Related Experiment Video
Updated: Mar 19, 2026
Interventional Diagnostic Procedure: A Practical Guide for the Assessment of Coronary Vascular Function
Published on: March 15, 2022
The influence of elective percutaneous coronary intervention on microvascular resistance: a serial assessment using
Tadashi Murai1, Tetsumin Lee2, Yoshihisa Kanaji2
1Cardiovascular Medicine, Tsuchiura Kyodo General Hospital, Tsuchiura, Ibaraki, Japan; and Department of Cardiovascular Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
Insights
Percutaneous coronary intervention (PCI) significantly reduces hyperemic microvascular resistance (MR) in patients with stable angina. Pre-procedure MR levels predict the extent of this improvement, which is sustained at follow-up.
Area of Science:
- Cardiology
- Interventional Cardiology
- Vascular Physiology
Background:
- Stable angina pectoris is often treated with percutaneous coronary intervention (PCI).
- Microvascular resistance (MR) plays a crucial role in coronary blood flow regulation.
- The impact of elective PCI on hyperemic MR, assessed by the index of microcirculatory resistance (IMR), requires further investigation.
Purpose of the Study:
- To investigate the influence of elective PCI on hyperemic MR using the IMR.
- To assess the changes in IMR before, immediately after, and at 10-month follow-up.
- To determine the correlation between pre-PCI IMR and post-PCI changes in IMR.
Main Methods:
- Prospective study of 71 patients with stable angina undergoing elective PCI.
- Measurement of IMR before PCI, after PCI, and at a 10-month follow-up.
- Correlation analysis between pre-PCI IMR and changes in IMR, and comparison of IMR values in territories with IMR decrease versus increase.
Main Results:
- IMR significantly decreased from pre-PCI (median 19.8) to post-PCI (16.2) and follow-up (14.8) (P < 0.001).
- Pre-PCI IMR strongly correlated with IMR changes post-PCI (r=0.84) and at follow-up (r=0.93).
- Lower pre-PCI IMR predicted a greater decrease in IMR, associated with improved coronary flow.
Conclusions:
- Elective PCI effectively reduces hyperemic MR, with sustained improvement at follow-up.
- Pre-PCI IMR is a significant predictor of the magnitude of MR reduction after PCI.
- The observed changes in hyperemic MR following PCI may influence post-procedural coronary flow dynamics.
Abstract:
This study investigates whether hyperemic microvascular resistance (MR) is influenced by elective percutaneous coronary intervention (PCI) by using the index of microcirculatory resistance (IMR). Seventy-one consecutive patients with stable angina pectoris undergoing elective PCI were prospectively studied. The IMR was measured before and after PCI and at the 10-mo follow-up. The IMR significantly decreased until follow-up; the pre-PCI, post-PCI, and follow-up IMRs had a median of 19.8 (interquartile range, 14.6-28.9), 16.2 (11.8-22.1), and 14.8 (11.8-18.7), respectively (P < 0.001). The pre-PCI IMR was significantly correlated with the change in IMR between pre- and post-PCI (r = 0.84, P < 0.001) and between pre-PCI and follow-up (r = 0.93, P < 0.001). Pre-PCI IMR values were significantly higher in territories with decreases in IMR than in those with increases in IMR [pre-PCI IMR: 25.4 (18.4-35.5) vs. 12.5 (9.4-16.8), P < 0.001]. At follow-up, IMR values in territories showing decreases in IMR were significantly lower than those with increases in IMR [IMR at follow-up: 13.9 (10.9-17.6) vs. 16.6 (14.0-21.4), P = 0.013]. The IMR decrease was significantly associated with a greater shortening of mean transit time, indicating increases in coronary flow (P < 0.001). The optimal cut-off values of pre-PCI IMR to predict a decrease in IMR after PCI and at follow-up were 16.8 and 17.0, respectively. In conclusion, elective PCI affected hyperemic MR and its change was associated with pre-PCI MR, resulting in showing a wide distribution. Overall hyperemic MR significantly decreased until follow-up. The modified hyperemic MR introduced by PCI may affect post-PCI coronary flow.
