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-month follow-up. The IMR significantly decreased until follow-up; the pre-PCI, post-PCI, and follow-up IMRs had a median of 19.8 (IQR 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 shorting 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.
- microvascular resistance
- coronary artery disease
- percutaneous coronary intervention
- index of microcirculatory resistance
- fractional flow reserve
- Copyright © 2015, American Journal of Physiology - Heart and Circulatory Physiology