Related Experiment Video
Updated: Mar 24, 2026
Evaluation of Coronary Flow Reserve After Myocardial Ischemia Reperfusion in Rats
Published on: June 28, 2019
Coronary Flow Reserve and Microcirculatory Resistance in Patients With Intermediate Coronary Stenosis
Joo Myung Lee1, Ji-Hyun Jung1, Doyeon Hwang1
1Department of Internal Medicine and Cardiovascular Center, Seoul National University Hospital, Seoul, South Korea.
Insights
Microvascular dysfunction, assessed by coronary flow reserve (CFR) and index of microcirculatory resistance (IMR), impacts prognosis in patients with high fractional flow reserve (FFR). Low CFR with high IMR indicates poor outcomes.
Area of Science:
- Cardiovascular Medicine
- Interventional Cardiology
- Physiology
Background:
- Prognostic significance of microvascular status in high fractional flow reserve (FFR) patients remains unclear.
- FFR alone may not fully capture the risk associated with coronary microvascular dysfunction.
Purpose of the Study:
- Investigate the prognostic implications of coronary flow reserve (CFR) and index of microcirculatory resistance (IMR) in patients undergoing FFR measurement.
- Assess the added value of microvascular parameters in risk stratification.
Main Methods:
- Patients with high FFR (>0.80) were categorized into four groups based on CFR (≤2) and IMR (≥23 U) levels.
- Patient-oriented composite outcome (POCO) including death, myocardial infarction, and revascularization was assessed.
- Median follow-up was 658 days.
Main Results:
- Modest correlation and agreement were observed between FFR and CFR.
- Low CFR was associated with higher POCO.
- Patients with low CFR and high IMR exhibited the highest POCO (p=0.002).
- Overt microvascular disease, multivessel disease, and diabetes mellitus independently predicted POCO.
- Physiological indices significantly improved predictive model discrimination.
Conclusions:
- Coronary flow reserve (CFR) and index of microcirculatory resistance (IMR) enhance risk stratification in patients with high FFR.
- Low CFR combined with high IMR signifies a poor prognosis.
- Microvascular assessment is crucial for comprehensive risk evaluation in these patients.
Background:
The prognostic impact of microvascular status in patients with high fractional flow reserve (FFR) is not clear.
Objectives:
The goal of this study was to investigate the implications of coronary flow reserve (CFR) and the index of microcirculatory resistance (IMR) in patients who underwent FFR measurement.
Methods:
Patients with high FFR (>0.80) were grouped according to CFR (≤2) and IMR (≥23 U) levels: group A, high CFR with low IMR; group B, high CFR with high IMR; group C, low CFR with low IMR; and group D, low CFR with high IMR. Patient-oriented composite outcome (POCO) of any death, myocardial infarction, and revascularization was assessed. The median follow-up was 658 days (interquartile range: 503.8 to 1,139.3 days).
Results:
A total of 313 patients (663 vessels) were assessed with FFR, CFR, and IMR. Correlation (r = 0.201; p < 0.001) and categorical agreement (kappa value = 0.178; p < 0.001) between FFR and CFR were modest. Low CFR was associated with higher POCO than high CFR (p = 0.034). There were no significant differences in clinical and angiographic characteristics among groups. Patients with high IMR with low CFR had the highest POCO (p = 0.002). Overt microvascular disease (p = 0.008), multivessel disease (p = 0.033), and diabetes mellitus (p = 0.033) were independent predictors of POCO. Inclusion of a physiological index significantly improved the discriminant function of a predictive model (relative integrated discrimination improvement 0.467 [p = 0.037]; category-free net reclassification index 0.648 [p = 0.007]).
Conclusions:
CFR and IMR improved the risk stratification of patients with high FFR. Low CFR with high IMR was associated with poor prognosis. (Clinical, Physiological and Prognostic Implication of Microvascular Status; NCT02186093).
More Related Videos
05:07Author Spotlight: Improved Localization and Monitoring of Coronary Flow Reserve Using Modified PLAX View in Mice
Published on: August 25, 2023
06:39Ultrasound Based Assessment of Coronary Artery Flow and Coronary Flow Reserve Using the Pressure Overload Model in Mice
Published on: April 13, 2015
Related Concept Videos
01:22Mitral Stenosis I: Introduction
01:20Vascular Resistance
The primary determinants of vascular resistance are vessel diameter, blood viscosity, and vessel length. Among these, vessel diameter plays the most significant role due to the fourth power relationship described by...