Endurant Evo US Clinical Trial: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Endurant Evo US Clinical Trial (NCT02393716), a na na study. The primary outcome is The Percentage of Subjects Experiencing a Major Adverse Event (MAE) Within 30 Days Post-implantation..

2. Clinical Question

The study summary states that its purpose was to demonstrate the safety and effectiveness of the Endurant Evo system for endovascular treatment of infrarenal abdominal aortic or aortoiliac aneurysms. The primary endpoint focused on early major adverse events, rather than a comparison of outcomes between treatment groups. The endpoint included all-cause mortality, bowel ischemia, myocardial infarction, paraplegia, procedural blood loss of at least 1000 cc, renal failure, respiratory failure, and stroke. These components make the primary measure a composite: a participant is counted if any listed event occurs within the specified period. The record also lists secondary outcomes covering mortality, procedures, adverse events, conversion to open surgery, and aneurysm rupture. Those additional outcomes do not change the primary question or create a concurrent control group. The registry status is TERMINATED; the reason for termination is not reported in the registry record.

3. Trial Design

The registry describes the Endurant Evo US Clinical Trial as a single-group study with 139 participants enrolled. Its one listed arm is Endovascular Repair, using the Endurant Evo AAA Stent Graft System. The intervention list also names endovascular aneurysm repair as a procedure. Allocation is recorded as NA, and masking is listed as NONE. The record does not describe a randomized allocation or a masked comparison. Consequently, the posted primary result is an outcome observed in the study group, not a treatment contrast against a concurrent control group.

The listed condition is abdominal aortic aneurysm, also abbreviated AAA. The study summary describes the intended use as endovascular treatment of infrarenal abdominal aortic or aortoiliac aneurysms. The registry lists the sponsor as Medtronic Cardiovascular and the phase as NA. The recorded start is 2015-04, and primary completion is 2021-06-25. The study status is TERMINATED. The reason for termination and details of the termination process are not reported in the registry record.

The primary endpoint was a participant count and percentage for major adverse events within 30 days post-implantation. The record lists 15 outcome measures and 2 analyses, but the analysis methods for each outcome and the relationship between those analyses are not reported in the registry record. Recruitment methods, site details, eligibility criteria beyond the stated aneurysm context, follow-up completeness, and protocol deviations are also not reported in the registry record. These omissions limit how fully the single-group design and the observed population can be characterized from the registry entry.

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:

Analysis population for the primary outcome, as defined in the registry: Globally, 4 out 139 Subjects experienced a MAE within 30 days (2.9%).

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 Percentage of Subjects Experiencing a Major Adverse Event (MAE) Within 30 Days Post-implantation., measured over 30-days.

The primary endpoint measures the occurrence of at least one major adverse event within 30 days after implantation. The registry defines the composite to include all-cause mortality, bowel ischemia, myocardial infarction, paraplegia, procedural blood loss of at least 1000 cc, renal failure, respiratory failure, or stroke. The reported outcome is a participant count, with a percentage also given: 4 out 139 Subjects experienced a MAE within 30 days (2.9%).

A composite endpoint can capture several clinically important types of events in one measure. It can be useful when a study aims to describe a broad safety outcome, but its overall result does not show which component occurred or how often each component occurred. The component-level results for this primary composite are not reported in the registry record. Nor does the primary result indicate event severity beyond the endpoint definition, timing within the follow-up period, or whether a participant experienced more than one component.

The 30-day window makes the endpoint a measure of early post-implantation events, not a summary of all later risks. The registry also lists outcomes such as mortality, secondary procedures, serious adverse events, conversion to open surgery, and aneurysm rupture. Those measures address other aspects of outcome and should not be treated as interchangeable with the primary composite.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary measure is binary at the participant level: a participant either met the major adverse event composite within the stated time window or did not, according to the endpoint definition. The registry reports a count and percentage for this outcome. In general, a proportion describes the share of an analyzed group meeting a specified event definition. It is a descriptive summary; by itself, it does not show whether the intervention caused the outcome or how the result compares with a different treatment.

The composite endpoint combines all-cause mortality, bowel ischemia, myocardial infarction, paraplegia, procedural blood loss of at least 1000 cc, renal failure, respiratory failure, and stroke. Composite measures can make a broad outcome easier to summarize and can include multiple forms of important harm. Their interpretation depends on the component definitions and how results are tabulated. A single overall result does not show the contribution of each component, and a frequent component can influence the composite more than a rare component. Component-specific primary results are not reported in the registry record.

For a binary outcome, an interval estimate around the proportion can communicate its statistical uncertainty. In general, wider intervals indicate less precision, and narrower intervals indicate greater precision under the chosen method and assumptions. The method used for any interval estimate, and a confidence interval for the primary result itself, are not reported in the registry record. The registry also does not report a primary-outcome p-value. A p-value, in general, addresses how compatible data are with a specified null model; it is not a measure of clinical importance, and it cannot create the missing comparison group in a single-group study.

The design is central to what can be estimated. A single-group study can describe the outcome frequency in its participants, but it does not directly estimate a between-group treatment effect. Differences from outcomes in another study would not be randomized comparisons, and could reflect differences in enrollment, care, definitions, follow-up, or other factors. Allocation is listed as NA and masking as NONE. Details of randomization are not reported in the registry record, and no randomized comparison is listed.

The record gives planning assumptions for sample-size illustrations: two-sided significance level 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of the observed effect. These are planning assumptions, not evidence that the study used that design or that an achieved level of power was observed. The registry describes the actual study as single-group, so the equal-allocation two-arm scenario is an illustration rather than a description of the listed study design. Sample-size illustrations are hypothetical calculations for planning under their assumptions; they are not observed power. The particular sample-size values and effect fractions are not reported in the registry record.

In general, over-dispersion matters when observed variation is greater than a statistical model expects. A model that assumes too little variation can produce uncertainty estimates that are too small. This is especially relevant to some count or clustered data settings. The primary endpoint is reported as a binary participant outcome, and the registry's model details, variance assumptions, and any assessment of over-dispersion are not reported in the registry record. It would be inappropriate to infer that such a check was or was not needed from the summary outcome alone.

The registry identifies 15 outcome measures and 2 analyses. It lists secondary measures including all-cause mortality, aneurysm-related mortality, procedures to correct Type I and III endoleaks, other secondary procedures, serious adverse events, conversion to open surgery, aneurysm rupture, and major adverse events. The analysis population for each measure, the statistical methods for those analyses, and any adjustment for multiple testing are not reported in the registry record. General statistical interpretation should keep the primary endpoint distinct from secondary outcomes, since multiple outcomes can produce multiple opportunities to observe findings and may have different definitions or time windows.

Follow-up and missingness also affect interpretation. If some participants lack outcome data, a reported proportion can depend on how those records are handled. In general, missing-data methods require assumptions about why information is absent and how it relates to outcomes. The registry does not report whether primary outcome data were complete, how missing observations were handled, or whether any sensitivity analyses were performed. These methodological details matter for judging the reliability and scope of the reported proportion.

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("Endovascular Repair")
n      <- c(139)
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  Endovascular Repair  139  4  2.9  0.8  7.2  1.1  7.2  1.2  7.2

11. Multiplicity, Missing Data and Analysis Populations

The record lists 15 outcome measures and 2 analyses, including the primary major adverse event outcome and several secondary outcomes. When many outcomes are examined, the chance of at least one apparently notable result can increase, depending on the analyses and decision rules. Statistical approaches can address multiplicity by defining a hierarchy, adjusting thresholds, or controlling an error rate. Whether any such strategy was planned or used is not reported in the registry record. No multiplicity-adjusted primary or secondary results are stated in the available registry entries.

The analysis populations are also not fully described. The primary result is reported as 4 out 139 Subjects experiencing a MAE, while the detailed definitions of the analysis set and handling of participants without evaluable follow-up are not reported in the registry record. It is not reported in the registry record whether the primary analysis included every enrolled participant, whether a modified population was used, or whether exclusions occurred. The enrollment count should not automatically be interpreted as a complete-case denominator without analysis-population details.

Missing data can affect a proportion when outcome status is unknown for some participants. In general, an analysis that excludes missing outcomes relies on assumptions about the excluded observations, while imputation or sensitivity analyses rely on their own assumptions. The registry does not report the amount or pattern of missing primary outcome data, the method used to handle missingness, or sensitivity analyses. These details are important for evaluating whether the posted estimate could be affected by incomplete follow-up.

In addition, the registry does not report a statistical analysis plan, interim analyses, or rules for selecting among analyses. Their absence from the record does not establish what may have been done outside the registry. It means the posted information does not permit evaluation of those decisions or their effect on inference.

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: stent-graft endoleak (11.5%), pneumonia (7.9%), acute myocardial infarction (5.0%), atrial fibrillation (5.0%), urinary tract infection (5.0%).

The adverse-event record for the Endovascular Repair group lists 105 participants with serious adverse events, 38 with other adverse events, and 29 deaths. These are registry counts, and they should be read as distinct reported safety summaries rather than as a direct comparison with another group. The registry also lists serious-event terms with percentages: STENT-GRAFT ENDOLEAK (11.5%), PNEUMONIA (7.9%), ACUTE MYOCARDIAL INFARCTION (5.0%), ATRIAL FIBRILLATION (5.0%), URINARY TRACT INFECTION (5.0%), and CARDIAC FAILURE CONGESTIVE (3.6%).

The listed terms are event categories, not estimates of the primary composite. The registry does not report in this record the denominator, observation period, or detailed counting rules for each term's percentage. A participant may also have more than one event, so event terms should not be added together or treated as mutually exclusive. The record's serious-event counts do not by themselves indicate causation or establish that an event was caused by the device or procedure. Further details about event attribution, severity grading, and timing are not reported in the registry record.

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

The primary result means that the registry records 4 out 139 Subjects as having experienced at least one major adverse event within 30 days after implantation, reported as 2.9%. This is the main quantitative description of the primary endpoint for the single Endovascular Repair group. It addresses an early composite outcome defined by the listed event types.

The result does not show how the outcome would compare with a different device, a different procedure, or no intervention. There is no comparator arm listed, and the study is described as single-group. Therefore, the result should not be interpreted as a randomized estimate of treatment benefit or harm. Nor does it demonstrate that the device or procedure caused, prevented, or changed the likelihood of any event.

The composite result also does not reveal which component events occurred. Component-specific primary endpoint counts, a confidence interval, and a primary-outcome p-value are not reported in the registry record. The 30-day period does not describe longer-term outcomes. Secondary safety results broaden the reported context, but the record's additional counts and event terms do not answer the missing comparative question.

The study summary states an aim to demonstrate safety and effectiveness for endovascular treatment of infrarenal abdominal aortic or aortoiliac aneurysms. An aim is not itself a finding. The posted result should be interpreted according to the information available: an observed group-level outcome in the registry, with limited precision information and no concurrent control comparison. The status is TERMINATED, but the reason is not reported in the registry record. No conclusion about why the study ended or what that status implies about the outcome can be drawn from the stated details.

These distinctions are useful when separating descriptive results from causal claims. The count and percentage describe the recorded study outcome. They do not, on their own, establish how outcomes would differ under another treatment, how representative the enrolled group is of a broader population, or how complete follow-up was. Those questions require design and analysis details not reported in the registry record.

14. Why This Trial Matters Statistically

This trial matters statistically because its primary endpoint is easy to state but requires careful interpretation. It reports a binary composite outcome in one study group: 4 out 139 Subjects experienced a major adverse event within 30 days post-implantation (2.9%). A count and proportion offer a direct description of observed outcomes, but they do not supply a control-based estimate of treatment effect or a measure of precision around the estimate.

The single-group design makes the distinction between safety description and comparative inference especially important. A group-level event frequency can inform what was recorded among the enrolled participants, while a comparison requires a credible reference group and suitable design or assumptions. No comparator arm is listed. Without one, the posted primary result cannot isolate the effect of the device or procedure from other influences.

The composite endpoint also illustrates a common statistical trade-off. Combining event types can summarize a broad safety question, but the overall result may conceal which events contributed and their individual frequencies. Component-level primary results are not reported in the registry record. Readers therefore need to avoid treating the composite percentage as if it applied separately to every listed event.

Finally, the registry lists other safety outcomes and event terms, but does not report analysis-population details, missing-data methods, multiplicity procedures, or a confidence interval for the primary outcome. These omissions are consequential for interpretation, not merely technical details. The record is useful for identifying the study's stated question and posted results, while the design and reporting limits define how far statistical conclusions can reasonably extend.

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 primary limitation for interpreting the result is the single-group design. The record lists no comparator arm, so it cannot provide a randomized between-group estimate. Allocation is recorded as NA and masking as NONE. The registry status is TERMINATED, but the reason for termination is not reported in the registry record.

The primary outcome is a composite, and the registry gives an overall count and percentage without reporting the component-specific results. A confidence interval and p-value for the primary endpoint are not reported in the registry record. Precision and the contribution of individual event types therefore cannot be evaluated from the posted primary summary alone.

Further methodological details are not reported in the registry record, including the primary analysis population, missing-data handling, follow-up completeness, analysis plan, and any multiplicity adjustment. The eligibility criteria, participant characteristics, study sites, and details of event attribution are also not reported in the registry record. These omissions limit assessment of generalizability, risk of bias, and the context of the adverse-event findings.

The registry lists 105 participants with serious adverse events, 38 with other adverse events, and 29 deaths, alongside percentages for selected serious-event terms. The relevant observation periods and detailed denominators for these safety summaries are not reported in the registry record. The event figures should not be combined or interpreted as proof of causation. Together, these limits mean the posted material supports a narrow description of recorded outcomes rather than a broad comparative conclusion.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Endurant Evo US Clinical Trial — NCT02393716.
• Registry record last updated 2022-12-06; status last verified 2022-11.
• Results first posted 2022-12-06.
• 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 Endurant Evo US Clinical Trial is listed as a single-group study sponsored by Medtronic Cardiovascular, with 139 participants enrolled. The study's stated purpose was to evaluate safety and effectiveness of the Endurant Evo AAA Stent Graft System for endovascular treatment of infrarenal abdominal aortic or aortoiliac aneurysms. Allocation is NA, masking is NONE, phase is NA, and status is TERMINATED. The recorded start is 2015-04, with primary completion on 2021-06-25.

The primary endpoint was the percentage of participants experiencing a major adverse event within 30 days post-implantation. The registry reports 4 out 139 Subjects experienced a MAE within 30 days (2.9%). The endpoint combines several event types, and component-specific primary results are not reported in the registry record. No comparator arm is listed, so the primary result is a descriptive outcome for the study group rather than a randomized treatment comparison.

The registry also lists secondary outcomes and adverse-event summaries. Details of missing data, analysis populations, multiplicity, and the reason for termination are not reported in the registry record.