Therapy Cool Path Ablate VT: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Therapy Cool Path Ablate VT (NCT00925522), a na na study. The primary outcome is Primary Safety is Defined as the Incidence of Intra-procedural, Acute or Sub-chronic, Serious Cardiac Adverse Events, up to 7 Days Post-procedure..

2. Clinical Question

This question is narrower than a full assessment of the device. It concerns the frequency of a specified set of serious cardiac events over a defined post-procedure period. It does not, by itself, establish whether ventricular tachycardia was eliminated, whether any change lasted, or how the intervention compares with another approach. Those questions require outcome data and, for comparative claims, an appropriate comparison. The registry lists one outcome measure and no analyses. Accordingly, the record supports describing the study’s stated safety question and the adverse-event entries, but not drawing a conclusion about the primary endpoint or comparative benefit.

3. Trial Design

NCT00925522 is a single-group clinical study listed under the title “Therapy Cool Path Ablate VT.” Its official title describes clinical evaluation of the Therapy Cool Path Duo Cardiac Ablation System for treatment of ischemic ventricular tachycardia. The registry records Abbott Medical Devices as sponsor and enrollment of 20. The study start is recorded as 2009-06, and primary completion as 2010-04. Its status is TERMINATED.

All eligible patients in the arm description were to receive the cardiac ablation procedure using the named system. The model is single group; allocation is NA, and masking is NONE. The registry therefore does not describe random assignment, masking, or a concurrent control arm. It records phase as NA. The reason for termination and whether termination affected recruitment, follow-up, or outcome collection are not reported in the registry record.

The registry lists one outcome measure, the primary safety endpoint, and zero analyses. The primary measure is a count of participants, with a timeframe of 7 days. Although the brief summary also states an objective concerning elimination of ischemic VT, an efficacy result for that objective is not reported in the registry record. Nor are details of the statistical analysis plan, sample-size justification, or analysis population reported. These design details matter when interpreting the posted adverse-event counts: a single-group record can describe events observed among participants, but it cannot establish how those events compare with what would have occurred under another treatment or without the intervention.

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: This is a non-randomized study.

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 Primary Safety is Defined as the Incidence of Intra-procedural, Acute or Sub-chronic, Serious Cardiac Adverse Events, up to 7 Days Post-procedure., measured over 7 days.

The registered primary endpoint is “Primary Safety is Defined as the Incidence of Intra-procedural, Acute or Sub-chronic, Serious Cardiac Adverse Events, up to 7 Days Post-procedure.” It is measured as the number of participants, over a 7-day timeframe. In plain terms, the endpoint is intended to count participants experiencing qualifying serious cardiac adverse events during the procedure or within the stated period after it.

Such an endpoint is used to describe an important safety outcome over a specified interval. Defining the event type and timeframe helps make clear which events are relevant to the endpoint and when they are counted. A participant count is also directly interpretable as a number of people meeting the endpoint definition, provided the outcome result and denominator are available.

The registry record does not report a result for this primary endpoint. The adverse-event listing reports serious adverse-event counts, but it does not establish in the record that every listed serious event meets the primary endpoint definition, including its cardiac-event criteria and timeframe. Those figures should therefore be read as adverse-event information, not treated automatically as the primary endpoint result. The endpoint’s rationale in the protocol and its detailed event-adjudication rules are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical interpretation begins with the type of study and the type of endpoint. This record describes a single-group device study and a binary safety outcome summarized as participants with an event. It does not describe random allocation or a comparison arm. As a result, the directly interpretable quantity is a count of participants recorded with adverse events, rather than an estimated difference between treatment groups.

What does a participant count represent?

For an outcome expressed as participants with an event, the count identifies how many people in the stated group met the event definition. The denominator identifies how many participants were at risk or included in that adverse-event summary. The registry’s adverse-event record gives a group at-risk count of 20 and reports 7 participants with a serious adverse event and 16 with another adverse event. These summaries are descriptive. They do not, by themselves, say when each event began, whether a participant experienced more than one event, or whether an event was judged to be caused by the device or procedure.

A participant-based count is distinct from an event count. One person may experience more than one event, and one event term may be recorded alongside another term for the same person. Unless the registry clarifies that categories are mutually exclusive, counts or percentages for different terms should not be combined to infer a total number of people. The listed serious-event terms are best read as individual safety categories, not as pieces of a total that can be added together.

Why does the single-group design matter?

A comparison requires information from both the intervention group and a suitable comparator group, measured in a way that supports a fair contrast. This registry describes no control arm and no random allocation. There is consequently no direct estimate in the record of how the event frequency differed from another treatment or from no treatment. General statistical principle: a one-group event frequency can characterize what was recorded among participants, but it cannot isolate the effect of an intervention from underlying illness, procedure-related circumstances, or other causes.

Even a well-defined percentage in a single group is not equivalent to a causal effect. A causal comparison depends on the groups being comparable in relevant ways, which is why randomized designs are commonly used for comparative questions. Here the record expressly describes a single group, so comparative conclusions cannot be recovered from the adverse-event counts alone.

What would a confidence interval add?

General statistical explanation: a confidence interval gives a range of values compatible with the observed data under a specified statistical model and procedure. It conveys precision as well as the point estimate: a wider interval indicates less precision than a narrower interval. An interval does not repair limitations of study design, make an uncontrolled comparison, or establish causation. For this record, no primary endpoint estimate or interval is reported. No interval should be inferred from the adverse-event summary alone, particularly because the primary endpoint definition and the broader adverse-event categories are not shown to be identical.

Counts from a limited group can be sensitive to each observed participant. This is a general feature of small samples: a small number of observations can materially affect a descriptive estimate, and uncertainty may remain substantial. The registry does not report an uncertainty interval for the primary endpoint, so the precision of that endpoint cannot be stated from the posted results.

How should the planning illustrations be read?

The registry’s planning assumptions describe an illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is expressed as a stated fraction of the observed effect. Such calculations are planning illustrations, not observed power and not a report of the trial’s own design justification. They posit two arms even though the actual study is single-group, so they should not be mistaken for a comparative analysis performed in this study.

General statistical explanation: a sample-size calculation depends on assumptions about the effect of interest, variability or event frequency, allocation, significance level, and desired power. Changing an assumption changes the calculated sample size. A calculation based on an effect seen in the study is especially dependent on that observed estimate; it does not show that the study was adequately powered before it began. The protocol’s sample-size rationale is not reported in the registry record.

The planning description distinguishes time-to-event calculations, which express a total number of events, from other calculations, which express participants per arm. Those are different units and must be interpreted according to the type of outcome. No additional sample-size values or observed-power result should be inferred from the description alone.

What can be concluded from the analysis record?

The registry lists one outcome measure and zero analyses. The primary endpoint is described as a participant count, but no result for it appears in the record. The absence of a reported analysis means there is no posted model, adjustment, hypothesis test, or interval estimate to interpret for the primary question. General statistical principle: analysis choices should match the endpoint and study design, and their interpretation depends on transparent definitions and reporting. In this record, the event definitions, missing-data approach, and analysis population are not reported in the registry record. That leaves the safety entries useful as descriptive information, but insufficient for a formal estimate of the primary endpoint or a comparative conclusion.

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("Therapy Cool Path Duo Catheter")
n      <- c(20)
events <- c(7)
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  Therapy Cool Path Duo Catheter  20  7  35.0  15.4  59.2  18.1  56.7  18.1  57.0

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure, identified as the primary safety endpoint, and zero analyses. The approach to multiplicity is not reported in the registry record. A single listed outcome does not establish whether other outcomes were assessed, whether additional analyses were planned, or how multiple comparisons would have been handled. General statistical explanation: multiplicity arises when several hypotheses or outcomes are examined; repeated testing can increase the chance of a nominally positive finding. A prespecified analysis plan helps clarify which results are primary and how other analyses should be interpreted. No such plan is reported.

Missing-data handling is not reported in the registry record. The record does not state whether all participants contributed to the primary endpoint, how incomplete follow-up was treated, or whether any imputation or sensitivity analysis was used. This matters because an outcome can be biased if participants with missing observations differ systematically from those with complete data. Without a reported denominator and missingness account for the primary endpoint, its completeness cannot be assessed.

The analysis population is also not reported in the registry record. The record gives an enrollment of 20 and adverse-event at-risk counts of 20, but does not describe analysis-set definitions or explain whether all enrolled participants were included in each endpoint analysis. These details should not be inferred from the adverse-event denominator.

General statistical explanation: analysis populations can be defined in different ways, and the choice affects which participants contribute to an estimate. The population and exclusions should be stated so readers can understand what the result represents. Since the registry has no primary analysis result and does not report these methods, no claim about adherence to a particular analysis population or missing-data strategy is supported.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

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: arrhythmia(s) including afl, af or vt (25.0%), cardiac effusion with tamponade (10.0%), congestive heart failure (5.0%), hypotension (5.0%), cardiac effusion without tamponade (5.0%).

The adverse-event record lists 7 of 20 participants with a serious adverse event and 16 of 20 with another adverse event in the Therapy Cool Path Duo group. These are participant counts in the registry’s safety listing. They are distinct summaries and should not be combined. The record also lists serious-event terms and their percentages: Arrhythmia(s) including AFL, AF or VT, 25.0%; Cardiac Effusion with Tamponade, 10.0%; Congestive Heart Failure, 5.0%; Hypotension, 5.0%; and Cardiac Effusion without Tamponade, 5.0%.

The percentages describe the listed terms; the record does not establish whether a participant could appear under more than one term. They therefore should not be added or read as a count of unique people. The adverse-event entries are also not automatically equivalent to the primary endpoint, which specifically concerns serious cardiac events up to 7 days after the procedure. The registry does not report the primary endpoint result or enough detail to confirm that the adverse-event summaries use the same event criteria and timeframe.

Deaths are not reported in the registry record. This should not be interpreted as evidence that no deaths occurred. The record also does not provide causal attribution for each event, so the counts describe reported safety events rather than proving that the device caused them.

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

The registry record describes a terminated, single-group study of the Therapy Cool Path Duo Cardiac Ablation System in ischemic ventricular tachycardia. It specifies a primary safety question focused on serious cardiac adverse events occurring during the procedure or up to 7 days afterward. The adverse-event listing reports serious events in 7 of 20 participants and other adverse events in 16 of 20. These figures characterize the safety entries recorded for the intervention group; they are not a comparison with another treatment.

The primary endpoint result itself is not reported in the registry record. Although the brief summary mentions an aim to demonstrate elimination of ischemic VT, no efficacy result for that aim is reported either. Thus the available record does not answer whether the stated primary safety endpoint was met, nor does it establish an efficacy finding.

General statistical interpretation: a descriptive count is not a causal estimate. Without a comparator, it cannot show how many events would have occurred under a different intervention or in the absence of this procedure. The adverse-event listing also does not establish that every reported serious event satisfies the endpoint’s specific cardiac-event and 7-day criteria. The event terms may overlap, and the record does not report causal attribution or deaths.

The status TERMINATED is part of the record, but the reason for termination is not reported in the registry record. It cannot be used alone to infer a safety problem, a favorable or unfavorable efficacy result, or the completeness of the data. Likewise, planning calculations based on an observed effect are not evidence of observed power and do not substitute for a prespecified sample-size justification or a reported analysis.

The defensible conclusion is therefore limited: the registry records adverse-event counts for the single intervention group and states a short-term serious cardiac safety endpoint, but it does not post an analysis or result for that endpoint. Stronger conclusions about risk, comparative safety, or effectiveness are not supported by the information recorded.

14. Why This Trial Matters Statistically

This trial matters statistically because its stated clinical aim and its registered primary endpoint are not the same kind of question. The brief summary refers to eliminating ischemic VT while also raising safety, whereas the primary outcome measure is a count of participants with serious cardiac adverse events up to 7 days after the procedure. Separating safety and efficacy questions prevents an objective in the summary from being mistaken for a measured or reported result.

The single-group structure is also central to interpretation. The adverse-event counts can describe what was recorded among participants who received the procedure, but there is no concurrent control group to support a treatment contrast. This distinction is important whenever a result is presented as though it demonstrates a change attributable to an intervention. Statistical precision cannot compensate for the absence of a comparator when the question is comparative.

The record also illustrates why endpoint definitions and time windows matter. A broad serious adverse-event summary and a primary endpoint restricted to serious cardiac events up to 7 days may not refer to precisely the same set of events. Without a posted primary result and further event-level detail, it is not possible to treat these summaries as interchangeable.

Finally, the record illustrates the limits of registry information when the analysis is absent. The stated enrollment, design, endpoint and adverse-event entries help describe the study, but missing analysis methods and an absent endpoint result limit assessment of precision and completeness. Planning illustrations can support hypothetical design discussion, but they do not establish observed power or replace the study’s own design rationale. Clear distinctions among design, endpoint, adverse-event listing, and analysis help keep descriptive evidence from being overstated.

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 important limitation is that the registry does not report a result for the primary safety endpoint. It also lists zero analyses, so there is no posted primary estimate, uncertainty interval, or hypothesis test to evaluate. The adverse-event counts should not be assumed to be the primary endpoint result because the registry does not establish that they follow the same cardiac-event definition and 7-day timeframe.

The single-group design has no like-for-like control comparison. As a result, the record cannot distinguish the observed adverse events from the background risk associated with the condition, the procedure, or other circumstances, and it cannot estimate a comparative treatment effect. The registry does not describe random allocation or masking.

Further limitations concern incomplete methodological detail. The reason for termination, eligibility criteria, baseline participant characteristics, analysis population, missing-data handling, and detailed event-adjudication rules are not reported in the registry record. Causal attribution for the adverse events and deaths are also not reported. Without these details, completeness and comparability of outcome ascertainment cannot be assessed.

The adverse-event list includes several serious-event terms, but the record does not clarify whether terms can overlap within participants. Their percentages should not be combined to estimate unique affected participants. The recorded enrollment is 20, and the listed safety group has 20 at risk; the limited group size constrains how broadly the descriptive experience can be generalized. The registry’s planning assumptions are hypothetical illustrations using a two-arm setup, not the study’s single-group design, and the study’s own sample-size justification is not reported.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Therapy Cool Path Ablate VT — NCT00925522.
• Registry record last updated 2019-04-17; status last verified 2019-04.
• Results first posted 2016-05-27.
• 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

NCT00925522, “Therapy Cool Path Ablate VT,” is a single-group device study sponsored by Abbott Medical Devices. It evaluates the Therapy Cool Path Duo Cardiac Ablation System for ischemic ventricular tachycardia. The registry records enrollment of 20, study start in 2009-06, primary completion in 2010-04, masking as NONE, allocation as NA, phase as NA, and status as TERMINATED.

The primary endpoint is the number of participants with serious cardiac adverse events during the procedure or up to 7 days afterward. The registry lists one outcome measure and zero analyses. The primary endpoint result, efficacy result, reason for termination, analysis plan, and sample-size justification are not reported in the registry record.

The adverse-event listing reports 7 of 20 participants with a serious adverse event and 16 of 20 with another adverse event. These are descriptive safety entries from a single group, not a controlled comparison, and they are not confirmed as the primary endpoint result.