NHLBI Transmural Electrosurgery LeafLet Traversal And Laceration Evaluation (TELLTALE) BASILICA-TAVR Trial: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for NHLBI Transmural Electrosurgery LeafLet Traversal And Laceration Evaluation (TELLTALE) BASILICA-TAVR Trial (NCT05666713), a na na study. The primary outcome is Number of Participant That Experienced Technical Success With the TELLTALE Guidewire System.

2. Clinical Question

3. Trial Design

The TELLTALE BASILICA-TAVR Trial is registered as NCT05666713 and is sponsored by the National Heart, Lung, and Blood Institute. The registry identifies the study as a device intervention with a single-group model, allocation listed as NA, and no masking. It records an enrollment of 90 and a completed status. The recorded start date is 2023-02-21, and the primary completion date is 2025-02-14. The phase is listed as NA.

The intended participants are people at high risk of coronary artery obstruction during TAVR. The eligibility description specifies people aged 21 years and older. The group description includes severe aortic stenosis or failure of a surgically implanted bioprosthetic valve, with BASILICA performed during TAVR using the TELLTALE system.

The registry summary describes screening and routine pre-procedure tests, along with assessments of quality of life, physical abilities, and stroke risk. It also describes repeating physical-ability and quality-of-life assessments after the procedure. These details describe planned assessments; the registry record does not report their results. The primary endpoint focuses on procedural technical success, assessed at 1 minute following procedure discharge from the catheterization laboratory.

Because there is no randomized comparator, this design can describe outcomes among participants undergoing the procedure but cannot isolate the effect of the device from other features of care or participant characteristics. The registry record does not report a statistical analysis plan, a sample-size justification, or details of interim analyses.

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:

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 Number of Participant That Experienced Technical Success With the TELLTALE Guidewire System, measured over 1 minute following procedure discharge (Exit from the catheterization laboratory).

The primary endpoint is the number of participants who experienced technical success with the TELLTALE Guidewire System. Technical success is defined by meeting all the specified procedural criteria: successful electrosurgical leaflet traversal with the guidewire, successful electrosurgical leaflet laceration with the guidewire, and successful retrieval of the guidewire system. The endpoint is assessed at 1 minute following procedure discharge, which the record defines as exit from the catheterization laboratory.

This composite endpoint is used to capture whether the device completes the key procedural steps for which it is being evaluated. Requiring all listed steps means that success is not established by traversal or laceration alone; retrieval is also part of the definition. The measure is a participant count, not a continuous measurement or time-to-event outcome.

The registry record defines the endpoint but does not report the number of participants who met it. It also does not report an estimate of the proportion meeting the endpoint, a confidence interval, or a statistical test for the primary outcome. Accordingly, the endpoint definition can be described, but its observed result and precision cannot be assessed from the posted results.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record identifies the endpoint and design, but does not report an analysis plan or primary-endpoint result. The explanations below describe general statistical concepts relevant to interpreting a single-group procedural trial; they are not claims about methods used by this trial unless explicitly stated.

What does a participant-count endpoint represent?

The primary endpoint is a count of participants who meet a defined success criterion. In general, such an outcome classifies each participant according to whether every required component was achieved. A participant who does not meet one or more required components would not meet the composite definition of technical success. The registry states the components but does not report the observed count. It also does not report how any incomplete or unevaluable procedures were classified.

A count can describe the number meeting an endpoint, but the count alone is not an estimate of uncertainty. A confidence interval, when reported, describes the range of values compatible with the observed data under the specified statistical method. It communicates precision rather than guaranteeing that the true value lies within a particular interval. No confidence interval for technical success is reported in the registry record.

What can a single-group design estimate?

In general, a single-group study can summarize outcomes observed among people receiving an intervention. Without a comparison group, it cannot directly estimate how those outcomes would differ under another intervention or under a different care strategy. The TELLTALE trial is recorded as single-group, with allocation listed as NA and masking as none. The record does not identify a comparator. Thus, interpretation should remain descriptive rather than causal or comparative.

Random allocation, when used in a comparative study, can help balance measured and unmeasured participant characteristics between groups on average. That protection is not available as a between-group safeguard in this single-group record. This does not make descriptive data meaningless; it limits which questions those data can answer. Procedural success and safety counts can describe the experience recorded in the study group, but cannot alone establish what would have occurred with another approach.

Why does endpoint definition matter?

Composite endpoints combine multiple criteria into one success definition. In general, requiring every component can make the outcome clinically and operationally specific, but it also means the overall result depends on all components being achieved and recorded. A composite count may conceal variation among its parts: a reported total would not, by itself, show how often each component was achieved unless component-specific results were also reported. The registry defines traversal, laceration, and retrieval as required, but does not report component-specific counts.

The timing of assessment also defines what the endpoint captures. This primary endpoint is assessed at 1 minute following procedure discharge from the catheterization laboratory. It therefore describes immediate technical success according to the registry definition; it is not, by itself, a measure of later clinical outcomes. The record does not report a later primary-endpoint assessment.

What does a confidence interval add?

As a general statistical explanation, a confidence interval presents uncertainty around an estimate and helps readers judge how precisely the data locate the quantity being estimated. A narrow interval generally indicates greater precision than a wide interval, conditional on the method and assumptions. It does not resolve design limitations such as the absence of a comparator, and it does not correct for missing outcome reporting. Because no primary estimate or interval is reported, the precision of technical success cannot be evaluated.

How should planning illustrations be read?

Sample-size calculations are planning illustrations, not observed trial results and not observed power. General illustrations can show how a hypothetical future study’s size depends on assumptions about the effect to detect, significance level, allocation, and statistical approximation. The record describes a planning approach based on a fraction of the observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. Those assumptions do not establish that they were the trial’s original design assumptions. The sample-size justification and statistical plan are not reported in the registry record. Any planning illustration should be read as hypothetical, not as evidence that the current trial was adequately powered or that its endpoint result was statistically significant.

What does over-dispersion mean in general?

General explanation: over-dispersion occurs when observed variability in count data is greater than a statistical model expects. If a model assumes less variability than the data contain, estimated uncertainty may be too small. That concern can matter for some count outcomes, but the primary endpoint is described as a count of participants meeting a binary success definition. The registry record does not report a model for the primary endpoint or an over-dispersion assessment, so no claim about its relevance to the trial’s analysis can be made.

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("Participants Undergoing TAVR With BASILICA Using T")
n      <- c(90)
events <- c(90)
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  Participants Undergoing TAVR With BASILICA Using T  90  90  100.0  96.0  100.0  95.9  100.0  96.0  100.0

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 3 outcome measures and identifies technical success as the primary efficacy endpoint. It also lists “Freedom From Safety Events” as a secondary outcome. However, the record reports 0 analyses and does not provide results for the primary or secondary outcomes beyond the safety counts described separately. It does not report a statistical analysis plan specifying how outcomes were tested or interpreted.

Multiplicity refers, in general, to the increased chance of a false-positive finding when multiple hypotheses are tested. Statistical plans may address this by defining a primary outcome, ordering tests, or adjusting inference. The registry record does not report whether any multiplicity strategy was planned or used. Since no outcome analyses or p-values are reported, it is not possible to assess the consequences of multiple testing for this trial.

The registry record does not report missing-data counts, reasons for missingness, or methods for handling missing outcome assessments. It also does not report whether the primary analysis used all enrolled participants, only participants who underwent the procedure, or another analysis population. These details matter because the denominator and handling of participants without an evaluable endpoint can affect an outcome estimate. No assumptions about those issues can be inferred from the recorded enrollment alone.

As a general principle, missing observations can affect both the estimated outcome and its uncertainty, particularly when missingness is related to participant status or procedural outcomes. Complete-case analysis, imputation, and other approaches rely on different assumptions. The registry record does not identify an approach, so readers cannot determine how missingness was addressed or whether a sensitivity analysis was performed.

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: anemia (8.9%), stroke (6.7%), arterial injury (5.6%), atrioventricular block complete (5.6%), heart failure (3.3%).

The safety record reports 36 participants with serious adverse events among 90 at risk, and 62 participants with other adverse events among 90 at risk. It reports 0 deaths. These are participant counts. They should not be added together: a participant may be represented in more than one category, and the record does not specify overlap. The counts are not a comparison between treatment groups, because the trial has a single-group design.

The record lists anemia at 8.9%, stroke at 6.7%, arterial injury at 5.6%, complete atrioventricular block at 5.6%, heart failure at 3.3%, and hypoxia at 2.2% among the top serious adverse-event terms. These percentages describe the entries as reported in the safety record; they do not establish causation. The registry does not provide a comparator group or an analysis attributing these events to the device.

Serious adverse-event counts are distinct from the primary technical-success endpoint. They describe reported safety events, while technical success requires completion of the specified procedural steps. The registry record does not provide further detail about event timing, duration, severity grading beyond the serious classification, or attribution. The counts should therefore be interpreted as a descriptive account of reported events in the study group, not as a measure of comparative risk.

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

This trial is designed to evaluate a device used for leaflet traversal and laceration during BASILICA and TAVR. The registry gives a clear operational definition of technical success: all specified traversal, laceration, and retrieval criteria must be met. That definition identifies what the primary endpoint is intended to measure, but the registry record does not report how many participants achieved it.

The record does report safety counts for the single study group, including serious adverse events, other adverse events, and deaths. These figures describe what was recorded among participants at risk. In the absence of a comparator, they do not quantify how safety outcomes would differ with another device or procedure. They also do not establish that any particular event was caused by the TELLTALE system.

The study’s completed status and enrollment of 90 provide context about the trial record, but do not answer the primary efficacy question. The lack of a reported primary result means readers cannot assess the observed technical-success frequency, its uncertainty, or whether the endpoint’s component steps were achieved consistently. The record also does not report a formal outcome analysis or a confidence interval.

The study cannot establish comparative effectiveness from its single-group design. A descriptive outcome in a treated group is not the same as an estimate of the difference between treatment strategies. The posted information likewise does not support a conclusion about long-term clinical outcomes, since the primary endpoint is defined at 1 minute following procedure discharge and later primary-endpoint results are not reported.

Overall, the registry record supports an account of the study’s population, intervention, design, endpoint definition, and reported safety counts. It does not supply the primary efficacy result needed to judge technical success, and it does not support claims that the device does or does not improve outcomes.

14. Why This Trial Matters Statistically

The trial addresses a procedural question in a defined setting: use of a purpose-designed guidewire system for BASILICA during TAVR among people at high risk of coronary artery obstruction. Statistically, this makes the endpoint definition especially important. Technical success is not a broad clinical outcome; it is a composite procedural measure requiring traversal, laceration, and retrieval. Clear criteria help specify what the study intends to count, but interpretation still depends on reporting the observed result and its uncertainty.

The single-group design shapes what can be learned. It can describe outcomes among people undergoing the procedure, but it cannot supply a randomized comparison with another strategy. This distinction is central when interpreting both efficacy and safety: a count of successes or adverse events in one group is not a comparative treatment effect. The absence of masking is also part of the recorded design and should be considered when assessing outcome ascertainment, although the record does not report how endpoint assessment was conducted.

The record’s missing primary result is consequential. Enrollment and completion status do not replace an endpoint estimate, and a detailed endpoint definition cannot show how often it was met. Without the count and an uncertainty estimate, readers cannot judge the observed technical-success result or its precision. Without a comparator, even a reported single-group result would have limited ability to support causal or comparative claims.

The safety counts remain informative as descriptive reporting, but they need cautious interpretation. Event categories may overlap, and the record does not report event attribution or a control group. Together, the design and reporting illustrate why clinical-trial interpretation requires more than a study label or enrollment figure: the outcome results, analysis methods, missing-data handling, and comparison structure determine the scope of statistical conclusions.

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 defines the primary endpoint without reporting its observed count. No primary efficacy estimate, confidence interval, or statistical test is reported. As a result, the central technical-success outcome cannot be evaluated from the posted results.

The single-group design, with allocation listed as NA and masking as none, provides no randomized comparison. Any descriptive outcome is limited to the study group and cannot establish how outcomes would differ under another device or procedural approach. The registry record also does not report a statistical analysis plan, sample-size justification, interim analyses, or an analysis population.

Important details about endpoint completeness are not reported in the registry record. The record does not state whether all enrolled participants had an evaluable primary endpoint, how missing assessments were handled, or whether the three procedural components were reported separately. It also does not report the timing or attribution of adverse events beyond the listed safety information. These omissions limit assessment of outcome ascertainment and safety context.

The primary endpoint is a procedural measure assessed at 1 minute following procedure discharge from the catheterization laboratory. It does not, on its own, answer questions about longer-term clinical outcomes. Although the registry summary describes additional quality-of-life and physical-ability assessments, their results are not reported in the registry record. These limitations constrain interpretation to the design and descriptive safety figures that are available, without supporting a broader efficacy or causal conclusion.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: NHLBI Transmural Electrosurgery LeafLet Traversal And Laceration Evaluation (TELLTALE) BASILICA-TAVR Trial — NCT05666713.
• Registry record last updated 2026-02-03; status last verified 2026-01.
• Results first posted 2026-02-03.
• 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

NCT05666713 is the completed, single-group TELLTALE BASILICA-TAVR device trial sponsored by the National Heart, Lung, and Blood Institute. The registry records an enrollment of 90, a start date of 2023-02-21, and a primary completion date of 2025-02-14. Allocation is listed as NA, masking as none, and phase as NA.

The primary endpoint counts participants achieving technical success, requiring successful electrosurgical leaflet traversal, laceration, and guidewire-system retrieval. Its timeframe is 1 minute following procedure discharge from the catheterization laboratory. The primary endpoint result and its statistical analysis are not reported in the registry record.

The safety record reports 36 participants with serious adverse events among 90 at risk, 62 with other adverse events among 90 at risk, and 0 deaths. With no comparator group and no reported primary efficacy result, the record supports descriptive interpretation but not a comparative treatment-effect conclusion.