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Risk Score for Predicting Contrast-Associated Kidney Injury
Quick Takes
- Risk score using eight clinical variables (age, clinical presentation, eGFR, congestive heart failure, diabetes, hemoglobin, basal glucose, and LVEF) predicts risk of contrast-associated kidney injury among patients undergoing PCI.
- Patients with contrast-associated kidney injury have a higher 30-day and 1 year mortality.
- Whether specific treatment strategies can reduce risk of contrast-induced kidney injury and improve clinical outcomes among patients considered high risk using this scoring system warrants further study.
Study Questions:
Can a simple risk score estimate contrast-associated acute kidney injury (AKI) after percutaneous coronary intervention (PCI)?
Methods:
Consecutive patients undergoing PCI at a large tertiary care center between January 1, 2012, and December 31, 2020, with available creatinine measurements both before and within 48 hours after the procedure, were included; only patients on chronic dialysis were excluded. Patients treated between 2012 and 2017 comprised the derivation cohort and those treated between 2018 and 2020 formed the validation cohort. The primary endpoint was contrast-associated AKI, defined according to the Acute Kidney Injury Network. Independent predictors of contrast-associated AKI were derived from multivariate logistic regression analysis. Model 1 included only preprocedural variables, whereas Model 2 also included procedural variables. A weighted integer score based on the effect estimate of each independent variable was used to calculate the final risk score for each patient. The impact of contrast-associated AKI on 1-year deaths was also evaluated.
Results:
The derivation cohort consisted of 14,616 patients (mean age 66.2 years, 29.2% female) and 5,606 were included in the validation cohort (mean age 67 years, 26.4% women). Contrast-associated kidney injury occurred in 4.3% of patients. Independent predictors of contrast-associated AKI included in Model 1 were: clinical presentation, estimated glomerular filtration rate (eGFR), left ventricular ejection fraction (LVEF), diabetes, hemoglobin, basal glucose, congestive heart failure (CHF), and age. Additional independent predictors in Model 2 were: contrast volume, periprocedural bleeding, no flow or slow flow post-procedure, and complex PCI anatomy. The occurrence of contrast-associated AKI in the derivation cohort increased gradually from the lowest to the highest of the four risk score groups in both models (2.3% to 34.9% in Model 1 and 2.0% to 38.8% in Model 2). Inclusion of procedural variables in the model only slightly improved the discrimination of the risk score (C-statistic in the derivation cohort, 0.72 for Model 1 and 0.74 for model 2; in the validation cohort, 0.84 for Model 1 and 0.86 for Model 2). The risk of 1-year death significantly increased in patients with contrast-associated AKI (10.2% vs. 2.5%; adjusted hazard ratio, 1.76; 95% confidence interval, 1.31-2.36; p = 0.0002), which was mainly due to excess 30-day deaths.
Conclusions:
A contemporary simple risk score based on readily available variables from patients undergoing PCI can accurately discriminate the risk of contrast-associated AKI, the occurrence of which is strongly associated with subsequent death.
Perspective:
Prior scores to predict contrast-associated kidney injury have been limited by low discriminating power. For the current study, the authors used registry data from a single center to derive and validate a score using eight clinical variables (age, clinical presentation, eGFR, CHF, diabetes, hemoglobin, basal glucose, and LVEF) and four procedural variables (contrast volume, procedural bleed, slow coronary flow at completion, and complex anatomy). Overall discrimination power was good without significant change when procedural variables were added. Contrast-associated kidney injury predicted increased mortality at 30 days, which persisted at 1 year; however, significant confounding by higher-risk patients could be responsible for this particular finding. Whether specific treatment strategies can reduce risk of contrast-induced kidney injury and improve clinical outcomes among patients considered high risk using this scoring system warrants further study.
Clinical Topics: Diabetes and Cardiometabolic Disease, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Prevention, Acute Heart Failure
Keywords: AHA21, AHA Annual Scientific Sessions, Acute Kidney Injury, Contrast Media, Creatinine, Diabetes Mellitus, Glomerular Filtration Rate, Glucose, Heart Failure, Hemoglobins, Kidney Diseases, Metabolic Syndrome, Percutaneous Coronary Intervention, Primary Prevention, Risk Factors, Stroke Volume
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