Category: New Technology: Stones

MP22-14 - Ureteroscopic Doppler Ultrasonography: Mapping Renal Blood Flow from the Inside-Out

Sat, Sep 22
2:00 PM - 4:00 PM

Introduction & Objective :

Herein we describe the evaluation of a novel Doppler transducer sufficiently small to be passed through a flexible ureteroscope.  The probe was used to assess in vivo porcine renal forniceal and papillary blood flow.

Methods :

A Doppler transducer (Vascular Technology Inc.) mounted to a catheter with an overall diameter of 3Fr and a working length of 120cm was passed through the working channel of a flexible ureteroscope (Figure 1A, 1B and 1C). Pyeloscopy was performed based on the retrograde pyelogrm (Figure 1D) in six female Yorkshire pigs. Blood flow was mapped at the 12, 3, 6, and 9 o’clock forniceal positions and at the center of the papilla. A 365-micron holmium laser fiber was then fired in the mapped regions until it penetrated approximately 1cm into the urothelium and bleeding times were assessed.

Results : An audible signal was produced when the Doppler transducer was placed upon a vessel within which there was flow; vessels up to a depth of 1 cm could be detected with this unit. Based on the intensity of the Doppler auditory signal, each reading was categorized from 0 (no flow) to 3 (high flow). The data was pooled and images were created of the anterior and posterior calyces respectively (Figure 2). Laser entry into high flow areas resulted in increased bleeding times when compared to areas of low flow (p=0.01). Distribution of blood flow did not differ significantly between anterior and posterior calyces (p=0.475) with further analysis also showing no significant difference among the upper pole, middle, and lower pole calyces (p=0.78).  Multivariate analysis demonstrated the 6 o’clock forniceal position had significantly greater flow as compared to any other location within each calyx (p=0.03). On the other hand, the center of each papilla had significantly less blood flow (p<0.001) compared to any region along the fornix.

Conclusions : A miniaturized Doppler ultrasound probe can be used during ureteroscopy to assess renal blood flow.  The renal papilla has the least amount of calyceal blood flow.

Roshan M. Patel

Assistant Clinical Professor
University of California, Irvine, Department of Urology
Orange, California

Kamaljot S. Kaler

Clinical Assistant Professor
University of California, Irvine; University of Calgary
Orange, California

Mitchell L. O'Leary

Clinical Researcher
University of California, Irvine, Department of Urology
Orange, California

Vinay Cooper

Clinical Researcher
University of California, Irvine, Department of Urology
Orange, California

Egor Parkhomenko

Boston Medical Center
Boston, Massachusetts

David Regan

Vascular Technology Incorporated
Nashua, New Hampshire

Jaime Landman

Professor and Chair
Department of Urology, University of California, Irvine, Orange, CA
Orange, California

Professor Landman completed his medical training at Columbia University. He then completed his Urology residency at Mt. Sinai Hospital in New York before moving to St. Louis to complete his minimally invasive urology training at Washington University under the guidance of Dr. Ralph Clayman. Dr. Landman’s fellowship training focused on the minimally invasive treatment of renal diseases.

Prof. Landman focuses on developing new clinical approaches to minimally invasive and more effective treatments for surgical renal diseases such as renal cell carcinoma, urolithiasis and ureteropelvic junction obstruction. For the past decade, his clinical practice has been focused almost exclusively on the minimally invasive management of kidney disease with a focus on renal oncology and urolithiasis.

Since 2002 Dr. Landman has directed an active minimally invasive urology laboratory. His laboratory has focused largely on innovative minimally invasive solutions in the diagnosis and treatment of urologic malignancies, kidney stones and the development of minimally invasive surgical technologies.

A major focus of Dr. Landman’s efforts has been the didactic and technical training of students, residents and fellows. Dr. Landman has had an active role in medical student and resident education since 2001. Since 2002 Dr. Landman has been actively directing the Endourology sanctioned clinical and research fellowship, and he was until recently the program director for the UC Irvine Urology residency. Dr. Landman engendered and currently directs the LIFT (Leadership Innovation Fellowship Training) program at UC Irvine and has focused on helping medical students become academic leaders in Urology.

A current focus of Dr. Landman’s research remains didactic and technical training for students, residents and fellows. His research team continues to develop novel strategies for surgical education.

Ralph V. Clayman

University of California, Irvine, Department of Urology
Orange, California