Presented by: Anne Hong MD
Austin Health

Introduction

Complications after pyeloscopy have been attributed to raised intrarenal pressures. Pyelovenous backflow has been reported as a possible mechanism of ascending infection. However, the urothelium is lined with umbrella cells connected by tight junctions, forming a robust barrier. Thus, the exact mechanism of pathogen passage to the renal parenchyma and the vasculature remains a question. We examine ex vivo animal models and describe some possible mechanisms.

Materials

21 ex vivo porcine kidney models were used. Each ureter was cannulated with a 10Fr dual lumen ureteral catheter. A Comet Pressure Guidewire (Boston Scientific, Massachusetts, USA) for pressure measurement was inserted through one lumen and positioned in the renal pelvis, with irrigation fluid flowing through the second lumen. The irrigation fluid used was undiluted India ink (Royal Talens, Netherlands). The kidney models were irrigated for 5 minutes at intrarenal pressures of 5, 30, 60, 90, 120, 150 and 200 mmHg. At the conclusion of irrigation, the renal units were bivalved and macroscopically examined for location of India ink.

Results

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The control renal units subjected to 5mmHg demonstrated no staining of the renal parenchyma. From 30mmHg onwards, the renal parenchyma is unevenly affected, with each renal unit containing areas that are macroscopically unstained. The number of renal pyramids and percentage of renal cortex affected is summarised in Table 1.

Conclusion

Staining of the renal cortex is demonstrated at IRPs of 30mmHg and higher, suggesting that backflow may affect the renal parenchyma from 30mmHg. However, this appears to be significantly greater from 90mmHg. These may contribute to infectious complications after pyeloscopy.

Funding

The authors received no funding for this research

Co-Authors

Justin Du Plessis, MD
Austin Health

Cliodhna Browne, MD
Austin Health

Greg Jack, MD, PhD
Austin Health

Damien Bolton, PhD
Austin Health