Simple Score Predicts Risk of Contrast-Associated AKI After PCI

NEW YORK (Reuters Health) – A risk score based on readily available variables from patients undergoing percutaneous coronary intervention (PCI) accurately predicted the risk of contrast-associated acute kidney injury (CA-AKI) in a modeling study.

“CA-AKI is an important complication and is associated with long-term mortality, mostly driven by mortality in the first 30 days after PCI,” Dr. Roxana Mehran of the Icahn School of Medicine at Mount Sinai in New York City told Reuters Health by email.

“We developed a very user friendly and highly embraced, well validated risk score (Mehran CIN risk score) back in 2004,” she said. “We knew for sure that a risk score that is almost 20 years old would need a re-calibration but took the opportunity to see if there are new risk factors that can be assessed before, as well as during, the procedure.”

“I was thrilled to see that the rates of AKI after contrast media injection/PCI have decreased despite higher-risk patients with increasing PCI complexity,” she said. “We observed different rates depending on which definition was used for AKI, and endorse the standardization of definitions to identify those at risk who would also be at higher risk for late mortality.”

“We also identified new parameters, like hyperglycemia, as an important predictor in the risk score,” she added.

For the update, published in The Lancet, 14,616 patients who underwent PCI between 2012-2017 were included in the derivation cohort (mean age, 66.2; 29.2% women) and 5,606 treated from 2018-2020 were included in the validation cohort (mean age. 67; 26.4% women).

The primary endpoint — CA-AKI, defined according to the Acute Kidney Injury Network — occurred in 860 (4.3%) patients overall.

Model 1 included only pre-procedural variables: clinical presentation, estimated glomerular filtration rate, left ventricular ejection fraction, diabetes, hemoglobin, basal glucose, congestive heart failure, and age.

Model 2 also included procedural variables: contrast volume, peri-procedural bleeding, no flow or slow flow post-procedure, and complex PCI anatomy.

CA-AKI occurrence in the derivation cohort increased gradually from the lowest to the highest of the four risk score groups in both models (2.3%-34.9% in model 1; 2.0%-38.8% in model 2).

Inclusion of procedural variables only slightly improved 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 death at one-year follow-up increased significantly in patients with CA-AKI (10.2% vs. 2.5%; adjusted hazard ratio 1.76), mainly due, as Dr. Mehran indicated, to excess 30-day deaths.

The authors state, “Our study confirms the increased risk of (CA-AKI) in high-risk subgroups of patients, such as older people and those with congestive heart failure or impaired renal function, underlining the need for tailored preventive strategies in these patients, as well as allowing (CA-AKI) prevention measures to be abbreviated in patients at low risk.”

Dr. Mehran said, “We feel that the score should await external validation, despite an excellent C-statistic for the internal validation process. We are working with our colleagues to externally validate this score, and applaud those who are already working on this.”

Drs. Estelle Nijssen and Joachim Wildberger of Maastricht University Medial Centre in the Netherlands, coauthors of a related editorial, commented in an email to Reuters Health, “What is intriguing is that the risk score appears to highlight the importance of the heart for risk assessment in the setting of contrast procedures, where the focus previously lay on the kidneys and contrast material. This is a major paradigm shift.”

“However, it may be important for clinicians to realize that there are no firm data to either confirm or reject a causal link between contrast administration and kidney injury or adverse events,” they said. “Nor is there firm evidence that prophylactic strategies improve outcomes in the long term.”

“On a practical level, implementation in daily clinical practice could be complicated because it might not always be clear what to do with a patient who has a high score,” they noted. “Extra vigilance can of course always be applied, but prophylactic strategies (mainly intravenous hydration before and/or after contrast administration) carry risk, which is especially relevant for high-score cardiac patients.”

SOURCE: https://bit.ly/3I6RQQO and https://bit.ly/3cOUpII The Lancet, online November 15, 2021.

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