Postprocedural Contrast-Associated Acute Kidney Injury and Prognosis of Patients Undergoing Recanalization of Chronic Total Occlusions

Percutaneous coronary intervention (PCI) for chronic total occlusions (CTOs) requires advanced techniques and prolonged procedural efforts, often necessitating high contrast volumes, which may increase the risk of contrast-associated acute kidney injury (CA-AKI). However, evidence suggests that factors beyond contrast exposure contribute to CA-AKI, though data specific to CTO PCI remain limited. Patients undergoing contemporary CTO PCI at our university-affiliated tertiary care center were enrolled. CA-AKI was defined according to KDIGO criteria, and patients were stratified based on the presence of postprocedural CA-AKI. Baseline and procedural characteristics, including osmotic factors, were compared between the groups. The primary outcome was all-cause mortality at one year, and the secondary outcome was all-cause mortality at three years. A total of 145 patients were enrolled, with a mean age of 67 years, and 75% were male. Baseline creatinine levels, electrolytes, and osmotic factors did not differ significantly between groups. Lesion parameters and J-CTO scores were also comparable. The contrast volume and procedural duration were numerically higher in patients who developed CA-AKI. Patients with CA-AKI received a higher radiation dose (22.1 vs. 13.2 Gy·cm , = 0.041). CA-AKI emerged as an independent predictor of all-cause mortality at one year (adjusted HR 5.3, CI [1.52-18.51], = 0.009) but not at three years. In this retrospective analysis, CA-AKI was an independent predictor of all-cause mortality at one year following CTO PCI but lost predictive value at three years. Baseline renal function and contrast volume alone did not predict CA-AKI. Instead, procedural complexity, reflected by higher radiation exposure, was associated with an elevated risk of CA-AKI.