Serum myoglobin and renal morbidity and mortality following thoracic and thoraco-abdominal aortic repair: does rhabdomyolysis play a role?

OBJECTIVES: The intractability of renal dysfunction following thoracic and thoraco-abdominal aortic repair leads us to believe that the accepted mechanisms of renal injury - ischaemia and embolism - are incompletely explanatory. We studied postoperative myoglobinaemia and renal dysfunction following aortic surgery. METHODS: Between September 2006 and February 2008, we studied serum myoglobin in 109 patients requiring thoracic/thoraco-abdominal repair for three postoperative days. Forty-two of the 109 (38%) patients were female. The median age was 67 years (range 23-84 years). As we have focussed more attention on renal function, our independent renal consultants have dialysed more aggressively. We divided dialysis into: (1) creatinine indication, (2) non-creatinine indication and (3) no dialysis. RESULTS: Thirteen of the 109 (12%) patients met creatinine indication for dialysis (>4 mg dl(-1)) and an additional 28 (26%) were dialysed for other reasons. Overall mortality was 12 out of 109 (11%) cases: 11 out of 41 (27%) in dialysed patients and one out of 68 (1.5%) in non-dialysed patients. Mortality did not differ between the indications for dialysis. Predictors of mortality were baseline glomerular filtration rate (GFR), postoperative myoglobin and dialysis. The only predictor of dialysis was postoperative myoglobin. CONCLUSION: A strong relationship between postoperative serum myoglobin and renal failure suggests a rhabdomyolysis-like contributing aetiology following thoraco-abdominal aortic repair. We postulate a novel mechanism of renal injury for which mitigation strategies should be developed.