Suprarenal Proximal Cuff Study for Treatment of Abdominal Aortic Aneurysm: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Suprarenal Proximal Cuff Study for Treatment of Abdominal Aortic Aneurysm (NCT00739401), a na na study. The primary outcome is Number of Subjects With Proximal Type I Endoleak.

2. Clinical Question

In practical terms, this was an evaluation of an extension device used as part of endovascular treatment in subjects whose anatomy or leakage was addressed with a proximal cuff. The primary question concerns a specific post-treatment leakage outcome over a defined early follow-up period. The record also names secondary areas including major adverse events, stent graft integrity and performance, endoleak, aneurysm morphology changes, and renal function. It lists 7 outcome measures overall, but does not provide results for the primary endpoint or those secondary outcomes. The evidence described is therefore a single-group account, not a test of the device against another treatment or a control group.

3. Trial Design

The registry describes a completed, single-group device study sponsored by Endologix. It lists the intervention as the Suprarenal Proximal Cuff Extension and the condition as abdominal aortic aneurysm. The study summary says the extension device was used during the index AAA procedure to accommodate the patient's anatomy and to prevent or repair leakage. The arm description refers to test subjects requiring endovascular treatment of abdominal aortic or aorto-iliac aneurysms, including a proximal cuff extension.

Enrollment was 44. Allocation is recorded as NA, and masking as none. There was no control arm identified in the record. Accordingly, the design does not support a randomized comparison, and differences from a separate group cannot be assessed from these data. The record gives the study start as 2006-05-05, primary completion as 2008-08, and status as COMPLETED. Phase is listed as NA.

The primary endpoint was the number of subjects with proximal type I endoleak within 30 days. Although 44 subjects enrolled, the registry says that 2 withdrew before reaching the 30-day follow-up visit mark; 42 subjects were analyzed for the primary outcome. The reasons for withdrawal and the outcome status of those subjects are not reported in the registry record.

The registry lists secondary outcome areas related to major adverse events, stent graft integrity and performance, endoleak, aneurysm morphology changes, and renal function. It reports 7 outcome measures and 0 analyses. The outcome descriptions, numerical findings, and statistical comparisons beyond the stated primary endpoint are not reported in the registry record. In particular, there is no reported comparison group, adjusted effect estimate, or analysis plan to interpret. The design should thus be read as a single-group evaluation with a defined early endpoint, but with limited outcome results 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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Out of the 44 subjects enrolled 2 subjects withdrew even before reaching the 30day follow-up visit mark. Thus, 42 subjects were analyzed for the primary outcome.

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.

Population: All available data is reported

6. Primary Endpoint

The registry lists the primary outcome as Number of Subjects With Proximal Type I Endoleak, measured over Within 30 Days.

The primary endpoint is the number of subjects with proximal type I endoleak within 30 days. The registry's endpoint description characterizes it as the incidence of type I proximal endoleak at 30 days post-treatment. It is a binary participant outcome: each participant either meets the defined event criterion during the endpoint period or does not. The record does not report the observed event count or proportion, so the endpoint's result cannot be summarized numerically.

General explanation: A clearly defined endpoint makes explicit what outcome is counted and when it is assessed. A fixed follow-up window also helps distinguish events occurring during the period of interest from events outside it. For a binary endpoint, the event count and the number of participants analyzed are important for understanding the observed frequency and its precision. Here, the registry reports that 42 subjects were analyzed for the primary outcome after 2 of the 44 enrolled subjects withdrew before the 30-day visit mark, but it does not give the event count.

The endpoint is relevant to the stated study purpose because the study summary describes use of the extension device to accommodate anatomy and prevent or repair leakage. That connection does not establish a result: the registry record does not say how many participants experienced proximal type I endoleak, nor does it report an estimate of uncertainty. The named endpoint and follow-up period can be described; the primary finding itself is not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The methods information in the registry record is limited. It identifies a single-group study, lists allocation as NA and masking as none, specifies a binary primary endpoint, and reports that 42 subjects were analyzed for that endpoint. It also states that 0 analyses are reported. The statistical methods used for the primary endpoint, any confidence intervals, any hypothesis tests, and any adjustment procedures are not reported in the registry record.

What a binary endpoint means

General explanation: A binary endpoint classifies each participant according to whether a specified event occurred during the endpoint period. A basic description usually includes the number of participants with the event and the number evaluated. Those quantities support an estimate of event frequency. The endpoint in this study is described as proximal type I endoleak within 30 days, and the analyzed population is given as 42 subjects. The event count is not reported, so the frequency cannot be stated.

A binary endpoint is different from a continuous measure, such as a laboratory value, because it records whether a defined event occurred rather than the magnitude of a measurement. It is also different from a time-to-event endpoint, which incorporates how long participants are followed until an event or censoring. The record describes the primary outcome as a count of participants, not as a time-to-event analysis. It does not report the number of events or individual event times.

What a single-group design can estimate

General explanation: In a single-group study, observed outcomes describe the participants who received the intervention under the study conditions. Without a concurrent control group, the data do not directly estimate a between-group treatment difference. Potential changes over time, participant characteristics, and other influences cannot be separated from the intervention by a randomized comparison when no such comparison is present. This does not make descriptive outcome reporting impossible, but it constrains what causal or comparative claims can be made.

For this study, the record identifies one intervention group and no control arm. It does not report a control condition, allocation procedure, or masking beyond listing allocation as NA and masking as none. No adjusted comparative estimate is reported. Thus, any interpretation must remain descriptive and limited to the single study group, and the missing primary event count prevents even a numerical description of the primary endpoint.

Precision and confidence intervals

General explanation: A confidence interval expresses statistical uncertainty around an estimate, under the assumptions of the method used. For a binary outcome, an interval around an event proportion can help show how much uncertainty remains, especially when the number of events is limited. The interval does not establish clinical importance, and its interpretation depends on the chosen method and study design. The registry record does not report a confidence interval or an estimate for the primary endpoint. It is therefore not possible to characterize the precision of the primary result.

Precision is not interchangeable with statistical significance. A result can be estimated with varying degrees of uncertainty, while a significance test answers a narrower question under a specified null hypothesis and analysis. The registry does not report a test, a null hypothesis, or a p-value for the primary endpoint. No significance claim can be made from the endpoint definition or the analyzed population size alone.

Over-dispersion and other model considerations

General explanation: Over-dispersion occurs when observed variability is greater than a statistical model assumes. It can matter for count outcomes or clustered data because a model that understates variability may produce uncertainty estimates that are too narrow. The record identifies the primary outcome as a count of participants with a binary event, but does not report a model, a dispersion estimate, clustering, or an over-dispersion assessment. There is consequently no basis to say that over-dispersion was assessed or affected the analysis.

More generally, statistical methods should be interpreted in relation to the data structure and the question being asked. A binary participant outcome, a repeated measure, and a time-to-event outcome can require different approaches. The record's primary endpoint description supports identifying the endpoint type and timeframe, but not reconstructing the analysis method. The statistical analysis plan is not reported in the registry record.

Planning illustrations

The record includes assumptions for a planning illustration computed from an observed effect, rather than a description of the trial's original design. The stated assumptions are 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. It further distinguishes participant-per-arm outputs from total event counts for time-to-event tables.

General explanation: A planning calculation estimates the sample size that might be needed for a future study under specified assumptions. It is not an observed result, and it does not show the power achieved by the completed study. When the planning effect is based on an observed effect, the illustration remains conditional on that effect and the listed assumptions. The numerical planning outputs are not reported in the registry record described, and no original sample-size justification or trial-specific design calculation is reported. These illustrations should not be treated as evidence about the primary outcome or as observed power.

In summary, the registry supports describing the design, endpoint, enrollment, and primary analysis population. It does not report enough information to reproduce the primary statistical analysis, evaluate its uncertainty, or verify a statistical conclusion. Any more detailed account of estimation or testing would require information not reported in the registry record.

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("Suprarenal Proximal Cuff Extension")
n      <- c(42)
events <- c(2)
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  Suprarenal Proximal Cuff Extension  42  2  4.8  0.6  16.2  1.3  15.8  1.5  15.8

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 7 outcome measures and 0 analyses. It names major adverse events, stent graft integrity and performance, endoleak, aneurysm morphology changes, and renal function among the secondary outcome areas. Aneurysm morphology changes appears twice in the listed outcomes. The specific outcome definitions and results for the secondary measures are not reported in the registry record.

Multiplicity concerns arise when a study evaluates multiple outcomes or conducts multiple statistical tests. General explanation: As the number of tests increases, the chance of at least one apparently unusual result can increase if each test is considered separately. A prespecified hierarchy, adjustment method, or clear distinction between primary and exploratory outcomes can help readers interpret multiple findings. The registry record does not report a multiplicity strategy, a hierarchy beyond identifying the primary endpoint, or any adjustment for multiple testing. Because 0 analyses are reported, there are no posted test results from which to assess the impact of multiplicity.

For missing outcome information, the registry says that 2 of the 44 enrolled subjects withdrew before reaching the 30-day follow-up visit mark and that 42 subjects were analyzed for the primary outcome. It does not state the reasons for withdrawal, whether any other endpoint data were missing, or how missing data were handled. It does not report an intention-to-treat analysis, a sensitivity analysis, or an imputation method. The record therefore does not show whether the missing primary follow-up could have affected the endpoint estimate.

The analyzed population is identified as 42 subjects for the primary outcome, but other analysis populations are not reported in the registry record. No per-protocol population, safety population definition, or rules for inclusion in particular analyses are given. The primary event count itself is also not reported. These omissions prevent a detailed assessment of analysis-population choices, missingness, or the robustness of the primary result.

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: gastrointestinal disorders (11.4%), respiratory disorders (9.1%), implant-related events (6.8%), supplemental procedure (6.8%), vascular disorders (6.8%).

The registry reports adverse-event information for the Suprarenal Proximal Cuff Extension group. It lists 44 participants at risk for serious adverse events and 11 affected, 44 at risk for other adverse events and 12 affected, and 3 deaths. These are counts from a single study group; the record includes no control group for comparison. The counts should not be read as comparative risks or as evidence about whether the device caused an event.

The record also lists serious adverse-event categories with percentages: Gastrointestinal Disorders, 11.4%; Respiratory Disorders, 9.1%; Implant-Related Events, 6.8%; Supplemental Procedure, 6.8%; Vascular Disorders, 6.8%; and Blood and Lymphatic Disorders, 4.5%. It does not provide category-specific participant counts in this record or explain whether categories can overlap. The percentages should therefore be retained as reported rather than converted into counts or added together.

General explanation: Adverse-event summaries describe events observed during a study; they do not by themselves establish causation. Interpretation depends on how events were defined, collected, timed, and attributed, as well as on the population and duration of follow-up. Those details are not reported. The serious and other adverse-event counts also have different labels and should not be combined. The record does not state whether the 3 deaths overlap with participants counted among the serious adverse events, so that relationship cannot be inferred. The figures describe the posted single-group safety information, not a comparison of safety between treatments.

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

The record documents a completed single-group study of the Suprarenal Proximal Cuff Extension in subjects requiring endovascular treatment of abdominal aortic or aorto-iliac aneurysms. It identifies proximal type I endoleak within 30 days as the primary endpoint and reports that 42 subjects were analyzed after 2 of 44 enrolled subjects withdrew before the 30-day follow-up visit mark. These registry entries describe the study's scope and its primary outcome definition.

What the record does not provide is the result for that primary endpoint. It does not report how many of the 42 analyzed subjects experienced proximal type I endoleak, an estimated event frequency, or uncertainty around an estimate. It also does not report statistical tests or a primary-endpoint analysis. Consequently, the posted information cannot establish the observed primary outcome or its precision.

The single-group design is another important boundary. There is no control arm, and allocation is listed as NA. The record cannot support a randomized comparison with another device, procedure, or control condition. Even a reported event frequency in a single group would describe that group's observed experience rather than directly quantify a comparative effect. The registry also does not provide enough detail to separate outcomes associated with the intervention from other influences.

The adverse-event counts and listed serious-event category percentages provide safety information for the study group, but they are not comparative estimates. The record does not report category-specific counts, event attribution procedures, or whether the 3 deaths overlap with participants counted for serious adverse events. The secondary outcome domains are named, but their numerical results are not reported in the registry record.

General explanation: A study can be informative about the question it sets out to measure while still leaving uncertainty about the size, precision, and comparative meaning of its findings. Here, the endpoint definition and study population are recorded, but the primary result is absent. No conclusion about the frequency of the primary event, comparative performance, or causation can be drawn from the information recorded. Planning illustrations, if considered, are calculations under stated assumptions, not observations from the trial and not a substitute for its missing outcome result.

14. Why This Trial Matters Statistically

This study is statistically notable for the gap between a defined primary endpoint and the outcome information recorded for it. The registry specifies a concrete event—proximal type I endoleak within 30 days—and identifies 42 subjects in the primary analysis population. Yet it does not report the endpoint count or an estimate. That distinction matters because a clearly stated outcome is not the same as a reported result, and the population size alone cannot answer how often the event occurred.

The single-group design also shapes the statistical question. With no control group and allocation listed as NA, the study record is not a randomized comparison. It can describe an intervention and a target population, but it cannot quantify a between-group difference from the information recorded. A statistical interpretation should keep the design in view rather than treating the study as if it had a comparator.

The record's reporting of 7 outcome measures alongside 0 analyses raises a separate interpretive issue. Multiple outcome domains can be useful for describing different aspects of a study, but methods for selecting, prioritizing, or adjusting analyses affect how results should be read. Such methods are not reported in the registry record. The record also names several secondary domains without numerical results, so the breadth of the outcome list does not translate into a broad set of interpretable findings.

General explanation: Transparent reporting of event counts, analysis populations, uncertainty, and analysis choices allows readers to distinguish a study's observations from the strength of conclusions drawn from them. In this record, enrollment, withdrawals before the follow-up mark, and the primary analysis population are stated, while the endpoint result and statistical analysis are not. Recognizing both the available design information and these omissions is essential to a calibrated reading of the study.

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 direct limitation of the registry record is that it does not report the primary endpoint result. Although it identifies the outcome and states that 42 subjects were analyzed, it gives no event count, proportion, confidence interval, or test result. The primary outcome therefore cannot be interpreted quantitatively from this record.

The single-group design provides no concurrent control comparison. Allocation is listed as NA and masking as none. This limits comparative interpretation and leaves no basis in the record for estimating differences against another treatment or control. The study summary and arm description identify the setting and intervention, but do not supply a comparative framework.

The record says that 2 subjects withdrew before the 30-day follow-up visit mark. It does not report the reasons, their outcome status, or how missing outcome information was handled. It also does not provide sensitivity analyses or other analysis-population definitions. The impact of these withdrawals on the primary endpoint cannot be assessed from the posted information.

Other important details are not reported in the registry record, including a statistical analysis plan, sample-size justification for the trial, endpoint analysis methods, uncertainty estimates, and a multiplicity approach. The registry lists 7 outcome measures and 0 analyses, while the secondary outcome domains have no numerical results reported in this record. The serious adverse-event category percentages are listed without category-specific participant counts or an explanation of overlap between categories. The relationship between the 3 deaths and the serious adverse-event count is also not stated.

These limitations concern what can be interpreted from the registry record. They do not establish that particular methods were or were not used outside the information recorded. The record supports a description of the design, enrollment, endpoint definition, and adverse-event counts, but not a full assessment of the primary outcome or its statistical precision.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Suprarenal Proximal Cuff Study for Treatment of Abdominal Aortic Aneurysm — NCT00739401.
• Registry record last updated 2021-12-10; status last verified 2021-12.
• Results first posted 2021-12-10.
• 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

NCT00739401 is a completed, single-group study sponsored by Endologix, with phase listed as NA. It enrolled 44 subjects and evaluated the Suprarenal Proximal Cuff Extension in subjects requiring endovascular treatment of abdominal aortic or aorto-iliac aneurysms. Allocation is listed as NA and masking as none. The registry gives the study start as 2006-05-05 and primary completion as 2008-08.

The primary endpoint was the number of subjects with proximal type I endoleak within 30 days. The record states that 2 subjects withdrew before the 30-day follow-up visit mark and that 42 were analyzed for the primary outcome, but it does not report the endpoint result. It lists 7 outcome measures and 0 analyses.

Adverse-event information includes 11 of 44 participants affected by serious adverse events, 12 of 44 affected by other adverse events, and 3 deaths. The record also lists serious adverse-event category percentages. With no comparator and no reported primary outcome result, the registry supports a description of the study design and recorded safety counts, but not a quantitative interpretation of the primary endpoint or a comparative conclusion.