This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for GORE® VIABAHN® Endoprosthesis Post-Marketing Surveillance Study (JPS 16-03) (NCT04706273), a registered phase not stated study. The primary outcome is Primary Assisted Patency.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04706273 |
| Phase | Phase not stated |
| Condition | Peripheral Arterial Disease |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 321 |
| Arms in the primary outcome | n/a |
| Lead sponsor | W.L.Gore & Associates |
| Results posted | Yes |
2. Clinical Question
Population
Participants with symptomatic peripheral arterial disease and lesions in the superficial femoral artery. The registry record lists enrollment of 321.
Intervention
The GORE® VIABAHN® Endoprosthesis, a device evaluated after its launch in a clinical setting.
Comparator
No comparator group is described. The registry record does not state an allocation method, and this is not a randomized comparison.
Primary question
What is primary assisted patency among treated participant limbs at 12 and 24 months, as estimated using Kaplan-Meier methods?
The study’s stated purpose was to confirm device efficacy and safety after launch for treatment of symptomatic peripheral arterial disease in the superficial femoral arteries. The primary outcome focuses on whether flow through a treated device is maintained without target lesion revascularization to restore flow after total occlusion. It is defined for participant limbs treated, rather than as a patient-level symptom or quality-of-life measure.
The registry record does not report numerical primary assisted patency estimates or their confidence intervals. It therefore does not give a numerical answer to the primary question in the recorded results. Without a described comparator, the study also does not provide a randomized estimate of how outcomes differ between the device and another treatment or control. Its purpose and design are best read as post-marketing surveillance, with the recorded patency definition and adverse-event information interpreted as observations from the study population rather than comparative treatment effects.
3. Trial Design
This was a post-marketing surveillance study of the GORE® VIABAHN® Endoprosthesis for symptomatic peripheral arterial disease in superficial femoral artery lesions. The registry lists enrollment of 321 and identifies W.L. Gore & Associates as the sponsor. The recorded start date is 2016-08-25, primary completion is 2019-07-11, and status is COMPLETED.
The intervention listing contains the device, and the arm description refers to participants with symptomatic peripheral arterial disease in superficial femoral artery lesions. The registry record does not describe a separate comparator arm. Allocation is not stated, and the record identifies the study as not being a randomized comparison. Consequently, there is no like-for-like control comparison described from which to estimate a randomized between-group effect.
The primary outcome is primary assisted patency, defined for participant limbs treated and assessed at 12 and 24 months. The description says Kaplan-Meier estimates were created for each time point and identifies a 95% confidence interval as the dispersion measure. However, the numerical estimates and confidence intervals are not reported in the registry record.
The record lists four outcome measures and zero recorded analyses. A detailed statistical analysis plan, sample-size justification, interim analysis plan, and further description of allocation are not reported in the registry record. The planning framework described for sample-size illustrations uses a hypothetical two-arm arrangement; that assumption should not be mistaken for the design of this surveillance study. Such illustrations are planning exercises, not observed power and not a substitute for the registry’s missing endpoint estimates.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Overall Study
| Stage | GORE® VIABAHN® Endoprosthesis |
|---|---|
| STARTED | 321 |
| COMPLETED | 136 |
| NOT COMPLETED | 185 |
Reasons for not completing this period:
| Reason | GORE® VIABAHN® Endoprosthesis |
|---|---|
| Withdrawal by Subject | 27 |
| Physician Decision | 1 |
| Lost to Follow-up | 42 |
| Death | 85 |
| Amputation that removes study device | 2 |
| Surgical bypass | 3 |
| Changing hospital | 23 |
| Unable to attend hospital | 2 |
Analysis population for the primary outcome, as defined in the registry: Participant limbs treated
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
| Characteristic | Unit | GORE® VIABAHN® Endoprosthesis |
|---|---|---|
| Participants analysed | 321 | |
| Age, Continuous | years | 73.9 (SD 8.7) |
| Sex: Female, Male: Female | Participants | 73 |
| Sex: Female, Male: Male | Participants | 248 |
| Race and Ethnicity Not Collected | Participants | — |
| Region of Enrollment: Japan | participants | 321 |
6. Primary Endpoint
The registry lists the primary outcome as Primary Assisted Patency, measured over 12 and 24 months.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | 95% Confidence Interval |
| Unit | probability |
| Endpoint classification | not reduced to a single comparison |
Primary assisted patency is the study’s primary measure of flow through a treated device. The registry defines it as hemodynamic evidence of flow through a device that had not required target lesion revascularization to restore flow after total occlusion. The outcome is assessed in participant limbs treated, with Kaplan-Meier estimates specified at 12 and 24 months.
As a general statistical concept, a patency measure captures whether flow is maintained over follow-up while incorporating the timing of events. Kaplan-Meier methods are commonly used for time-to-event outcomes because they can estimate the probability of remaining event-free over time when follow-up lengths differ or when some participants’ event status is not observed through the full period. The method relies on how events and censoring are defined and recorded; details of censoring and follow-up handling are not reported in the registry record.
The endpoint is useful for describing device-related vessel patency in the treated limbs. It is not, by itself, a direct measure of symptoms, function, or quality of life, and it does not establish comparative benefit without a suitable comparator. Although the registry specifies a 95% confidence interval as the measure of uncertainty, it does not report the numerical patency estimates or the corresponding intervals. The definition and planned time points can therefore be described, but the magnitude and precision of the observed estimates cannot be assessed from the recorded results.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies primary assisted patency as the primary outcome and states that Kaplan-Meier estimates were created at 12 and 24 months. It also specifies a 95% confidence interval. The numerical estimates and intervals themselves are not reported in the registry record. This means the outcome’s observed level and its statistical precision cannot be evaluated from the posted results described in the record.
A confidence interval is, in general, a range expressing uncertainty around an estimate under the assumptions of the statistical method. A narrow interval usually indicates greater precision than a wide interval, but neither the width nor the location of an interval can be discussed without its reported values. The stated confidence level alone does not reveal whether the patency estimate was high or low, or whether it was precise.
The registry lists enrollment of 321, but that enrollment figure is not the number of limbs necessarily contributing information at each time point. The endpoint is defined for participant limbs treated, and the record does not report the number of limbs analyzed, the number remaining under observation, or how missing follow-up was handled. Those omissions matter when interpreting a time-to-event estimate, because the amount and pattern of follow-up contribute to its uncertainty.
The record lists four outcome measures but zero recorded analyses. It does not report numerical results for the primary endpoint in the registry record. Nor does it report an analysis plan with details such as covariate adjustment, censoring rules, or sensitivity analyses. Without those details, an independent reader cannot assess whether the reported method was implemented as intended or whether alternative analytic choices would change the estimates.
The study is not described as a randomized comparison, and no comparator group is given. Thus, the recorded design does not support a randomized estimate of a treatment difference. Even if a patency estimate were available, a result from a single device group would describe outcomes observed in that group; it would not, by itself, isolate the effect of the device from other factors that could influence outcomes.
For sample-size planning, the described illustration uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect set as a stated fraction of the observed effect. These are planning assumptions, not a description of the surveillance study’s design. The planning values do not represent observed power, and they cannot fill the gap left by absent primary endpoint estimates. Because no numerical effect estimate is reported in the registry record, the illustration’s assumptions should not be read as evidence about the study’s precision or findings.
The safety information is also descriptive. Serious adverse events were recorded for 188 of 321 at risk, while other adverse events were recorded for 0 of 321 at risk; deaths are listed as 85. Serious-event terms include device occlusion and vascular stent-graft stenosis, among others. These figures require careful interpretation because the registry record does not report all definitions, timing, or event-level details needed to connect the counts and listed percentages to a specific clinical course or causal conclusion.
9. Statistical Methods Explained
The registry describes a time-to-event approach for primary assisted patency. It states that Kaplan-Meier estimates were created for each of the 12 and 24 month time points, and lists a 95% confidence interval as the dispersion measure. However, numerical estimates and intervals are not reported in the registry record. The method can therefore be explained, but its numerical results and precision cannot be assessed.
What does Kaplan-Meier estimation do?
As a general statistical method, Kaplan-Meier estimation uses the observed timing of events to estimate the probability that an event has not occurred by a particular time. In this study’s endpoint, the event concept is tied to loss of the specified primary assisted patency condition: hemodynamic evidence of flow through a device without target lesion revascularization to restore flow after total occlusion. The registry’s outcome description says that estimates were created at the stated time points.
Time-to-event methods can use information from participants whose follow-up ends before an event is observed. Such observations are typically censored at the last time their status is known. This general feature makes the method useful when participants have different follow-up durations, but interpretation depends on sound definitions of events and censoring. The registry record does not report the censoring rules, the number censored, the number of events, or the number contributing to each time point. Those omissions prevent a detailed audit of the calculation or its risk sets.
How should a confidence interval be understood?
In general, a confidence interval describes statistical uncertainty around an estimate under the assumptions of the method used. Its endpoints and width help readers judge the precision of an estimate. The registry identifies a 95% confidence interval for primary assisted patency, but does not report its numerical limits. A confidence level without the estimate and interval does not show the direction, magnitude, or precision of the result.
Intervals also do not resolve design limitations. A confidence interval around a result from a single group would quantify uncertainty in that group’s estimate; it would not create a randomized comparison or remove potential confounding. This study is not identified as a randomized comparison, and no comparator is described in the registry record.
What is the role of the adverse-event summaries?
The registry reports serious adverse events for the device group, including the number at risk and the number affected, and separately reports other adverse events. It also lists selected serious-event terms with percentages. These summaries are descriptive safety information. As a general concept, an event count and a percentage answer different questions: counts state the recorded number of events or affected participants, while percentages express frequency relative to a denominator. The registry record does not provide enough detail to infer that every listed term represents a unique participant, or to reconcile the listed terms with the total number of deaths. The entries should therefore be read as registry summaries rather than as a complete event-level account.
Safety interpretation also depends on how events were defined, collected, and attributed. A serious adverse event occurring during a study is not automatically caused by the device. The registry record does not report a causal assessment method, event timing, exposure duration, or detailed adjudication procedures. These missing details limit conclusions about relationships between the device and individual events.
What do the planning assumptions mean?
The sample-size planning framework is described as using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It defines the effect to detect as a stated fraction of the observed effect. For time-to-event outcomes, the framework specifies a total number of events; other planning illustrations use participants per arm. These are planning conventions, not observed trial outcomes.
The surveillance study itself has no comparator arm described and is not a randomized comparison. A hypothetical equal-allocation, two-arm calculation therefore should not be mistaken for the study’s actual enrollment structure or design. Sample-size illustrations are not observed power. They also do not establish that the study was adequately powered, because the registry record does not report its own sample-size justification or numerical primary endpoint results.
More broadly, analysis choices affect how an estimate should be read. The registry record does not report whether the primary analysis was adjusted, how multiple outcomes were handled, what analysis populations were used, or what sensitivity analyses were performed. Those are general considerations for evaluating clinical-trial statistics, not details that can be attributed to this study. The recorded method and endpoint definition are available, but the absent numerical results and analysis details leave substantial limits on independent statistical interpretation.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists four outcome measures and zero recorded analyses. It does not report a multiplicity plan describing how statistical error across multiple outcomes or repeated assessments would be handled. As a general statistical issue, examining multiple outcomes can increase the chance of finding an apparently notable result by chance if no plan controls or contextualizes those comparisons. The number of outcomes alone does not show that such a problem occurred; it means that the analysis strategy is important, and that strategy is not reported.
The primary endpoint is specified at 12 and 24 months. The record does not explain whether these time points were treated as separate inferential tests, how the confidence intervals were constructed across time, or whether one time point had priority for a formal conclusion. Numerical estimates and confidence intervals are not reported in the registry record, so no multiplicity-adjusted or unadjusted result can be assessed.
The endpoint population is described as participant limbs treated. The registry does not report the analysis population in further detail, including whether all enrolled participants or all treated limbs were included in the primary analysis. It also does not report missing-data counts, reasons for missing follow-up, or methods used to address missingness. These details matter because a time-to-event analysis depends on the observed follow-up and the assumptions used when observations end before an event.
The record does not report an interim analysis plan, a statistical analysis plan, or sensitivity analyses. Their existence or absence beyond the recorded information cannot be inferred. These reporting gaps limit assessment of how outcomes were selected and analyzed, but do not establish that a particular analysis was biased or improperly conducted.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| GORE® VIABAHN® Endoprosthesis | 188 | 321 | 58.6% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| GORE® VIABAHN® Endoprosthesis | 85 of 321 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| GORE® VIABAHN® Endoprosthesis | 0 of 321 |
Most frequent serious adverse event terms
| Event term | Organ system | GORE® VIABAHN® Endoprosthesis |
|---|---|---|
| Device occlusion | Product Issues | 45 of 321 |
| Vascular stent-graft stenosis | General disorders | 24 of 321 |
| Superficial femoral artery occlusion | Vascular disorders | 18 of 321 |
| Death | General disorders | 12 of 321 |
| Pneumonia | Infections and infestations | 10 of 321 |
| Superficial femoral arterial stenosis | Vascular disorders | 8 of 321 |
| In-stent arterial stenosis | General disorders | 7 of 321 |
| Pneumonia aspiration | Infections and infestations | 6 of 321 |
| Lung cancer | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 6 of 321 |
| Cerebral infarction | Nervous system disorders | 6 of 321 |
Serious events with the highest arm-level rate: device occlusion (14.0%), vascular stent-graft stenosis (7.5%), superficial femoral artery occlusion (5.6%), death (3.7%), pneumonia (3.1%).
For the GORE® VIABAHN® Endoprosthesis group, the registry lists 321 at risk for serious adverse events and 188 affected. It lists 321 at risk and 0 affected for other adverse events. Deaths are separately listed as 85. The selected serious-event terms and percentages are device occlusion, 14.0%; vascular stent-graft stenosis, 7.5%; superficial femoral artery occlusion, 5.6%; death, 3.7%; pneumonia, 3.1%; and superficial femoral arterial stenosis, 2.5%.
These entries are registry summaries, not a complete account of timing, duration, severity details, or causal attribution. The record does not explain the relationship between the deaths count and the listed percentage for the serious-event term Death, or provide enough event-level detail to reconcile them. The listed percentages should not be assumed to represent distinct participants or mutually exclusive events. In general, an adverse event recorded during follow-up does not by itself establish that the device caused it. A comparator group is not described, so these safety entries do not support a randomized comparison of event rates.
12. What the Result Does, and Does Not, Mean
The registry record describes a post-marketing surveillance study of the GORE® VIABAHN® Endoprosthesis for symptomatic peripheral arterial disease in superficial femoral artery lesions. It specifies primary assisted patency as the primary outcome, defines the endpoint, and identifies Kaplan-Meier estimates at 12 and 24 months with a 95% confidence interval. It also records adverse-event summaries for the device group.
What the posted record does not report is the numerical primary assisted patency estimate or its confidence interval. Consequently, the recorded information does not establish the observed level of patency or the precision of that estimate. The enrollment of 321 is not a substitute for endpoint results, and it does not reveal how many limbs contributed information at each time point or how much follow-up was available.
The study is not described as randomized and has no comparator group described. It therefore cannot provide a randomized estimate of the difference between the device and another treatment. A single-group surveillance result, even when numerical results are available, is descriptive of outcomes observed in that setting and does not by itself determine what would have happened under a different treatment or no device.
The safety figures indicate that serious adverse events were recorded for 188 of 321 at risk, other adverse events for 0 of 321 at risk, and deaths as 85. The registry also lists selected serious-event terms and percentages. These figures should not be taken as proof of causation or as a complete account of all event details. The registry record does not report the event definitions, timing, or causal assessment information needed for those conclusions.
In short, the record supplies the study purpose, design context, endpoint definition, and selected safety summaries, but not the numerical primary endpoint findings or a detailed analysis plan. It supports a description of what the study set out to measure and what safety categories were recorded; it does not support a quantitative conclusion about the primary patency result or a comparative treatment effect.
13. Why This Trial Matters Statistically
This study illustrates a central distinction in clinical-trial interpretation: a clearly defined outcome and a stated statistical method are not the same as an interpretable numerical result. The registry identifies primary assisted patency, specifies the limb-level population, and describes Kaplan-Meier estimation at 12 and 24 months. It also identifies a 95% confidence interval. Without the numerical estimates and interval limits, however, readers cannot judge either the observed patency or its precision.
The record is also a useful setting for distinguishing surveillance from comparative evaluation. It describes post-marketing monitoring in a clinical setting, with no comparator group and no randomized allocation stated. Such a design can contribute descriptive information about outcomes and adverse events in the study group. It does not, by itself, separate device effects from other influences on those outcomes.
The safety summaries highlight another statistical reading skill: event counts, affected-participant counts, and percentages are not interchangeable. The record gives serious-event and other-event summaries alongside selected event terms and percentages, but does not provide all event-level or timing details. Readers should avoid treating those entries as a causal comparison or assuming that listed terms are mutually exclusive.
Finally, the recorded information makes the limits of planning illustrations important. A hypothetical two-arm sample-size framework is not the actual design of this surveillance study and is not observed power. Planning calculations cannot replace outcome estimates, confidence intervals, or clear analysis-population information. The key statistical lesson is to distinguish what is defined, what is reported numerically, and what remains unreported in the registry record.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The main limitation for interpreting efficacy is the absence of numerical primary assisted patency estimates and confidence intervals in the registry record. The endpoint definition and the 12 and 24 month time points are reported, but the actual results and their precision are not. Therefore, the primary outcome cannot be quantitatively assessed from the recorded results.
The design is not described as randomized, and no comparator is listed. The record does not state allocation, so it does not support a like-for-like controlled comparison. This limits interpretation to the study group and prevents a randomized estimate of a treatment difference.
Although the primary endpoint is defined for participant limbs treated, the registry does not report how many limbs were analyzed or how the analysis population was constructed. It also does not report missing follow-up, censoring counts, censoring rules, event counts, or sensitivity analyses. These are important for understanding a time-to-event estimate and its uncertainty.
The registry lists four outcome measures and zero recorded analyses, but does not report a multiplicity strategy, a detailed analysis plan, an interim analysis plan, or a sample-size justification. The sample-size framework described for planning assumes two arms and equal allocation, unlike the study design described in the record; it should not be used to infer observed power.
Safety reporting is limited by the absence of detailed event definitions, timing, causal assessment, and event-level information. The record lists deaths as 85 and also includes Death among selected serious-event terms at 3.7%, without explaining the relationship between those entries. These limitations leave the safety summaries descriptive and prevent a more detailed reconciliation or causal interpretation.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: GORE® VIABAHN® Endoprosthesis Post-Marketing Surveillance Study (JPS 16-03) — NCT04706273.
- Registry record last updated 2024-09-20; status last verified 2023-10.
- Results first posted 2024-09-20.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
NCT04706273 is a completed post-marketing surveillance study sponsored by W.L. Gore & Associates. The registry lists enrollment of 321, a start date of 2016-08-25, and primary completion on 2019-07-11. It concerns the GORE® VIABAHN® Endoprosthesis in symptomatic peripheral arterial disease involving superficial femoral artery lesions.
The primary outcome is primary assisted patency in participant limbs treated, defined by hemodynamic evidence of flow without target lesion revascularization to restore flow after total occlusion. Kaplan-Meier estimates are specified at 12 and 24 months, with a 95% confidence interval. Numerical endpoint results are not reported in the registry record.
The record describes no comparator and does not state allocation. It lists serious adverse events for 188 of 321 at risk, other adverse events for 0 of 321 at risk, and deaths as 85, alongside selected serious-event terms and percentages. Four outcome measures and zero recorded analyses are listed. Further statistical-plan, missing-data, and analysis-population details are not reported in the registry record.