This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Evaluate the Efficiency Impact of Conducting Active Temperature Management During Cardiac Cryoablation Procedures (NCT04087122), a na na study. The primary outcome is Total Time of Active Ablation Procedure.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04087122 |
| Phase | NA |
| Condition | Atrial Fibrillation |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 20 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Advanced Cooling Therapy, Inc., d/b/a Attune Medical |
| Results posted | Yes |
2. Clinical Question
Population
Patients with atrial fibrillation enrolled for left atrial catheter ablation using cryoablation. The registry record reports enrollment of 20 participants, but does not report further eligibility details or the characteristics of the enrolled group.
Intervention
Use of the Attune Medical Esophageal Heat Transfer Device to warm the esophagus during the ablation procedure. The stated study aim is to evaluate procedural efficiency with esophageal heat transfer during left atrial cryoablation.
Comparator
There is no separate control group in this single-group study. The allocation is listed as NA, and the record does not describe a randomized comparison or a like-for-like control arm. Consequently, the record does not support a between-group estimate of the device's effect.
Primary question
What is the total time of the active ablation procedure when the esophageal warming device is used? The measure runs from trans-septal puncture to achievement of pulmonary vein isolation, during left atrial cryoablation. Although the question concerns procedure efficiency, the numerical result is not reported in the registry record.
The clinical context in the registry record discusses thermal esophageal injury associated with left atrial ablation. It describes earlier work on active esophageal cooling during radiofrequency ablation and identifies this study's aim as evaluating warming during cryoablation. Those are distinct procedural approaches: the study's stated intervention is warming, not cooling. The registry record does not report an injury-prevention endpoint as the primary question. Instead, it names total active ablation time, with procedure pauses and fluoroscopy duration listed among secondary outcomes.
The clinical question is therefore narrowly about procedural efficiency in patients receiving the device. Without a control group or reported outcome results, the record cannot establish whether procedure time differed from what would have occurred without the device. It also does not provide numerical estimates for the secondary outcomes. The described purpose and measures should not be confused with evidence of a particular efficiency effect.
3. Trial Design
This is a completed, single-group device study in patients with atrial fibrillation. The registry record lists enrollment of 20 and identifies the intervention as the Attune Medical Esophageal Heat Transfer Device, used for esophageal warming. The study title and summary frame its purpose as evaluating the efficiency impact of active temperature management during cardiac cryoablation procedures.
The design is listed as single group, with allocation recorded as NA and masking recorded as none. The record does not describe a randomized allocation, a control arm, or a blinding procedure. It therefore does not provide the structure needed for a direct comparison between participants receiving warming and participants undergoing the procedure without it. Any interpretation of a device-related difference would require a valid comparison that is not described in the registry record.
The primary outcome is total time of active ablation procedure. It is defined as the time from trans-septal puncture to achievement of pulmonary vein isolation, measured during left atrial ablation with cryoablation. The timeframe is Study Day 1 for all enrolled patients. The registry record also names total procedure time, number of procedural pauses during left atrial instrumentation, and total duration of fluoroscopy use as secondary outcomes.
The record gives a start date of 2019-09-30, a primary completion date of 2020-07-30, and a completed status. It does not report site details, eligibility criteria, participant characteristics, or additional details of how the device was applied. A formal statistical analysis plan, the method used to select the enrollment target, and whether any interim analyses were planned are not reported in the registry record. The available design information supports describing the study as a single-group evaluation, but not attributing a causal contrast to 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.
Overall Study
| Stage | Esophageal Warming |
|---|---|
| STARTED | 20 |
| COMPLETED | 20 |
| NOT COMPLETED | 0 |
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.
| Characteristic | Unit | Esophageal Warming |
|---|---|---|
| Participants analysed | 20 | |
| Age, Continuous | years | 68.5 (SD 8.4) |
| Sex: Female, Male: Female | Participants | 11 |
| Sex: Female, Male: Male | Participants | 9 |
| Race and Ethnicity Not Collected | Participants | — |
6. Primary Endpoint
The registry lists the primary outcome as Total Time of Active Ablation Procedure, measured over Study Day 1 for all patients enrolled, during left atrial ablation procedures using cryoablation.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | minutes |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is total time of the active ablation procedure, measured in minutes. The registry record defines the interval as beginning at trans-septal puncture and ending when pulmonary vein isolation is achieved. It is measured during left atrial ablation procedures using cryoablation, on Study Day 1 for all enrolled patients.
Procedure time is used as an operational measure of efficiency: it records how long the specified active ablation interval takes. The endpoint does not, by itself, describe why a procedure took a particular length of time, nor does it measure all aspects of workflow, safety, or clinical outcome. The listed secondary measures—total procedure time, procedural pauses during left atrial instrumentation, and fluoroscopy duration—cover related but distinct aspects of procedural conduct.
The registry record specifies the primary outcome parameter as a mean and its intended dispersion as a 95% confidence interval. General statistical interpretation: a mean describes the average value in the analyzed group, while a confidence interval expresses uncertainty around an estimate under the statistical method used. A narrower interval generally indicates greater precision; the interval does not establish that an intervention caused an outcome or that an effect is clinically important.
The record does not report the observed mean, confidence-interval limits, or an analysis for this endpoint. It is therefore not possible to describe the observed procedure time or the precision of its estimate from the registry record. The endpoint definition and planned summary format are available, but the result itself is not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes a single group of patients receiving an esophageal warming device during left atrial cryoablation, with enrollment of 20. It identifies total active ablation time as the primary outcome and lists the measurement interval and unit. However, the numerical mean and its 95% confidence interval are not reported in the registry record. No numerical primary-outcome estimate can therefore be interpreted, and neither its direction nor its precision can be assessed from the recorded results.
The study has no described control group. Its allocation is listed as NA and its model as single group. Accordingly, even if a group mean were available, that mean alone would describe observed procedure time among participants in this study; it would not show what their procedure times would have been without the warming device. The registry record does not report a comparative estimate, so a causal difference attributable to the device is not established.
The registry record names three secondary outcomes: total procedure time, number of procedural pauses during left atrial instrumentation, and total duration of fluoroscopy use. Numerical results for those measures are not reported in the registry record. There are four outcome measures listed in total, but no numerical results or analyses are recorded. The absence of reported results should not be read as evidence that an outcome was unchanged, favorable, or unfavorable.
The primary outcome is specified as a mean with 95% confidence-interval dispersion. General statistical interpretation: the mean provides a central summary, and the confidence interval communicates uncertainty in that estimate under the analysis assumptions. Precision cannot be judged without its bounds. An interval's relationship to a clinically meaningful threshold also cannot be assessed when neither the interval nor such a threshold is reported.
The status is completed, with primary completion dated 2020-07-30. Completion status does not substitute for outcome reporting. The registry record also does not report whether the analysis followed a prespecified plan, how missing observations were handled, or what analysis population was used. Those omissions limit assessment of how the posted outcomes, if available elsewhere, were derived. On the information recorded, the appropriate conclusion is descriptive: a single-group study was registered to assess procedure efficiency, but its numerical outcome findings and statistical analysis are not reported in the registry record.
9. Statistical Methods Explained
The primary outcome is a continuous measure: time in minutes from trans-septal puncture to achievement of pulmonary vein isolation. The record specifies a mean as the summary parameter and a 95% confidence interval as the dispersion measure. The numerical estimate and interval bounds are not reported in the registry record. Nor does the record identify the statistical procedure used to calculate them.
What does a mean describe?
General statistical explanation: a mean is the arithmetic average of the observations included in an analysis. It gives a single summary of the group's measured procedure times, but it does not show how much individual times vary. The distribution of observations, extreme values, and the count actually included in an analysis can matter when interpreting a mean. Those details are not reported in the registry record for this endpoint.
A mean is not a treatment contrast. In a study with a control group, a contrast might compare group means under a specified analysis. This record describes a single group and no like-for-like control comparison. Its primary endpoint, even if numerically reported, would therefore be a summary of observed times in that group rather than an estimate of a between-group difference attributable to warming.
How should a confidence interval be read?
General statistical explanation: a confidence interval describes uncertainty around an estimated quantity using a method with stated assumptions. The interval's width is relevant to precision: a narrower interval generally corresponds to a more precise estimate than a wider one. A confidence interval is not a guarantee that the true value lies within its limits, and it does not by itself establish practical importance or causation. For this study, the record names a 95% confidence interval, but the numerical limits are not reported in the registry record. Its precision therefore cannot be evaluated.
The confidence interval method, any distributional assumptions, and whether the analysis accounted for features of the observations are not reported in the registry record. Because no estimate or interval is available, there is no basis for reconstructing uncertainty from the posted information. A summary statistic cannot be recreated without the relevant observed data or sufficient summary information.
What do the other outcomes measure?
The registry record lists total procedure time, the number of procedural pauses during left atrial instrumentation, and total duration of fluoroscopy use as secondary outcomes. These measures address different facets of procedural workflow. Total procedure time is broader than the primary active-ablation interval; pauses count interruptions during a specified phase; fluoroscopy duration records use of fluoroscopy. Their precise operational definitions, summary methods, and numerical results are not reported in the registry record.
General statistical explanation: continuous outcomes are commonly described using a central measure and a measure of variability or uncertainty, while counts can be summarized in ways suited to their distribution. The appropriate approach depends on the data and analysis plan. No particular method for the secondary outcomes can be inferred from their names, and the registry record does not report the analyses.
What can the planning assumptions tell readers?
The registry record describes a planning illustration based on the observed effect, not the trial's own design. It states assumptions of a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect described as a stated fraction of the observed effect. For time-to-event planning, the stated quantity is a total number of events; for other planning calculations, it is participants per arm. These are planning conventions and do not turn the single-group study into a two-arm trial.
The numerical planning outputs are not reported in the registry record. The record also does not report a sample-size justification for the actual study, or identify those planning assumptions as the protocol's basis for enrolling 20 participants. General statistical explanation: sample-size planning estimates the amount of information a hypothetical design might need under specified assumptions. Such illustrations are not observed power, do not describe the study's actual enrollment structure, and cannot replace a reported estimate with its uncertainty. With no control group and no numerical effect estimate reported, the two-arm assumptions should be read only as a planning scenario, not as evidence of a comparative result.
What analysis details are missing?
The registry record reports no analyses. It does not identify an estimator beyond the stated mean, a confidence-interval calculation method, a statistical model, covariate adjustment, an approach to outliers, or handling of missing observations. These choices can affect estimates and uncertainty; their absence means readers cannot assess whether a particular method was appropriate or reproduce the analysis. General statistical explanation: analysis methods should be interpreted alongside the study design and the outcome's data structure, not inferred solely from the name of an endpoint.
10. Multiplicity, Missing Data and Analysis Populations
The registry record names one primary outcome and three secondary outcomes, for four outcome measures in total. It does not report numerical analyses for these measures. It also does not report a statistical analysis plan, a hierarchy for testing outcomes, or a method for accounting for multiple comparisons. Whether any multiplicity adjustment was planned or applied is not reported in the registry record.
General statistical explanation: when several outcomes or hypotheses are examined, the chance of at least one apparently notable result can be affected by how many comparisons are made and how they are handled. A prespecified outcome hierarchy or adjustment can help clarify the intended interpretation. The existence of several registered measures alone does not show that a multiplicity problem occurred; the analysis strategy is needed to evaluate it. Here, no such strategy is reported.
The record does not report missing-data counts, reasons for missingness, imputation, or sensitivity analyses. It also does not identify an analysis population, such as whether all enrolled participants were included for each outcome. Enrollment is listed as 20, but that figure does not establish how many participants contributed data to a particular measure. The outcome-specific analyzed counts are not reported in the registry record.
General statistical explanation: missing observations can affect both the estimate and its uncertainty, particularly if availability is related to the outcome or participant characteristics. The direction or size of any effect cannot be presumed without information about the missing data and analysis. With neither analysis details nor numerical outcomes reported, readers cannot assess the handling of missingness or multiplicity in this study.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Esophageal Warming | 0 | 20 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Esophageal Warming | 0 of 20 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Esophageal Warming | 0 of 20 |
For the Esophageal Warming group, the registry record lists 20 participants at risk for serious adverse events and 0 affected. It also lists 20 at risk for other adverse events and 0 affected, with 0 deaths. No top serious-event terms are listed. These are the recorded safety counts for the group.
General statistical interpretation: a recorded count of 0 means that no affected participants were recorded for that category in the registry entry. It does not establish that the underlying risk is zero, nor does it show how completely or how long events were monitored. The record does not report the event-collection procedures, follow-up duration for safety, severity definitions, or whether all participants completed safety observation. Those details are not reported in the registry record.
The figures should be read as descriptive counts, not as a comparative safety estimate. There is no control group described, so the counts cannot establish a difference in adverse events relative to another procedure or device condition. The registry record also does not provide event narratives or detailed categories beyond the listed serious and other adverse-event totals. These figures alone do not support a broader conclusion about safety.
12. What the Result Does, and Does Not, Mean
The record establishes that a completed, single-group study enrolled 20 participants and evaluated use of an esophageal warming device during left atrial cryoablation. It identifies total active ablation procedure time as the primary outcome, defines the interval from trans-septal puncture to pulmonary vein isolation, and specifies a mean with a 95% confidence interval as the summary format. It also names procedure time, pauses, and fluoroscopy duration as secondary outcomes.
What the registry record does not establish is the size or direction of any observed efficiency result. The numerical outcomes and analyses are not reported in the registry record. There is no reported mean or confidence interval for the primary outcome, and no numerical findings for the secondary outcomes. Therefore, readers cannot judge the observed duration, the precision of an estimate, or whether any measured change was practically important.
The design also does not provide a concurrent control group. A single-group mean can describe the participants' recorded procedure times, but it cannot by itself show what those same procedures would have taken without the device. The record does not report a comparative effect estimate or a randomized comparison. It consequently does not establish that warming caused a change in procedural efficiency.
The safety counts are likewise descriptive: 0 serious adverse events, 0 other adverse events, and 0 deaths are recorded among 20 participants at risk in the group. These counts are not evidence that risk is absent, and no comparative safety inference is available. Details of safety monitoring are not reported in the registry record.
The careful reading is limited to the study's purpose, registered design, outcome definitions, and recorded safety counts. Claims about efficacy, injury prevention, comparative procedure efficiency, or broader safety are not supported by the numerical results reported in the registry record, because those results are not reported. Completion status indicates the study is marked completed; it does not fill in the missing statistical results.
13. Why This Trial Matters Statistically
This study is statistically notable because its stated efficiency question is paired with a single-group design. A study can measure the time required for a procedure in participants receiving an intervention, but a measured group average is not the same as a comparative effect. Without a control group or another clearly specified comparator, the record cannot distinguish a device-associated difference from other influences on procedure time.
The endpoint is concretely defined: active ablation time from trans-septal puncture through achievement of pulmonary vein isolation. That operational definition helps identify the interval of interest and separates it conceptually from total procedure time, pauses, and fluoroscopy duration. The distinction matters because these measures capture different elements of procedural workflow and should not be treated as interchangeable.
Precision is also central to interpreting a continuous endpoint. The registry record specifies a mean and a 95% confidence interval, but reports neither the estimate nor its interval. Without those values, readers cannot determine how variable or precise the estimated procedure time was. In addition, no analysis is reported, so the methods used to summarize the observations cannot be assessed.
The planning assumptions describe a hypothetical two-arm illustration, including equal allocation and a two-sided significance level of 0.05. That scenario differs from the registered single-group design. It is useful to distinguish a planning illustration from the actual study design and from observed evidence; the assumptions do not supply a comparator or an outcome result.
Finally, the record lists several outcomes but does not describe multiplicity handling, missing-data methods, or analysis populations. These omissions limit reproducibility and the interpretation of any potential findings. The statistical importance of the study therefore lies not in a reported estimate, which is absent, but in recognizing how design, endpoint definition, precision, and complete reporting shape what readers can conclude.
14. 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 for interpreting the registered results is that the numerical primary and secondary outcome findings are not reported in the registry record. Although the primary measure and its intended summary are specified, there is no mean, confidence-interval bound, or analysis to evaluate. The study's completion status does not resolve this reporting gap.
The single-group design is another important limitation. The record does not describe a control arm or randomized comparison, so it cannot provide a direct estimate of the difference between procedures with and without the warming device. The allocation is listed as NA and masking as none. The registry record does not report further information that would support a controlled comparison.
Enrollment is listed as 20, but participant characteristics, eligibility criteria, and outcome-specific analysis counts are not reported in the registry record. The actual sample-size rationale and any protocol-based justification are also not reported. This makes it difficult to assess who the findings might represent or how much information was available for each outcome.
The record does not report the statistical analysis plan, analysis methods beyond the stated mean and confidence interval format, treatment of missing data, multiplicity strategy, or whether interim analyses were planned. It does not provide detailed definitions for secondary outcomes beyond their names, or describe safety-monitoring procedures and follow-up. The generalizability of the findings and the precision of any estimates cannot be evaluated from the recorded information.
These limitations are specific to the information and design recorded; they should not be replaced by assumptions about the protocol or conduct. The results may have been reported elsewhere, but they are not reported in the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Evaluate the Efficiency Impact of Conducting Active Temperature Management During Cardiac Cryoablation Procedures — NCT04087122.
- Registry record last updated 2022-05-12; status last verified 2022-03.
- Results first posted 2021-09-05.
- 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.
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18. Record Summary
The registry record describes a completed, single-group device study in atrial fibrillation, with enrollment of 20. The intervention is the Attune Medical Esophageal Heat Transfer Device, used to warm the esophagus during left atrial cryoablation. Allocation is listed as NA and masking as none.
The primary outcome is total active ablation procedure time, in minutes, from trans-septal puncture to achievement of pulmonary vein isolation. It is specified as a mean with a 95% confidence interval. Secondary outcomes are total procedure time, procedural pauses during left atrial instrumentation, and fluoroscopy duration. Numerical outcome results and analyses are not reported in the registry record.
The recorded safety counts are 0 serious adverse events, 0 other adverse events, and 0 deaths, among 20 participants listed at risk. The registry record gives a start date of 2019-09-30, a primary completion date of 2020-07-30, and a completed status. It does not report a control comparison, statistical analysis plan, missing-data approach, or numerical efficiency estimate.