Uterine Artery Embolization, and the Treatment of Uterine Fibroids: Evolution, Science and Politics


Submitted on Fri, 09/05/2008 - 16:36

<sup>1</sup>Mark O. Baerlocher and <sup>2</sup>Murray R. Asch

The ebb and flow of medical advancement The field of vascular intervention, particularly percutaneous, is a rapidly expanding field. With a decrease in complication and readmission rates and procedural costs coupled with an increase in success and patient satisfaction rates, the number of treatments offered and the variety of diseases targeted is growing at a quickening pace. The increasing complexity of the field is reflected by its multidisciplinary nature (one need not look further than the inspiration behind Vascular Disease Management). Relatively new procedures rapidly replace traditional ones that have been the standard for decades. The impetus is not surprising, in circumstances where there are two procedures with comparable measures of success), the procedure with the lesser amount of body invasion will be preferable (at the least, by the patient). The enthusiasm for adopting new procedures must be tempered, regardless of how promising they appear, because they are “new,” and often “unproven.” There is a well-established process by which new procedures enter clinical practice. They must first work in theory and then be extensively proven in animal models. Various measures of success and failure must be meticulously recorded and then followed by a small clinical trial in human patients. If successful, additional, more extensive trials are conducted. Eventually, large scale trials are performed, followed by meta-analyses combining the results of many trials. Many factors play into the success of a new technology, such as the obvious (success rates, complication rates), the discrete (cost, patient satisfaction, procedural time and difficulty), and the subtle (politics). At any point, a new technology can be squashed. If and once a new technology is proven superior, however, physicians have a duty to adopt it. A physician today would be unlikely to get away with practicing many of the procedures that were status-quo 50 years ago. Disruptive versus sustaining technologies Clayton Christensen described technology as being either “sustaining” or “disruptive”.1 A sustaining technology is one that incrementally builds and improves upon existing technologies. An example is drug-eluting stents, which built upon an existing technology, regular stents. Another example is many of the advances in cardiac surgery, particularly the studies on cardiac protection during coronary artery bypass surgery.2 In many ways, this can be seen as refining existing technology. This is in contrast to a “disruptive technology,” which is an entirely new and radically different technology that eventually overturns the previously dominant technology. An example of a disruptive technology is balloon angioplasty,2 which overtook much of the market previously held by the cardiac surgeons. An example of a technology that may become a disruptive technology is the percutaneous heart valve replacement. Disruptive technologies are often initially inferior to existing technologies by traditional performance measures but come to dominate by either filling vacant markets that the existing technology could not fill, or by incremental improvements until it is the superior technology. Disruptive technologies may be superior in success rate, cost, efficiency, simplicity and/or safety. Uterine artery embolization: a disruptive technology. Uterine artery embolization (UAE) should be considered a “disruptive technology.” The existing technology was the hysterectomy. Various sustaining technologies improved upon the original hysterectomy procedure, including medication regimen, technique and type of hysterectomy, and most recently, method of hysterectomy (i.e., from abdominal- to vaginal- to laparoscopically-assisted- and now to total-laparoscopic hysterectomy.3,4 Then, the first transcatheter embolization of the uterine arteries for symptomatic leiomyomata was reported by Ravina and colleagues in 1995.5 Initially, the complication rate was not particularly good, and certainly not better than hysterectomy.5 But as the procedure was developed and refined, its popularity quickly grew, so that by the year 2000, over 10,000 UAEs had been performed. UAE had also made it into the popular press, particularly after Condoleeza Rice underwent the procedure, with reports on major media publications and television shows (e.g., Newsweek,™ NBC Nightly News,™ 20/20,™ and USA Today Weekly™). The procedure had rapidly established itself as a viable treatment option for women with uterine fibroids and had become a major focus of research among interventional radiologists.6–9 Uterine artery embolization: past the validation period. As a result of the intense amount of interest in UAE as a treatment for uterine fibroids, a large amount of time, effort and money has been spent on researching the procedure. While the old stand-by, the hysterectomy, is a major operation with a complication rate between 17 and 23%,10 UAE has a technical success rate over 95%, a procedural complication rate of 5%11 and a short- and mid-term success rate of approximately 90%.12 Furthermore, due to the minimally-invasive nature of the procedure, the hospital stay is much shorter: UAE can be performed as an inpatient procedure with a hospital stay of 1–2 days,13 or as an outpatient procedure, with a post-procedural stay of 6–8 hours.7 UAE also allows for post-treatment pregnancy.14 As a result of a combination of these factors, UAE likely leads to high satisfaction rates of approximately 90%.7,13,15 Uterine artery embolization also compares well to myometcomy. For example, Razavi et al. examined the outcomes of 111 patients who underwent either abdominal myomectomy (n = 44) or UAE (n = 67), and found that UAE led to a higher success rate (92% versus 64% for UAE and abdominal myomectomy, respectively; p 16 In terms of cost, Al-Fozan, et al.6 examined the inpatient teaching hospital costs of abdominal myomectomy (AM), total abdominal hysterectomy (TAH), vaginal hysterectomy (VH), and (inpatient) UAE, and found that UAE was both cheaper and associated with shorter hospital stay (Table 1). The hospital stay for laparoscopic hysterectomy has been reported to be between 2.0–2.6 days.8,9 Furthermore, in the study by Al-Fozan et al.,6 the authors looked only at inpatient UAE. We recently completed a Canadian study in which we compared patient satisfaction rates, complication/readmission rates, and costs between inpatient and outpatient UAE, and found that outpatient UAE was as safe, led to equally high patient satisfaction, and was cheaper than inpatient UAE (unpublished data). An American study by Siskin et al.7 found similar results where a savings of 490.25 was realized. The results mentioned only scratch the surface of what has been done. However, the sum total of UAE research shows it is a safe and effective treatment for uterine fibroids that leads to both cost-savings and high patient satisfaction. Therefore, UAE is now well past its validation period and should be considered the standard treatment recommendation of physicians seeing a patient with fibroid-related complaints. The politics of fibroids. The more subtle aspects of medical advancement now come into the discussion. Once a procedure is “proven,” there can still be great obstacles, particularly if the disruptive technology is within the realm of a specialty other than that which the traditional technology was within. Thus, referring power can have a tremendous impact on the adoption of the new technology. For example, coronary angioplasty, performed most often by cardiologists, took over much of the market previously held by the cardiac surgeon. In this case, the referring power and the realm of the technology were aligned: the cardiologist sees the patient before the cardiac surgeon, and the cardiologist performs the angioplasty. In fact, it was Charles Dotter, a radiologist, who performed the first angioplasty procedure, in which he successfully dilated a stenosed superficial femoral artery in an elderly lady who refused to undergo amputation.2 Many would argue that the interventional radiologist would still be performing the majority of coronary angioplasties had they been given a choice. However, as the cardiologist wished to perform the procedure, and also had the referring power, the radiologist lost out (although the authors acknowledge that Dotter personally trained many cardiologists). In the case of UAE, the referring power and the sphere of the technology are misaligned. It is usually the interventional radiologist who performs the procedure, and the gynecologist who makes the referral. It is also the gynecologist who traditionally performs the hysterectomy. The gynecologist therefore loses out on what was previously a significant source of business. This creates a problem as to whether or not the gynecologist should refer and lose business or attempt to learn to perform the procedure him/herself. We recently completed a study in which we surveyed patients who had undergone UAE (unpublished data). We did not specifically inquire as to the method by which each patient learned about the option of the UAE procedure, however a number of patients brought the subject up. We were somewhat surprised when we learned that a sizable minority of patients were not told about the UAE procedure by their gynecologist. We were even more surprised and disappointed when we learned that in several cases, the gynecologist had put a very large amount of effort into dissuading the patient away from considering a UAE procedure, to the point that the patient was left with a negative attitude toward the gynecologist because of it. It would likely seem ironic and even hypocritical to the lay public that physicians are quick to point out that they are overworked, yet on many levels shuffle for the ability to perform specific procedures. Such turf wars, while apparently hidden, seem ever-present, particularly within fields such as interventional radiology.17 Still, the better technology, disruptive or not, will surely prevail. As additional evidence finds UAE to be safe, effective and comparatively cheaper to many of the currently offered fibroid treatments continues to gather, it will become increasingly difficult to ignore the procedure and avoid recommending it to patients. In terms of who should be performing UAEs, the answer is simple: whoever is better at them. We would argue that the interventional radiologist is the preferred choice in this case, as they have the greatest amount of relevant training and experience with both percutaneous intervention and radiation protection. Turf wars are an extremely important issue with an associated mortality. To illustrate, suppose 10,000 procedures of some type are performed per year, and that 80% of these are performed by an interventional radiologist, while the remaining 20% are performed by the specialists who refer patients to the interventional radiologist. The IR has a mortality and morbidity rate of 0.2% and 4%, respectively while the other specialist has a rates of 0.4% and 7%. This means that of the 10,000 procedures, 20 patients die and another 300 have complication rates that would have been avoided had the IR performed the procedure. This would clearly be quite significant: these 20 patients died because of these turf wars. The difficulty is how can we control who performs procedures such as UAE, particularly when the physician who refers to the more experienced specialist is effectively “losing business” by doing so? In the case of UAE, one approach has been to publish practice guidelines.18 These are not enforceable however, and nothing prevents two societies, representing two different specialties, from publishing their own unique guidelines. In the case of UAE, McLucas,19 a gynecologist, published a route by which he believed gynecologists could be adequately trained to perform UAEs (although this was subsequently seen as inadequate by interventional radiologists).20 Unfortunately, until large scale randomized control trials comparing the success rates between gynecologists and interventional radiologists is performed, there is no easy way to prove that one specialist is better than another at performing UAEs. If such large trials are not performed, and the issue remains, it may be necessary for interventional radiologists to accept self-referrals from patients (something that would likely be feasible in this case). In our opinion, this would not be ideal. Patient care is best when the interventional radiologist and gynecologist work together as a team, particularly when there is a complication. Furthermore, there are times when a hysterectomy may be the better choice. Finally, many patients find interventional radiologists on their own or are referred from family physicians. By including the gynecologist, it increases the number of referrals, which may help offset the lost source of income from fewer hysterectomy patients. Sustaining technologies: the next step. Now that UAE is an established technology, it is the time for development of the corresponding sustaining technologies. The basic procedure should be further tweaked and refined, so that the success and patient satisfaction rates are all improved and the cost decreased further. Two current examples of sustaining technologies related to UAE that are in development are investigations into whether UAE may be safely performed as an outpatient procedure,7,15 and whether the type of embolic material affects patient outcome.21 Other examples include the possibility for pregnancy following embolization,14 as well as development of complementary techniques such as new closure techniques.23 As UAE is further refined, it will become increasingly difficult to ignore as a first-line treatment option. Even now, several representative organizations and societies, representing both the interventional radiologists,18,24 and the gynecologists25 are creating guidelines regarding UAE. Some associations representing each specialty have produced combined guidelines.26,27 In the next few years, other related technologies may themselves become “disruptive” from the viewpoint of UAE, such as radiofrequency ablation or MRI-guided focused ultrasound.28 Conclusion Medicine is a very dynamic and complex field. New technologies are developed and improved upon daily, which must undergo and successfully pass a barrage of hurdles and tests in order to be “proven” effective and efficient, before entering mainstream clinical practice. These hurdles are not only clinical, but also political as well, particularly if the technology is “disruptive” and threatens to fill a previously occupied niche held by another specialty. The UAE procedure is a “disruptive” procedure that should now be considered proven, ready for widespread use, and a new platform upon which “sustaining” technologies may be developed. More subtle and subversive political issues, particularly so-called turf wars, must be monitored so that patients are ensured optimal treatment. Editorial Commentary Uterine artery embolization (UAE) for treatment of fibroids is an increasingly popular and accepted procedure. Interventional radiologists perform most of them, but it can be safely predicted that other specialists will venture into the field in the near future. The technique, in conception and evolution, is a great example of the power of “disruptive technologies.” Together with several others – i.e. angioplasty and stents – they have revolutionized and forever changed traditional standards of care. In so doing, they have also become the backdrop for “turf wars” (see Editor’s Corner) that seem all but inevitable as specialties “invade” each other in their quest for supremacy. This article by Baerlocher, et al. contains an excellent summary of the state of the art with UAE. I suspect that a majority of VDM readers will find it interesting and provocative.