Post-CABG Renal Injury Raises Mortality Risk


Major Finding: Post-CABG acute kidney injury was significantly linked with long-term mortality.

Data Source: Swedish study of 6,447 patients.

Disclosures: None reported.

SAN DIEGO — Acute kidney injury after coronary artery bypass grafting is significantly associated with long-term mortality, even after adjustment for potential confounders, results from a large Swedish study showed.

“At follow-up of CABG, whether it's by the cardiologist or the family practitioner, we should be aware of acute kidney injury,” Dr. Martin J. Holzmann said in an interview during a poster session at the annual meeting of the American Society of Nephrology.

The cause of the association is unclear, “but it means something in the long run for these patients. It may have to do with their coexisting medical conditions. I think we should treat them more aggressively when it comes to lipids and blood pressure,” said Dr. Holzmann of Karolinska University Hospital, Stockholm.

He and his associates evaluated the impact of acute kidney injury in 6,447 patients who underwent a first isolated CABG procedure between 2005 and 2008, had preoperative and postoperative serum creatinine levels drawn, and were alive 60 days after the procedure.

The patients' mean age was 65 years. The researchers used postoperative increases in serum creatinine levels measured 48 hours after surgery to categorize the patients according to the RIFLE criteria, which classifies renal disease as risk, injury, failure, loss, or end-stage renal disease. A total of 290 patients (4.5%) were in the risk category for acute renal failure, 103 (1.6%) were in the injury category, and 22 (0.3%) were in the failure category.

During a median follow-up of 7.3 years, 1,297 patients died (20%).

After adjustment for age, gender, preoperative estimated glomerular filtration rate, left ventricular function, diabetes mellitus, extr a corporeal circulation, body mass index, and unstable angina, the hazard ratio for mortality increased with each progressive RIFLE category: 1.34 (risk category), 1.63 (injury category), and 1.70 (failure category).

At hospital discharge, more patients who did not have acute kidney injury were treated with beta-blockers and statins (87% and 67%, respectively), compared with their counterparts who had acute kidney injury (79% and 61%, respectively).

However, ACE inhibitors were more frequently prescribed among those who had acute kidney injury (38%), compared with those who did not (32%).

This is “a surprising finding,” Dr. Holzmann said, adding that it is “difficult to draw conclusions from it.”

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