Kristie Kahl

 video series titled “Enteric Hyperoxaluria, Understanding the Disease.” I’m Kristie Kahl, vice president of content for 

®. We have Dr Kyle Wood, an assistant professor in the department of urology at the University of Alabama at Birmingham, with us today. Thank you for joining us, Dr Wood. Let’s get started. Dr Wood, can you start by defining what hyperoxaluria is?

 Sure. Hyperoxaluria is based on 24-hour urine collections. First, we need to be focused on collecting 24-hour urine and following the AUA [American Urological Association] Guidelines. Once we get the 24-hour urine data, we need to ensure that it’s an accurate collection. That’s done by looking at creatinine excretion throughout that 24-hour time frame. Hyperoxaluria is defined as oxalate levels 40 mg or greater, per day, in that collection. There are some data, and there are some publications that suggest you can look at 45 mg as the cutoff. But most people look at about 40 mg per day as the cutoff that defines hyperoxaluria.

 The 3 types of hyperoxaluria are broken down into primary hyperoxaluria. There are 3 known conditions. They’re all monogenetic causes. They’re all involved in the glyoxylate-oxalate pathway within the liver. Each has to do with a mutation of a gene that’s involved in that process, which results in increased oxalate excretion in the urine because of increased endogenous production. Idiopathic, or secondary hyperoxaluria, are those patients who have high oxalate in the urine without a known cause. It’s not a genetic mutation, nor is it enteric hyperoxaluria. Those are probably a combination or a multifactorial process, which may include dietary indiscretion, some component of enteric hyperoxaluria, or some other unknown cause. Enteric hyperoxaluria has to do with fat malabsorption processes. Fat malabsorption in the gut and saponification of calcium are done by bile salts or fat. You have increased oxalates, which can be absorbed because they’re not binding to calcium, and thus you have increased urinary oxalate excretion through the kidneys. That’s really the hallmark of enteric hyperoxaluria—the most common of which is gastric bypass procedures, and bariatric, or bariatric surgery, procedures.

Can you discuss the need for education to help others understand this disease?

 If we talk about the state of hyperoxaluria as a whole, it’s important to understand that there are multiple reasons why an individual can have high oxalate in their urine, and that the pathophysiology of each of those causes can lead to various treatment options. It also really focuses on, or teaches us, that we need to have a good history and physical exam, because knowing the patient’s history may lead you to 1 of these diagnoses or causes of hyperoxaluria.

Who should be screened for hyperoxaluria?

 If you follow the AUA Guidelines, any recurrent kidney stone former or first-time kidney stone former who’s interested in a work-up should have a metabolic evaluation, which would include these 24-hour urines. In my practice, what all urologists should be focusing on is if you have a recurrent stone former or a high-risk stone former, all of them should be evaluated for hyperoxaluria. That would be done by a 24-hour urinalysis. Those first-time stone formers who desire a work-up should also receive a 24-hour urinalysis and be screened for hyperoxaluria.

How often do patients with kidney stones see a doctor?

 There are individuals who can pass their kidney stones without seeing a physician. But for the most part, when they have an acute event, they present to the emergency department, a primary care physicians, or a urologist. Many times, they require intervention with a urologist. Those kidney stone formers are really the population that we should be treating and evaluating for hyperoxaluria. What’s interesting is the disconnect between what the patients desire and what the urology community is doing. If you look at patients, or if you ask a kidney stone former whether they would want to be further worked up, greater than 90% of them say that they would want to be further worked up and try treatment—or medical, or dietary options—to prevent stones. Yet when you look at urology, there are published data that suggest we order 24-hour urine analyses in only about 7% to 8% of our population. There is that disconnect between greater than 90% of patients desiring treatment, and us ordering 7% to 8% in the studies or of the population. Stone formers present in many ways. But at least from urology, the contact point is usually to discuss surgical interventions. Most stone formers probably present because of the pain and issues that are afflicted during a stone event.

Videos

Kyle Wood, MD, provides insight on the types of hyperoxaluria, the importance of disease education, and who should be screened for the disease.

Overview of Hyperoxaluria

 Can you discuss fluoroscopic tables, where we are, and where we are going?

There are numerous fluoroscopic tables out there. They are quite expensive, but you are getting a very large piece of medical equipment, so it is a capitol purchase for these hospitals or surgery centers. A lot of people are moving toward cheaper, smaller alternatives, like these mobile cystoscopy tables. Those are also very good, but you do potentially decrease your imaging quality when you move to that table.

There are permanent cysto-tables that are firmly secured in the room. They are great. The things you can do with them are amazing: the variability, the surgeon independence that you have, the image control, and the table control. They are really fantastic. The image quality that we are getting with these tables is just amazing. You could do virtually any procedures on them. You can do percutaneous treatments, cystoscopies, and ureteroscopies on them. You can make it multidisciplinary. You can have GI [gastrointestinal] procedures; gastroenterology can do things on that table. They are a staple for us as urologists. We use them every single day in our practice.

 In your experience, where would you particularly use the fluoroscopic tables?

I use a fluoroscopic table during 100% of my ureteroscopy procedures. We use them for probably 30% to 40% of our percutaneous dome procedures.

 Do you have any last thoughts on the state of urological imaging and the industry as a whole?

I am excited to see what comes next. For those of us who are in the clinical world, and certainly those who dabble in the research world, this is an exciting time. We never know what is going to come out next and what is out there. All of us are always excited to see the next level of technology and the next breakthrough. We will just sit on the sideline and wait for things to happen. I am really excited to see what comes out.

The rationale for utilizing fluoroscopic imaging as well as other evolving technologies that are currently being developed and explored in urology.

Fluoroscopic Imaging and Other Developments in Urology

: To help bring everything together, what do you see as the trends in imaging for men’s health?

Things keep getting better. They keep getting smaller. It is important to keep the footprints in the operating room small and to maintain room in the operating room. The image quality, with the advanced technology of imaging and optics, is becoming quite incredible. Patient safety is paramount, so we need to decrease the risk of radiation exposure to patients; anything we can do to lower radiation doses while maintaining the high quality of the imaging is crucial. Artificial intelligence [AI] might be a key component in the future. Planning—preoperative planning—might be an exciting area to track developments. The overall push toward better and keener technology is exciting. Also important is more safety introductions, more safety education, to be put in place for patients and the staff. All those things are exciting and are part of current trends.

 Can you share your thoughts on the potential impact on image quality as it relates to patients with prostate cancer?

 I do not treat a lot of patients with prostate cancer. I am not really sure what is coming down the line in regard to that, to be truthful with you. The area of prostate cancer is a moving target and a very hot topic in reference to technological breakthroughs. As I said, AI is really going to have a huge role in our treatments in the future. I know technology is being developed to better diagnose prostate cancer, improve grading, and provide better information in regard to how serious that prostate cancer is. It will be a huge breakthrough for those people who do treat it.

Reactions to advances in the quality and safety of newer imaging tests used in prostate cancer.

Advances in Imaging in Prostate Cancer

 In your experience, how important is image quality?

Realistically, it is probably the single most important component of all the imaging systems. The image quality is what you use to make a diagnosis. When you look at the impact of clinical outcomes and the medical care of the patients that we are treating, image quality could mean the difference between success and failure. It could mean the difference between seeing a defect and not seeing a defect.

High image quality could mean the difference between tracking the wire up into the kidney and actually having successful placement of the wire vs failing and then not being able to perform a retrograde approach. We would then have to convert it to an antegrade approach, thereby changing the entire outcome of that patient’s disease process. The quality of the imaging is key. You have to see what you are doing and you have to be able to track the course of the procedure to make sure it is going in the direction you want it to go. It is very crucial.

: How satisfied are you with the image quality of your current system in your workflow? What features are you most satisfied with?

We have the most current system, and of course I’m very happy with it. One of the beauties of the system that I use—which is a Liebel-Flarsheim system—is the independence the surgeon has when employing the system. We can control almost everything with foot pedals. We do not need anyone in the room to push buttons. We do not need the circulators to get involved and adjust settings. We can do virtually everything we want with just our foot pedals: we can magnify, do spot films, fluoroscopies, cone in, and cone out.

As surgeons, we can really have complete independence when dealing with these systems. That gives us real-time information and actually has been shown, in the literature, to decrease the amount of fluoroscopy that we use when we control that. The surgical independence is fantastic. The image quality is fantastic, and we can make some very high-level treatment decisions based on what we are seeing real time.

Dr Brad Schwartz comments on his satisfaction with current imaging systems used in urology and the impact of image quality on treatment decisions and clinical outcomes.

Kristie Kahl

Articles

Overview of Hyperoxaluria

Fluoroscopic Imaging and Other Developments in Urology

Advances in Imaging in Prostate Cancer

Urology Testing: Image Quality and Clinical Outcomes