Patient Population

The present study was a patient‐level pooled analysis of 3 prospective registries whose results have been previously published.9, 10, 11, 12, 13 The first study prospectively enrolled consecutive patients from 5 university hospitals in Korea (519 patients, 737 vessels), each undergoing clinically indicated invasive coronary angiography, and FFR, coronary flow reserve (CFR), and index of microcirculatory resistance (IMR) measurement for at least 1 coronary artery.10 The second study was an institutional registry of Tsuchiura Kyodo General Hospital, Ibaraki, Japan that included 643 patients (643 vessels) submitting to invasive angiography and physiologic assessment, including FFR, CFR, and IMR.13 The third study prospectively enrolled patients with FFR, CFR, and IMR data on at least 1 intermediate‐grade stenosis from Hospital Clinico San Carlos, Madrid, Spain.11 In all these studies, patients with hemodynamic instability, left ventricular dysfunction, or a culprit vessel of acute coronary syndrome were excluded. Individual patient data for pooled analysis were collected using standardized spreadsheets. For all variables included, standardized definitions were used. Invasive physiologic indices were also cross‐checked and confirmed by each study's principal investigators (T.K., J.E., B.K.).

Among the 1397 patients (1694 vessels) enrolled overall, those undergoing PCI were excluded. In the presence of multiple coronary stenoses, a single vessel with the most severely decreased FFR value was used for the present analysis. Of the remaining 914 patients with deferred revascularization, this study enrolled 879 deferred patients with lesions showing FFR values >0.75 (Figure 1). Only 1 patient of all the study cohort was lost to follow‐up. Study protocols were designed in accordance with the Declaration of Helsinki and were authorized by institutional review boards or ethics committees at corresponding centers. All patients granted written informed consent. The study protocol of the International Collaboration of Comprehensive Physiologic Assessment was registered at http://clinicaltrials.gov ({"type":"clinical-trial","attrs":{"text":"NCT03690713","term_id":"NCT03690713"}}NCT03690713).

The Consolidated Standards of Reporting Trials flow diagram. FFR indicates fractional flow reserve, PCI, percutaneous coronary intervention.