Periprocedural assessment of coronary microcirculatory function to predict clinical outcomes after elective PCI

Abstract Background Percutaneous coronary intervention (PCI) could restore epicardial blood flow through the stent-based angioplasty. However, coronary microcirculatory function also impacts clinical outcomes and can be quantified by the angiography-derived index of microcirculatory resistance (angio-IMR). The prognostic significance of periprocedural angio-IMR in patients undergoing elective PCI remains unclear. Aims This study aimed to assess angio-IMR before and after PCI, as well as their association with long-term prognosis. Methods Data from 1,768 patients with stable coronary artery disease (CAD) undergoing elective PCI were analyzed. The primary endpoint was major adverse cardiac events (MACE) comprising death and unfatal myocardial infarction. Results The median angio-IMR was 11.3 (interquartile range IQR, 7.7 - 15.0) and 17.0 (IQR, 14.1 - 20.4) before and after PCI, respectively. During a median follow-up period of 20 months, MACE occurred in 53 patients (3.0%). Periprocedural angio-IMR changes (Δangio-IMR) exhibited superior predictive power for MACE compared with post-PCI angio-IMR alone. Specifically, Δangio-IMR 10 was independently associated with an increased risk of MACE (adjusted hazard ratio, 2.32; 95% confidence interval, 1.28 - 4.21; p = 0.006). In comparison with traditional factors, Δangio-IMR 10 could provide additional prognostic value in predicting MACE (C-index, 0.681 vs. 0.635, p 0.05; net reclassification index, 0.302, p = 0.030; integrated discrimination improvement: 0.010; p = 0.007). Conclusions Δangio-IMR was a strong predictor of MACE in patients with stable CAD undergoing elective PCI. Incorporating Δangio-IMR could enhance the identification of patients at high risk of MACE.FLow chart of the study Results