Clinical Trial Investigating the Combination Therapy With Luminor DCB and iVolution Stent in TASC C and D Femoropopliteal Lesions: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Clinical Trial Investigating the Combination Therapy With Luminor DCB and iVolution Stent in TASC C and D Femoropopliteal Lesions (NCT03347383), a na na study. The primary outcome is Freedom From Clinically-driven TLR at 12 Months.

2. Clinical Question

3. Trial Design

This was a physician-initiated, prospective, non-randomized, Belgian multicenter study. The registry lists a single-group model, no masking, and enrollment of 100. The study status is completed. The recorded study start date is 2017-09-19, and the primary completion date is 2019-10-16. The phase is listed as not applicable.

All participants were assigned to the combination therapy of Luminor drug-coated balloon and iVolution stent; the record does not describe a control arm. The target disease involved TASC C and D femoropopliteal lesions in the native superficial femoral artery and/or popliteal artery. In the treatment sequence described in the registry, Oceanus balloon pre-dilatation was mandatory, then the Luminor DCB was used, and iVolution stenting followed. Post-dilatation was left to physician discretion.

Follow-up visits were planned at 1, 6, 12, 24, 36, 48 and 60 months after the procedure. The primary efficacy outcome was freedom from clinically driven TLR at 12 months. Secondary outcomes included primary patency, technical success, freedom from clinically driven TLR at other listed follow-up times, clinical success, and serious adverse events. The registry lists six outcome measures but no analyses. Details of the statistical analysis plan, the number and identities of participating centers, and the reasons for the selected enrollment target are not reported in the registry record.

Because treatment was not randomized and there was no separate comparator, the design can describe outcomes among enrolled participants but does not establish a comparative treatment effect. Physician discretion in post-dilatation is also part of the treatment context. The registry record does not give additional protocol details that would clarify how this procedural variation was handled analytically.

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: All enrolled patients were treated with the study device.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: At twelve month, 5 patients had a TLR, 7 patients died, 1 withdrew his consent and 1 patient was lost-to-follow-up

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 Freedom From Clinically-driven TLR at 12 Months, measured over 12-month.

The primary endpoint is freedom from clinically driven target lesion revascularization at 12 months. TLR refers to repeat intervention to maintain or re-establish patency in the treated arterial vessel, including the region extending 5mm proximal and distal to the treated lesion edge. In general, a time-specific freedom-from-event endpoint summarizes whether participants experienced the defined event by a stated follow-up time.

This type of endpoint is used to capture whether further intervention was needed in the treated region, rather than measuring only an imaging finding. The “clinically driven” qualifier indicates that the endpoint is not simply any repeat procedure; the registry’s definition ties it to intervention to maintain or re-establish patency. The specific criteria used to determine whether a TLR was clinically driven are not reported in the registry record.

The registry reports that 5 participants had a TLR at twelve month. It also reports 7 deaths, 1 consent withdrawal and 1 participant lost to follow-up at that time. These counts do not, by themselves, establish the number classified as free from TLR or the denominator used for the primary endpoint. The registry does not report the endpoint estimate, its uncertainty, or the handling of deaths and other incomplete follow-up in that estimate.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical methods help define what an outcome count means, which participants contribute to an estimate, and how much uncertainty surrounds a result. In general, an endpoint estimate is most informative when its definition, analysis population, handling of incomplete observations and uncertainty measure are all stated. The registry record does not report those details for the primary endpoint, so interpretation must remain limited to the counts it does report.

What does a single-group design estimate?

In a single-group study, outcomes are described among participants receiving the study intervention. The design does not generate a randomized between-group contrast because there is no separate comparator and no random allocation. General statistical reasoning distinguishes a within-group description from a treatment effect: a treatment effect requires a comparison and assumptions that support attributing differences to treatment. Without a comparator, changes or event frequencies cannot be separated from other influences on outcomes.

That distinction matters for the TLR endpoint. The record reports 5 participants with a TLR at twelve month, but does not report the total number classified as free from TLR or an estimated probability of freedom from TLR. The registry also notes deaths, withdrawal and loss to follow-up. How those observations enter the primary endpoint analysis is not reported. A count of events is not interchangeable with a time-to-event estimate, a proportion with complete follow-up, or a statistical estimate that accounts for censoring.

Why do follow-up and censoring matter?

In general, time-to-event methods use information about when events occur and how long participants are observed. Participants without an event may have different follow-up lengths. If follow-up ends before an event is observed, an analysis may treat the participant as censored at the last known observation, subject to assumptions about why follow-up ended. Death can also affect whether a later TLR could occur. The appropriate handling depends on the endpoint definition and planned analysis. The registry record does not report whether the primary endpoint was analyzed as a simple status at 12 months, with time-to-event methods, or in another way.

A confidence interval, in general, expresses uncertainty around an estimated quantity under the statistical model used. It does not describe every source of uncertainty, and it cannot correct design limitations such as the absence of a comparator. No confidence interval or other uncertainty measure for the primary endpoint is reported in the registry record. As a result, the precision of any primary endpoint estimate cannot be evaluated from the posted outcomes.

What do the planning illustrations mean?

The registry’s sample-size assumptions describe planning illustrations based on the observed effect, not the trial’s own design. They specify a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and effects to detect expressed as stated fractions of the observed effect. The record says time-to-event illustrations give total events, while other illustrations give participants per arm. These are hypothetical planning calculations, not observed power and not evidence that the single-group study had two randomized arms.

In general, a sample-size calculation asks how much information a proposed study might need to detect a specified effect under chosen assumptions. Its output depends on the effect size, variability or event rate, design, significance level and desired power. The registry record does not report the trial’s own sample-size justification, a target power for this study, or a protocol-based calculation. The planning illustrations should therefore not be treated as confirmation that the trial was adequately sized for its primary endpoint.

Why can over-dispersion matter?

General statistical models sometimes assume that observations vary according to a particular distribution. Over-dispersion means the observed variation is greater than that model assumes. If ignored, uncertainty can be understated and intervals or tests can be poorly calibrated. This is a general issue in statistical analysis, not a reported feature of this study: the registry record does not describe a model for the primary endpoint or indicate whether over-dispersion was assessed.

What can be learned from the posted counts?

Counts can communicate how many participants or events were recorded, but interpretation depends on their unit and denominator. The primary endpoint unit is participants, and the record gives the number with TLR as well as counts of deaths and incomplete follow-up. It does not explain whether the latter categories overlap with TLR or with one another, nor does it state the primary endpoint denominator. For safety, the record gives participants at risk and participants affected, as well as selected event terms. In general, a participant count and an event count are different quantities: one participant may experience more than one event. The registry does not supply event-level data to distinguish these possibilities.

Finally, a p-value, when reported, addresses compatibility of data with a specified statistical model and null hypothesis; it is not a measure of clinical importance or a guarantee of replication. No p-values or analysis results are listed in the registry record. With no reported inferential analysis, the interpretation should stay descriptive rather than implying statistical significance or an estimated comparative effect.

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("Combination Therapy DCB + Stent")
n      <- c(100)
events <- c(5)
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  Combination Therapy DCB + Stent  100  5  5.0  1.6  11.3  2.2  11.2  2.2  11.2

11. Multiplicity, Missing Data and Analysis Populations

The study lists a primary endpoint and several secondary outcome types, assessed at multiple follow-up times. In general, examining multiple outcomes or time points creates multiplicity: the more questions tested, the greater the chance of a nominally unusual result occurring by chance if each is treated as a separate test. A prespecified hierarchy, adjustment procedure or clear distinction between confirmatory and exploratory analyses can help readers interpret such results. The registry record does not report a multiplicity strategy, a testing hierarchy, or analyses for the listed secondary outcomes.

Missing outcome information also affects interpretation. At twelve month, the record reports 5 participants with TLR, 7 deaths, 1 withdrawal of consent and 1 loss to follow-up. It does not report the analysis population, the amount of follow-up available for each participant, whether those categories overlap, or how death and incomplete follow-up were handled in the primary endpoint. Without these details, the counts cannot be converted into a clearly defined endpoint estimate. In general, missingness can affect an estimate when participants with incomplete follow-up differ in outcome risk from those fully observed.

The record lists no analyses. It does not report whether the primary analysis used all enrolled participants, an evaluable subset, or another analysis population. It also does not report imputation, sensitivity analyses, or rules for withdrawing participants from analysis. Those omissions limit assessment of robustness and possible bias. They should not be filled by assuming a standard approach: the actual analysis choices are not reported in the registry record.

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 1% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: arterial stenosis/occlusion (39.0%), deterioration of general health resulted in death (10.0%), foot wound (8.0%), other (7.0%), fracture (5.0%).

The safety record lists 100 participants at risk for serious adverse events, with 80 affected, and 100 at risk for other adverse events, with 44 affected. It also lists 39 deaths. These are participant counts in the registry’s adverse-event summary; they are not a comparison between treatment groups because the study has one group.

The listed serious-event terms include arterial stenosis/occlusion (39.0%), deterioration of general health resulted in death (10.0%), foot wound (8.0%), other (7.0%), fracture (5.0%) and heart failure (4.0%). The record does not explain whether participants could be counted under more than one term, how terms were coded, or the observation period associated with each figure. In general, a participant may experience multiple events, so participant counts and event-term counts should not automatically be treated as mutually exclusive categories.

The 39 deaths in the safety summary and the 7 deaths noted in the twelve-month primary endpoint population description appear in different registry contexts. The record does not explain their relationship or timing. These figures should not be reconciled by assumption. No comparator, adjusted safety analysis, or additional event-level detail is reported.

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

The registry record answers a focused descriptive question: it documents a prospective, single-group study of a specified combination treatment in participants with complex femoropopliteal lesions and identifies freedom from clinically driven TLR at 12 months as the primary efficacy endpoint. It also records selected outcome and safety counts. This is useful for understanding what the study set out to assess and what information was entered in the registry.

It does not report a primary endpoint estimate, uncertainty interval, or analysis result. The count of 5 participants with TLR is not enough to determine the proportion free from TLR because the endpoint denominator and handling of deaths and incomplete follow-up are not reported. The record also gives no timing details to support interpretation of an event-time analysis. Thus, the posted counts should not be treated as a complete efficacy estimate.

The design does not support a randomized comparison. There is no separate comparator group, and the registry lists no allocation to different treatments. Outcomes among participants in a single group cannot establish how outcomes would have differed under another treatment or no treatment. General statistical interpretation requires separating observed outcome description from causal comparison.

The safety counts likewise describe recorded events in the study group; they do not establish comparative safety. The record reports serious and other adverse events and selected serious-event terms, but lacks event-level details and comparative data. The listed 39 deaths in the safety summary should be read alongside, but not assumed to be equivalent to, the 7 deaths in the twelve-month endpoint description; the registry does not explain the difference.

Overall, the information supports a description of study design, planned follow-up and selected reported counts. It does not establish a precise primary efficacy result, a causal treatment effect, or a comparative safety profile. Those limits reflect what is and is not reported, rather than a conclusion about the intervention.

14. Why This Trial Matters Statistically

This trial is statistically notable because its primary question concerns a clinically defined event in a single-group setting. Freedom from clinically driven TLR combines a time point with an event definition tied to repeat intervention in the treated arterial region. For readers, this makes the analysis population, follow-up completeness and treatment of death particularly important parts of interpreting the endpoint.

The registry reports 5 TLRs at twelve month, along with deaths, withdrawal and loss to follow-up, but does not provide the endpoint estimate or the rules used to handle these observations. This illustrates why event counts alone may not be enough to interpret a time-specific outcome. A transparent report ordinarily needs a clearly stated denominator, follow-up accounting and an uncertainty measure, as well as the analysis method. Those details are not reported in the registry record.

The single-group, non-randomized design also illustrates the difference between describing outcomes and estimating a comparative effect. Even a complete outcome summary in one group would not, by itself, show what would have happened under a different treatment. This is an important distinction for clinical researchers reading registry results and planning subsequent studies.

Finally, the safety record contains substantial event information, including serious-event counts and selected terms, yet lacks comparator data and event-level context. Statistical interpretation depends not only on counts but also on denominators, definitions, time at risk, overlap and analysis methods. The registry’s gaps make it a useful example of why transparent reporting is necessary to assess both precision and scope of inference.

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 endpoint result is not reported in the registry record. Although the record gives the number of participants with TLR at twelve month, it does not state the endpoint estimate, its denominator, or an uncertainty measure. It also does not explain how deaths, withdrawal of consent and loss to follow-up were handled, whether the categories overlap, or whether the endpoint was evaluated using a fixed-time status or a time-to-event method.

The study is non-randomized and single-group, with no separate comparator. Consequently, it cannot provide a randomized estimate of the difference between this treatment and another approach. The record does not report adjustment methods or other analyses that would alter that design limitation. It also does not report the statistical analysis plan, sample-size justification for the study itself, or any analysis results.

The safety summary gives participant counts and selected serious-event terms, but event timing, event-level detail and the relationship between the 39 deaths in the adverse-event record and the 7 deaths noted in the twelve-month endpoint population are not reported. The record also does not state whether participants could contribute to more than one event category. Interpretation of the safety information is therefore limited to the registry’s reported counts and terms.

Additional protocol details, including the number of centers and the criteria used to determine clinically driven TLR, are not reported in the registry record. The absence of these details limits assessment of outcome adjudication, site variation and the generalizability of the posted findings.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Clinical Trial Investigating the Combination Therapy With Luminor DCB and iVolution Stent in TASC C and D Femoropopliteal Lesions — NCT03347383.
• Registry record last updated 2025-03-06; status last verified 2024-10.
• Results first posted 2025-03-06.
• 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

NCT03347383 is a completed, prospective, non-randomized Belgian multicenter study of Luminor drug-coated balloon and iVolution stent combination therapy for TASC C and D femoropopliteal lesions. The registry lists a single-group design, no masking, enrollment of 100, a start date of 2017-09-19 and primary completion date of 2019-10-16.

The primary endpoint was freedom from clinically driven TLR at 12 months. The record notes 5 participants with TLR, 7 deaths, 1 consent withdrawal and 1 loss to follow-up at that time, but does not report the primary endpoint estimate or analysis method. Safety information lists 80 participants with serious adverse events, 44 with other adverse events and 39 deaths among 100 at risk. No analyses are listed. The registry does not report a comparator-based effect or the statistical plan.