Renal perfusion with venous blood extends the permissible suprarenal clamp time in abdominal aortic surgery
Received 11 October 2007; accepted 7 January 2008. published online 04 April 2008.
Objective
Suprarenal clamping in abdominal aortic surgery is associated with a significant risk of postoperative renal failure, general morbidity, and mortality. Arterial access for temporary shunting in these patients is difficult, and arterial perfusion techniques are typically complex. This study evaluated if renal perfusion with venous blood using a minimal pump setup and intermediate-level heparinization prevents a decline in postoperative renal function in patients requiring suprarenal clamping for aortic reconstructive surgery.
Methods
Renal perfusion was achieved using a roller pump supplied with venous blood from a central venous catheter under medium-level heparinization to feed two perfusion balloon catheters. The calculated glomerular filtration rate was observed for 10 postoperative days and compared with the rate in patients with suprarenal clamping without renal perfusion.
Results
From 2001 to 2007, 158 patients underwent surgical reconstruction involving the pararenal aorta through a midline abdominal incision. Renal perfusion was started in 2006 and was always attempted if suprarenal clamping was anticipated preoperatively. Twenty-six patients received renal perfusion, and 132 also requiring suprarenal clamping did not. Of the latter, 109 were included in the control group. Five patients died ≤30 days (3.7%), one in the perfusion group. On average, there was a postoperative loss of renal performance in both groups. Dialysis was required postoperatively in 13 patients without renal perfusion, 4 of them long term (3.7%), but not in patients with renal perfusion. The reduction in glomerular filtration rate at 10 days in the nonperfused group was significantly higher than in the perfused group (7.24 vs 0.89 mL/min) despite a significantly longer suprarenal clamp time in the latter (25.5 vs 45.5 minutes). Multivariate analysis showed a significant reduction in the loss of glomerular filtration rate with perfusion (P = .007) if clamp time and preoperative renal function were taken into account. Patients with preoperative renal impairment showed the greatest benefit from the perfusion.
Conclusion
The setup for renal perfusion with venous blood during suprarenal clamping was simple and safe. Perfusion significantly reduced the reduction of renal function in the immediate postoperative period, suggesting that clamp time may thus be safely be extended to allow for complex reconstruction of the pararenal aortic segment. The benefit was most marked for patients with preoperative renal impairment.
aDepartment of Cardiac, Thoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany
bDepartment of Biometrics, Hannover Medical School, Hannover, Germany.
Reprint requests: Dr. Maximilian Pichlmaier, MA (Cantab), Herz-, Thorax-, Transplantations- und Gefäßchirurgie, Medizinische Hochschule Hannover, Carl-Neuberg-Str 1, D-30625 Hannover, Germany.
ABSTRACT