everlinQ endoAVF Post Market Study: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for everlinQ endoAVF Post Market Study (NCT02682420), a na na study. The primary outcome is Participants With Primary Patency of the endoAVF at 6 Months Post-Index Procedure.

2. Clinical Question

This question is focused on a defined post-procedure outcome in the treated group, rather than on a difference between treatment strategies. A registry entry of this kind can describe the planned endpoint and study context, but without the numerical endpoint result it cannot show the observed level of patency at the specified time. Nor can a single-group record establish how that outcome compares with what would have occurred under another approach. The study status is listed as terminated; the reason for termination is not reported in the registry record.

3. Trial Design

The everlinQ endoAVF Post Market Study is listed as a prospective, multi-center study of the everlinQ endoAVF System. The stated purpose was to evaluate the system when used to create an endovascular arteriovenous fistula for patients requiring vascular access for hemodialysis. The registry lists Chronic Kidney Disease as the condition and enrollment as 100.

The design is classified as single-group. Allocation is listed as NA, and masking is listed as none. There is no separate control arm in the registry record, so the design supports description of outcomes among participants receiving the device procedure but does not provide a randomized treatment contrast. The study is not assigned a phase; phase is listed as NA. The sponsor is C. R. Bard.

The registry gives a start date of 2016-09-20 and primary completion in 2019-08. Its current status is terminated. Neither the reason for termination nor details about whether enrollment or follow-up differed from the original plan are reported in the registry record. The arm description contains no additional details about care within the endoAVF group.

The primary endpoint is defined as participants with primary patency of the endoAVF at 6 months post-index procedure. The registry record lists 13 outcome measures and no analyses. It does not include a numerical result for the primary endpoint or an inferential estimate for that outcome. Additional protocol details—including the intended analysis population, missing-data approach and statistical analysis plan—are not reported in the registry record. This distinction matters: the study design and endpoint can be described, but the clinical result for the primary question cannot be assessed from the information recorded.

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 Participants With Primary Patency of the endoAVF at 6 Months Post-Index Procedure, measured over endoAVF creation through 6 months.

The primary endpoint is the percentage of participants with primary patency of the endoAVF at 6 months after the index procedure. The registry defines primary patency as the interval from access placement until an intervention designed to maintain or re-establish patency, access thrombosis, access abandonment or the time of measurement of patency. In practical statistical terms, the endpoint asks whether the access has remained patent under this definition through the stated assessment point, without an event that ends primary patency.

Patency is used to characterize whether a created access remains usable without the specified events or interventions. A fixed assessment time makes the outcome interpretable for a particular follow-up point, while the definition clarifies which events count as ending primary patency. The composite definition also means that the endpoint reflects more than thrombosis alone: an intervention to preserve or restore patency and access abandonment are included as well.

The endpoint is expressed as a percentage of participants, making it a binary participant-level outcome at the assessment time. The registry record does not report the number or percentage meeting this endpoint, the number assessed at 6 months, or a confidence interval. Consequently, the endpoint can be explained, but its observed frequency and precision cannot be evaluated from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies a participant-level binary endpoint: whether primary patency was present at 6 months. A binary outcome classifies each participant according to whether the defined outcome occurred or did not occur by the assessment point. The percentage is a way to express the frequency of participants meeting the endpoint within the analysis population. The registry record does not report the primary endpoint count, percentage or analysis population, so no primary-outcome estimate can be interpreted.

What does a confidence interval convey?

In general, a confidence interval describes the statistical uncertainty around an estimated outcome frequency. A narrower interval indicates greater precision under the assumptions of the method; a wider interval indicates less precision. The interval does not correct for bias, missing follow-up, an unsuitable outcome definition or lack of a comparator. No confidence interval for primary patency is reported in the registry record, so its precision cannot be assessed.

What does the single-group design allow?

A single-group study can describe outcomes observed among participants who receive the intervention. It does not, by itself, distinguish an intervention effect from the course that would have occurred without that intervention or under a different one. Random allocation is not listed, and the record has no comparator group. Thus, any observed proportion would be descriptive rather than a randomized comparative effect. The registry record does not report adjusted analyses or a model that would provide a comparative estimate.

How should the endpoint definition be read?

The definition of primary patency includes several events that end the interval: an intervention intended to maintain or re-establish patency, access thrombosis, access abandonment or the patency measurement. These components make the endpoint a composite clinical measure. A participant may meet an event criterion because of an intervention even if thrombosis or abandonment has not occurred. Interpretation therefore depends on the stated definition, not on an informal reading of patency as a single event type. The registry does not provide component-specific primary outcome results.

Why do denominators and missing outcomes matter?

For a binary endpoint, the numerator represents participants meeting the endpoint and the denominator represents those included in the analysis. If some participants lack an assessment, the resulting percentage can depend on how those missing outcomes are handled. Excluding participants, treating missing outcomes as failures, or using a model to account for incomplete follow-up can lead to different estimates. These are general statistical possibilities, not descriptions of the study's methods. The analysis denominator, follow-up completeness and missing-data method are not reported in the registry record.

What can be concluded from the inferential record?

Inferential methods can quantify uncertainty or assess a specified hypothesis, but their interpretation depends on the analysis plan, endpoint, data and design. The registry record lists no analyses and gives no primary-outcome p-value or confidence interval. It also does not report whether there were interim analyses, adjustments for covariates or other model-based methods. These details are not reported in the registry record and should not be inferred from the endpoint description.

Multiple outcomes raise a general multiplicity issue: when many outcomes or comparisons are examined, the chance of at least one apparently unusual result can increase. Methods such as prespecifying a primary outcome or adjusting inference can address different aspects of this issue, but the appropriate approach depends on the study plan. The record lists 13 outcome measures but does not report a multiplicity strategy. No particular adjustment should be assumed.

The described sample-size calculations are planning illustrations, not the trial's design justification and not observed power. Their stated setup uses a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation and an effect to detect defined as a stated fraction of the observed effect. This is a planning framework; it does not turn the single-group trial into a two-arm comparison, nor does it show the probability that the completed study detected an effect. The sample-size justification in the protocol is not reported in the registry record. No sample-size result is needed to interpret the missing primary endpoint result.

Over-dispersion is a general concern when outcomes vary more than a statistical model assumes, potentially making standard errors and uncertainty estimates too small if the model is not suitable. The primary endpoint is a participant-level binary outcome, and the registry record does not report a model or evidence of over-dispersion. It is therefore not possible to determine whether a model-based issue of that kind arose in the analysis. More generally, methods should be judged in relation to the actual outcome data and analysis plan, neither of which is fully recorded for the primary endpoint.

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("endoAVF")
n      <- c(54)
events <- c(38)
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  endoAVF  54  38  70.4  56.4  82.0  57.2  80.9  57.1  80.9

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists 13 outcome measures, but does not report how multiplicity was handled. When several outcomes are examined, a general statistical concern is that some results may appear noteworthy by chance. A prespecified primary endpoint can help focus interpretation, but the record does not give a multiplicity procedure or state how secondary outcomes were to be interpreted. No adjustment method should be assumed.

Missing outcome data are also important for a percentage endpoint. The record does not report how many participants had a 6-month patency assessment, whether follow-up was incomplete, or how missing endpoint status was handled. Different approaches to missing outcomes can change the estimate and its uncertainty. The registry record does not specify an analysis population, such as whether all enrolled participants or only those with an available assessment were included.

The registry lists enrollment as 100, but that entry does not provide the primary endpoint denominator or establish how many participants were assessed at the stated time. The analysis count is listed as 0, and no primary endpoint estimate or analysis is reported. Details about interim analyses, exclusions, protocol deviations and sensitivity analyses are not reported in the registry record. Without those details, it is not possible to assess whether the reported outcome—if any outside this record—would reflect a prespecified population and method.

These absences are reporting limitations, not evidence that missing data or multiplicity necessarily caused bias. They do mean that the precision and robustness of the primary endpoint cannot be evaluated from the registry record.

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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: stenosis (5.0%), thrombosis (4.0%), infection (4.0%), pseudoaneurysm (3.0%), bruising/hematoma (3.0%).

The registry lists safety figures for the endoAVF group, with 100 at risk for serious adverse events and 24 affected, and 100 at risk for other adverse events and 7 affected. It also lists 3 deaths. These are registry counts; the record does not provide enough information to determine the timing of events, whether a participant could contribute to more than one event term, or the follow-up duration for the safety entries.

The serious-event terms with the largest listed percentages are stenosis at 5.0%, thrombosis at 4.0%, infection at 4.0%, pseudoaneurysm at 3.0%, bruising/hematoma at 3.0% and compartment syndrome at 2.0%. These percentages should be read as the registry's reported term entries, not as evidence of causation. The record does not state whether each event was considered related to the device or procedure, and it does not report an adjudication method.

Counts and percentages alone do not establish comparative safety. There is no control group, and information on event onset, duration, recurrence, seriousness criteria and exposure time is not reported in the registry record. The figures can describe what was entered, but they cannot determine excess risk or attribute an event to the intervention.

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

The registry record documents a prospective, multi-center, single-group evaluation of the everlinQ endoAVF System for endoAVF creation in patients requiring vascular access for hemodialysis. It specifies primary patency at 6 months as the primary endpoint and gives a definition that includes interventions to maintain or re-establish patency, thrombosis, abandonment and the measurement time. These details clarify what the study was intended to assess.

The numerical result for that primary endpoint is not reported in the registry record. As a result, the record does not establish how often primary patency was observed, how complete the 6-month assessments were or how precisely the outcome was estimated. The absence of a posted result should not be interpreted as a positive finding, a negative finding or a failed statistical test.

The design also limits what could be concluded even if a group outcome were available. With a single group and no comparator, the study cannot provide a randomized estimate of how outcomes differ from another treatment strategy. An observed outcome would be descriptive of participants in this study, not a causal comparison. The registry does not report an adjusted comparative analysis.

The safety entries provide counts and percentages for selected events, alongside the number at risk and deaths. They do not establish that the device or procedure caused the events, and they do not allow comparison with another approach. Relatedness, timing and detailed follow-up are not reported in the registry record.

In short, the record supports a clear account of the study design, endpoint definition and selected safety reporting. It does not provide the primary outcome estimate needed to judge the study's main clinical question, nor does it support a comparative efficacy or safety conclusion. The status is listed as terminated, but the reason is not reported in the registry record.

14. Why This Trial Matters Statistically

This study illustrates why an endpoint definition and a numerical result serve different purposes. The definition explains what counts as primary patency, including the role of interventions, thrombosis and access abandonment. Without the observed frequency and its uncertainty, however, the definition alone cannot show how participants fared at the stated assessment time.

Its single-group structure is also statistically important. A descriptive outcome can be useful for characterizing experience with a device in a clinical setting, but it does not provide the same evidence as a concurrent comparison. Without a control group, differences from other evidence may reflect differences in participants, care, outcome definitions or follow-up rather than intervention effects. This distinction helps prevent a group percentage from being mistaken for a comparative treatment effect.

The record also makes clear how much interpretation depends on reporting. The registry lists 13 outcome measures but no analyses, and it does not report the primary patency result, an analysis denominator or missing-data methods. That leaves uncertainty not only about the endpoint estimate, but also about how it would have been calculated and how robust it might be.

Finally, safety counts require context. Counts and listed percentages are informative as descriptive entries, but attribution and comparison require further detail. The record does not report event relatedness, timing or a control group. The statistical lesson is not that the listed events prove harm or safety; it is that descriptive safety reporting and causal safety evaluation answer different questions. In this record, the design and reporting limits define what conclusions can responsibly be drawn.

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 most consequential limitation is that the primary patency outcome is not numerically reported. The registry record does not include the number meeting the endpoint, the percentage, a confidence interval or an analysis denominator. Because primary patency is the stated primary endpoint, this omission prevents direct assessment of the study's main question.

The single-group design provides no concurrent control. It cannot separate the outcome associated with the procedure from changes that might occur under another care strategy, and it does not support a randomized comparison. The registry record also does not report details of participant eligibility beyond the broad clinical description, procedural implementation, follow-up schedule or co-interventions.

The study status is terminated, but the reason for termination is not reported in the registry record. The record does not explain whether termination affected enrollment, endpoint ascertainment, follow-up completeness or analysis. Although enrollment is listed as 100, the primary endpoint population and the number assessed at 6 months are not reported.

Other important methodological details are absent: the protocol's sample-size justification, prespecified analysis plan, missing-data methods, analysis populations, interim analyses, handling of the 13 outcome measures and any sensitivity analyses. The listed safety counts lack reported timing, relatedness and detailed follow-up. These gaps constrain interpretation; they do not establish that a particular bias or problem occurred.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: everlinQ endoAVF Post Market Study — NCT02682420.
• Registry record last updated 2025-12-11; status last verified 2025-11.
• Results first posted 2021-11-17.
• 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 NCT02682420, the everlinQ endoAVF Post Market Study, sponsored by C. R. Bard. It is a prospective, multi-center, single-group study of the everlinQ endoAVF System for endoAVF creation in patients requiring vascular access for hemodialysis. Enrollment is listed as 100; the study started on 2016-09-20, primary completion is listed as 2019-08, and status is terminated.

The primary endpoint is participants with primary patency at 6 months, using a definition that includes intervention, thrombosis, abandonment or the patency measurement. The numerical result and analysis are not reported in the registry record. The record lists 13 outcome measures and no analyses. Safety entries include 24 serious adverse events among 100 at risk, 7 other adverse events among 100 at risk and 3 deaths. The single-group design and missing primary outcome result limit conclusions about comparative effects.