Randomized comparison of cold blood and cold crystalloid renal perfusion for renal protection during thoracoabdominal aortic aneurysm repair.

OBJECTIVE: More effective adjuncts are needed to reduce the incidence of acute renal injury after thoracoabdominal aortic aneurysm (TAAA) repair. The purpose of this randomized trial was to determine whether renal perfusion with cold blood provides better protection against renal ischemia than perfusion with cold crystalloid in patients undergoing TAAA repair with left heart bypass. METHODS: One hundred seventy-two patients were enrolled. Strict inclusion criteria were used, including planned Crawford extent II or III TAAA repair with left heart bypass. The patients were randomly assigned to receive intermittent renal perfusion with either 4 degrees C lactated Ringer's solution (n = 86) or 4 degrees C blood (n = 86). Renal complications within 10 days of operation were stratified by renal dysfunction score (RDS). Postoperative changes in the levels of five urinary biomarkers-retinol binding protein, alpha-1 microglobulin, microalbumin, N-acetyl-beta-D-glucosaminidase, and intestinal alkaline phosphatase-were compared to assess potential differences in subclinical renal injury. RESULTS: Although total ischemic times were longer in the cold blood group, unprotected ischemic times were similar between the two groups. Twenty-seven patients in the cold blood group (31%) and 21 patients in the cold crystalloid group (24%) had peak RDS >or=2 (serum creatinine >50% above baseline; P = .4). There were no differences between the cold blood and cold crystalloid groups in the incidence of early death (7/86 [8%] vs 5/86 [6%], respectively; P = .8) or renal failure requiring hemodialysis (3/86 [3%] in both groups). Changes in renal biomarker levels were also similar in the two groups. Spinal cord deficits developed in 5 patients in the cold blood group (6%); there were no such deficits in the cold crystalloid group (P = .06). CONCLUSION: Cold renal perfusion during TAAA repair provides effective protection against renal injury. Using cold blood instead of cold crystalloid does not enhance renal protection.

Renal perfusion during thoracoabdominal aortic operations: cold crystalloid is superior to normothermic blood.

BACKGROUND: Renal failure remains a common complication of thoracoabdominal aortic aneurysm repair. The purpose of this randomized clinical trial was to compare two methods of selective renal perfusion--cold crystalloid perfusion versus normothermic blood perfusion--and determine which technique provides the best kidney protection during thoracoabdominal aortic aneurysm repair. METHODS: Thirty randomized patients undergoing Crawford extent II thoracoabdominal aortic aneurysm repair with left heart bypass had renal artery perfusion with either 4 degrees C Ringer's lactate solution (14 patients) or normothermic blood from the bypass circuit (16 patients). Acute renal dysfunction was defined as an elevation in serum creatinine level exceeding 50% of baseline within 10 postoperative days. RESULTS: One death occurred in each group. One patient in the blood perfusion group experienced renal failure requiring hemodialysis. Ten patients (63%) in the blood perfusion group and 3 patients (21%) in the cold crystalloid perfusion group experienced acute renal dysfunction (p = 0.03). Multivariable analysis confirmed that the use of cold crystalloid perfusion was independently protective against acute renal dysfunction (p = 0.02; odds ratio, 0.133). CONCLUSIONS: When using left heart bypass during repair of extensive thoracoabdominal aortic aneurysms, selective cold crystalloid perfusion offers superior renal protection when compared with conventional normothermic blood perfusion.