The PQ Bypass Pivotal IDE Intra-arterial Stent Graft Study: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for The PQ Bypass Pivotal IDE Intra-arterial Stent Graft Study (NCT04130737), a na na study. The primary outcome is Freedom From a Major Adverse Event (MAE).

2. Clinical Question

This question combines safety and a clinically consequential repeat procedure in one endpoint. The composite is intended to capture whether any of its defined events occurred during the stated timeframe, rather than to report each event as the primary outcome separately. Those components can differ in frequency and clinical meaning, so a composite result would not by itself show which component contributed most. The record does not give component-level primary endpoint counts or an analysis of the components.

The trial objective also refers to evaluating the device’s safety and effectiveness for the specified lesions. That objective describes what the study was designed to evaluate; it is not evidence of an observed benefit. Without a reported primary endpoint result or a comparison group, the record cannot quantify the outcome relative to another intervention.

3. Trial Design

The registry record identifies NCT04130737 as the TORUS 2 study, formally titled The PQ Bypass Pivotal IDE Intra-arterial Stent Graft Study for Occlusive and Re-stenotic Fem-pop Revascularization - 2 Trial: TORUS 2. It is a completed, single-group device study sponsored by Endologix. Phase is listed as NA, allocation is listed as NA, and masking is listed as NONE.

The intervention is the TORUS Stent Graft System. The registry describes it as comprising a Stent Graft and a Stent Graft Delivery System. The study objective is to evaluate safety and effectiveness for obstructive atherosclerotic lesions of the native SFA or the superficial femoral and/or proximal popliteal arteries. Peripheral arterial disease is listed as the condition.

Enrollment is recorded as 188. The study start date is 2018-08-13, and the primary completion date is 2023-01-06. The record gives no comparator arm. Because the design is single-group, the treatment outcomes cannot be directly contrasted within this study against outcomes under a control intervention. A single-group study can describe outcomes among participants who received the device, but such descriptions alone do not isolate the device’s effect from other possible influences.

The primary endpoint is freedom from a major adverse event at 30 days. Secondary outcomes listed in the record include technical success, procedural success, major adverse event rate, major amputation on the target limb, patency rate, clinically driven target lesion revascularization, Walking Improvement Questionnaire assessment, and quality-of-life assessment by the EQ5D VAS. The record lists 14 outcome measures in total, but does not provide results for these outcomes in the information recorded.

Completion status and a recorded enrollment describe the study’s registry status and planned or recorded study size; they do not supply the missing endpoint findings. The registry record does not report the rationale for the enrollment target, detailed eligibility criteria, or a statistical analysis plan.

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.

Before assignment: The TORUS 1 clinical study was conducted in Germany and Latvia and enrolled a total of 60 subjects. Subject enrollment for TORUS 1 was closed on July 1, 2019. As per the TORUS 2 Statistical Analysis Plan (SAP) version 2, the last 30 subjects enrolled in TORUS 1 study are included in the endpoint analysis for the TORUS 2 study. Subject 30 in the TORUS 1 study was rolled-over into the TORUS 2 cohort, and was enrolled on August 13, 2018.

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.

Population: A total of 188 subjects (TORUS 2: 158 and TORUS 1: 30) were enrolled.

6. Primary Endpoint

The registry lists the primary outcome as Freedom From a Major Adverse Event (MAE), measured over 30 days.

The primary endpoint is titled freedom from a major adverse event (MAE), measured as a count of participants, with a timeframe of 30 days. An MAE is defined as all-cause death, major amputation of the target limb, or clinically driven target lesion revascularization. In plain terms, the endpoint asks how many participants had no event meeting that definition during the stated period.

A composite endpoint combines several events into one outcome. This can capture more than one type of important event within a single measure, but the components are not interchangeable: death, amputation, and a repeat procedure have different meanings. A reported composite count would therefore be most informative when accompanied by component-specific counts and a clear account of how events were assessed. Component-level primary endpoint results are not reported in the registry record.

The endpoint is used to evaluate both safety-related events and the need for clinically driven treatment of the target lesion. The timeframe matters: an endpoint measured at 30 days describes events within that window and does not, by itself, characterize outcomes over other periods. The registry record does not report the number of participants meeting the primary endpoint, a proportion, or an uncertainty interval. Consequently, the endpoint definition is available, but its observed result cannot be interpreted from this record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record describes a single-group study and lists a participant-count primary endpoint. The statistical information needed to reproduce or assess an endpoint analysis is not reported in the registry record. The following concepts explain how such results are generally interpreted; they do not describe analyses confirmed to have been performed for this study.

What does a participant count tell the reader?

A count records how many participants meet a defined outcome. For a binary endpoint, each participant is classified according to whether the event definition was met within the specified timeframe. The count is meaningful only alongside its denominator, the outcome definition, and the rules used to determine whether an event occurred. For a freedom-from-event endpoint, the count would represent participants with no qualifying event under the stated definition. The registry record defines the endpoint but does not report that count or its denominator for the primary outcome.

A proportion is often used to express a binary outcome relative to the number assessed. It should not be calculated without a clear numerator and denominator, and the denominator should correspond to the analysis population and timeframe. In this record, there is no primary endpoint result from which to derive a proportion. No additional primary endpoint percentage can be inferred from the enrollment figure or from the separate safety counts.

Why does uncertainty matter?

An estimate from a study is subject to sampling variation. A confidence interval is a way to communicate that uncertainty: under its assumptions, it identifies a range of values compatible with the data and method. A narrower interval generally indicates greater precision than a wider one, but precision is not the same as freedom from bias, and an interval does not resolve limitations in study design. No confidence interval for the primary endpoint is reported in the registry record, so the precision of that outcome cannot be judged.

Statistical tests and confidence intervals address related but different questions. A test evaluates compatibility with a specified null hypothesis under a model, while an interval presents a range of estimates and their uncertainty. Neither is a substitute for the design needed to make a credible comparison. Since no comparator group is listed, a test of a treatment difference between groups is not described by the study design information. A p-value for the primary endpoint is not reported in the registry record.

What is the consequence of a single-group design?

In a single-group study, outcome summaries can describe what occurred among participants receiving the intervention. Without a concurrent comparison group, those summaries do not establish what would have occurred under another intervention. Differences in participant characteristics, care, or other influences cannot be separated from the intervention’s effect using a between-group contrast that the design does not include. This is a general limitation of interpretation, not a claim about any unreported feature of the study.

Allocation is recorded as NA and masking as NONE. Those entries describe the registry’s design fields; the record does not provide further methods for enrollment, outcome assessment, or event adjudication. It is not appropriate to infer those procedures from the study title or objective.

How should the planning illustrations be understood?

The registry’s sample-size assumptions describe planning illustrations based on a stated fraction of an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. These are planning assumptions, not evidence that the trial used a two-arm design: the study itself is recorded as single-group. The record does not report the trial’s own sample-size justification or establish that these illustration assumptions governed its design.

For the planning illustrations, time-to-event calculations are described as using a total event count, while other calculations are described as participants per arm. These outputs have different interpretations and should not be conflated. A planning sample size is a prospective illustration under stated assumptions; it is not an observed outcome and is not observed power. The record does not report the underlying effect estimate or the numerical illustration results in the information recorded.

What does over-dispersion mean in general?

Over-dispersion occurs when observed variability is greater than a statistical model assumes. If a model ignores that extra variability, its uncertainty estimates may be too small, making results appear more precise than warranted. This concept is particularly relevant to some count-data models, but the registry record does not report a count-data model, an over-dispersion assessment, or an analysis addressing it for this trial.

More broadly, a statistical analysis depends on prespecified definitions, analysis populations, missing-data rules, and methods appropriate to the endpoint. The record does not report those details. As a result, readers cannot determine from the registry information whether results were adjusted, how missing outcomes were handled, or which population would have been used for each analysis.

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("TORUS Stent Graft System")
n      <- c(188)
events <- c(184)
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  TORUS Stent Graft System  188  184  97.9  94.6  99.4  94.7  99.2  94.7  99.1

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 14 outcome measures, including the primary endpoint and secondary outcomes such as technical success, procedural success, major adverse event rate, major amputation on the target limb, patency rate, clinically driven target lesion revascularization, Walking Improvement Questionnaire assessment, and EQ5D VAS quality-of-life assessment. Assessing multiple outcomes can raise a multiplicity issue: when many hypotheses are tested, the chance of at least one apparently unusual result can increase. Statistical plans may address this through prespecified outcome hierarchies or other methods, but the registry record does not report a multiplicity strategy.

The record reports zero analysis entries. It does not provide outcome estimates, tests, confidence intervals, or details of any adjustment for multiple comparisons. The absence of analysis entries means the registry information does not establish which outcomes were tested or how results were interpreted. No multiplicity-adjusted or unadjusted primary result is reported in the registry record.

Missing-data methods and analysis populations are also not reported in the registry record. It does not state how participants with incomplete follow-up would be handled, whether participants were included according to treatment received, or which population was used for each outcome. The enrollment figure alone does not establish the denominator for a particular analysis; the number enrolled and the number with assessable outcome data need not be the same.

The primary endpoint has a stated 30-day timeframe, but the record does not describe the completeness of follow-up for that endpoint or provide a participant flow. Timeframes for the listed secondary outcomes are not included in the information recorded. Without those details and the outcome results, readers cannot assess the impact of missing observations, the analysis population, or the control of false-positive findings across outcomes.

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: vascular disorders (31.9%), general disorders and administration site conditions (9.0%), infections and infestations (7.4%), cardiac disorders (4.8%), musculoskeletal and connective tissue disorders (4.8%).

For the TORUS Stent Graft System group, the registry records 85 participants affected by serious adverse events among 188 at risk, and 136 participants affected by other adverse events among 188 at risk. It also records 24 deaths. These are safety summaries; the registry information does not state that these counts correspond to the primary endpoint’s 30-day timeframe.

The listed serious adverse event terms include vascular disorders at 31.9%, general disorders and administration site conditions at 9.0%, infections and infestations at 7.4%, cardiac disorders at 4.8%, musculoskeletal and connective tissue disorders at 4.8%, and injury, poisoning and procedural complications at 3.7%. The denominator for these term percentages is not reported in the registry record. They should therefore be read as the registry’s listed category values, not assumed to be percentages of all participants.

Serious adverse event counts, other adverse event counts, and deaths are different summaries and should not be added together. The record does not report whether categories overlap, the timing of each event, or whether events were considered related to the device or procedure. An adverse event listing describes reported events; without attribution information, it does not establish causation. These safety figures also do not supply the missing primary endpoint result.

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

The registry record establishes that TORUS 2 was a completed, single-group device study with a recorded enrollment of 188 and a primary endpoint focused on freedom from a defined major adverse event at 30 days. It also records safety counts for serious and other adverse events and deaths. These details describe the study and the safety information entered in the registry.

The record does not report the primary endpoint result, an uncertainty interval, or a statistical test. It therefore does not show how many participants met the primary endpoint definition or how precise any estimate would be. The available safety summaries cannot fill that gap because their relationship to the primary endpoint timeframe and components is not reported.

The study has no listed comparator and is identified as single-group. Its design can support description of outcomes in the intervention group, but it cannot by itself estimate a difference against another treatment. The registry’s stated aim to evaluate safety and effectiveness is not a finding that either was established. A completed status likewise does not establish a favorable or unfavorable result.

The record also does not report analysis populations, missing-data handling, multiplicity methods, or component-specific primary endpoint results. Without those details, the statistical robustness and scope of any result cannot be assessed. The secondary outcomes listed in the registry indicate the range of measures considered, but their results are not reported in the information recorded.

Accordingly, the defensible interpretation is limited: the registry documents the study design, its endpoint definition, and certain safety counts. It does not provide enough outcome or comparative evidence to quantify treatment effects or draw a conclusion about effectiveness. These are limits of the information in the registry record, not proof that the outcomes were absent from other sources.

14. Why This Trial Matters Statistically

This study illustrates why design and reporting details matter as much as an endpoint’s name. A clearly defined endpoint identifies which events count and when they are assessed. Here, freedom from a major adverse event is defined using all-cause death, target-limb major amputation, and clinically driven target lesion revascularization within 30 days. That definition gives the clinical question a specific structure, but without the observed endpoint result it does not answer the question.

The single-group design also shapes what statistical conclusions are possible. Counts in an intervention group may describe observed experience, but a treatment contrast requires a suitable comparator. The registry lists no comparator group, so the record cannot provide a within-study comparison of the device against another intervention. This distinction helps prevent a descriptive result from being mistaken for evidence of comparative effectiveness.

The record’s multiple outcome measures raise another general statistical concern: when many outcomes are assessed, interpretation depends on a clear analysis plan and attention to multiplicity. The registry lists 14 outcome measures and no analysis entries. Without analysis results or a reported multiplicity approach, readers cannot assess the strength of any outcome-specific claim.

Finally, the safety counts show why denominators, timeframes, and event attribution are essential. Counts alone do not establish causation, and category percentages without a stated denominator have limited interpretability. The record’s gaps make it important to distinguish what is documented—the design, definitions, and listed counts—from what remains unreported, including the primary endpoint estimate and its precision.

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.

Several trial-specific limitations follow directly from the registry information. The study is recorded as single-group, with no comparator, allocation listed as NA, and masking listed as NONE. It therefore does not provide a like-for-like comparison within the study. The registry record does not give detailed eligibility criteria or participant characteristics, limiting assessment of the population represented by the enrollment figure.

The primary endpoint definition and 30-day timeframe are reported, but its observed result is not. No primary endpoint count, estimate, confidence interval, or test is reported in the registry record. Component-specific results are also not reported, so the contribution of death, major amputation, and clinically driven target lesion revascularization cannot be distinguished.

The record lists 14 outcome measures but no analysis entries. It does not report analysis populations, missing-data procedures, outcome-assessment methods, or a multiplicity strategy. The safety summaries do not include a reported relationship to the primary endpoint timeframe or information on event attribution. The denominators for the listed serious adverse event term percentages are not reported in the information recorded.

The registry record also does not report the statistical analysis plan, sample-size justification, interim analyses, or numerical results for the planning illustrations. Phase is listed as NA. These omissions limit assessment of the planned analyses and the precision or completeness of outcome reporting. They do not establish that these details or analyses were absent from other study materials; they are not reported in the registry record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: The PQ Bypass Pivotal IDE Intra-arterial Stent Graft Study — NCT04130737.
• Registry record last updated 2026-07-10; status last verified 2026-04.
• Results first posted 2026-07-10.
• 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

NCT04130737 is the registry record for the TORUS 2 study, sponsored by Endologix. It is listed as completed, with a single-group design and an enrollment of 188. The recorded study start date is 2018-08-13, and the primary completion date is 2023-01-06. Phase and allocation are listed as NA; masking is listed as NONE.

The intervention is the TORUS Stent Graft System, described as a Stent Graft and a Stent Graft Delivery System. The study concerns obstructive atherosclerotic lesions of the native SFA or the superficial femoral and/or proximal popliteal arteries. Its primary endpoint is freedom from a major adverse event at 30 days, defined as all-cause death, major amputation of the target limb, or clinically driven target lesion revascularization.

The registry lists safety counts and 14 outcome measures, but no analysis entries. The primary endpoint result and its statistical uncertainty are not reported in the registry record.