Assessment of the coronary microcirculation in the cardiac catheterisation laboratory

Cuneyt Ada,Andy Yong

doi:10.20517/2574-1209.2021.51

Abstract

The coronary microcirculation is a key determinant of blood supply to the myocardium and outweighs the epicardial arteries in its abundance and distribution. Recent studies have shown the clinical benefit of assessing the microcirculation, and this practice has now been given a recommendation within the latest international guidelines and consensus statements. However, the uptake of assessing the microcirculation remains low. We continue to focus our efforts in diagnosing and managing epicardial coronary disease in the cardiac catheterisation laboratory and mostly ignore the microvasculature. This is in large part due to the lack of familiarity with available tools to perform these assessments. This review aims to summarise the various techniques available to invasively assess the coronary microcirculation in the catheterisation laboratory. The advantages, disadvantages, pitfalls and clinical implications of each method are discussed.

Highlights

Assessment of coronary microcirculatory function in the cardiac catheterisation laboratory is valuable for both treatment of angina[1] and prognostication[2,3,4] and has recently been incorporated into European Society of Cardiology guidelines[5] as well as a consensus document by the European Association of Percutaneous Coronary Intervention[6]
In addition to serving as capacitance vessels holding 90% of the myocardial blood volume, the microcirculation is the major source of regulation of myocardial blood flow, a role which becomes vital in the presence of a stenosis where coronary autoregulation is required to maintain flow[9]
We found the true thermodilution-derived coronary flow reserve (CFR) to fall between the Pressure-bounded CFR (PB-CFR) estimated limits less than 50% of the time

Summary

Introduction

Assessment of coronary microcirculatory function in the cardiac catheterisation laboratory is valuable for both treatment of angina[1] and prognostication[2,3,4] and has recently been incorporated into European Society of Cardiology guidelines[5] as well as a consensus document by the European Association of Percutaneous Coronary Intervention[6]. Indications for assessment of coronary microvascular function include, but are not limited to, ischemia and no obstructive coronary artery disease (INOCA)[1], myocardial infarction with non-obstructive coronary arteries[7], ST-elevation myocardial infarction (STEMI)[3] and those with stable coronary artery disease[5]. The coronary microcirculation is broadly defined as vessels smaller than 300 microns, or more generally through pre-arterioles, arterioles, capillaries and venules[8]. In addition to serving as capacitance vessels holding 90% of the myocardial blood volume, the microcirculation is the major source of regulation of myocardial blood flow, a role which becomes vital in the presence of a stenosis where coronary autoregulation is required to maintain flow[9]. In the absence of a stenosis, the microvasculature acts in the same way to regulate flow in response to varying physiological demands such as exercise[10]

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Conclusion