Diagnostic Value of Angiography-Derived IMR for Coronary Microcirculation and Its Prognostic Implication After PCI

Neng Dai; Wenliang Che; Lu Liu; Wen Zhang; Guoqing Yin; Bin Xu; Yawei Xu; Shaofeng Duan; Haojun Yu; Chenguang Li; Kang Yao; Dong Huang; Junbo Ge

doi:10.3389/fcvm.2021.735743

Diagnostic Value of Angiography-Derived IMR for Coronary Microcirculation and Its Prognostic Implication After PCI

Front Cardiovasc Med. 2021 Oct 15:8:735743. doi: 10.3389/fcvm.2021.735743. eCollection 2021.

Authors

Neng Dai^{1

2}, Wenliang Che³, Lu Liu³, Wen Zhang³, Guoqing Yin³, Bin Xu³, Yawei Xu³, Shaofeng Duan⁴, Haojun Yu⁵, Chenguang Li^{1

2}, Kang Yao^{1

2}, Dong Huang^{1

2}, Junbo Ge^{1

2}

Affiliations

¹ Department of Cardiology, Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai, China.
² National Clinical Research Center for Interventional Medicine, Shanghai, China.
³ Department of Cardiology, Shanghai Institute of Cardiovascular Diseases, Shanghai Tenth People's Hospital, Tongji University, Shanghai, China.
⁴ GE Healthcare China, Shanghai, China.
⁵ Department of Nuclear Medicine, Zhongshan Hospital, Fudan University, Shanghai, China.

Abstract

Background: Angiography-derived index of microcirculatory resistance (angio-IMR) is an emerging pressure-wire-free index to assess coronary microvascular function, but its diagnostic and prognostic value remains to be elucidated. Methods and Results: The study population consisted of three independent cohorts. The internal diagnostic cohort enrolled 53 patients with available hyperemic microcirculatory resistance (HMR) calculated from myocardial blood flow and pressure. The external diagnostic cohort included 35 ischemia and no obstructive coronary artery disease (INOCA) patients and 45 controls. The prognostic cohort included 138 coronary artery disease (CAD) patients who received PCI. Angio-IMR was calculated after the estimation of angiography-derived fractional flow reserve (angio-FFR) using the equation of angio-IMR = estimated hyperemic Pa × angio-FFR × [vessel length/(K × V_diastole)]. The primary outcome was a composite of cardiac death or readmission due to heart failure at 28 months after index procedure. Angio-IMR demonstrated a moderate correlation with HMR (R = 0.74, p < 0.001) and its diagnostic accuracy, sensitivity, specificity, and area under the curve to diagnose INOCA were 79.8, 83.1, 78.0, and 0.84, respectively, with a best cut-off of 25.1. Among prognostic cohort, patients with angio-IMR ≥25.1 showed a significantly higher risk of cardiac death or readmission due to heart failure than those with an angio-IMR <25.1 (18.6 vs. 5.4%, adjusted HR 9.66, 95% CI 2.04-45.65, p = 0.004). Angio-IMR ≥25.1 was an independent predictor for cardiac death or readmission due to heart failure (HR 11.15, 95% CI 1.76-70.42, p = 0.010). Conclusions: Angio-IMR showed a moderate correlation with HMR and high accuracy to predict microcirculatory dysfunction. Angio-IMR measured after PCI predicts the risk of cardiac death or readmission due to heart failure in patients with CAD. Clinical Trial Registration: Diagnostic and Prognostic Value of Angiography-derived IMR (CHART-MiCro), NCT04825028.

Keywords: INOCA; coronary microcirculation; functional angiography; index of microcirculatory resistance; prognosis.

Associated data

ClinicalTrials.gov/NCT04825028