X-Seal EU Post-Market Clinical Follow-Up Protocol: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for X-Seal EU Post-Market Clinical Follow-Up Protocol (NCT02406612), a na na study. The primary outcome is Major Complications.

2. Clinical Question

3. Trial Design

This was a completed post-market clinical follow-up protocol for the X-Seal 6F Vascular Closure Device. The registry lists the study model as single group, allocation as NA, and masking as none. The intervention description says the device was used to achieve hemostasis in diagnostic and interventional procedures using up to a 6F procedure sheath. The record lists 47 participants enrolled.

Participants are described in diagnostic and interventional categories. These categories describe procedure types, not randomized treatment assignments. The record does not identify a concurrent standard-compression group. Rather, the study summary describes comparison with standard compression techniques using data from literature surveys. This is not a like-for-like comparison: differences between the study participants and people described in literature may reflect differences in populations, practice, or how outcomes were measured.

The primary endpoint is major complications within approximately 30 days following the procedure. Secondary outcomes listed are time to ambulation and adverse events. Although the study rationale refers to time to hemostasis, the outcome list does not identify it as one of the listed secondary outcomes. The registry lists four outcome measures, but a complete set of outcome definitions and results is not reported in the registry record.

The study is marked completed. Its phase is listed as NA. The registry record does not report details of the protocol’s sample-size justification, planned interim analyses, or a statistical analysis plan. It also does not report the flow of participants through follow-up, analysis populations, or whether all enrolled participants contributed data to each outcome.

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

Reasons for not completing this period:

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 Major Complications, measured over 30 days.

The primary endpoint counts participants who experienced a major complication within approximately 30 days after the procedure. It is a participant-level binary outcome: each participant is classified according to whether the defined complication outcome occurred during the specified follow-up period. A count can communicate how many participants had an event, but interpretation also depends on knowing the denominator, the precise event definition, completeness of follow-up, and how events were adjudicated.

Complications are used as safety outcomes because they capture clinically important events after a procedure. The approximately 30-day timeframe defines the period in which the registry intended to assess the primary outcome; it does not by itself establish how follow-up was conducted or whether every participant was observed for that whole period. Those operational details are not reported in the registry record.

The registry record names the endpoint and timeframe but does not report the primary result, a denominator for its analysis, a confidence interval, or a statistical test. Therefore, it is not possible to describe the observed major-complication count or estimate the precision of that result from this record. The listed adverse-event figures are not a substitute for the primary endpoint result: the record does not establish that those figures correspond exactly to the major-complication definition.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical interpretation depends first on the design and the outcome being analyzed. This study is recorded as single group, with allocation listed as NA and masking as none. The intervention was the X-Seal 6F Vascular Closure Device. The diagnostic and interventional categories indicate procedure types; they are not randomized assignments to device and control. The study summary refers to literature surveys for standard compression, so any reference to that technique is not a concurrent randomized comparison in this record.

What does a participant count measure?

The primary outcome is a count of participants with major complications within approximately 30 days after the procedure. A participant-level event outcome distinguishes whether each person experienced the defined event during follow-up. A count by itself does not fully convey risk: interpretation also needs the number of participants assessed, a clear outcome definition, and information about missing follow-up. The primary count and its analysis denominator are not reported in the registry record.

Why does a confidence interval matter?

General statistical explanation: a confidence interval expresses the uncertainty around an estimated quantity under the assumptions of the analysis method. It helps readers distinguish a relatively precise estimate from one that is compatible with a broad range of values. A point estimate without an interval gives less information about precision, and a significance test alone does not show the range of plausible effect sizes. The registry record does not report a primary estimate or confidence interval, so the precision of the major-complication result cannot be assessed.

What can a comparison establish?

General statistical explanation: a comparative treatment effect requires a defined contrast between groups and an analysis suited to how those groups were formed. Random allocation can help balance measured and unmeasured factors on average, while an uncontrolled or nonrandomized comparison may be affected by differences in participant characteristics, clinical practice, or outcome ascertainment. Here, the record describes one device study group and literature-based reference data for standard compression, not a concurrent randomized comparator. A causal contrast with standard compression is therefore not available from the posted design description.

How should the adverse-event counts be read?

The registry reports counts of participants at risk and affected, separated into diagnostic and interventional procedure categories, as well as deaths. These are descriptive summaries. They should be read with the stated group labels and denominators rather than treated as adjusted estimates or proof of a difference between procedure categories. General statistical explanation: small event counts can be especially sensitive to whether one or a few events are included, so uncertainty is important when interpreting them. No confidence intervals or inferential analyses for these safety counts are reported.

What does the planning illustration represent?

General statistical explanation: a sample-size calculation describes the number of participants that would be needed under stated design assumptions to detect a chosen effect with a specified statistical operating characteristic. It is a planning exercise, not a measurement of how likely the completed study was to find an effect. The stated illustration assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is described as a stated fraction of the observed effect. These assumptions do not describe the single-group study design. The registry record does not report the protocol’s own sample-size justification, and no planning count is reported in the registry record for interpretation.

What analyses are available?

The registry lists zero analyses. That means the record does not provide a documented analysis with which to evaluate the primary outcome or a comparative effect. The statistical analysis plan, including any model, adjustment variables, hypothesis-testing procedure, or interim analysis, is not reported in the registry record. Without those details and outcome results, readers cannot assess whether the analysis followed a prespecified plan or how alternative analytic choices might affect the conclusions.

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("Diagnostic", "Interventional")
n      <- c(23, 18)
events <- c(0, 0)
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  Diagnostic  23  0  0.0  0.0  14.8  0.0  14.3  0.1  14.2
ARM  Interventional  18  0  0.0  0.0  18.5  -0.0  17.6  0.1  17.6

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists four outcome measures and identifies major complications within approximately 30 days as the primary outcome. It also lists time to ambulation and adverse events as secondary outcomes. The record does not describe how multiple outcomes were handled statistically, whether any multiplicity adjustment was planned, or which outcomes were intended to support confirmatory claims. The statistical analysis plan is not reported in the registry record.

The record lists zero analyses. It does not report a planned approach to missing data, participant exclusions, or the analysis populations used for each outcome. It is therefore not possible to determine whether all enrolled participants were followed, whether some outcomes were unavailable, or how any unavailable observations were treated. A lack of reported missing-data details should not be interpreted as proof that follow-up was complete.

For the primary endpoint, the registry gives the outcome definition and timeframe but not the observed count, analysis denominator, or an estimate of uncertainty. The safety summaries include participants at risk and affected within diagnostic and interventional categories, but do not specify how these counts relate to the analysis populations for the primary outcome. These reporting gaps limit assessment of outcome completeness, multiplicity, and the robustness of any conclusion.

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: new catheterization (4.8%), hypertension (4.8%), pneumonia (4.8%), arrhythmia (4.8%), pancreatitis (3.8%).

The safety summaries separate diagnostic and interventional procedures. For serious adverse events, the diagnostic group lists 26 participants at risk and 1 affected; the interventional group lists 21 at risk and 4 affected. For other adverse events, the corresponding diagnostic figures are 26 at risk and 1 affected, while the interventional figures are 21 at risk and 6 affected. Deaths are listed as 0 for both groups.

The registry also lists New catheterization, Hypertension, Pneumonia, and Arrhythmia at 4.8% each, and Pancreatitis at 3.8%. These are descriptive safety entries. The record does not report whether individual participants could contribute more than one event term, how event seriousness was determined, or the relationship between these terms and the major-complication endpoint. They should not be summed or treated as mutually exclusive categories.

These figures do not compare the device with a control group: both categories are procedure types in a single-group study. The registry does not report adjusted comparisons or uncertainty intervals for the event counts. Descriptive counts alone cannot establish whether an event was caused by the device or procedure.

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

The record establishes that a post-market follow-up study of the X-Seal 6F Vascular Closure Device was completed, with 47 participants enrolled. Its primary endpoint was major complications within approximately 30 days after the procedure. It also records safety counts by diagnostic and interventional procedure category and lists secondary outcomes concerning ambulation and adverse events.

It does not report the primary endpoint result, a primary analysis denominator, or a confidence interval. As a result, the record does not provide a quantitative estimate of the frequency or precision of major complications. The safety counts describe events among the listed procedure categories, but they do not constitute a randomized comparison and do not establish a causal effect of the device.

The study summary describes the aim of assessing hemostasis and ambulation in relation to standard compression techniques using literature surveys. Because the registry record does not describe a concurrent compression group or a reported comparative analysis, it cannot provide a direct estimate of the difference between device use and standard compression. The record also does not report time-to-hemostasis results, despite referring to that outcome in the study rationale.

These reporting limits do not imply that the device is safe or unsafe, effective or ineffective. They mean that the registry record, as reported, does not contain the outcome results and analysis details needed to quantify those questions. The distinction is important: a completed study designation is not itself evidence of a particular outcome, and the absence of a posted result is not a result of zero events.

14. Why This Trial Matters Statistically

This study illustrates why design labels matter when reading clinical results. A single-group post-market study can describe outcomes among people who received a device, but it does not by itself establish what would have happened to comparable participants under another approach. The record’s literature-based reference to standard compression is distinct from a concurrent control group. That distinction limits direct causal interpretation, even when descriptive event counts are available.

The record also demonstrates the importance of reporting the denominator and uncertainty alongside an outcome count. The primary endpoint is clearly named, but its result and analysis denominator are not reported in the registry record. Without them, readers cannot assess the observed frequency or precision of major complications. Likewise, listed adverse-event counts are informative descriptions but are not a substitute for the primary endpoint or a comparative analysis.

Post-market follow-up is relevant because it describes device use in the clinical setting identified by the protocol. The value of such evidence depends on transparent reporting of the population followed, endpoint definitions, completeness of follow-up, and analysis methods. Those details are not reported in the registry record. Thus, the statistical lesson is not a conclusion about device performance; it is the need to separate the question a study was designed to address from what the available results can actually support.

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 central limitation for interpretation is that the registry record names the primary endpoint but does not report its result. It gives no primary endpoint analysis denominator, confidence interval, or statistical test. The number of participants enrolled is reported as 47, but enrollment alone does not establish how many participants contributed to each outcome.

The study is listed as single group, with allocation NA and masking none. The diagnostic and interventional categories are not randomized comparison groups. Standard compression is mentioned as a literature-based reference, but a concurrent control group and an adjusted comparison are not reported. Differences between observed outcomes and literature data could therefore reflect differences in participant selection, clinical practice, follow-up, or outcome definitions.

The registry lists adverse-event counts but does not report detailed event definitions, adjudication procedures, event timing, or the relationship of those events to the primary major-complication endpoint. It also does not report participant flow, follow-up completeness, missing-data handling, analysis populations, or a statistical analysis plan. The record lists zero analyses, limiting assessment of inferential results and prespecification.

The available information does not explain how the study’s planned enrollment was justified, whether interim analyses were planned, or how multiple outcomes were handled. Those omissions prevent evaluation of several design and analysis choices. They do not establish that the study lacked such procedures; those details are simply not reported in the registry record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: X-Seal EU Post-Market Clinical Follow-Up Protocol — NCT02406612.
• Registry record last updated 2018-10-29; status last verified 2018-01.
• Results first posted 2018-10-29.
• 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 completed study is a single-group post-market follow-up protocol for the X-Seal 6F Vascular Closure Device. The registry lists 47 participants enrolled and describes use in diagnostic and interventional procedures with up to 6F sheaths. The primary endpoint is the count of participants with major complications within approximately 30 days. Secondary outcomes include time to ambulation and adverse events.

The record lists diagnostic and interventional safety counts, including serious adverse events, other adverse events, and deaths. It does not report the primary endpoint result, its analysis denominator, or a statistical analysis. Standard compression is referenced through literature surveys rather than a concurrent control group. The protocol’s sample-size justification, missing-data approach, analysis populations, and multiplicity plan are not reported in the registry record.