Long-term Outcomes of Renal Function Following CTO PCI: Insights on Contrast Exposure

The impact of contrast volume on long-term renal outcomes after chronic total occlusion (CTO) percutaneous coronary intervention (PCI) remains uncertain, and the causal role of contrast exposure is increasingly questioned, particularly beyond the acute phase. The aim of this study was to evaluate the association between procedural contrast volume and long-term deterioration in renal function among patients undergoing CTO PCI. This retrospective cohort study included consecutive patients undergoing CTO-PCI between 2019 to 2025 and had both baseline and ≥90-day follow-up creatinine measurements available. The main endpoint was persistent kidney dysfunction (≥25% decline in estimated glomerular filtration rate (eGFR)). Other relevant endpoints included Kidney Disease: Improving Global Outcomes (KDIGO) stage progression (≥1 stage), and rapid progression (≥2 stages). Contrast volume was analyzed as a continuous variable and by quartiles. Multivariable regression models and sensitivity analysis (using a ≥40%eGFR decline threshold and baseline chronic kidney disease) were performed. A total of 275 patients were included with a median follow-up of 3.3 years. Renal function significantly declined (median ΔeGFR: -17.0 ml/min/1.73 m²; p < 0.001). Persistent kidney dysfunction occurred in 52.4% of patients, KDIGO stage progression in 60.7% and rapid progression in 12.0%. Contrast volume (median 215 mL) was not independently associated with persistent kidney dysfunction (p = 0.267) and no dose-response relationship was observed across quartiles. Findings were consistent across models for ΔeGFR, KDIGO-based, subgroups and sensitivity analyses. Patient-related factors including age, male sex, hypertension, and diabetes emerged as independent predictors of renal decline. Notably, baseline renal function showed an inverse association with progression (p <0.001), suggesting a "ceiling effect" in advanced stages. In patients undergoing CTO-PCI, contrast volume is not independently associated with long-term renal deterioration. Persistent kidney dysfunction appears primarily driven by patient-related factors rather than procedural contrast exposure.