Boston Scientific AMS 800 Mode D'emploi page 8

Patient Information Form (PIF) Analysis – A retrospective analysis of patients implanted
(n=12,713) in the U.S during the five-year period 1995-1999. The analysis examined
PIF data voluntarily sent to the manufacturer by the implanting physician for original
implants and revisions. PIF data is required to be on file with the manufacturer in order
to be eligible for product replacement. Revision data presented in Table 4 and Table 5
below are based on a total of 2,116 revisions reported for 2,014 patients that required
one or more revisions during the five-year period of the analysis.
Retrospective Clinical Study – The retrospective clinical study was an analysis of patients
implanted (n=390) in the U.S. between 1987-1990. The study examined pre- and post-
implant medical records and follow-up data collected by questionnaires and physician
examinations. Post-implant data was available for 356 patients. The study followed
patients for up to ten years (mean: 4.1 years; range: 0.03-10.3 years). The revision data
presented in Table 4 and Table 5 below are based on a total of 317 revisions reported on
164 patients that required one or more revisions during the ten-year period of the study.
The data in Table 4 presents the percentage of patients revised during the specified
follow-up period, the average number of revisions conducted on patients requiring a
revision, and the number of revisions expected per 100 patients for these studies in
comparison with the data of the prospective clinical study.
Table 4. Comparison of Revision Data from Three Different Clinical Studies
Prospective
Study
(85 pts. over
24 months)
% patients (pts.) revised 16.5%
(14/85)
avg. # of revisions per 1.07
patients revised (15/14)
# of revisions per 18
100 patients (15/85)
Table 5 shows revision data stratified by each reported reason for revision from
three different studies of male patients implanted with the AMS 800
PIF Analysis and Retrospective Study, multiple reasons were sometimes provided
for a single revision. Therefore, in order to stratify this revision data by reason, all
occurrences were included and presented as "% reason." The total number of reasons
therefore exceeds the total number of revisions reported for these studies.
Table 5. Reasons for Revision in Three Different Studies
Prospective
Study (n=85)
Revision Reason
a
revisions
%
Infection 2.4%
Infection/erosion 1.2%
Erosion 2.4%
Recurring Incontinence 2.4%
Fluid Loss -
Fluid Transfer Impaired -
Pressure Too Low -
Mechanical Malfunction 3.5%
Migration/Malposition 3.5%
Iatrogenic Complications -
Reimplantation/ -
Replacement
Pain 1.2%
Patient Dissatisfaction 1.2%
Other -
c
Not Indicated -
a Note that some adverse events in the table such as fluid loss, pressure too low, fluid transfer impaired and
malposition could fall into the category of mechanical malfunction or iatrogenic error. Since information is not
available to place them in either category, they are listed separately.
b Numbers of reasons can vary for the same percentage due to rounding.
c Other includes: double cuff, pressure too high, unable to activate, unable to deactivate, atrophy, difficult to
operate, urinary retention, air in the system, hematoma.
Black (K) ∆E ≤5.0
PIF Analysis Retrospective
(12,713 pts. over Study
5 years) (356 pts. over
9 years)
15.8% 46.1%
(2,014/12,713) (164/356)
1.05 1.93
(2,116/2,014) (317/164)
17 89
(2,116/12,713) (317/356)
AUS. Under the
™
PIF Analysis Retrospective
(n=12,713) Study (n=356)
reasons b reasons
# % # % #
(2) 2.3% (297) 8.1% (29)
(1) - - -
(2) 3.6% (451) 22.5% (80)
(2) 5.7% (724) 42.4% (151)
- 2.3% (298) 9.3% (33)
- 0.3% (38) -
- 1.1% (140) -
(3) 0.7% (89) 13.8% (49)
(3) 0.4% (46) 4.8% (17)
- 0.4% (51) 0.6% (2)
- - - 3.1% (11)
(1) 0.2% (22) 1.4% (5)
(1) 0.2% (27) 1.7% (6)
- 2.4% (305) -
- 1.9% (242) -
Device Survival
Although it is not possible to predict exactly how long an implanted prosthesis will
function in a particular patient, data was gathered from two sources on device removals
and revisions to help gain insight into product performance over time. Although these
sources included information gathered from male patients, it is expected that similar
data would result from analyzing data exclusively from female patients. Figure 11
presents device survival results from the prospective clinical study and a Bayesian
analysis that uses data from the prospective clinical study and the PIF Analysis to
estimate device survival at five years.
Prospective Clinical Study – A device survival curve was calculated from data collected
during a prospective clinical study (n=85) with two-year follow-up. Using Kaplan-Meier
analysis, the two-year revision-free rate for the AMS 800 AUS was 79.5% (95% CI with
95% lower confidence bound 69.8%).
Bayesian Analysis – A Bayesian hierarchical model was used to evaluate device safety
in the prospective clinical study. The Bayesian model estimated device survival using
historical data (PIF Analysis n=12,713) and prospective clinical study data (n=85) on the
AMS 800 AUS. A log-normal distribution fit the AMS 800 AUS historical data. Based on the
log-normal hierarchical model, it was estimated that the five-year revision-free rate for the
AMS 800 AUS is approximately 73.8% with 95% CI ranging from 67.3% to 79.6%. The results
met the primary safety endpoint for the clinical study of a five-year revision free rate at
75% using a 10% delta with two-sided 95% lower bound greater than 65% (Figure 11).
Figure 11. Estimated device survival rates for AMS 800 AUS
Device Use
Retrospective Clinical Study – The study included male AMS 800 AUS patients (n=390)
implanted between 1987-1990. Data from this study was used to estimate the device
use for patients (n=356) with available data through 1997 (range: 0.03-10.3 years). For
the retrospective study, "device use" means the span of time from implant to removal,
-
including revisions. Life table analysis indicated that the probability for a 9-year span of
device use was 83.9%. Thirty-three (33) of the 356 patients had their device removed.
The remaining 323 patients had a functioning device at last contact.
Clinical Information – Females
The AMS 800 AUS is indicated for the treatment of urinary incontinence in females. A
-
literature review was performed to evaluate the safety and efficacy of the AMS 800
-
AUS in female patients. A total of seventeen documents, specifically reporting clinical
information for female patients only, were analyzed. Clinical data, including patient
demographics, etiology, complications, and success criteria and rates are reported
below.
Patients
Clinical efficacy has been reported for 938 female patients, ages ranging from 9-85,
implanted with the AMS 800 AUS
800 patients was 3.6 years
neuropathic bladder dysfunction
trauma , congenital defects (exstrophy)
7,10,18,19
-
nonneurogenic bladder , intrinsic sphincter deficiency
8,19
spinal injury 19 , and cerebral palsy
-
patients .
8,9,11,12,14,16,18,21,22
These studies involved only devices without Inhibizone.
Adverse Events–Females
Table 6 summarizes the reported adverse events for 938 patients receiving an AMS 800
AUS. The most common reported complication was bladder injury, which occurred in
5.8% of patients (n=54). There may have been more than one reported complication for
each patient.
8
. The mean reported follow-up on 785 AMS
7-23
. Various patient etiologies were reported, including
7-23
, stress incontinence
7,8,9,10,19 7,10,12,13,14,15,18,21,22,23
, hysterectomy , radiotherapy
7 7
, myelomeningocele
8,12
20 . Prior surgery or radiotherapy were reported in 354
, pelvic/perineal
, cystectomy ,
7 7
,
19,20