Safety and Efficacy of the GORE® Septal Occluder to Treat Ostium Secundum Atrial Septal Defects: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Safety and Efficacy of the GORE® Septal Occluder to Treat Ostium Secundum Atrial Septal Defects (NCT01711983), a na na study. The primary outcome is Number of Subjects With 6-Month Composite Clinical Success.

2. Clinical Question

3. Trial Design

This completed study evaluated the GORE® CARDIOFORM Septal Occluder for transcatheter closure of ostium secundum atrial septal defects. The registry lists W.L.Gore & Associates as the sponsor, enrollment of 400, and a start date of 2012-10. The primary completion date is 2018-11-26. The record classifies the study as single-group, with allocation listed as NA and masking listed as none. Its phase is listed as NA.

The intervention arm is titled Test Device and is described as ASD closure with the GORE® CARDIOFORM Septal Occluder. Because no concurrent control arm is reported, outcomes describe participants treated within this study; they do not provide a randomized estimate of the difference between the device and another treatment. The brief summary refers to comparison with outcomes from prior studies of the GORE® HELEX® Septal Occluder. The registry record does not supply the design or results of such a historical comparison as part of the reported trial results.

The primary endpoint is a six-month composite clinical success count. Secondary outcomes listed include technical success, procedure success, serious adverse events through 30 days, and closure success at six, 12, and 36 months. Seven outcome measures and one analysis are recorded, but the record does not provide further detail about the analysis plan or explain the relationship between the recorded analysis count and each outcome. The planned enrollment is not a reported endpoint result, and the record does not give a sample-size justification.

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.

6-Month Clinical Success Evaluation

Reasons for not completing this period:

6-Month Closure Evaluation

Reasons for not completing this period:

36-Month Closure Evaluation

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: All enrolled subjects with 6-month clinical success evaluation

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 6-Month Composite Clinical Success, measured over 6 months.

The primary endpoint counts participants who satisfy every component of the six-month composite clinical success definition. The components cover technical success, safety success, and closure success. Technical success requires successful deployment and retention of the GORE® CARDIOFORM Septal Occluder at the end of the index procedure. Safety success requires freedom from any serious adverse event through 30 days after the procedure, and freedom from specified device events from completion of the implant procedure through six months (195 days) after the procedure. Closure success requires the Echo Core Lab to assess the residual defect as occluded or clinically insignificant at the six-month evaluation.

A composite can summarize several clinically distinct dimensions in a single endpoint. Requiring all components means that a participant counts as a success only if each specified criterion is met; a failure to meet any component prevents classification as composite success. This can make the endpoint more demanding than a measure based on closure alone, but it also means that the overall count does not by itself show which component most often determined the result. Component-level results would be needed to understand that pattern.

The registry record states that the endpoint is a count of participants, but does not report the count meeting the composite. It also describes the endpoint among subjects with attempted study-device closure while identifying the primary population as all enrolled subjects with a six-month clinical success evaluation. Further details about how these descriptions were reconciled are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record identifies the primary outcome as a count of participants, a binary-outcome format in which each participant is classified according to whether the defined event or success criterion was met. Here, the primary event of interest is meeting the full six-month composite success definition. Counts can be informative, but an outcome count needs a clear denominator and analysis population to support interpretation as a rate or proportion. The record gives a primary population description and an endpoint description that refer to different eligibility phrasing: all enrolled subjects with a six-month clinical success evaluation, and subjects with attempted study-device closure. How those descriptions were applied is not reported in the registry record.

What does a composite endpoint combine?

In general, a composite endpoint combines multiple outcomes into one overall measure. It can reflect several dimensions of a clinical result, but the components may differ in importance, frequency, or meaning. For a composite requiring every component, success is conditional on satisfying all listed criteria. A total composite count therefore cannot reveal the component-specific pattern. Component-level results and a clear explanation of how each component was assessed help readers interpret what contributes to the overall classification. The registry record lists the criteria but does not report the primary composite count or component-specific results for that endpoint.

What can a single-group design estimate?

In general, a single-group study can describe observed outcomes among participants who received the study intervention. It does not directly estimate what would have happened to those same participants under a different intervention. A concurrent comparison group can help address that question, especially when allocation makes groups comparable; this study is recorded as single-group, with allocation listed as NA. The record also lists no masking. The absence of a concurrent randomized comparison means that observed counts should be treated as descriptive rather than as estimates of a causal treatment contrast.

How should precision be considered?

In general, a confidence interval conveys uncertainty around an estimated quantity under the assumptions of its statistical method. A narrower interval indicates greater statistical precision, while a wider interval indicates greater uncertainty. Precision is distinct from whether an outcome is clinically important and does not correct for bias or confounding. The registry record does not report a confidence interval or another uncertainty measure for the primary endpoint. Since the endpoint count itself is not reported, its precision cannot be assessed from this record.

What is known about the analysis plan?

The record lists one analysis, but does not describe the statistical model, estimation method, covariate adjustment, handling of repeated assessments, or inferential testing for the primary endpoint. Those details are not reported in the registry record. A listed analysis count alone is not enough to infer which methods were planned or used. Similarly, the record does not state whether there were interim analyses, how any analysis decisions were made, or whether the reported outcome population followed a prespecified analysis plan.

How do planning calculations differ from observed results?

In general, a sample-size calculation is a planning exercise based on assumptions about an effect, variability, significance level, allocation, and analysis method. It does not describe how many participants experienced an outcome, and it is not a measure of observed power. The registry record states that planning illustrations were computed from the observed effect using a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and effects defined as fractions of the observed effect. For time-to-event outcomes, it describes total-event calculations using the Schoenfeld method; other calculations are expressed as participants per arm. The record does not give the calculated planning values in the registry record for this analysis. It also does not report that these illustrations formed the original design justification, so they should not be treated as the trial’s own prospective sample-size rationale.

Over-dispersion is a general concern when count data vary more than a chosen statistical model expects; it can make standard uncertainty estimates too small if ignored. The primary outcome is described as a participant count, not as a count process requiring an over-dispersion model. The registry record does not report a model or indicate that over-dispersion was assessed. No inference about use of such a method is warranted.

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("Test Device")
n      <- c(368)
events <- c(332)
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  Test Device  368  332  90.2  86.7  93.1  86.8  92.8  86.7  92.8

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists a primary composite endpoint and several secondary outcomes, including technical success, procedure success, serious adverse events through 30 days, and closure success at six, 12, and 36 months. It records seven outcome measures and one analysis. However, the record does not describe a multiplicity strategy, such as a prespecified testing hierarchy or an adjustment for conducting multiple statistical tests. It is therefore not possible to determine whether the outcome analyses were intended to support formal claims or were primarily descriptive. The record does not report which outcomes, if any, were included in a family of statistical tests.

Missing-data handling is not reported in the registry record. The primary population is described as all enrolled subjects with a six-month clinical success evaluation, while the endpoint description refers to subjects with attempted study-device closure. The record does not explain how participants without an evaluation, with incomplete component information, or without an attempted closure were treated in the primary analysis. It also does not report a missingness count, imputation method, sensitivity analysis, or assumptions about missing outcomes.

Analysis-population details are limited. The registry record does not state whether the primary analysis used an intention-to-treat, per-protocol, or other defined population. Although the endpoint description identifies subjects with attempted closure, the exact analysis denominator and participant flow are not reported. These omissions matter because the number and characteristics of participants included in an endpoint analysis can affect its interpretation. Without the analysis population definition and missing-data procedures, readers cannot determine how completely the primary endpoint represents all enrolled participants.

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: asthma (0.5%), lymphadenitis (0.2%), angina pectoris (0.2%), atrial thrombosis (0.2%), atrioventricular block first degree (0.2%).

The Test Device group has 400 participants at risk for the serious adverse event count and 28 participants recorded as affected. The count for other adverse events is 260 among 400 at risk. The registry record lists 0 deaths. These are participant counts in the posted safety information, not comparisons between treatment groups. Because the study has no concurrent control arm, the counts alone cannot show whether events occurred more or less often than they would have under another treatment or without the device.

The record lists asthma (0.5%), lymphadenitis (0.2%), angina pectoris (0.2%), atrial thrombosis (0.2%), atrioventricular block first degree (0.2%), and coronary artery disease (0.2%) among the top serious adverse event terms. These term-specific percentages are reported as written; the registry information does not describe their attribution, timing, severity beyond their listing as serious terms, or whether participants could contribute more than one term. A participant count and a count of event terms are not necessarily interchangeable.

In general, adverse-event listings describe events recorded during a study and do not by themselves establish causation. The registry record does not report a comparative safety analysis or enough detail to determine how each event relates to the device, procedure, or underlying condition. The composite endpoint’s safety component separately defines freedom from serious adverse events through 30 days and freedom from specified device events through six months (195 days); the group safety counts should not be assumed to be identical to that component’s analysis.

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

The record establishes that a completed, single-group study evaluated the GORE® CARDIOFORM Septal Occluder for transcatheter closure of ostium secundum atrial septal defects. It also gives a detailed definition of six-month composite clinical success and reports adverse-event counts for the Test Device group. Those details describe the intended endpoint and the safety information recorded, but they do not reveal the primary success result: the number of participants meeting the composite endpoint is not reported in the registry record.

Without the primary endpoint count, readers cannot assess the observed frequency of composite success or its statistical precision. The record also does not report component-specific results that would show technical success, safety success, or closure success separately. The composite criteria indicate what counted as success, not how many participants satisfied those criteria. Likewise, the listed secondary outcomes do not substitute for their missing results.

The adverse-event counts describe events among participants in the study, but do not prove that the device caused them. A single-group design has no concurrent randomized comparator, so the record cannot establish how the outcomes compare with another treatment under similar conditions. The brief summary’s reference to earlier HELEX® studies does not supply a comparative analysis or demonstrate that the study groups were comparable.

These limitations do not make the registry information uninformative. It defines the study’s design, intervention, follow-up timing, primary endpoint criteria, and some safety counts. They do constrain the conclusions: the registry record supports a description of the study and its reported counts, not a conclusion about comparative effectiveness, a causal safety effect, or the magnitude and precision of six-month composite clinical success. The endpoint result and additional analysis details are not reported in the registry record.

14. Why This Trial Matters Statistically

This study illustrates why an endpoint definition and an endpoint result answer different questions. The registry record specifies what counted as six-month composite clinical success, combining technical success, safety criteria, and Echo Core Lab assessment of residual defect status. That definition permits readers to understand the intended outcome, but without the observed count and analysis denominator it does not show how often the outcome occurred. A precise, interpretable endpoint requires both a clear rule for classifying participants and results that apply that rule to a defined analysis population.

The single-group design also matters to interpretation. It can document outcomes in a cohort treated with the device, but without a concurrent comparator it cannot isolate the effect of the device from other influences. The summary mentions prior HELEX® study outcomes as a point of reference, yet the record does not report a formal comparison or its methods. Historical comparisons can be difficult to interpret when populations, follow-up, and outcome assessment are not shown to be alike.

The composite endpoint demonstrates a common statistical trade-off. Combining components can represent several aspects of clinical outcome, while making the overall result dependent on all components meeting their criteria. A composite count may therefore conceal meaningful differences among its components. The listed secondary outcomes could contribute context, but their results are not reported in the registry information.

Finally, the record distinguishes neither a detailed analysis plan nor a sample-size justification. It describes planning illustrations based on the observed effect, but those are planning calculations rather than observed trial outcomes or evidence of the trial’s original design rationale. These features make the study useful for discussing transparent reporting: design, population, endpoint rules, analysis methods, missing data, and uncertainty all affect what readers can infer from clinical trial results.

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.

The main trial-specific limitation in interpreting the registry record is that it does not report the primary endpoint result. Although the outcome is defined as a count of participants with six-month composite clinical success, no count, proportion, or uncertainty interval is available in the information summarized. The listed secondary outcomes also lack outcome results, so they do not provide a reported clinical-success estimate or clarify the components of the composite.

The study is classified as single-group, with allocation listed as NA and masking listed as none. There is no concurrent control group in the record, limiting direct comparative interpretation. The brief summary refers to outcomes from prior GORE® HELEX® studies, but comparative methods and results are not reported. The record also does not describe participant characteristics, eligibility details beyond the condition, or the clinical context needed to evaluate how broadly the findings might apply.

The primary population description refers to all enrolled subjects with a six-month clinical success evaluation, whereas the endpoint description refers to subjects with attempted device closure. The registry record does not explain the analysis denominator or how participants missing an evaluation or component assessment were handled. Missing-data methods, analysis-population definitions, and sensitivity analyses are not reported.

Further limitations include the absence of a described statistical analysis plan, uncertainty measures for the primary outcome, and multiplicity procedures. The registry record does not report whether interim analyses were planned or conducted. It lists adverse-event counts, but does not provide comparative safety estimates or detailed attribution information. These gaps prevent evaluation of the endpoint’s precision, the robustness of any analysis, and the relationship of recorded adverse events to the device or procedure.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Safety and Efficacy of the GORE® Septal Occluder to Treat Ostium Secundum Atrial Septal Defects — NCT01711983.
• Registry record last updated 2020-08-21; status last verified 2020-08.
• Results first posted 2020-08-21.
• 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

NCT01711983 is a completed, single-group study sponsored by W.L.Gore & Associates, evaluating the GORE® CARDIOFORM Septal Occluder for transcatheter closure of ostium secundum atrial septal defects. The record lists enrollment of 400, a start date of 2012-10, and primary completion on 2018-11-26. Allocation is listed as NA, masking as none, and phase as NA.

The primary outcome is the number of subjects with six-month composite clinical success, requiring technical success, specified safety success, and closure success. The registry record does not report the primary endpoint result, its uncertainty, or detailed statistical and missing-data methods. Safety information lists 28 participants with serious adverse events, 260 with other adverse events, and 0 deaths among 400 at risk in the Test Device group. These descriptive counts do not constitute a comparison with another treatment.