Independent predictors of FIR.

<div><p>Background</p><p>Among patients with multivessel disease and ST-elevation myocardial infarction (MVD-STEMI), complete revascularization (CR) has been shown with improved outcomes. However, it is controversial whether diabetes mellitus (DM) status affects the outcomes. Quantitative flow ratio (QFR), as a newer non-invasive tool for identifying functional coronary stenosis and determining the presence of functional CR (FCR), may open up a new perspective for studying the above issues. The aim of this retrospective study was to investigate an association between QFR-based FCR and clinical outcomes in MVD-STEMI patients under DM status.</p><p>Methods</p><p>A total of 623 patients were included in the final analysis. The patients were divided into nonDM cohort and DM cohort. Within each cohort, patients were further stratified into functional CR (FCR) layer and functional incomplete revascularization (FIR) layer based on QFR assessment. The primary outcomes were 3-year major adverse cardiovascular events (MACEs), encompassing cardiac death, ischemia-driven revascularization (target vessel and non-target vessel), rehospitalization due to unstable angina pectoris, and non-fatal myocardial infarction.</p><p>Results</p><p>The incidence of MACEs was significantly lower in the FCR layer than in the FIR layer (12.6% vs 24.0%, log-rank <i>P<</i>0.001). In the nonDM cohort, the incidence of MACEs was also lower in the FCR layer than in the FIR layer (9.8% vs 18.5%, log-rank <i>P</i> = 0.032). Similar situations occurred in the DM cohort (16.1% vs 27.9%, log-rank <i>P</i> = 0.017). In addition, the multivariate Cox analysis showed that rSS<sub>QFR</sub> (QFR-derived residual SYNTAX score) was significantly associated with the increased risk of MACEs in the nonDM cohort (HR (95% CI) = 1.18 (1.10–1.26), <i>P</i><0.001) and DM cohort (HR (95% CI) = 1.13 (1.09–1.18), <i>P</i><0.001). ROC analysis showed adding rSS<sub>QFR</sub> into the model of clinical risk factors yielded a significant improvement in prediction of MACEs, especially in the DM cohort (AUC (95% CI) = 0.747 (0.675–0.819), <i>P</i> = 0.001) than in the nonDM cohort (AUC (95% CI) = 0.697 (0.602–0.791), <i>P</i> = 0.033). Furthermore, additional multivariate Cox analysis showed that rSS<sub>QFR</sub> was associated with the increased risk of MACEs in patients with moderate lesions (DS of 50%-89%) after procedure (HR (95% CI) = 1.16 (0.11–1.22), <i>P</i><0.001).</p><p>Conclusions</p><p>In patients with MVD-STEMI, the incidence of MACEs was lower in FCR than in FIR, and the decrease was particularly significant in the DM cohort. The association between QFR-derived rSS<sub>QFR</sub> and MACEs was independent of baseline characteristic differences, and rSS<sub>QFR</sub> provided higher prognostic predictive ability in DM cohort than in nonDM cohort. Additionally, QFR had the additional utility of identifying moderate residual lesions that require revascularization.</p></div>