Preventing hysterectomies for dysfunctional uterine bleeding with the HTA™: a survival analysis
© Springer-Verlag 2006
Published: 10 October 2006
A questionnaire was sent to 121 women with dysfunctional uterine bleeding who had been treated with the HTA™. Prior to treatment the women had received advice about the failure rate of the HTA™. There was a 68% (82) response rate, of which 11% (9/82) of patients had a hysterectomy. Of these patients 7.3% (6/82) were performed for persistent pelvic pain and 1.2% (1/82) for irregular vaginal bleeding. The projected Kaplan-Meier survival rate for the device over a 5-year period was 89%. The amenorrhoea rate was 42.7% and the oligomenorrhoea rate was 81.7%. The HTA™ is an effective form of treatment for DUB and the majority of women are likely to avoid a hysterectomy at 5 years.
The HydroThermal ablator (HTA™) is a second generation endometrial ablation device used to treat women with dysfunctional uterine bleeding (DUB). The reported success rates range from 77–88% [1, 2]. However, a hysterectomy may have to be performed following treatment with the HTA™ for a variety of reasons. Previous studies have reported rates ranging from 1–7.1% [1–3] over a 12 month follow-up period. Long term outcome data following second generation endometrial ablation procedures is limited, but follow-up studies on patients who underwent first generation endometrial ablation-resection indicate that the rate of hysterectomy can vary between 5–21% and that it increases with time [4–7]. In order to overcome these limitations and determine the proportion of women who can be expected to avoid a hysterectomy after an HTA™ procedure over a 5 year period, a survival analysis on a cohort of patients was carried out. The indications for hysterectomy, and the patient’s menstrual status were also quantified.
One hundred and twenty one women with a history of menorrhagia, without intra-uterine pathology, were recruited for the study at a district general hospital. Patients were eligible if they had a uterine cavity (excluding the cervical length) measuring between 6 and 10 cm in length at hysteroscopy or on transvaginal ultrasound scan. The patients were aged between 26 and 52 years (mean age 43.4 years). They were excluded if there was intra-uterine pathology or endometrial and cervical abnormalities on histological and cytological examination. Intra-mural and extra-uterine pelvic disease were considered a relative contraindication. Histories of previous caesarean section(s) or clotting abnormalities were not considered a contraindication.
The HTA™ device consists of an insulated polycarbonated sheath (7.8 mm/24 F), which accepts a 3 mm hysteroscope and a microprocessor controlled heater. The sheath is positioned inside the uterus to give a panoramic view of the cavity. Gravity determines the maximum hydrostatic pressure (50 mmHg) and a pump recirculates the fluid. The heater raises the saline temperature to 90°C and the treatment cycle lasts for 10 min.
All 121 patients had HTA™ performed to treat the DUB in a “One Stop” Clinic for abnormal uterine bleeding. They had received both verbal advice and patient information leaflets about the side effects of the HTA™ prior to the operation. A postal questionnaire was sent to all the women. The date of treatment with the device, and the patient’s age was recorded. The patients were asked if they had a hysterectomy performed. If they had, they specified the time after HTA this had occurred, and the reason for performing a hysterectomy. If they had not had a hysterectomy, the patients were asked to specify whether they still had periods. Those women who still had a menstrual bleed (more than spotting) were asked to specify whether it was lighter, heavier or unchanged compared to their periods before the device was inserted.
Data for analysis was recorded on Microsoft Excel software. The survival analysis was undertaken in SPSS version 12.0. Survival probabilities by Kaplan Meier method for censored data were plotted.
A cohort of 121 women were sent a questionnaire. There was a 68% (82/121) response rate. Of these patients 11% (9/82) had a subsequent hysterectomy. The reasons for hysterectomy were pelvic pain 66.6% (6/9), irregular vaginal bleeding 11.1% (1/9), and 22.2% (2/9) were women had a hysterectomy for unrelated reasons (ovarian cysts). All the women who had hysterectomies for pelvic pain had reported debilitating dysmenorroea prior to the HTA procedure, and subsequent histological examination of excised specimens demonstrated adenomyosis or intra mural fibroids. There were no serious intra operative complications in this series.
Menstrual status at the time of follow-up
Number of cases
Hysterectomy rates following first generation endometrial ablation procedures
Hysterectomy following second generation endometrial ablation procedures
One of the features of HTA which distinguishes it from other second generation devices is that it allows the operator to directly visualize the uterine cavity during the treatment which in turn promotes patient safety. In our series there were no intra operative complications and very few were reported in the RCT  or cohort studies [2, 3]. Age was not found to be significantly different between the group of women who became ammoenorrhoeic, or in the women who had subsequent hysterectomies. However, the device has the potential to be used on large, irregular uterine cavities with submucous fibroids, polyps, and septae because it relies on freely circulating fluid. This particular feature means that the surgeon can potentially treat a wider range of patients with the HTA compared to other second generation devices. In this series 67% (6/9) of patients who had a subsequent hysterectomy did so because of pelvic pain. All of these women reported debilitating dysmenorroea prior to the HTA procedure, and subsequent histological examination of excised specimens demonstrated adenomyosis or intra mural fibroids. Previous studies have also concluded that adenomyosis may be a risk factor for failed endometrial ablation [17, 18]. This study has demonstrated that counseling of women with irregular uterine cavities or known intra mural pathology where pre operative pelvic pain is a presenting feature needs to include discussion of the higher hysterectomy rate.
Besides being a clinically effective device, HTA also has economical advantages and this study can be used to demonstrate this. In our unit the average bed stay following hysterectomy is 5 days and 90 min of theatre time (2 TAH/3 hr list) is allocated per patient. National figures demonstrate that 42% of hysterectomies are performed for DUB [10, 11]. In the case of HTA™ the average bed stay is 0 days and 40 min of theatre time (4.5 HTA’s/3 hr list) is allocated per patient. This study has demonstrated a survival rate (avoidance of hysterectomy) of 89%, that is, 11% of women who have an HTA will go on to have a hysterectomy over the subsequent 5 years. Therefore, for every 100 hysterectomies performed in our unit, 42 are for DUB and we would expect an additional 4.6 to have subsequent hysterectomies, leaving 37.4 patients who have to have a successful HTA procedure.
On the basis of these figures the number of bed days saved/year/100 hysterectomies is 37.4 (no. successful HTA’s)×5 (length of hospital stay)=187. The number of operating lists saved/year/100 hysterectomies can also be calculated. Patients who avoid a hysterectomy (37.4) would require 19 operating lists (rate: 2 per 3 hrs) while 37.4 HTA’s requires 8 operating lists (rate: 4.5 per 3 hrs). Therefore 11 operating lists can be saved/year/100 hysterectomies. This survival analysis also allows us to predict direct savings in terms of costs.
Cost analysis of hysterectomy vs HTA
Cost difference per case (B-A)
In this series the amenorrhoea rate following HTA was 42.7% and the success rate was 81.7%. Survival analysis demonstrates that up to 89% of women can expect to avoid a hysterectomy over a 5 year period. Using this data it can be seen that the use of HTA will reduce the overall unit cost of treating DUB. Therefore, HTA is both a clinically and economically effective alternative to hysterectomy in women with DUB.
The authors would like to thank Dr Gordon Taylor, University of Bath, UK for his advice regarding the statistical analysis of the data and Dr Gourab Misra, SpR in Obstetrics and Gynaecology, for his help in compiling the statistics.
Conflict of interest statement
Mr. K.D. Jones acts as a preceptor and proctor for Boston Scientific.
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