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Invasive coronary microcirculation assessment--current status of index of microcirculatory resistance
Yuhei Kobayashi1, William F Fearon
1Division of Cardiovascular Medicine, Stanford University Medical Center.
Abstract:
Assessment of the coronary microvasculature in the clinical setting is a key issue, given that microvascular dysfunction itself has a predictive value for cardiovascular events. The index of microcirculatory resistance (IMR) is an invasive method of interrogating the microvasculature and provides further insight into the physiology of cardiovascular diseases. It is simple and readily applicable in the cardiac catheterization laboratory where many patients first present for evaluation of their coronary circulation. In contrast to other invasive and non-invasive tests, this method is known to be stable and reproducible under various hemodynamics and even in the presence of epicardial coronary artery stenosis. IMR has been shown to have prognostic value in patients with ST-segment elevation myocardial infarction; therefore it can be a surrogate marker of cardiovascular events. At the same time, it has the potential to be a therapeutic as well as an investigational tool in the physiology of cardiovascular diseases. This review summarizes the development of IMR, tips and tricks for its measurement, and its usefulness in various clinical settings.
Insights
The index of microcirculatory resistance (IMR) is a reliable invasive method to assess coronary microvascular function. Its stability and prognostic value in myocardial infarction make it a key tool for cardiovascular disease evaluation.
Area of Science:
- Cardiology
- Physiology
- Medical Technology
Background:
- Assessing coronary microvasculature is crucial as dysfunction predicts cardiovascular events.
- Microvascular dysfunction is an independent predictor of adverse cardiovascular outcomes.
- Current assessment methods lack stability and reproducibility in diverse clinical scenarios.
Purpose of the Study:
- To review the development and clinical utility of the index of microcirculatory resistance (IMR).
- To provide practical guidance on IMR measurement techniques.
- To highlight IMR's role in understanding cardiovascular disease physiology.
Main Methods:
- The review synthesizes existing literature on IMR.
- Focuses on IMR's application in cardiac catheterization laboratories.
- Discusses IMR's stability and reproducibility across different hemodynamic conditions.
Main Results:
- IMR is a stable and reproducible invasive measure of coronary microvascular function.
- IMR demonstrates prognostic value in ST-segment elevation myocardial infarction.
- IMR serves as a surrogate marker for cardiovascular events.
Conclusions:
- IMR is a valuable tool for interrogating the coronary microvasculature.
- It offers insights into cardiovascular disease physiology and prognosis.
- IMR has potential as a therapeutic and investigational instrument.
