Risk factors and safe contrast volume thresholds for postcontrast acute kidney injury after peripheral vascular interventions.

Objective: Postcontrast acute kidney injury (PC-AKI) is a dreaded complication of peripheral vascular interventions (PVIs) that depends on the volume of contrast administered as well as a patient's baseline kidney function. However, there is currently no guidance on the volume of contrast that is considered safe especially for patients with advanced chronic kidney disease (CKD). This study aims to characterize the incidence, risk factors for, and outcomes after PC-AKI and define thresholds of safety for contrast volume.

Methods: The Vascular Quality Initiative files for PVI (2010-2018) were reviewed. Patients on dialysis, with renal transplants, or who developed a bleeding complication were excluded. Only records with complete data on baseline creatinine, contrast volume, and PC-AKI (creatinine increase of ≥0.5 mg/dL, or new dialysis requirement) were included. The cumulative incidence of PC-AKI with contrast volume at each stage of CKD was derived. A safe threshold for contrast volume was defined as the volume at which the cumulative incidence of PC-AKI is 0.5% or less. Multivariable logistic regression was used to define risk factors for PC-AKI, and survival analysis was performed using Kaplan-Meier and multivariable Cox proportional hazards regression.

Results: A total of 53,780 procedures were included. There were 16,062 patients (29%) with normal kidney function or CKD1, 21,769 (39%) with CKD2, 14,234 (25%) with CKD3, 1471 (3%) with CKD4, and 199 (<1%) with CKD5. The incidence of PC-AKI was 0.9% and increased with each stage of CKD (CKD1, 0.39%; CKD2, 0.45%; CKD3, 1.5%; CKD4, 4.3%; and CKD5, 7.5%). The safe thresholds for contrast volume for advanced CKD were 50, 20, and 9 mL for CKD3, CKD4, and CKD5, respectively. Regression analysis demonstrated that white race (odds ratio [OR], 0.67; 95% confidence interval [CI], 0.54-0.82) and elective surgery (OR, 0.77; 95% CI, 0.62-0.95) were associated with decreased risk of PC-AKI, whereas inpatient status (OR, 14.5; 95% CI, 9.97-21.2), diabetes (OR, 1.27; 95% CI, 1.02-1.58), advanced CKD (CKD3: OR, 3.65; 95% CI, 2.68-4.98; CKD4: OR, 6.98; 95% CI, 4.72-10.3; CKD5: OR, 8.94; 95% CI, 4.53-17.6), critical limb ischemia (OR, 1.51; 95% CI, 1.14-2.00), acute limb ischemia (OR, 2.47; 95% CI, 1.70-3.59), and contrast-to-eGFR ratio (CGR) (2 ≤ CGR < 3: OR, 1.33; 95% CI, 1.02-1.74; 3 ≤ CGR < 4: OR, 1.90; 95% CI, 1.32-2.75; CGR ≥ 4: OR, 1.79; 95% CI, 1.18-2.70) were significantly associated with increased risk for PC-AKI. Patients who developed PC-AKI had worse in-hospital (16.1% vs 0.45%; P < .01) mortality and long-term survival (log-rank P < .01) compared with those without PC-AKI.

Conclusions: PVI are associated with low risk of PC-AKI that significantly increases when patients with advanced CKD undergo high acuity cases. Given the strong association with short-term and long-term mortality, risk of PC-AKI should be minimized by using safe thresholds of contrast volume.