Safety and Performance Evaluation of WIRION™ EPD in Patients Undergoing Carotid Artery Stenting: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Safety and Performance Evaluation of WIRION™ EPD in Patients Undergoing Carotid Artery Stenting (NCT01783639), a na na study. The primary outcome is The Rate of Peri-procedural (Within 30 Days of Procedure) Death, Stroke, and Myocardial Infarction..

2. Clinical Question

This is a device-safety and performance question in a procedural setting, not a randomized comparison of two treatments. The record describes one study group receiving the WIRION™ Embolic Protection System during carotid artery stenting. Because there is no concurrent control group, the study cannot directly estimate a randomized between-group effect. Its stated external benchmark is a performance goal drawing on prior studies, but the registry record does not state the numerical goal, the details of the prior-study analysis, or whether the goal was met.

The endpoint combines death, stroke, and myocardial infarction during the specified peri-procedural period. A composite can capture more than one kind of clinically important event in a single safety measure. However, without the posted primary endpoint result or component-specific counts, the registry record does not show how many participants experienced the composite or which event types contributed. The secondary outcome titles include device success, clinical success, access site complications, neurological events, angiographic success, and procedural success, but their results are not reported in the registry record.

3. Trial Design

The WISE Study is described as a pivotal study evaluating the safety and performance of the WIRION™ Embolic Protection System in patients undergoing carotid artery stenting. The registry lists a single-group model, no masking, and enrollment of 120. The listed intervention is a carotid artery stent procedure; the arm description identifies the WIRION™ Embolic Protection System. The study is marked completed.

The registry dates the study start to 2013-02 and primary completion to 2013-12. It gives the conditions as carotid artery diseases and stroke. The phase is listed as NA, and allocation is listed as NA. A specific randomization scheme is not reported in the registry record; the single-group description and absence of a concurrent arm mean that there is no randomized control comparison described.

The stated study purpose was to compare safety and performance with a performance goal based on analyses of results from previous US IDE carotid stenting studies with embolic protection. This is an external benchmark concept rather than a concurrent control group. The registry record does not state the benchmark value, its statistical decision rule, or the details of the historical studies used to derive it. It also does not report a sample-size justification or a detailed statistical analysis plan.

The primary outcome is the number of participants with peri-procedural death, stroke, or myocardial infarction within 30 days of the procedure. The listed timeframe is within 30 days of procedure, and the record describes follow-up during that period. The record names several secondary outcomes, including device and clinical success, access site complications, neurological events, angiographic success, and procedural success. Their definitions, analysis results, and denominators are not reported in the registry record. The record lists zero analyses. That means the posted registry entry does not contain analysis results to interpret; it does not establish whether analyses were conducted outside the 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 The Rate of Peri-procedural (Within 30 Days of Procedure) Death, Stroke, and Myocardial Infarction., measured over Within 30 Days of procedure.

The primary endpoint is the number of participants experiencing peri-procedural death, stroke, or myocardial infarction within 30 days of the procedure. The registry describes the endpoint as a way to evaluate device safety. It is a composite: a participant can contribute through any of the listed event types, while the measure is defined as a participant count rather than a total number of event episodes.

Composite endpoints are often used to represent several important outcomes in one summary measure. General statistical interpretation: combining outcomes may give a broader view of safety than reporting only one event type, but the overall count does not reveal which component occurred or whether some components were more frequent than others. Component-specific counts are therefore useful for understanding what contributes to a composite.

The record specifies a 30-day period after the procedure and lists a 95% confidence interval as the dispersion measure. A confidence interval expresses uncertainty around an estimate; a narrower interval generally indicates greater precision, while a wider interval indicates less precision. In this case, the registry record does not report the primary endpoint count or its confidence interval. It therefore provides the endpoint definition, but not a numerical estimate or an indication of its precision. Component-specific primary outcome results and the stated performance-goal value are also not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a single-group study with no masking and enrollment of 120. Allocation is listed as NA. General statistical explanation: a single-group design estimates outcomes among participants receiving the evaluated procedure or device, but does not create a concurrent randomized group against which to estimate a treatment contrast. This design can describe event counts and rates, but comparisons with an external performance goal depend on the goal’s definition and the suitability of the historical evidence used to set it.

What does a participant count represent?

The primary endpoint is specified as the number of participants with peri-procedural death, stroke, or myocardial infarction within 30 days of the procedure. A participant count records how many people experienced the endpoint, not necessarily the total number of event episodes. General statistical explanation: when an endpoint is a composite, a participant with more than one component event is usually counted once for the composite participant count, while separate component summaries can describe each event type. The registry entry does not report the primary count or its component-specific results, so neither the overall endpoint burden nor its composition can be evaluated from this record.

What does a confidence interval add?

The endpoint lists a 95% confidence interval as its dispersion measure. General statistical explanation: an estimate describes the observed value in the study sample; a confidence interval conveys uncertainty around that estimate under the statistical method used. It is not a guarantee that the true value falls within the reported limits, and it does not account for every possible source of bias. The registry record does not report the primary estimate or interval, and the calculation method is not reported in the registry record.

How does a performance goal differ from a control group?

The stated purpose is to compare the study’s safety and performance with a goal based on analyses of previous US IDE carotid stenting studies with embolic protection. General statistical explanation: an external performance goal can be used as a reference value for judging whether a single-group result is compatible with a specified benchmark. It is not a randomized control arm. The benchmark’s numerical value, derivation, and decision rule are not reported in the registry record. Without them, the planned comparison cannot be reconstructed or interpreted.

A historical benchmark may also differ from the current study group in ways that affect outcome frequency. General statistical explanation: differences in patient characteristics, procedural practice, event definitions, follow-up, and event ascertainment can complicate comparisons across studies. This is a general consideration, not evidence that any particular difference occurred in this study. The registry record does not report enough detail to assess comparability with the historical studies.

What can be said about statistical planning?

A sample-size illustration based on an observed effect is not the same as the trial’s original sample-size justification. Such an illustration describes a hypothetical design under stated assumptions; it does not report the number of events observed, and it is not observed power. General statistical explanation: power calculations describe the chance of detecting a specified effect under assumptions about the design and analysis. They do not establish that an effect is real, and post hoc calculations using an observed effect can be particularly difficult to interpret because that effect is uncertain.

The stated illustration assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect described as a stated fraction of the observed effect. Those assumptions describe the illustration, not the single-group study design. The registry record does not report a trial sample-size justification or the observed primary endpoint effect needed to evaluate such an illustration in this study. The illustration should not be read as evidence that the actual study had a particular power or met its primary objective.

What does the absence of posted analyses mean?

The registry lists zero analyses and does not report the primary endpoint count, confidence interval, or results for the named secondary outcomes. General statistical explanation: an analysis plan typically specifies outcome definitions, analysis populations, handling of missing observations, and methods for estimating effects and uncertainty. Those details help readers distinguish prespecified methods from later analyses and understand which participants contribute to each result. The plan and those analysis details are not reported in the registry record. The absence of posted analyses limits the statistical conclusions that can be drawn from this entry, but does not establish what analyses may have been performed elsewhere.

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("Arm 1")
n      <- c(120)
events <- c(4)
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  Arm 1  120  4  3.3  0.9  8.3  1.3  8.3  1.4  8.2

11. Multiplicity, Missing Data and Analysis Populations

The registry names several secondary outcomes in addition to the primary safety endpoint: device success, clinical success, access site complications, neurological events within 30 days including strokes and transient ischemic attacks, angiographic success, and procedural success. It reports seven outcome measures overall, but does not provide the full set of definitions or results. The record lists zero analyses.

When a study assesses several endpoints, general statistical interpretation: the chance of at least one apparently unusual result can increase if many comparisons are examined. A statistical plan may address this through prespecified priorities or multiplicity adjustments. Whether any such approach was planned or used is not reported in the registry record. No secondary outcome results are available to interpret, and no multiplicity adjustment can be inferred from the outcome list alone.

The registry entry does not report missing-data counts, an analysis population definition, exclusions, or methods for handling participants without complete follow-up. These details matter because a participant who cannot be assessed may affect the denominator and the estimated event frequency. The record describes a 30-day follow-up period for the primary endpoint, but does not state how incomplete follow-up or unevaluable outcomes were handled.

The absence of a reported analysis plan also leaves the statistical treatment of the external performance goal unclear. Its numerical value, decision rule, and analysis population are not reported in the registry record. Consequently, the entry does not establish whether missing observations, multiple outcomes, or any other analysis choices affected a comparison with that goal.

12. Safety Results

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

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

Serious events with the highest arm-level rate: neurological/ nervous system (5.8%), cardiovascular (3.3%), low hemoglobin level (1.7%), severe anemia related to gastrointestinal bleeding (0.8%), admission at hospital with pain in segment l5/s1, protrusion of intervertebral discs (0.8%).

The registry lists a WIRION serious-adverse-event group with 120 participants at risk and 18 affected. It separately lists 120 at risk and 0 affected in the other-adverse-event group. The record does not explain how these two categories relate to one another, so they should be read as distinct registry entries rather than added together or treated as parts of a single outcome.

The listed serious adverse event terms and percentages are neurological/ nervous system, 5.8%; cardiovascular, 3.3%; low hemoglobin level, 1.7%; severe anemia related to gastrointestinal bleeding, 0.8%; admission at hospital with pain in segment L5/S1, protrusion of intervertebral discs, 0.8%; and incomplete occulomoric paresis because of hypotension, 0.8%. The registry does not report further details about event timing, severity criteria, relatedness to the device or procedure, or whether participants could have more than one listed term.

These entries do not replace the primary composite endpoint result. The record does not report the count of participants with peri-procedural death, stroke, or myocardial infarction, and deaths are listed as null rather than with a count. A missing death count should not be interpreted as zero deaths. The serious-event descriptions are informative as registry safety listings, but their definitions and relationship to the primary endpoint are not reported in the registry record.

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

The record establishes that the study evaluated WIRION™ Embolic Protection System use during carotid artery stenting in a single group, with 120 participants enrolled. It defines a primary safety endpoint of peri-procedural death, stroke, or myocardial infarction within 30 days of the procedure and describes an intended comparison with a performance goal based on prior studies. It also records serious adverse event information for the WIRION group.

Those design details do not provide the primary outcome result. The number of participants with the composite endpoint and its 95% confidence interval are not reported in the registry record. The stated performance goal and the result of any comparison with it are also not reported. As a result, the record does not show whether the observed primary outcome was above, below, or consistent with the intended benchmark.

The registry’s serious-adverse-event entries describe 18 affected among 120 at risk in the WIRION group and list several event terms with percentages. These entries should be interpreted within the categories recorded; the record does not provide enough detail to establish their relation to the primary composite, their attribution, or the number of unique participants represented by each term. The null death entry is not a reported zero.

General statistical interpretation: an uncontrolled study can document outcomes in the enrolled group, but cannot by itself establish what would have happened under a different device or procedure. A comparison to historical experience may provide context, but its strength depends on the benchmark’s derivation and the comparability of the studies. Those details are not reported in the registry record. The named secondary outcomes also lack posted results. Accordingly, the available entry supports description of the study design and listed safety information, but not a conclusion that the device did or did not meet the primary safety goal.

14. Why This Trial Matters Statistically

This study illustrates a common statistical challenge in evaluating devices used during procedures: a single-group design may be compared with an external performance goal rather than with a concurrent randomized control group. The choice of benchmark and its construction are central to interpretation. In this record, the goal is described as drawing on previous US IDE carotid stenting studies with embolic protection, but its value and derivation are not reported.

The primary endpoint is a clinically important composite that brings death, stroke, and myocardial infarction together over a defined 30-day period. Composite endpoints can provide a concise summary across multiple event types. General statistical explanation: the overall composite count must be interpreted alongside its components, because an aggregate estimate does not show which events contribute or how the component pattern is distributed. Neither the composite result nor component-specific results are reported in the registry record.

The entry also demonstrates why a study’s completion status and enrollment count are not substitutes for outcome reporting. Although the study is marked completed and lists 120 participants, the primary estimate, confidence interval, benchmark comparison, and secondary outcome results are absent. The record’s serious-event listings add safety detail but do not resolve those omissions.

Statistically, the central questions are not only whether an event count was recorded, but also how precisely it was estimated, how the benchmark was set, and how participants with incomplete outcome information were handled. The registry record does not report the information needed to answer those questions. The study is therefore relevant as an example of the distinction between a well-defined safety question and the availability of results needed to quantify an answer.

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 important limitation for interpreting the registry entry is the absence of the primary endpoint result. Although the endpoint and its 30-day timeframe are defined, the number of participants with peri-procedural death, stroke, or myocardial infarction and the stated 95% confidence interval are not reported in the registry record. The record also does not report component-specific counts.

The study is described as single-group, with no concurrent control arm and no masking. Its stated comparison is with an external performance goal, but the goal value, derivation, decision rule, and result of that comparison are not reported. This prevents evaluation of whether the study met its intended benchmark. The record also does not give enough information about the prior studies to assess how comparable their participants, procedures, endpoint definitions, or follow-up were.

The registry lists 120 enrolled and 120 at risk for the WIRION serious-adverse-event group, but does not report a primary analysis population, exclusions, missing-data counts, or handling of incomplete follow-up. The death field is null; this is not an explicit report of zero deaths. Further detail on serious event definitions, timing, attribution, and overlap between terms is not reported in the registry record.

Secondary outcome titles are present, but their definitions and results are not reported. The entry lists zero analyses, and a detailed statistical plan, multiplicity approach, and sample-size justification are not reported in the registry record. These limitations restrict assessment of the safety estimate, the external benchmark comparison, and the robustness of any analyses beyond what the registry entry explicitly records.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Safety and Performance Evaluation of WIRION™ EPD in Patients Undergoing Carotid Artery Stenting — NCT01783639.
• Registry record last updated 2017-08-07; status last verified 2017-06.
• Results first posted 2015-07-22.
• 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 WISE Study evaluated the safety and performance of the WIRION™ Embolic Protection System during carotid artery stenting. The registry describes a completed, single-group, unmasked study with 120 participants enrolled; the study start is listed as 2013-02 and primary completion as 2013-12.

The primary endpoint is the number of participants with peri-procedural death, stroke, or myocardial infarction within 30 days of the procedure, with a 95% confidence interval specified. The stated purpose includes comparison with a performance goal based on previous US IDE carotid stenting studies with embolic protection. The primary endpoint result, confidence interval, numerical performance goal, and comparison result are not reported in the registry record.

The record lists 18 affected among 120 at risk in the WIRION serious-adverse-event group, alongside named adverse event terms. It lists zero affected among 120 at risk in the other-adverse-event group; deaths are recorded as null. Secondary outcome results and a detailed statistical analysis plan are not reported in the registry record.