Prognostic Value of Angiographic Microcirculatory Resistance After Coronary Intervention: Insights From the FAVOR III China Trial

Background: A novel computational angiographic microcirculatory resistance (AMR) derived from a single angiographic view presents a feasible alternative to the pressure wire‐based index of microcirculatory resistance. However, its prognostic significance in patients undergoing percutaneous coronary intervention (PCI) remains insufficiently established. Methods: This is a post hoc analysis of 3404 patients undergoing PCI from the FAVOR III China (Comparison of Quantitative Flow Ratio Guided and Angiography Guided Percutaneous Intervention in Patients With Coronary Artery Disease) trial. Pre‐ and post‐PCI AMR were measured in target vessels, with percentage change in AMR before and after PCI calculated as (100×post‐PCI AMR−pre‐PCI AMR/pre‐PCI AMR). The primary model used was the log‐rank test, and the proportional hazards model was also used to assess the association between AMR and the 3‐year risk of major adverse cardiac events, defined as a composite of all‐cause death, myocardial infarction, or ischemia‐driven revascularization. Results: Patients with percentage change in AMR before and after PCI ≥85 (23.7%) versus <85 (76.3%) had comparable baseline characteristics but received more and longer stents per patient. Overall major adverse cardiac events risk was similar between groups (14.8% versus 12.4%; hazard ratio HR, 1.18 0.95–1.45; log‐rank P =0.064). However, in patients with post‐PCI AMR ≥250, percentage change in AMR before and after PCI ≥85 showed a significant increase in the major adverse cardiac events risk (16.3% versus 10.8%; HR, 1.52 1.14–2.04), contrasting with no difference when post‐PCI AMR <250 (12.3% versus 13.4%; HR, 0.89 0.63–1.25; P interaction =0.019). Conclusions: In patients undergoing PCI from the FAVOR III China population, significant AMR elevation (percentage change in AMR before and after PCI ≥85) in target vessels alone did not predict outcomes, but in the subgroup with post‐PCI AMR ≥250 it identified patients at increased 3‐year cardiovascular risk. Registration: https://www.clinicaltrials.gov ; Unique identifier: NCT03656848.