial ischemia; quantitative flow ratio (QFR).