Post-Procedural Angiography-Based Physiological Indices and Clinical Outcomes After Drug-Coated Balloon Treatment of In-Stent Restenosis

Drug-coated balloons (DCBs) represent an accepted approach for in-stent restenosis (ISR); however, post-procedural predictors for risk stratification remain limited. Angiography-based physiological parameters, including quantitative flow ratio (QFR), microvascular QFR (μQFR), and coronary angiography–derived fractional flow reserve (caFFR), enable noninvasive functional assessment, but their clinical implications after DCB intervention for ISR are not well established. A comprehensive literature search of PubMed, Embase, and the Cochrane Library from inception to May 2026 was conducted to identify studies evaluating post-procedural angiography-based physiological parameters in ISR patients treated with DCB. Pooled relative risks (RRs) with 95% confidence intervals (CIs) were calculated using random-effects models, and heterogeneity was assessed using the I 2 statistic. Five studies comprising 1702 patients were included. Mean age ranged from 59 to 75 years, with 75–78% males. Patients with lower post-procedural physiological index values had a significantly higher risk of vessel-oriented composite outcomes (a composite of cardiac death, target vessel myocardial infarction, and target vessel revascularization) compared with those with higher values (28.0% vs 10.3%; RR 4.65, 95% CI 1.67–12.91; P = 0.014; 5 studies). Similarly, target vessel revascularization was more frequent in the lower-value group (28.8% vs 7.5%; RR 4.88, 95% CI 1.26–18.91; P = 0.034; 4 studies). No significant associations were observed for myocardial infarction, target lesion revascularization, or cardiovascular death. Post-procedural angiography-derived physiological indices provide important prognostic information after DCB treatment for ISR. Lower values are associated with an increased risk of adverse clinical outcomes, supporting their role in risk stratification.