Safety, Efficacy, Longitudinal Costs and Patient-Centered Outcomes Using a TAAA Debranching Device: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Safety, Efficacy, Longitudinal Costs and Patient-Centered Outcomes Using a TAAA Debranching Device (NCT03637374), a non-randomized na study. The primary outcome is Freedom From Major Adverse Events (MAEs) at 30 Days.

2. Clinical Question

3. Trial Design

The registry record describes a parallel, non-randomized study with no masking. Its title concerns safety, efficacy, longitudinal costs, and patient-centered outcomes using a TAAA debranching device. Johns Hopkins University is listed as the sponsor. The condition is thoracoabdominal aortic aneurysm, and the phase is recorded as NA. Enrollment is 2. The study status is TERMINATED; the record lists a start date of 2020-09-08 and a primary completion date of 2022-03-21.

The intervention is the TAAA Debranching Stent Graft System. The listed device components are the Visceral Manifold and Thoracic Bifurcation and the Unitary Manifold. The record names a Primary Study Arm and an Expanded Selection Arm, and describes the Expanded Selection Arm as being treated the same as the Primary Study Arm. It states that the doctor determines which arm a participant is in. It does not report randomized allocation or masking.

Non-randomized allocation means that treatment groups are not formed through random assignment. General statistical interpretation: differences between groups in such a study may reflect differences in who entered each group, as well as differences associated with treatment. That makes direct causal comparisons less secure than in a randomized comparison, particularly when the record does not report adjustment methods or detailed baseline characteristics.

The stated primary outcome is freedom from major adverse events at 30 days. Treatment success at 1 Year is listed as a secondary outcome. The study summary also describes assessment of costs, patient quality-of-life domains, and technical and treatment success at follow-up. The registry record does not report results for those additional aims in the registry record for this analysis.

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: Enrolled patients with non-staged, completed procedures were analyzed.

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: Enrolled patients who underwent staged/non-staged procedures were analyzed.

6. Primary Endpoint

The registry lists the primary outcome as Freedom From Major Adverse Events (MAEs) at 30 Days, measured over 30 days.

The primary endpoint is Freedom From Major Adverse Events (MAEs) at 30 Days, measured as a count of participants. The registry defines major adverse events as death, bowel ischemia, myocardial infarction, paraplegia, renal failure, respiratory failure, and stroke. The outcome is framed as freedom from these events over the stated 30-day timeframe, rather than as a measure of change in symptoms, anatomy, or quality of life.

A composite endpoint combines multiple event types into one outcome. General statistical rationale: a composite can capture a range of important complications in one measure, which may be useful when a treatment is being evaluated for safety. However, the component events can differ in severity, frequency, and clinical meaning. An overall composite result therefore does not by itself describe which event types occurred or their individual contributions.

The record says that enrolled patients with non-staged, completed procedures were analyzed. It does not report an arm-level primary endpoint result, a confidence interval, or a statistical test for this outcome. The posted adverse-event counts do not, by themselves, establish the value of the defined freedom-from-MAEs endpoint. The registry record does not explain how the endpoint was derived from the safety entries.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

General statistical explanation: a clinical endpoint is a defined outcome used to address a study question. Its definition should specify what counts as an event, the population in which it is assessed, and the time period. In this study, the primary endpoint is freedom from major adverse events at 30 days. The listed components are death, bowel ischemia, myocardial infarction, paraplegia, renal failure, respiratory failure, and stroke. The record describes the measure as a count of participants and says that enrolled patients with non-staged, completed procedures were analyzed.

What does a composite endpoint mean?

General explanation: when an endpoint combines different events, a participant may meet the endpoint through any qualifying component. This can make the overall outcome relevant to a broad safety question, but it can also conceal differences among components. A result for the composite would not show, on its own, how many participants experienced each component or whether the components had comparable importance. For this study, the registry record does not provide the primary endpoint result or component-level results for the defined 30-day endpoint.

What does non-randomized allocation imply?

General explanation: random assignment is intended to make groups comparable, on average, with respect to both measured and unmeasured factors. In a non-randomized study, group membership may be related to participant characteristics, clinical decisions, anatomy, or other factors. As a result, observed group differences can be confounded. The record states that the doctor determines which arm a participant is in and identifies the allocation as non-randomized. It does not report a statistical adjustment strategy, baseline comparison, or causal analysis that would address possible group differences.

The record describes a parallel model and no masking. A parallel design compares groups followed during the same study, but the non-randomized allocation remains important to interpretation. No masking means treatment assignment is not concealed from those involved in the study as described in the record. General explanation: knowledge of assignment can affect care, event assessment, or reporting, depending on how outcomes are collected. The record does not describe outcome adjudication procedures, so their role cannot be assessed.

How should counts and uncertainty be read?

The posted safety entries are counts: in the Primary Study Arm, 2 were listed at risk, 1 with a serious adverse event, 0 with other adverse events, and 2 deaths; in the Expanded Selection Arm, each of these entries is 0. The record also identifies bowel ischemia at 50.0% among the top serious adverse event terms. These are descriptive entries. The registry record does not provide confidence intervals, a formal comparison, or a primary endpoint estimate alongside them.

General explanation: a confidence interval expresses the range of values compatible with data under a specified statistical method and assumptions. It communicates uncertainty rather than guaranteeing that a true value lies within the interval. With very sparse observations, estimates can be unstable and intervals, when calculated appropriately, may be wide. No confidence interval for the endpoint or adverse-event comparison is reported in the registry record, so precision cannot be assessed from an interval.

What can be inferred from a zero count?

General explanation: a zero observed count is not proof that an event cannot occur. It may reflect limited observation, a small group, or no events during the recorded period. Here, the Expanded Selection Arm has 0 listed at risk in the adverse-event entries. That means these entries do not provide evidence for estimating that arm's event frequency or comparing it with the Primary Study Arm. It is especially important not to read the zero entries as evidence of safety or as a treatment effect.

What is the role of planning calculations?

The registry describes the sample-size assumptions as a planning illustration based on the observed effect, using a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation; the effect to detect is described as a stated fraction of the observed effect. The record also distinguishes planning illustrations from the study's own design. Such calculations are hypothetical planning aids, not evidence that a study had a particular probability of detecting an effect. No planning sample-size values are reported in the registry record for this analysis. They should not be interpreted as observed power or as a justification for the actual enrollment.

The registry reports 0 analyses. It does not provide a statistical analysis plan, identify a model for the primary outcome, describe any interim analysis, or state how missing observations were handled. Those omissions prevent a fuller evaluation of whether the analysis approach matched the endpoint and study design. General statistical practice would require methods appropriate to the outcome and a transparent account of exclusions and missing data, but the record does not report those details.

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("Primary Study Arm")
n      <- c(2)
events <- c(1)
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  Primary Study Arm  2  1  50.0  1.3  98.7  9.5  90.5  9.4  90.6

11. Multiplicity, Missing Data and Analysis Populations

The record lists Freedom From Major Adverse Events (MAEs) at 30 Days as the primary outcome and Treatment Success at 1 Year as a secondary outcome. It also describes broader interests in costs, patient quality-of-life domains, and technical and treatment success at follow-up. The record reports 0 analyses. It does not describe a statistical analysis plan, a hierarchy among outcomes, or a method for handling multiple statistical tests. Multiplicity procedures are therefore not reported in the registry record.

General statistical explanation: when several outcomes or comparisons are tested, the chance of at least one apparently notable result can increase unless the analysis accounts for the testing strategy. A prespecified hierarchy or multiplicity adjustment can help clarify how results should be interpreted. The record does not state whether any such approach was planned or used, and it provides no inferential results for these outcomes.

The stated analysis population is enrolled patients with non-staged, completed procedures. The registry record does not explain whether any enrolled patients were excluded from that population, why a procedure might be staged or incomplete, or how such cases were treated in the analysis. It also does not report missing outcome data, loss to follow-up, censoring, imputation, or sensitivity analyses. These details matter because an analysis restricted to completed procedures may represent a different population from all enrolled patients, while unreported missingness can affect how outcome counts are understood.

General explanation: a transparent report should describe who was eligible for each analysis, the reasons for exclusions, and how unavailable measurements were handled. Without those details, the reader cannot assess whether the analyzed population was selected in a way that could influence the findings. The record's brief statement about the analysis population does not resolve those questions.

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

Serious events with the highest arm-level rate: bowel ischemia (50.0%).

The registry safety entries report that the Primary Study Arm had 2 participants at risk, 1 with a serious adverse event, 0 with other adverse events, and 2 deaths. The Expanded Selection Arm entries report 0 participants at risk, 0 serious adverse events, 0 other adverse events, and 0 deaths. Bowel ischemia is listed as a top serious adverse event term at 50.0%.

These figures should be read as registry-reported safety fields, not as a complete account of event timing, participant overlap, or causal attribution. The primary endpoint includes death as a major adverse event, but the record does not explain how deaths and serious adverse events relate to the primary endpoint calculation. It is not possible to reconstruct the 30-day freedom-from-MAEs result from these entries alone.

General statistical explanation: safety categories can overlap, and counts from separate fields should not be added unless the reporting rules establish that they are mutually exclusive. The record does not specify those rules. The absence of events in the Expanded Selection Arm cannot support an arm comparison because its posted at-risk count is 0. The sparse counts are descriptive and do not establish the frequency of events in a broader patient population.

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

The record establishes that a study of the TAAA Debranching Stent Graft System was registered for patients with thoracoabdominal aortic aneurysm, used non-randomized parallel arms, and had enrollment of 2. Its primary outcome was defined as freedom from major adverse events at 30 days. The registry also lists treatment success at 1 Year as a secondary outcome. These details identify the question and design, but they do not show whether the primary outcome was met.

The posted safety entries describe counts in the two named arms, including serious adverse events and deaths. They do not provide the primary endpoint estimate, a comparison between arms, or a measure of uncertainty. Because the Expanded Selection Arm has 0 participants at risk in those entries, the reported figures cannot support a meaningful comparison of safety between the arms. The listed percentage for bowel ischemia is a registry entry and does not establish the overall rate of the defined primary composite.

The result does not establish that the device system is safe or effective, nor does it establish that it is unsafe or ineffective. The record does not report the primary endpoint result or statistical analysis needed to evaluate those questions. It also does not report results for the stated cost and patient-centered aims in the registry record for this analysis.

General statistical explanation: an observed count describes what was recorded in the study; it is not automatically an estimate that can be generalized to other patients or settings. Generalization depends on how participants were selected, the size and composition of the study population, the completeness of outcome ascertainment, and the uncertainty around estimates. The non-randomized design also limits causal interpretation because group differences may reflect factors other than treatment.

The appropriate conclusion is narrow: the registry describes the study design, endpoint definition, and sparse safety entries, but does not report the result of the primary endpoint. No claim about treatment benefit, comparative performance, or event risk can be supported from the reported information alone.

14. Why This Trial Matters Statistically

This study is statistically notable because its central question concerns a defined safety composite, while the available record reports only sparse safety counts and no primary endpoint analysis. The distinction between defining an endpoint and reporting its result is essential: knowing that freedom from major adverse events at 30 days was the primary outcome does not reveal how participants fared on that outcome.

The study's non-randomized allocation also matters. The record identifies a Primary Study Arm and an Expanded Selection Arm, with the doctor determining arm placement. Without random assignment, a group difference could reflect participant selection or clinical judgment as well as treatment. In this record, the Expanded Selection Arm has 0 participants at risk in the safety entries, so the counts do not allow an informative comparison between the named arms.

The study also illustrates why a composite endpoint and its components need clear reporting. Death, bowel ischemia, myocardial infarction, paraplegia, renal failure, respiratory failure, and stroke are grouped within the primary outcome definition. The separately posted safety fields do not explain how those components were evaluated or combined. That leaves the primary endpoint result unrecoverable from the safety entries.

General statistical lesson: study design, outcome definition, analysis population, and uncertainty all shape interpretation. Small or sparse datasets require particular care: a count can be accurately reported while still offering little precision, and an unreported interval or comparison cannot be inferred from the count. Transparent reporting of participant flow, endpoint results, missing data, and analysis methods is necessary for readers to judge what the data can support.

The record makes clear why registry completeness is important. Enrollment, study status, outcome definitions, and safety fields provide context, but they do not substitute for the prespecified outcome analysis and its uncertainty. In the absence of those results, conclusions should remain descriptive and limited to the registry entries.

15. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The main limitation is that the primary endpoint result is not reported in the registry record. Although freedom from major adverse events at 30 days is defined, there is no arm-level estimate, confidence interval, or statistical test. The safety entries cannot be used to reconstruct the endpoint because the record does not explain how the entries relate to the composite definition.

Enrollment is 2, and the safety fields list 0 participants at risk in the Expanded Selection Arm. These entries do not support a reliable comparison between arms. The study is non-randomized, so even a reported difference would require caution about selection and confounding. The registry record does not report baseline characteristics, adjusted analyses, or a method for addressing those concerns.

The record does not give details on participant flow, the number excluded from the stated analysis population, or the reasons for exclusion. It says that enrolled patients with non-staged, completed procedures were analyzed, but does not explain how staged or incomplete procedures were handled. Missing outcome data, follow-up completeness, and event adjudication are not reported in the registry record.

Other stated aims include costs, quality-of-life domains, and technical and treatment success. The listed secondary outcome is Treatment Success at 1 Year, but results for these aims are not reported in the registry record. Statistical methods for the primary endpoint, multiplicity handling, and any analysis plan are also not reported. These limitations restrict interpretation to the study description and the posted safety counts, without supporting conclusions about comparative effects or broader patient populations.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Safety, Efficacy, Longitudinal Costs and Patient-Centered Outcomes Using a TAAA Debranching Device — NCT03637374.
• Registry record last updated 2022-08-19; status last verified 2022-07.
• Results first posted 2022-08-19.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

The registry record describes a non-randomized, parallel study with no masking of the TAAA Debranching Stent Graft System in patients with thoracoabdominal aortic aneurysm. Johns Hopkins University is the sponsor. Enrollment is 2, the phase is listed as NA, and the study status is TERMINATED. The record gives a start date of 2020-09-08 and a primary completion date of 2022-03-21.

The primary outcome is Freedom From Major Adverse Events (MAEs) at 30 Days, with death, bowel ischemia, myocardial infarction, paraplegia, renal failure, respiratory failure, and stroke included in its definition. Treatment Success at 1 Year is listed as a secondary outcome. The primary endpoint result is not reported in the registry record.

Safety entries report 2 at risk, 1 serious adverse event, 0 other adverse events, and 2 deaths for the Primary Study Arm; the Expanded Selection Arm entries are 0 for each field. Bowel ischemia is listed among the top serious adverse event terms at 50.0%. These descriptive entries do not establish a comparative result or resolve the unreported primary endpoint.