Calculation of the Index of Microcirculatory Resistance Without Coronary Wedge Pressure Measurement in the Presence of Epicardial Stenosis

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• 作者：Andy S. Yong ; MBBS ; PhD^? ; ^&dagger ; ; Jamie Layland ; MBChB^&Dagger ; ; ^§ ; ; William F. Fearon ; MD^? ; Michael Ho ; MD^? ; Maulik G. Shah ; MD^? ; David Daniels ; MD^? ; Robert Whitbourn ; MBBS ; BSc^§ ; ; Andrew MacIsaac ; MBBS ; MD^§ ; ; Leonard Kritharides ; MBBS ; PhD^&dagger ; ; Andrew Wilson ; MBBS ; PhD^&Dagger ; ; ^§ ; ; Martin K. Ng ; MBBS ; PhD^&dagger ; ; ^{mkcng@med.usyd.edu.au}
• 关键词：coronary intervention ; coronary microvascular function ; index of microcirculatory resistance ; microcirculation
• 刊名：JACC: Cardiovascular Interventions
• 出版年：2013
• 出版时间：January, 2013
• 年：2013
• 卷：6
• 期：1
• 页码：53-58
• 全文大小：766 K

文摘

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Objectives

This study sought to investigate a novel method to calculate the index of microcirculatory resistance (IMR) in the presence of significant epicardial stenosis without the need for balloon dilation to measure the coronary wedge pressure (P_w).

Background

The IMR provides a quantitative measure of coronary microvasculature status. However, in the presence of significant epicardial stenosis, IMR calculation requires incorporation of the coronary fractional flow reserve (FFR_cor), which requires balloon dilation within the coronary artery for P_w measurement.

Methods

A method to calculate IMR by estimating FFR_cor from myocardial FFR (FFR_myo), which does not require P_w measurement, was developed from a derivation cohort of 50 patients from a single institution. This method to calculate IMR was then validated in a cohort of 72 patients from 2 other different institutions. Physiology measurements were obtained with a pressure-temperature sensor wire before coronary intervention in both cohorts.

Results

From the derivation cohort, a strong linear relationship was found between FFR_cor and FFR_myo (FFR_cor = 1.34 ¡Á FFR_myo ? 0.32, r² = 0.87, p < 0.001) by regression analysis. With this equation to estimate FFR_cor in the validation cohort, there was no significant difference between IMR calculated from estimated FFR_cor and measured FFR_cor (21.2 ¡À 12.9 U vs. 20.4 ¡À 13.6 U, p = 0.161). There was good correlation (r = 0.93, p < 0.001) and agreement by Bland-Altman analysis between calculated and measured IMR.

Conclusions

The FFR_cor, and, by extension, microcirculatory resistance can be derived without the need for P_w. This method enables assessment of coronary microcirculatory status before or without balloon inflation, in the presence of epicardial stenosis.