Xeltis Bioabsorbable Pulmonary Valved Conduit Pivotal Study: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Xeltis Bioabsorbable Pulmonary Valved Conduit Pivotal Study (NCT03022708), a na na study. The primary outcome is Composite Rate of Events of Device Related Death, Re-operation or Re-intervention at 12 Months Follow-up..

2. Clinical Question

The study concerns a device used for right ventricular outflow tract reconstruction in patients with congenital heart malformations. Its registry description frames the work as a prospective assessment of safety and efficacy, with feasibility also described in the brief summary. The primary question combines device-related death and further procedures attributed to device failure into one endpoint. That combination makes the endpoint a count of participants who experience at least one of the specified events, rather than a comparison of separate treatments.

Because there is no control group, the record does not set up a randomized comparison of the conduit against another device or treatment. The results therefore cannot answer a comparative question about relative outcomes. They are intended to describe outcomes among participants who received the conduit. The registry record does not report a primary endpoint result, so the rate of participants meeting the composite endpoint cannot be described from this record. Details beyond the listed population description, including a complete account of eligible congenital malformations, are not reported in the registry record.

3. Trial Design

The registry describes a prospective, multi-center, single-group, non-randomized pivotal study of the Xeltis Bioabsorbable Pulmonary Valved Conduit. The device is described as bio-absorbable and polymer-based, and is used for right ventricular outflow tract correction or reconstruction. The record lists the study phase as NA, allocation as NA, and masking as NONE. With no randomized allocation and no separate control group, this is a study of outcomes in participants receiving the device, not a like-for-like comparison between arms.

The record lists an enrollment of 6. The stated start date is 2017-05-08, and the primary completion date is 2022-12-15. The current status is active, not recruiting. Those registry fields describe the record's status and timeline; they do not establish that every follow-up visit was completed or that results were posted. The primary endpoint is assessed at 12 months, with the description stating that it is measured once all 12 month follow-up visits have been completed.

The brief summary characterizes the study as assessing feasibility in subjects requiring right ventricular outflow tract correction or reconstruction due to congenital heart malformations. The official title frames the study as assessing safety and efficacy. The record lists 8 outcome measures and 0 analyses. A detailed statistical analysis plan, including methods for estimating the primary outcome or handling incomplete follow-up, is not reported in the registry record. No sample-size justification for the trial's own design is reported in the registry record.

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 Composite Rate of Events of Device Related Death, Re-operation or Re-intervention at 12 Months Follow-up., measured over 12 months.

The primary endpoint is the composite rate of events of device-related death, re-operation, or re-intervention at 12 months. The endpoint description specifies that re-operation or re-intervention is due to device failure. Its unit is participants, and the listed measurement is a count of participants. Thus, its intended summary is the number of participants meeting the composite definition, rather than a measurement on a continuous scale. The registry record does not report a result for this endpoint.

A composite endpoint brings several clinically distinct events into one outcome. In general, this can capture more than one way a device may fail to meet its intended purpose, while giving a single overall endpoint for assessment. It also means the combined result depends on which component events occur; a composite count alone would not show the contribution of each component. The registry record does not give a primary result by component, nor does it report details on how multiple qualifying events in one participant are handled.

The endpoint is assessed at 12 months, and the record says measurement occurs once all 12 month follow-up visits have been completed. This timing defines the intended observation point, but does not by itself provide the number assessed, the amount of missing follow-up, or the outcome count. Each of those results is not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What kind of outcome is the primary endpoint?

The primary endpoint is a count of participants meeting a binary composite definition at 12 months: device-related death, re-operation, or re-intervention due to device failure. In general, a binary outcome records whether each participant did or did not meet a specified definition. A count then totals the participants meeting it. The record names participants as the unit, but does not report the observed count or the number included in the primary analysis.

Combining event types into a composite can provide a single summary across several possible outcomes. In general, interpretation of a composite should consider its components as well as the combined result, because different components may have different clinical meanings and frequencies. The registry record does not report component-specific primary results. It also does not report whether a participant with more than one qualifying event is counted once or how event timing within the 12 month period is handled.

What does the study design allow?

The design is prospective, single-group, and non-randomized, with no comparator arm. General statistical context: randomization and a concurrent comparator can help distinguish treatment-group differences from other explanations, while a single-group study primarily describes outcomes in the group observed. The record does not permit a randomized between-group estimate. No adjusted or unadjusted primary analysis is reported in the registry record, and there are no listed analyses.

The enrollment of 6 is the registry's listed enrollment, not necessarily the number with complete primary endpoint follow-up or the number analyzed. Those counts are not reported in the registry record. In general, the amount of information available for a binary outcome depends on the number of participants observed and on how often the event occurs. With a small group, an event count can change notably when the outcome of one participant changes; uncertainty should therefore be considered alongside any estimate. No primary estimate or confidence interval is reported.

How should uncertainty and significance be understood?

General statistical context: a confidence interval gives a range of values compatible with an estimate under the assumptions of the analysis. Its width conveys precision; a wider interval indicates less precise information than a narrower one. A p-value, when used, describes how compatible data are with a specified null model under stated assumptions. Neither a confidence interval nor a p-value substitutes for the outcome definition, the design, or an assessment of practical meaning. The registry record reports no primary confidence interval, p-value, or statistical test.

The record's sample-size assumptions describe a planning illustration, not the trial's own design justification. The illustration uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; it considers effects that are stated fractions of the observed effect. For time-to-event tables, the stated quantity is the total number of events using the Schoenfeld approach; other tables use participants per arm. These assumptions do not describe this single-group study's allocation, because the trial has no two-arm randomized comparison. No trial-specific sample-size justification is reported in the registry record, and a planning calculation is not observed power or evidence that an effect was established.

Why might over-dispersion matter in other settings?

General statistical context: over-dispersion occurs when outcome variability is greater than a model assumes. If a model understates variability, standard errors may be too small and confidence intervals too narrow. It can matter for count outcomes when observations vary more than a simple model expects. The primary endpoint is specified as a participant count for a binary composite, but the record does not identify a statistical model or report an over-dispersion assessment. It would not be appropriate to claim that a particular model or correction was used.

What analysis details are absent?

The registry record does not report a primary statistical analysis method, a confidence interval procedure, covariate adjustment, a handling rule for missing 12 month outcomes, or an analysis population definition. It also does not report a statistical analysis plan or interim analyses. Those omissions mean the endpoint definition can be described, but the method used to turn participant outcomes into an inferential result cannot be reconstructed from the registry record. The posted information does not include a primary result to recalculate or compare with a sponsor analysis.

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("Xeltis Bioabsorbable Pulmonary Valved Conduit")
n      <- c(6)
events <- c(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  Xeltis Bioabsorbable Pulmonary Valved Conduit  6  0  0.0  0.0  45.9  0.0  39.0  0.4  41.0

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists 8 outcome measures and 0 analyses. The primary endpoint is a composite at 12 months; the record also lists secondary outcomes addressing device-related death, overall mortality, re-operation or re-intervention due to device failure, mean pressure gradient, and pulmonary regurgitation at stated follow-up times. The record does not report how the outcomes were prioritized for statistical testing, whether adjustment for multiple comparisons was planned, or whether the secondary outcomes were intended to be descriptive or confirmatory. A multiplicity strategy is not reported in the registry record.

In general, examining multiple endpoints can increase the chance of at least one apparently noteworthy result if each is tested without accounting for the collection of tests. Whether and how to adjust depends on the analysis objectives and the prespecified plan. Since no analyses are listed and the statistical plan is not reported, it is not possible to determine how multiplicity was handled or whether any results were selectively emphasized.

The primary endpoint description says it is measured once all 12 month follow-up visits have been completed. That statement does not specify how participants without a completed visit would be treated. The number with missing primary outcome data, reasons for missingness, imputation methods, and sensitivity analyses are not reported in the registry record. The record also does not define the analysis population, such as whether it includes all enrolled participants or only those with evaluable follow-up. These details are needed to understand which participants contribute to a result and how robust it is to incomplete data.

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: pneumonia (16.7%).

The registry's adverse-event figures for the Xeltis Bioabsorbable Pulmonary Valved Conduit group list 6 participants at risk for serious adverse events and 1 participant affected. For other adverse events, the figures list 6 at risk and 3 affected. The record lists 0 deaths. Pneumonia is included among the most frequent serious terms at 16.7%. These figures should be read as safety summaries, not as the primary composite endpoint result.

The registry record does not state that the listed adverse events were caused by the device. It also does not report the event-level details needed to determine whether an adverse event qualified as device-related death, re-operation, or re-intervention due to device failure. The serious and other adverse-event categories may not be assumed to be mutually exclusive; whether participants appear in both categories is not reported in the registry record. The pneumonia percentage is quoted as listed and should not be treated as a separate estimate of the primary outcome.

In general, adverse-event counts describe what was recorded in the study group. They do not, on their own, establish causality or provide a comparison with another treatment. The listed count of 0 deaths is a safety figure in this record; details on its scope and event attribution are not reported.

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

The record establishes that the study was designed to follow participants receiving a bio-absorbable pulmonary valved conduit and to assess a composite of device-related death, re-operation, or re-intervention due to device failure at 12 months. It also documents an enrollment of 6 and provides a limited set of adverse-event counts. These details describe the study question and the information recorded about safety.

The record does not report the result for the primary composite endpoint. It therefore cannot show how many participants met that definition, how precisely any estimated event rate was measured, or whether the components occurred individually. Nor does it provide a comparison group. The design cannot by itself establish how outcomes would differ under another treatment or separate device-related outcomes from other influences. No conclusion about comparative effectiveness or the cause of an adverse event follows from the listed design and safety figures alone.

General statistical context: an observed count is most informative when read with its denominator, endpoint definition, follow-up completeness, and a measure of uncertainty. Here, the total enrollment is listed, but the number with completed 12 month follow-up and the primary analysis denominator are not reported in the registry record. The absence of a primary result is distinct from a result of zero events; no such zero count is given for the primary endpoint.

The safety figures report 1 participant affected by serious adverse events, 3 by other adverse events, and 0 deaths, with pneumonia listed at 16.7% among serious terms. They should not be substituted for the primary endpoint, and they do not establish that the conduit caused the events. The registry record is useful for identifying the intended assessment and reported study status, but it does not provide enough outcome information to judge the primary endpoint's observed frequency or precision.

14. Why This Trial Matters Statistically

Statistically, this study illustrates the distinction between an endpoint definition and an endpoint result. The registry describes a clinically specific composite and its follow-up timing, but does not report the count or rate. Without that result, readers cannot assess the observed frequency, estimate its uncertainty, or examine the separate components. A carefully stated outcome is necessary for interpretation, but it is not a substitute for the data and analysis.

The single-group, non-randomized design also makes the inferential scope important. It can describe outcomes among participants receiving the conduit, but does not provide a concurrent comparator for estimating a treatment difference. This limits what a statistical analysis could establish even if outcome counts were posted. The enrollment of 6 further makes follow-up completeness and uncertainty especially relevant; the record does not report the analyzed denominator or an interval estimate.

The study is also a reminder that safety summaries and efficacy-related endpoints answer different questions. Adverse-event counts provide a view of recorded safety events, while the primary composite has a particular definition involving device-related death and further procedures due to device failure. Those summaries should not be merged or treated as interchangeable. The record does not report whether safety events correspond to the primary endpoint.

Finally, the registry lists outcome measures but no analyses and does not report a statistical plan, multiplicity handling, or missing-data methods. These omissions prevent a reader from checking how planned outcomes were translated into analysis. The study matters statistically as an example of why design, endpoint definition, follow-up, analysis methods, and posted results must be considered together when interpreting clinical evidence.

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 limitation for interpreting outcomes is that the registry record does not report a primary endpoint result. There is no primary count or rate, confidence interval, or component-specific summary to assess. The number of participants completing the 12 month follow-up and the denominator used for analysis are also not reported in the registry record. Although enrollment is listed as 6, it cannot be assumed that all enrolled participants contributed complete endpoint data.

The single-group, non-randomized design has no control arm. Consequently, the record cannot provide a randomized comparison with another treatment, and observed outcomes cannot be interpreted as a treatment difference. The small listed enrollment also means that any eventual estimate would need to be read with its uncertainty; the registry record supplies no such estimate or interval.

The registry record lists 8 outcome measures but 0 analyses. It does not report an analysis plan, multiplicity approach, handling of missing observations, analysis population, or interim-analysis details. The absence of these details makes it impossible to assess prespecification and reproduce an inferential analysis. The record does not provide a trial-specific sample-size justification.

The safety information is limited to the listed adverse-event counts and a serious-event term. Details on event timing, duration, severity beyond the serious classification, attribution, and overlap between categories are not reported in the registry record. The arm description also gives only a partial list of congenital malformations, so the full eligibility detail cannot be reconstructed from this record. These limitations concern what the registry reports and do not establish that additional information is unavailable elsewhere.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Xeltis Bioabsorbable Pulmonary Valved Conduit Pivotal Study — NCT03022708.
• Registry record last updated 2026-08-06; status last verified 2026-06.
• Results first posted 2026-08-06.
• 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 registry record describes a prospective, multi-center, single-group, non-randomized pivotal study of the Xeltis Bioabsorbable Pulmonary Valved Conduit for right ventricular outflow tract reconstruction. It lists enrollment of 6, study phase NA, masking NONE, and status active, not recruiting. The stated start date is 2017-05-08, and the primary completion date is 2022-12-15.

The primary endpoint is a participant count for a composite of device-related death, re-operation, or re-intervention due to device failure at 12 months. The registry record does not report the primary endpoint result, a statistical analysis, or a confidence interval. Safety figures list 1 participant affected by serious adverse events, 3 by other adverse events, and 0 deaths; pneumonia is listed at 16.7% among serious terms. The record lists 8 outcome measures and 0 analyses. Details on missing data, analysis populations, and multiplicity are not reported in the registry record.