LSA Reconstruction With Laser Fenestration During the TEVAR: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for LSA Reconstruction With Laser Fenestration During the TEVAR (NCT03845829), a na na study. The primary outcome is Freedom From All-cause Reintervention, All-cause Mortality and Major Adverse Events Within 30 Days After Procedure.

2. Clinical Question

3. Trial Design

This was a completed, single-group study of in-situ laser-assisted fenestration for the left subclavian artery during TEVAR for type B aortic dissection. The registry lists an enrollment of 100 and describes the treated group as patients with complicated and high-risk TBAD treated with TEVAR. The intervention was a procedure rather than a drug. The trial phase is listed as NA, allocation is listed as NA, and masking is listed as none.

The registry records a study start date of 2018-07-01 and a primary completion date of 2022-12-10. Its status is completed. The stated aim was to evaluate the feasibility, effectiveness, and safety of in-situ laser-assisted fenestration during thoracic endovascular aortic repair. The registry lists secondary outcomes that include aortic disease-related mortality, endoleak within 12 months, technical success during the procedure, and branch-stent patency 12 months after the procedure. Results for those secondary outcomes are not reported in the registry record.

Because the study has a single group, the endpoint results are descriptive observations among treated participants. There is no concurrent control group against which to estimate what would have happened under a different procedure or strategy. The registry record therefore does not support a randomized treatment comparison or a causal estimate of the effect of laser-assisted fenestration.

The record lists five outcome measures but no analysis records. Details of eligibility criteria, recruitment procedures, follow-up completeness, the planned analysis, and the rationale for the enrollment target are not reported in the registry record. The absence of those details limits assessment of how participants were selected and how the reported endpoint was assembled.

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: No patient was excluded in this study when enrolled.

Overall Study

Analysis population for the primary outcome, as defined in the registry: The primary safety endpoint was 84% (84/100), with 19 events occurring in 16 patients.

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 All-cause Reintervention, All-cause Mortality and Major Adverse Events Within 30 Days After Procedure, measured over within 30 days after procedure.

The primary endpoint is freedom from all-cause reintervention, all-cause mortality, and major adverse events within 30 days after the procedure. It is reported as a participant count and as 84% (84/100). The registry also reports 19 events occurring in 16 patients. The number of events and the number of patients with events are distinct quantities: one person can contribute more than one event to an event count.

A composite safety endpoint combines several clinically important outcomes into one measure. In general, this can provide a broad summary of whether participants experienced any of a defined set of adverse outcomes during a specified period. The registry’s definition of major adverse events includes mortality, stroke, myocardial infarction, rupture, paraplegia, type Ia endoleak, major bleeding, acute kidney injury, limb ischemia, bowel ischemia, retrograde dissection, stent-induced new entry, access-site complications, and unplanned reinterventions.

The endpoint is used to describe short-term safety following the procedure, but the combined result does not show which individual component accounts for the overall endpoint. The record does not report component-specific counts for the primary endpoint, nor does it report a confidence interval or a comparative estimate. A confidence interval, in general, expresses the uncertainty around an estimated quantity; it is not reported for this endpoint in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the primary measure count?

The primary outcome is a binary participant-level measure: a participant either met the definition of freedom from the listed events within 30 days or did not. In general, binary outcomes summarize whether an event or condition occurred, rather than measuring a continuous quantity such as a laboratory value. The registry reports the endpoint as 84% (84/100), and separately gives 19 events in 16 patients. The participant count and event count answer different questions and should not be treated as interchangeable.

The endpoint is composite. In general, a composite combines multiple outcomes under one definition, often counting a participant as having an endpoint if any listed component occurs. This can make a broad safety summary easier to present, but it can also conceal variation among components: frequent, less severe outcomes and uncommon, serious outcomes may both contribute to the same overall measure. The component-level breakdown for this primary endpoint is not reported in the registry record.

What does a single-group result estimate?

In a single-group study, a proportion describes the observed participants who met the endpoint definition. It does not directly estimate the difference between the intervention and a control strategy. A comparison requires outcome information from a comparator group or another clearly specified design and analysis. Neither a concurrent control group nor a randomized comparison is reported in the registry record.

General statistical interpretation distinguishes an observed proportion from a causal effect. The observed result can be influenced by participant selection, clinical characteristics, care practices, and follow-up. Without a comparator and relevant design information, these influences cannot be separated from the intervention’s contribution. The registry does not report an adjusted estimate that addresses these considerations.

How should uncertainty be assessed?

A confidence interval is a general statistical tool for expressing uncertainty around an estimate. It provides a range of values compatible with the data under a specified method and assumptions; it does not guarantee that the true value lies within that range. The registry record does not report a confidence interval for the primary endpoint. It also does not report a p-value or an inferential analysis for this outcome. As a result, the precision of the estimate cannot be evaluated from an interval estimate in the posted results.

Enrollment of 100 participants gives the context for the reported participant count, but enrollment alone does not show whether the study was designed to estimate the endpoint with a particular precision. The sample-size justification is not reported in the registry record. Any planning illustrations based on an observed effect are hypothetical design calculations, not observed power and not evidence that a study had a prespecified chance of detecting an effect.

What do the secondary outcomes add?

The registry lists aortic disease-related mortality, endoleak within 12 months, technical success during the procedure, and branch-stent patency 12 months after the procedure as secondary outcomes. In general, each outcome requires its own definition, time point, and analysis. Outcomes measured at different times may also depend on follow-up availability and the handling of participants without recorded follow-up. Those details and the secondary outcome results are not reported in the registry record.

The registry identifies five outcome measures in total, but no analysis records. This means the record does not give an analysis-level account of how outcomes were estimated or tested. The statistical analysis plan, including methods for uncertainty estimates, covariate adjustment, and handling of incomplete observations, is not reported in the registry record.

Why do event distributions matter?

For a binary endpoint, a simple proportion is a natural descriptive summary. Statistical methods must still address the definition of the outcome, the observation period, and whether all enrolled participants had ascertainable status. If follow-up is incomplete, excluding participants or treating missing outcomes as event-free can change interpretation. The registry does not report the number of participants with missing endpoint data or its approach to missing data, so completeness cannot be assessed from the record.

Over-dispersion is a general issue for count data when observed variability exceeds what a simple model assumes. It is not a reason to reinterpret this participant-level binary result as a count model. The primary measure is specified as a count of participants, and no model-based analysis is reported. The separate report of 19 events in 16 patients highlights why event totals and patient-level outcomes need clear definitions, but the registry does not describe a recurrent-event analysis.

Finally, a lack of posted inferential analyses does not mean that the observed descriptive values are invalid; it means that their uncertainty and comparative interpretation are not documented in the registry record. The available information supports a description of the recorded outcomes in this group, but not a statistical claim about how the procedure compares with an alternative.

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("Patients With Complicated and High-risk TBAD Treat")
n      <- c(100)
events <- c(84)
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  Patients With Complicated and High-risk TBAD Treat  100  84  84.0  75.3  90.6  75.6  89.9  75.6  89.9

11. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when several outcomes, comparisons, or analyses are examined. In general, testing many questions can increase the chance that at least one apparently notable result occurs by chance. The registry lists a primary safety endpoint and secondary outcomes concerning aortic disease-related mortality, endoleak within 12 months, technical success, and branch-stent patency at 12 months. The record does not report whether the secondary outcomes were treated as exploratory or whether any adjustment for multiple testing was planned.

The statistical analysis plan and interim-analysis procedures are not reported in the registry record. The record lists no analysis records, so it does not document inferential tests, confidence intervals, adjustment methods, or a hierarchy for interpreting outcomes. No conclusions about multiplicity control or prespecified analysis choices can be drawn from the posted record.

The approach to missing data is also not reported in the registry record. The record does not state whether all 100 participants had complete primary endpoint follow-up, how unavailable observations were handled, or whether any analysis population differed from the enrolled group. In general, missing outcome information can affect a proportion if participants without known status are excluded or classified in a particular way. The reported 84% (84/100) does not by itself describe how missingness was assessed.

Definitions of analysis populations, including any distinction between enrolled, treated, and evaluable participants, are not reported in the registry record. These omissions limit reproducibility and make it difficult to judge how robust the reported endpoint might be to alternative assumptions. The record supports a descriptive reading of the posted result, but not a detailed audit of the analysis process.

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: ia endoleak (5.0%), stroke (4.0%), acute kidney injury (2.0%), myocardial infarction (1.0%), mesenteric ischemia (1.0%).

The registry reports serious adverse-event terms in the treated group: Ia endoleak at 5.0%, stroke at 4.0%, acute kidney injury at 2.0%, myocardial infarction at 1.0%, mesenteric ischemia at 1.0%, and spinal cord ischemia at 1.0%. It lists 100 participants at risk and 16 affected participants in the serious-event group, along with 2 deaths. The registry also lists 0 affected participants in the other adverse-event category.

These figures should be read as event reporting within one group, not as differences from a control group. The record does not specify whether participants could have more than one listed event term, or whether event terms are mutually exclusive. It also does not report detailed timing or component-level links between these terms and the primary composite. The serious adverse-event percentages therefore do not, by themselves, explain the 30-day primary endpoint result or establish a comparative safety effect.

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

The result does mean that the registry records freedom from the defined composite endpoint for 84% (84/100) of participants within 30 days after the procedure. It also reports 19 events occurring in 16 patients. These observations describe outcomes in the enrolled group following in-situ laser-assisted fenestration during TEVAR. The safety-event summary provides additional listed terms and frequencies, including Ia endoleak, stroke, and acute kidney injury.

The result does not establish that the procedure caused the observed outcomes or that outcomes would have been different with another strategy. The study is recorded as single-group, with no comparator. Without a concurrent comparison, the observed endpoint cannot be interpreted as a difference attributable to the procedure. Nor does the result establish that the procedure works or does not work; it is a descriptive registry result, not a comparative effect estimate.

The composite endpoint does not reveal how each component contributed. The registry defines major adverse events with a broad list of outcomes, but component-specific primary endpoint results are not reported. The result also does not establish longer-term outcomes: the primary endpoint concerns the period within 30 days, while the registry’s secondary outcomes include measures at 12 months whose results are not reported in the registry record.

Precision and robustness are also unresolved. The registry does not report a confidence interval, a statistical analysis, the handling of missing data, or the number of participants with complete follow-up. The primary result can therefore be read as the observed proportion, but its uncertainty cannot be fully assessed from the record. The enrollment of 100 does not substitute for an interval estimate or a sample-size rationale.

The most defensible interpretation is limited to the defined group and observation period: the record describes the observed primary safety endpoint and selected serious adverse events among treated participants. It does not support a comparative conclusion, a causal claim, or a complete assessment of the secondary outcomes.

14. Why This Trial Matters Statistically

This trial is statistically informative as an example of how a single-group procedural study can describe observed safety outcomes while leaving comparative questions unanswered. The registry reports a defined 30-day composite endpoint for 100 treated participants, along with separate event and patient counts. This makes clear why endpoint definitions and units matter: 19 events occurred in 16 patients, so the event total is not the same as the number of participants affected.

The composite endpoint also illustrates a common trade-off in outcome design. Combining mortality, reintervention, and a broad range of major adverse events can yield one overall safety summary. At the same time, the composite can obscure which specific components contributed to the result. Component-level primary endpoint data are not reported in the registry record, so the overall proportion cannot answer questions about the individual outcomes on its own.

The design is equally important to interpretation. Because the study has one group and no reported comparator, a proportion among treated participants cannot estimate a treatment contrast. Statistical significance, even if it had been reported, would not remedy the absence of a suitable comparison for causal interpretation. The registry lists no analysis records, confidence interval, or statistical plan, making precision and analysis choices difficult to evaluate.

These features make the record useful for understanding what descriptive registry data can and cannot establish. It documents a completed study, a primary safety measure, and selected serious adverse-event terms. It also highlights the need for transparent reporting of comparator design, follow-up completeness, analysis methods, component outcomes, and uncertainty when readers assess procedural evidence.

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 principal limitation is the single-group design. There is no concurrent comparator in the registry record, so the observed outcome cannot show how the treated participants would have fared under another strategy. Allocation is listed as NA, and masking is listed as none. The record does not describe additional design features that could address confounding or selection effects.

The primary endpoint is a broad composite, but results for its individual components are not reported in the registry record. The registry reports 19 events in 16 patients, yet does not provide a detailed account of how event terms overlap or how each component contributes to the composite. This restricts interpretation of the overall proportion.

Statistical reporting is limited. No analysis records are listed, and the statistical analysis plan, confidence intervals, interim analyses, and sample-size justification are not reported in the registry record. The approach to missing outcomes and the definitions of analysis populations are also not reported. These gaps prevent assessment of precision, reproducibility, and sensitivity to analysis decisions.

The registry lists secondary outcomes with follow-up extending to 12 months, but their results are not reported in the registry record. Follow-up completeness and outcome ascertainment details are not reported either. Finally, the record’s description of a complicated and high-risk TBAD group does not include further participant characteristics or eligibility details, limiting assessment of how broadly the results may apply to other patient groups.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: LSA Reconstruction With Laser Fenestration During the TEVAR — NCT03845829.
• Registry record last updated 2025-02-18; status last verified 2025-02.
• Results first posted 2025-02-18.
• 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

NCT03845829 is a completed, single-group study of in-situ laser-assisted fenestration of the left subclavian artery during TEVAR for type B aortic dissection. The registry lists enrollment of 100, a start date of 2018-07-01, and a primary completion date of 2022-12-10. The primary endpoint was freedom from all-cause reintervention, all-cause mortality, and major adverse events within 30 days.

The registry reports the primary endpoint as 84% (84/100), with 19 events in 16 patients. It lists serious adverse-event terms including Ia endoleak at 5.0% and stroke at 4.0%, and reports 2 deaths. Secondary outcome results, analysis records, the statistical analysis plan, confidence intervals, and the approach to missing data are not reported in the registry record. With no comparator group, the posted outcomes describe the treated group and do not estimate a comparative effect.