Abstract 17658: The Impact of Elective Percutaneous Coronary Intervention on Coronary Microvascular Resistance

Abstract

Background: The influence of elective percutaneous coronary intervention (PCI) in patients with stable angina pectoris on coronary microvascular function has not been fully elucidated. We performed a prospective study to investigate serial changes of microvascular function in patients undergoing elective PCI. Methods and Results: The index of microcirculatory resistance (IMR) and fractional flow reserve (FFR) was measured before, after PCI, and at follow-up (10 months) in 52 patients treated with single vessel uncomplicated elective PCI (male 80.8%, age 66.5 ± 8.3). IMR was calculated by taking collateral flow into account. The median IMR values before, after PCI, and at follow-up were 24.2 (interquartile range (IQR) 13.1-31.3), 15.8 (IQR 11.8-21.6), and 14.7 (IQR 11.3-20.9), respectively. IMR values significantly decreased after PCI (P=0.006), and showed no further significant change at follow-up. There was no significant relationship between delta IMR (post-pre IMR) values and PCI-related cardiac troponin elevations that distributed in the range of (median: 0.50 ng/dL, IQR 0.22-1.02 ng/dL). Pre-PCI IMR was not correlated with pre-PCI FFR values. Post-PCI IMR was significantly correlated with pre-PCI IMR values (P=0.005). Periprocedural IMR decrease (Pre-Post) was inversely associated with pre-PCI FFR (P=0.008) and greater improvement of FFR values by PCI was significantly associated with greater reduction of IMR values at follow-up (P=0.03). Decrease in FFR values from immediately after PCI to follow-up was greater in patients with DM (P=0.01). Furthermore, IMR at follow-up was worse in patients with DM than those without (P=0.009). Conclusions: Removal of physiologically significant epicardial stenosis leads to a decrease in microvascular resistance in patients with stable angina undergoing electively performed uncomplicated PCI. The periprocedural decrease in microvascular resistance was influenced by the hemodynamic significance of the epicardial stenosis before PCI. The baseline status of microvascular function is a significant determinant of post-PCI and follow-up microvascular function in these patients, and diabetes has an impact on the serial changes in microvascular function after successful PCI.