Presented by: Bruce Gao MD
Department of Urology, University of California, Irvine, CA, USA

Introduction

A limiting factor in the passage of a ureteral access sheath (UAS) is the small diameter of the ureter.  Electromotive Drug Administration (EMDA) has the ability to drive a drug deep into the wall of the bladder urothelium. Accordingly, we used EMDA to test ureteral distensibility with three smooth muscle relaxants.

Materials

 In 18 female Yorkshire pigs, baseline distensibility of both ureters was determined by passing 35 cm long, Cook Medical® urethral dilators (10 Fr to 24 Fr) in 2 Fr increments at a maximal force of 3.5 Newtons as determined by the UCI UAS force sensor.  The size of the UAS passed and the highest ureteral location reached (i.e. proximal, middle, or distal ureter) was recorded.  Flexible ureteroscopy was performed and a post-ureteroscopic lesion scale (PULS) grade was recorded.  Next, a proprietary EMDA catheter was passed into both ureters.  On the experimental side, the EMDA catheter was activated while three different medications diluted in 100 ml sterile water were infused at 5 ml/min for 20 minutes: alfuzosin 10 mg, isoproterenol 1 mg, and aminophylline 500 mg (six pigs per drug). In the contralateral control ureter, the EMDA catheter was not activated while saline was infused at 5 ml/min for 20 minutes. Ureteral distensibility was determined at 3.5N; flexible ureteroscopy was performed and a PULS grade was recorded. Pigs were euthanized, and ureters were excised and snap-frozen for histopathological analysis.

Results

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Intraureteral EMDA administration of alfuzosin and isoproterenol resulted in insertion of a larger dilator in 2/6 and 1/6 experimental ureters, respectively.  When compared to their respective contralateral control ureter (i.e., R program, and Wilcoxon signed rank test) neither reached statistical significance (p = 0.17, p = 0.68, respectively).  No ureter in the aminophylline group accommodated a larger dilator. Among the ureters without augmentation in UAS size, there was increased progress of the same size UAS in 100%, 60% and 66% of the alfuzosin, isoproterenol and aminophylline infused ureters, respectively.  PULS grades were all low grade (i.e., < 2).    

Conclusion

Among three EMDA tested drugs, only alfuzosin trended to improve ureteral distensibility, albeit without attaining statistical significance. 

Funding

None

Lead Authors

Ralph V. Clayman, MD
Department of Urology, University of California, Irvine, CA, USA

Co-Authors

Zachary E. Tano, MD
Department of Urology, University of California, Irvine, CA, USA

Seyed Amiryaghoub M. Lavasani, Junior Research Assistant
Department of Urology, University of California, Irvine, CA, USA

Yi Xi Wu, PHD
Department of Urology, University of California, Irvine, CA, USA

Babak Naimi, PHD
Quantitative Biodiversity Dynamics – Utrecht University

Seyedamirvala Saadat, Junior Research Assistant
Department of Urology, University of California, Irvine, CA, USA

Ahmad Abdel-Aziz, MD
Department of Urology, University of California, Irvine, CA, USA

Sohrab Naushad Ali, MD
Department of Urology, University of California, Irvine, CA, USA

Pengbo Jiang, MD
Department of Urology, University of California, Irvine, CA, USA

Roshan M. Patel, MD
Department of Urology, University of California, Irvine, CA, USA

Jaime Landman, MD
Department of Urology, University of California, Irvine, CA, USA

Ralph V. Clayman, MD
Department of Urology, University of California, Irvine, CA, USA

Bruce Gao, MD
Department of Urology, University of California, Irvine, CA, USA