Ashley Baker: Perfect. Thank you. I'm Ashley Baker. I'm from Louisiana, as he said, and of the two or three of you who raised your hand about percutaneous renal biopsy in the ASC, one was my partner, so we'll talk a little bit more about that. Percutaneous renal biopsy historically was first performed in the early 1950s and was actually performed initially by a medical nephrologist at Rush Medical Center. And historically as I'm sure we could guess, specimen for biopsy were largely obtained with open surgical techniques performed by either urologists or transplant surgeons, or unfortunately at the time of autopsy by pathology.

Initial techniques were largely performed actually using IVP as the imaging guide, and the target was towards the lower pole of the kidney, and the patient was biopsied in a seated fashion. As you can imagine, the tissue quality and the success rates of obtaining that tissue were really only about 50%, and so as we migrated more towards percutaneous techniques, patient positioning changed, the imaging modalities changed, and success rates improved.

And so what we're looking for with percutaneous biopsy in the ASC is a procedure that obtains tissue adequately and also a procedure that's safe. And so I'm arguing that urologists should be involved in it and that it is safe to be performed in the ambulatory surgery center. Most of us know that the complications of renal biopsy are largely managed by a combination of urologists and also interventionalists. And so if we can beat the complication and be involved and caused our own complications, that to me is adequate.

Okay, so to go over a quick outline, history of the procedure, urologist role, patient selection, how the procedure is performed, precautions, and then reimbursement. As with any case in the ambulatory surgery center, really patient selection is a key component of that. And our current indications for renal biopsy are either focal biopsy, trying to target a renal mass or a renal lesion, or a non-focal biopsy looking at various uropathy or nephropathies, and then transplant rejection issues.

Contraindications currently are uncorrectable bleeding disorders, poorly controlled hypertension, active infection in the kidney or a solitary kidney relatively. And so part of the debate with this and in moving this into the ASC, is how long do you monitor these patients? Historically, people were kept in the hospital for 24 hours. And you can argue based on the literature currently that, complications from renal biopsy typically occur within the first four hours of biopsy. And even more specifically that the gross appearance of the first voided specimen is indicative of potential complications with the procedure. And so with appropriate patient selection and patient education, I do think that it is safe in the ASC, avoiding specific subsets of patients in that environment.

In terms of the overall cost burden for the equipment needed in the ASC, it's fairly low. Most of our ambulatory surgery centers are already outfitted with ultrasound. And using local anesthesia in combination with our anesthesia team for light sedation, we use a combination of ultrasound, the 16 gauge, 20 or 25 centimeter biopsy gun, and local anesthesia to safely perform renal biopsy. We do monitor our patients for one hour in the recovery room, and then also grossly inspect their first voided urine specimen. The biopsy gun that we use costs about $15 per gun.

Obviously, when performing any procedure in the ambulatory surgery setting, in addition to making sure that it's a safe procedure for our patients, we want to evaluate the cost of the procedure and the overall reimbursement. And so the chart shown here shows reimbursement data, from 2018 for percutaneous renal biopsy under ultrasound guidance. Obviously the disparity of reimbursements between the hospital setting and the ambulatory surgery center setting is a continued theme here, and while obviously it's not necessarily leading in your revenue generation, I would argue that it's generally a quick procedure and a safe procedure.

Additionally, urologists typically manage a lot of the disease states that lead to various obstructive uropathies or other problems that prevent... I mean that lead a patient to needing a renal biopsy, to begin with. And so for these reasons, I argue that as urologists, we should have a seat at the table regarding percutaneous renal biopsy under ultrasound. Thank you.

Evan Goldfischer: Thank you very much. You mentioned earlier that historically when these procedures are being done, the accuracy rate was only about 50%. What would you say the accuracy rate is now?

Ashley Baker: Using a 16-gauge biopsy, and that has to do with the size of the nephron and all of the glomerular apparatus, success rates are better than 95%.

Evan Goldfischer: 95%. So you don't actually have to have a pathologist then to do a frozen section at the time. Do you?

Ashley Baker: Correct. No, we do not do frozen section in the ASC.

Evan Goldfischer: Okay, great.

Ashley Baker: We do send two or three specimen to ensure that surely one of them will give adequate tissue.