The Impact of Aortic Clamping Site on Glomerular Filtration Rate after Juxtarenal Aneurysm Repair

Background

Open repair of juxtarenal abdominal aortic aneurysms (JAAAs), which necessitates clamping above one (interrenal clamping, interRC) or both renal arteries (suprarenal clamping, supraRC), is associated with an increased risk of perioperative renal derangements. We reviewed our experience to investigate the impact of aortic clamping site during JAAA repair on peri- and postoperative glomerular filtration rate (GFR).

Methods

Between January 2001 and March 2006, 32 patients (28 male, four female; mean age 70.5±5.6 years) were submitted to elective open repair of JAAA. SupraRC was required in 12 patients and performed with cold renal perfusion (CRP) in five cases; interRC was required in 20 and performed with CRP in eight. GFRs were estimated through postoperative day 4 using the Cockcroft-Gault equation and compared to those of concurrent controls undergoing infrarenal AAA repair, matched 1:1 by gender, age, aneurysm size, preoperative GFR, and left renal vein management. GFR values were also evaluated and compared between groups at a mean follow-up of 29.0±23.7 months. Renal dysfunction was defined as a decrease of GFR ≥20%. Statistics were determined as appropriate for the variables of interest.

Results

No perioperative mortality was recorded and no differences in major complication rates were observed between groups (p=0.16). Operative time was longer in JAAA patients (154±47 vs. 132±41min, p=0.019). Mean renal ischemia time was 16.7±7.7min. Postoperatively, GFR values up to day 4 were significantly worse in JAAA patients compared to controls (p=0.0007), with a fourfold risk of renal dysfunction at postoperative day 4 (34% vs. 9%, odds ratio [OR]=4.44, 95% confidence interval [CI] 1.1-18.1; p=0.029). At univariate analysis, supraRC was found to be the only factor associated with perioperative renal dysfunction (OR=11.3, 95% CI 2.0-63.1; p=0.003). At follow-up, two patients with supraRC died and another two required dialysis permanently. When compared to those with interRC or infrarenal clamping, patients with supraRC showed a persistent renal dysfunction at follow-up (p=0.005).

Conclusion

Elective JAAA repair with renal ischemia time ≤30min is safe, but supraRC entails a significant perioperative and mid-term GFR reduction. In contrast, interRC provides results similar to those obtained after infrarenal AAA repair, allowing postoperative recovery of renal function to preoperative values.