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Risk index helped predict new-onset renal failure after heart transplant
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TORONTO — A risk index that incorporates 13 risk factors may help predict the development of new-onset postoperative renal failure after orthotopic heart transplantation.
Although risk factors for postoperative renal failure after heart transplantation have been identified, there exists no clinical guide to estimate the overall risk for renal failure that would necessitate dialysis subsequent to heart transplantation, Arman Kilic, MD, from the division of cardiac surgery at Johns Hopkins Medical Institutions, said at the American Association for Thoracic Surgery Annual Meeting.
“The incidence of acute kidney injury after orthotopic heart transplantation ranges from 40% to 70%,” Kilic said.
Moreover, previous research has identified a link between acute renal failure and postoperative mortality, according to Kilic.
For this study, researchers used the United Network for Organ Sharing (UNOS) database to identify adult orthotopic heart transplantations performed between 2000 and 2010. They developed and validated a 100-point risk index that was generated using 13 significant risk factors associated with renal failure, including diabetes, older age and creatinine clearance <60 mL/min.
The study included 14,635 orthotopic heart transplantation recipients. Of those, 1,128 (7.7%) developed new-onset postoperative renal failure.
When Kilic and colleagues looked at actual rates of renal failure in the validation cohort and used the risk score to predict rates in the derivation cohort, they found a high degree of correlation (P<.001).
The researchers developed risk categories for renal failure based on probabilities determined in the derivation cohort:
- Low (<5% risk; score of 0-15);
- Average (5% to 10% risk; score of 16-26);
- Above average (10% to 20% risk; score of 27-39);
- High (>20% risk; score of 40 or higher).
According to the results, actual rates of renal failure in the validation cohort for the risk score ranges correlated with their assigned risk category: score 0 to 15, 4.1% rate; score 16 to 26, 6.8% rate; score 27 to 39, 13.2% rate; score 40 or higher, 20.2% rate.
“With each statistical analysis performed, we found that it was a very highly predictive risk score for renal failure,” Kilic said. “The idea is that this risk score for renal failure would help tailor perioperative management.”
As an example, the risk index could influence decisions such as the type of immunosuppressive medications that are administered, according to Kilic.
Hemodynamic variables did not affect rates of renal failure in univariate logistic regression analysis nor enhance the power of the multivariable model, he said.
A limitation of this study is that the UNOS database did not reliably capture some measures, such as hypotension, which would influence the risk for renal failure, the researchers noted. – by Louise Gagnon
For more information:
Kilic A. Abstract #33. Presented at: American Association for Thoracic Surgery Annual Meeting; April 26-30, 2014; Toronto.
Disclosure: Kilic reports no relevant financial disclosures.