Index of microcirculatory resistance: state-of-the-art and potential applications in computational simulation of coronary artery disease / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

The dysfunction of coronary microcirculation is an important cause of coronary artery disease (CAD). The index of microcirculatory resistance (IMR) is a quantitative evaluation of coronary microcirculatory function, which provides a significant reference for the prediction, diagnosis, treatment, and prognosis of CAD. IMR also plays a key role in investigating the interaction between epicardial and microcirculatory dysfunctions, and is closely associated with coronary hemodynamic parameters such as flow rate, distal coronary pressure, and aortic pressure, which have been widely applied in computational studies of CAD. However, there is currently a lack of consensus across studies on the normal and pathological ranges of IMR. The relationships between IMR and coronary hemodynamic parameters have not been accurately quantified, which limits the application of IMR in computational CAD studies. In this paper, we discuss the research gaps between IMR and its potential applications in the computational simulation of CAD. Computational simulation based on the combination of IMR and other hemodynamic parameters is a promising technology to improve the diagnosis and guide clinical trials of CAD.

Research Progress of Coronary Physiological Evaluation Development in 2021 / 医用生物力学

Cardiovascular disease is one of the most serious diseases endangering human life and health. In China, 2 out of every 5 people die of cardiovascular diseases. Myocardial ischemia is one of the important cardiovascular diseases. Fractional flow reserve (FFR) is used to quantify myocardial ischemia in epicardial stenoses. Index of microvascular resistance (IMR) is an invasive index for quantitative evaluation of coronary microcirculation. Traditional FFR and IMR measurements rely on guide wires to perform interventional measurements under the maximum hyperemia state,so as to assist the diagnosis of myocardial ischemia clinically. Coronary angiography-derived FFR and IMR without using invasive pressure-wire measurement, hyperemic stimulus and contraindications can assist the diagnosis and treatment of percutaneous coronary intervention by fast simultaneous calculation of FFR and IMR. In this review, the research progress of coronary angiography-derived FFR and IMR as well as other coronary physiological evaluation in recent years were summarized. It is of great clinical value to further study the combination of coronary angiography-derived FFR and IMR in functional research of coronary circulation from macro to micro.