Risk prediction of acute kidney injury in cardiac surgery and prevention using aminophylline

The incidence of acute kidney injury (AKI) after cardiac surgery remains high. The nonspecific adenosine receptor antagonist aminophylline has been shown to confer benefit in experimental and clinical acute renal failure (ARF) due to ischemia, contrast media, and various nephrotoxic agents. We conducted a prospective open label trial to assess the effectiveness of aminophylline for prevention of renal impairment after cardiac surgery. One hundred and thirty-eight patients undergoing cardiac surgery were risk stratified as per Cleveland score to assess for prediction of AKI. Sixty-three patients received a bolus aminophylline of 5 mg/kg and a subsequent continuous infusion of 0.25 mg/kg/h for up to 72 h, while 75 patients received usual postoperative care. Serum creatinine concentrations were measured preoperatively and daily until day 5 after surgery and the glomerular filtration rate estimated using Cockcroft and Gault formula. Hourly urine output was recorded and patients assigned to respective RIFLE stage of AKI. Cleveland score ≥6 was associated with higher incidence of AKI: I and F (P<0.005). Number needed to treat, an insight into the clinical relevance of a specific treatment, is 8. These results suggest that the perioperative use of aminophylline infusion is associated with lower incidence of deterioration in renal function following cardiac surgery in high-risk patients.