乌鸦传媒

There's a wide range in acute kidney injury (AKI) incidence and contrast use among physicians performing percutaneous coronary intervention (PCI), according to a large retrospective study.

Additionally, physicians don't appear to adjust the amount of contrast used in patients who are at higher risk of AKI, Amit P. Amin, MD, MSc, of Washington University School of Medicine in St. Louis, and colleagues

Overall, AKI occurred in 7% of the more than 1.3 million patients who got PCI. The study showed that operators ranged from having zero to 30% of their patients abruptly lose kidney function after the procedure, with a mean adjusted 43% excess likelihood of acute kidney injury if a patient went randomly to one physician rather than another.

At the same time, the average contrast volume ranged widely, from 79 mL to 487 mL. Operators themselves thus accounted for in contrast volume used (after adjustment), Amin and colleagues found.

Moreover, there was "minimal" correlation between contrast use and patients' risk of acute kidney injury (r=-0.054), Amin and colleagues found.

"Unlike the expectation that patients with higher risk of acute kidney injury would be treated with less contrast, we found a minimal reduction of contrast volumes in patients with higher risk of acute kidney injury," they wrote.

The study, which analyzed data from the National Cardiovascular Data Registry CathPCI Registry "highlights an important opportunity for reducing contrast use and acute kidney injury," the researchers said, adding that physician variation in AKI "did not change by PCI complexity, implying that variation in acute kidney injury is attributable to physician practices rather than case complexity."

Asked to suggest why operators may fail to reduce contrast usage in higher-risk patients, Hitinder S. Gurm, MBBS, of VA Ann Arbor Health Care System in Mich., told 乌鸦传媒 that "the importance of acute kidney injury as a preventable complication, unfortunately, is not universally recognized and this probably results in less attention to contrast volume at many institutions."

Yet that should be the minority, not the majority, he said. Like many others, Gurm's center has "worked really hard to ensure that contrast thresholds are part of procedure time-out and to limit the dose of contrast especially in high-risk patients."

"This is an important study and highlights an important quality chasm," he added. "These data reflect the contemporary U.S. practice and identify an important opportunity for improvement in care. It is clear that the operator performing the procedure is a major driver of the variation in the amount of contrast that is used per case and this should be a quality improvement target going forward."

The study by Amin and colleagues relied on the the CathPCI Registry for information on patients who got PCI from 2009 to 2012 (n=1,349,612). The study group had an average age 64.9 years at the time of stenting; 67.3% were men.

The investigators' analysis was limited to operators performing more than 50 PCIs a year. Acute kidney injury was defined as an increase of 0.3 mg/dL or 50% from preprocedural to peak creatinine.

Not surprisingly, the study found that for every 75 mL of contrast used, the risk of acute kidney injury jumped by 42% (95% CI 1.40-1.43).

Limitations to the registry study include the lack of reasoning for why operators chose how much contrast they used, as well as the possibility of residual confounding despite adjustment.

Gurm emphasized that the data are at least five years old, too: "There is growing awareness of acute kidney injury in recent years and I am hopeful that papers like this will help drive reduction in acute kidney injury in the near future."

Comment