GORE® TAG® Thoracic Endoprosthesis French Mandatory Registry: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for GORE® TAG® Thoracic Endoprosthesis French Mandatory Registry (NCT02266342), a registered phase not stated study. The primary outcome is Number of Subjects With All-cause Mortality (Long-term).

2. Clinical Question

3. Trial Design

This is a French registry mandated by the French National Health Authority. Its stated purpose is to assess long-term safety of the GORE® TAG® Thoracic Endoprosthesis in the treatment of diseases of the thoracic aorta. The registry record names W.L.Gore & Associates as sponsor, records enrollment of 154, and gives the status as completed. The recorded start is 2014-10, and primary completion is listed as 2021-12.

The intervention is a device, the GORE® TAG® Thoracic Endoprosthesis. Conditions listed in the record include thoracic aortic aneurysm, descending thoracic aortic dissection, aortic diseases, traumatic rupture of the thoracic aorta, and penetrating ulcer. The record does not give the number of participants in each condition or describe eligibility criteria in detail. It also does not report treatment or procedural characteristics that would clarify how the device was used across participants.

The registry does not describe a randomized comparison, and allocation is not stated. The posted safety results identify a device group, but no like-for-like control group is described. The design therefore does not support a direct comparison of outcomes between assigned treatment groups. Whether other treatments were used in clinical practice is not reported in the registry record.

The registered primary outcome is a participant count for all-cause mortality at 5 years. The record also lists secondary outcomes concerning excluded aneurysm, penetrating aortic ulcer, false lumen or rupture site; neurological, cardiac, renal, and pulmonary complications; device-related complications; surgical conversion; secondary procedures; and disease-related mortality. Follow-up procedures, completeness of follow-up, and how outcome events were ascertained are not reported in the registry record. The completed status does not by itself establish that every participant had complete follow-up through the stated timeframe.

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

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.

6. Primary Endpoint

The registry lists the primary outcome as Number of Subjects With All-cause Mortality (Long-term), measured over 5 years.

The primary endpoint is the number of participants with all-cause mortality, measured at 5 years. All-cause mortality counts deaths regardless of their cause. It is therefore distinct from disease-related mortality, which appears among the secondary outcomes and concerns a more specific cause category. The primary endpoint is expressed as a count of participants, not as a continuous measurement or a direct comparison between treatment groups.

As a general statistical concept, all-cause mortality is often used because it does not depend on assigning a cause to each death. Cause attribution can be difficult, and an all-cause measure avoids that particular classification step. However, a count alone does not describe when deaths occurred, how long participants were observed, or how many were still at risk over time. A time-to-event analysis can address event timing and differing follow-up, but such an analysis is not reported in the registry record.

The endpoint title and timeframe identify what the registry intended to measure. They do not establish an analyzed endpoint result. Although the adverse-event record separately lists 31 deaths, the registry record does not explain whether that count is the analyzed five-year primary endpoint, how it relates to primary-outcome follow-up, or whether all participants had outcome status assessed at 5 years. A primary estimate, confidence interval, and analysis population are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry records its primary endpoint as a count of participants with an event. In statistical terms, this is a binary outcome at the participant level: each participant either meets the event definition during the stated assessment period or does not. Reporting a count is a direct description of observed events, but a count alone does not convey the uncertainty in the underlying event frequency. A confidence interval is a range of values compatible with the observed data under a specified statistical model; it helps readers assess precision. No confidence interval for the primary endpoint is reported in the registry record.

What does a participant count tell the reader?

A participant count makes clear how many people are recorded as having an event in a defined group. It does not by itself explain how completely outcomes were observed, whether follow-up duration was equal, or whether an event happened shortly after treatment or much later. Those details matter when interpreting long-term outcomes. The primary timeframe is 5 years, but the record does not report follow-up completeness, censoring, event dates, or a time-to-event estimate. Consequently, the available information does not support reconstructing a survival curve or an event rate over time.

Counts can also be difficult to interpret without a clearly defined analysis population. The registry records enrollment of 154 and lists 154 at risk for the serious and other adverse-event summaries. It does not specify, in the posted results, the population used for the primary endpoint or whether exclusions from any analysis occurred. The numerical agreement between enrollment and the adverse-event denominators does not establish complete primary-endpoint follow-up.

Why is there no treatment comparison?

A treatment comparison requires outcome information for groups that can be meaningfully contrasted. This registry record does not describe random allocation, and allocation is not stated. The safety summary identifies a group treated with the GORE® TAG® Thoracic Endoprosthesis, but no like-for-like control group is described. Without such a comparator, the counts cannot estimate how outcomes would differ under another treatment strategy. Even a descriptive comparison with an external group would require comparable populations, outcome definitions, and follow-up; such a comparison is not reported.

As a general concept, randomization can help balance measured and unmeasured prognostic factors across groups. A registry may instead describe clinical experience, but conclusions from that experience depend on careful measurement and analysis of participant characteristics, follow-up, and potential sources of bias. Those analytical details are not reported in the registry record. The record should therefore be interpreted as a descriptive safety record rather than as a randomized estimate of a treatment effect.

How should the planning assumptions be read?

The registry information includes assumptions for a planning illustration based on an observed effect: a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The illustration considers a stated fraction of the observed effect. For time-to-event outcomes, its convention is to report the total number of events using the Schoenfeld method; for other outcomes, it reports participants per arm. These are planning assumptions, not evidence that the registry itself used those design choices.

A sample-size calculation estimates the scale of a future study under stated assumptions. It is not an observed result and does not indicate the power actually achieved by this registry. In particular, a calculation based on an observed effect is conditional on that effect estimate and its uncertainty. The record does not report an original sample-size justification or a statistical plan for the registry. No planning result should be interpreted as a trial result or as observed power.

What analyses are missing?

The record lists 0 analyses. It does not report a primary estimate, a confidence interval, a p-value, a model, or adjustment for participant characteristics. These absences prevent an assessment of statistical precision and make it impossible to determine how any reported outcomes were analyzed. They also mean that no recalculated analysis can be compared with a sponsor analysis from the information in the registry record.

As a general statistical concept, over-dispersion arises when observed variability exceeds what a chosen model expects. It matters when data are more variable than a model assumes, because standard errors and confidence intervals may then be too small if the model is not adapted. This registry’s reported primary measure is a participant count, and no model or dispersion estimate is reported. Over-dispersion therefore cannot be assessed from the posted results, and no model-based adjustment should be inferred.

Overall, the methods information establishes the endpoint type, timeframe, and planning assumptions, but not an analysis method for the observed primary outcome. The descriptive adverse-event data can be stated as recorded, while uncertainty, time patterns, and causal contrasts remain unquantified.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("GORE® TAG® Thoracic Endoprothesis")
n      <- c(154)
events <- c(31)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  GORE® TAG® Thoracic Endoprothesis  154  31  20.1  14.1  27.3  14.6  27.2  14.6  27.2

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists 8 outcome measures, including the primary all-cause mortality endpoint and secondary outcomes concerning anatomical exclusion, neurological and cardiopulmonary complications, device-related complications, surgical conversion, secondary procedures, and disease-related mortality. It lists 0 analyses. A multiplicity strategy—such as a hierarchy for testing outcomes, an adjustment to control false-positive findings, or a distinction between confirmatory and exploratory analyses—is not reported in the registry record.

Multiplicity is a general statistical concern when several outcomes or comparisons are tested: the chance of at least one apparently unusual result can increase as more tests are considered. That concern cannot be quantified for this registry because no outcome tests or analysis plan are reported. The outcome list alone does not show that statistical tests were performed.

Missing-data handling and analysis populations are also not reported in the registry record. It does not state how participants with incomplete follow-up were handled, how missing endpoint status was treated, or whether analyses included all enrolled participants. Although enrollment is recorded as 154 and the adverse-event summaries list 154 at risk, those entries do not establish that all participants had complete five-year primary-outcome data. The record also does not describe interim analyses, reasons for missing data, or sensitivity analyses. These omissions limit interpretation of both the primary endpoint and the safety counts.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: vascular (26.0%), other (15.6%), cardiac (8.4%), neurological (7.8%), pulmonary (7.8%).

The device-group safety summary lists 79 participants with serious adverse events and 38 with other adverse events; each category lists 154 at risk. It also lists 31 deaths. These are participant counts in the posted safety information. They are not estimates from a comparison with a control group, and the record does not give confidence intervals or a statistical test for these counts.

The serious adverse event terms are reported with percentages: Vascular, 26.0%; Other, 15.6%; Cardiac, 8.4%; Neurological, 7.8%; Pulmonary, 7.8%; and Renal, 3.9%. The denominator and calculation method for these percentages are not reported in the registry record. The record also does not say whether a participant could contribute to more than one term. The percentages should not be added or treated as a partition of all serious events.

Serious and other adverse events are different registry categories; their counts should not be combined to produce a total. The record does not provide event timing, duration, severity beyond the serious classification, or attribution to the device. It also does not establish whether the 31 deaths correspond to the primary five-year mortality analysis. These figures describe the posted safety record but do not by themselves establish causation or comparative risk.

13. What the Result Does, and Does Not, Mean

The result information has a clear descriptive component: the registry records counts for participants with serious and other adverse events and lists serious-event terms with percentages. It also specifies a planned primary outcome of all-cause mortality at 5 years. These details describe the safety questions the registry addressed and the form of the posted safety data.

However, the registry record reports 0 analyses. It does not provide a primary mortality estimate, a confidence interval, or a statistical test. The adverse-event count of 31 deaths is not accompanied by information that links it to the analyzed five-year endpoint, so it cannot be substituted for a reported primary endpoint analysis. The absence of an analysis does not mean there were no events; it means the posted record does not quantify the primary outcome using an analysis result.

As a general statistical principle, an event count in a treated group does not show what would have happened to similar participants under a different treatment. A causal interpretation requires a credible comparison and assumptions about factors that influence treatment choice and outcomes. This record does not describe random allocation or a like-for-like comparator. It therefore cannot establish whether the device caused, prevented, or changed the frequency of any listed outcome.

The record also does not report the completeness of follow-up, participant characteristics, event timing, missing-data methods, or the denominator underlying the serious-event term percentages. These gaps affect how precisely the counts can be interpreted and whether they represent all participants throughout the stated timeframe. The completed status is a registry status, not evidence that every intended assessment was observed or analyzed.

The appropriate reading is narrow: the posted safety summaries give descriptive counts and listed term percentages, while the primary endpoint is defined but not analyzed in the registry record. No conclusion about comparative safety, effectiveness, or individual treatment decisions follows from these data alone.

14. Why This Trial Matters Statistically

This registry matters statistically because it illustrates the difference between registering an outcome and reporting an analysis of that outcome. The record defines a clinically relevant long-term endpoint—participant count with all-cause mortality at 5 years—and lists a range of secondary safety outcomes. Yet it reports 0 analyses. Readers can identify the planned questions, but they cannot assess an estimated primary result, its uncertainty, or how it was derived.

It also illustrates why safety counts need context. The posted group has 79 participants with serious adverse events and 38 with other adverse events, each against 154 at risk, and a separate count of 31 deaths. Counts are valuable descriptive information, but interpretation depends on event definitions, follow-up completeness, timing, attribution, and analysis populations. The record does not report several of these details, so the limits should remain visible rather than being filled in by assumption.

The registry format also highlights the role of comparison groups. Without a described control group or stated allocation, treated-group experience cannot estimate a causal difference between treatment strategies. A descriptive registry can contribute information about clinical experience, but it cannot answer every comparative question on its own.

Finally, planning calculations and observed results serve different purposes. The record’s stated assumptions for a sample-size planning illustration do not constitute an analysis of the registered outcomes and do not reveal observed power. Keeping those concepts separate helps prevent a hypothetical design calculation from being read as evidence of an outcome. The central statistical lesson is that endpoint definitions, analysis methods, uncertainty, and follow-up reporting are all needed to interpret a long-term safety record.

15. 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.

Several limitations are specific to the information reported for this registry. The primary endpoint is defined as a participant count for all-cause mortality at 5 years, but no analysis of that endpoint is reported. There is no primary estimate or confidence interval with which to judge the precision of the mortality result. The separate adverse-event summary lists 31 deaths, but the record does not establish that this is the analyzed primary endpoint count or describe its follow-up window.

The record does not describe a randomized comparison, and allocation is not stated. It identifies a device safety group without a like-for-like control group. Consequently, the posted results cannot distinguish outcomes associated with the device from outcomes related to underlying aortic disease, clinical status, or other aspects of care. Baseline characteristics and condition-specific participant counts are not reported, further limiting assessment of case mix.

Follow-up completeness, outcome ascertainment, event timing, and missing-data handling are not reported. Although the stated primary timeframe is 5 years and the registry status is completed, those entries do not demonstrate that every participant was observed for the full period. The method used to determine whether a participant experienced an outcome is also not described in the record.

The serious adverse event term percentages lack a stated denominator and calculation method, and the record does not indicate whether terms overlap. Device attribution and the details behind the serious-versus-other classification are not reported. Finally, the registry lists 0 analyses and does not report a statistical analysis plan, multiplicity approach, interim analyses, or an original sample-size justification. These limitations preclude inferential and comparative conclusions from the posted information.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: GORE® TAG® Thoracic Endoprosthesis French Mandatory Registry — NCT02266342.
• Registry record last updated 2024-04-19; status last verified 2023-11.
• Results first posted 2024-04-19.
• 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.

19. Record Summary

The French Mandatory Registry evaluates the GORE® TAG® Thoracic Endoprosthesis for diseases of the thoracic aorta. W.L.Gore & Associates is listed as sponsor. The registry records enrollment of 154, a start date of 2014-10, primary completion of 2021-12, and completed status. Its stated purpose is long-term safety assessment.

The primary outcome is the number of participants with all-cause mortality at 5 years. Secondary outcomes address anatomical findings, complications, procedures, and disease-related mortality. The record lists 8 outcome measures and 0 analyses. It does not report a primary endpoint analysis or its uncertainty.

The device-group safety summary lists 79 participants with serious adverse events and 38 with other adverse events, each with 154 at risk, and records 31 deaths. Serious adverse event terms include vascular, other, cardiac, neurological, pulmonary, and renal categories with posted percentages. The registry record does not report a comparator, analysis methods, follow-up completeness, or the denominator for those term percentages. The counts are descriptive and do not establish a causal or comparative treatment effect.