Exercise Pulmonary Transit Time: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Exercise Pulmonary Transit Time (NCT04336995), a na phase 4 study. The primary outcome is Pulmonary Transit Time.

2. Clinical Question

The study title and brief summary focus on echocardiographic assessment of pulmonary transit time following exercise. The record describes the measure as the interval required for pulmonary blood volume to traverse the pulmonary circulation. It gives a primary-outcome timeframe of 3-10 seconds, but does not provide results showing the measured values, how they varied across participants, or whether a before-and-after contrast was analyzed.

The clinical question is consequently descriptive rather than a comparison of treatment groups: what pulmonary transit time measurements were obtained in this group in connection with exercise? The record does not state a specific hypothesis, a target difference, or an interpretation of a change. The observed outcome result and its uncertainty are not reported in the registry record.

3. Trial Design

The registry record describes a Phase 4 study with a single group and an enrollment of 14. Its status is completed. The study is titled “Exercise Pulmonary Transit Time,” and its official title refers to echocardiographic assessment of pulmonary transit time following exercise. The listed condition is heart failure with diastolic dysfunction.

Everyone is assigned to the Exercise arm. Allocation is listed as not applicable, masking as none, and the model as single group. These details indicate that the record does not describe a randomized allocation or a masked comparison between separate groups. The arm description explicitly says that everyone is in this arm. There is no like-for-like control arm against which to compare the measurements.

The listed intervention is contrast echocardiography, classified as a diagnostic test. The brief summary says the study seeks to measure pulmonary transit time via contrast echocardiography before and after exercise. The record does not give a detailed account of the exercise procedure, the imaging protocol, or how the timing of measurements was standardized.

The study start date is 2020-08-27, and the primary completion date is 2021-08-25. The record marks the study as completed. Completion status does not by itself mean that outcome results or statistical analyses are available: the registry record lists one outcome measure and no analyses, and does not report the primary outcome findings.

The record does not report further details about participant eligibility, recruitment, baseline characteristics, protocol deviations, or the planned statistical analysis. It also does not state whether all enrolled participants contributed a primary outcome measurement. Without those details and the measured results, the design can be described, but the magnitude and precision of any observed exercise-related pattern cannot be assessed.

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

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 Pulmonary Transit Time, measured over 3-10 seconds.

The primary endpoint is pulmonary transit time, a continuous measure recorded in seconds. The registry describes it as the interval required for pulmonary blood volume to traverse the pulmonary circulation. The brief summary says contrast echocardiography is used to measure this interval before and after exercise. The primary-outcome timeframe is recorded as 3-10 seconds.

A transit-time measure expresses how long passage through a defined circulation takes. In general, such a measure can help describe physiology and can be compared across measurement occasions when the protocol and timing are sufficiently clear. The record identifies the measure and its unit, but does not explain the measurement procedure in detail or state what value or change would be considered clinically meaningful.

The endpoint is summarized in the registry as a mean with standard deviation. In general, the mean describes the center of a set of measurements, while the standard deviation describes their spread around that center. Neither statistic is reported as an outcome result in the registry record. The record also does not report a confidence interval, an individual-level distribution, or an analysis comparing measurements before and after exercise. Thus, the endpoint’s intended role is clear, but its observed value and the uncertainty around it cannot be evaluated from the posted results.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies pulmonary transit time as a continuous outcome, measured in seconds, and specifies a mean and standard deviation as its summary. These choices describe the kind of endpoint and the intended summary statistics. They do not reveal the actual values: neither a mean nor a standard deviation for the primary outcome is reported in the registry record. The record also lists no analyses.

What does a mean describe?

In general, a mean is a measure of the center of a set of numerical observations. It is useful for describing the average measurement in a group or the average difference between paired observations, depending on the analysis. The interpretation depends on what observations are included and how they are collected. Here, the registry record does not report the outcome measurements or clarify which summary was calculated from them. The word “mean” in the endpoint description is not itself a reported result.

What does a standard deviation describe?

In general, a standard deviation summarizes how dispersed observations are around their mean. A smaller standard deviation indicates observations more closely clustered around that mean; a larger one indicates greater spread. It is not the same as a confidence interval and does not, on its own, describe how precisely the mean has been estimated. Since the outcome standard deviation is not reported in the registry record, the spread of transit-time measurements cannot be assessed.

How would before-and-after measurements be interpreted?

When the same participants are measured on two occasions, an analysis may focus on each participant’s change between occasions. This paired approach accounts for the fact that measurements from the same person are related. A separate analysis could instead summarize each occasion without directly estimating paired change. These approaches answer different questions and can yield different estimates and uncertainties. The brief summary mentions measurement before and after exercise, but the registry record does not report the analysis method, the measurement-level data, or a before-and-after estimate. It would be inappropriate to assume which method was used.

In general, interpretation of a change also depends on details such as the timing and consistency of measurements, the amount of missing data, and whether the same participants contribute measurements at each occasion. Those details are not reported in the registry record. No assumption about their handling can be made from the endpoint label alone.

What would a confidence interval add?

In general, a confidence interval gives a range of values compatible with an estimate under the statistical model used to calculate it. It conveys uncertainty about the estimate, rather than the spread of individual observations. A confidence interval for a mean change could help readers judge both the range of plausible changes and the precision of the estimate. No confidence interval or primary outcome estimate is reported in the registry record, so precision cannot be evaluated.

A p-value, if reported, would address how compatible the data are with a specified null hypothesis under the assumptions of an analysis. It would not measure the size or clinical importance of an effect. The registry record lists no analyses and reports no p-value for the primary outcome. There is no basis for describing statistical significance.

What do the planning assumptions mean?

The record describes a planning illustration based on the observed effect. It specifies a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is defined as a stated fraction of the observed effect. In general, a sample-size illustration asks how many participants might be needed under its assumptions to detect a specified effect with a chosen probability of rejecting a null hypothesis when that effect is present. The result is conditional on the assumed effect, variability, allocation, and statistical model.

This illustration is not the study’s observed result, and its two-arm assumptions do not match the recorded single-group design, in which everyone is in the Exercise arm. The primary outcome result needed to anchor an observed-effect-based illustration is not reported in the registry record. Planning sample sizes are not observed power and do not show that the study did or did not detect an effect. The registry record does not report the trial’s own sample-size justification or its statistical analysis plan.

More generally, the choice of a statistical model should reflect the study design and data structure. If measurement variability is greater than a model assumes, standard errors and confidence intervals can be misleading; methods that account for over-dispersion may be needed in settings where it occurs. This is a general statistical consideration, not a statement that over-dispersion occurred in this study. The registry record does not report diagnostic checks or model details.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Exercise")
n   <- c(14)
m   <- c(2.5)
sp  <- c(0.5)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Exercise  14  2.500  0.500  2.211  2.789

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists one primary outcome measure and no analyses. It does not report a multiplicity plan, such as how statistical inference would be handled if several outcomes, time points, or comparisons were tested. The absence of that information should be read as unreported, not as evidence that no multiplicity issue arose in the underlying study. The record does not provide results with which to assess whether multiple analyses were performed.

The brief summary refers to measurements before and after exercise, but the record does not describe whether both occasions were analyzed as separate outcomes, whether a change score was used, or whether other time points or outcomes were examined. The record’s single listed outcome measure does not establish the full set of analyses undertaken. Details of any planned interim analyses are not reported in the registry record.

Missing-data information is also not reported. The record gives enrollment of 14, but it does not say how many participants had usable primary outcome measurements, whether measurements were missing at either occasion, why any data might be missing, or how missing values were handled. Enrollment should not be assumed to equal the analysis population.

The registry record does not define an analysis population, such as all enrolled participants or a subset with complete measurements. It does not report exclusions, deviations, or sensitivity analyses. These omissions make it impossible to determine whether the primary endpoint analysis, if conducted, represented all enrolled participants or a narrower group. The record’s listing of zero analyses means no statistical analysis results are available in the registry record; it does not establish what analyses may have been conducted outside the record.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The safety figures are recorded for the Exercise group, with 14 participants at risk for serious adverse events and zero affected. For other adverse events, the record likewise lists 14 at risk and zero affected. It lists zero deaths. No top serious adverse-event terms are reported.

These figures should be read as the adverse-event counts recorded in the registry, not as proof that no adverse events of any kind occurred. The record does not provide event descriptions or further detail about how adverse events were collected, defined, monitored, or reported. A zero in the posted count means that no affected participants are recorded for that category in this entry; it does not establish the absence of all possible harms.

The group is single and there is no separate comparator, so the safety figures cannot support a between-group safety comparison. The record also does not report a statistical analysis of adverse events. These descriptive counts should therefore be interpreted within the limits of the registry information, without extending them beyond the participants and event categories recorded.

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

The study addresses measurement of pulmonary transit time by contrast echocardiography in relation to exercise. The registry record identifies a single group of 14 participants, all assigned to the Exercise arm, and defines pulmonary transit time as the interval required for pulmonary blood volume to traverse the pulmonary circulation. It also specifies seconds as the unit and a mean with standard deviation as the intended summary.

What the posted record does not establish is the actual transit time observed, the amount of variation among participants, or the change between measurements before and after exercise. No primary outcome results, confidence intervals, or statistical analyses are reported. The record therefore does not permit a conclusion about the size, direction, or precision of an exercise-related difference in this group.

The absence of a separate control group is important for interpretation. Even if a before-and-after change were reported, a single-group observation would not provide a randomized comparison against a group that did not undergo the same exercise protocol. In this record, the before-and-after measurements themselves are not reported, so the available registry information cannot characterize a change.

The safety entry records zero participants affected by serious adverse events, zero affected by other adverse events, and zero deaths among the listed group. Those counts describe the registry entry, not a general guarantee of safety or a comparison with another group. Additional detail about event ascertainment and reporting is not reported.

Accordingly, the record is informative about the study’s objective, intervention, design, endpoint definition, enrollment, and recorded safety counts. It is not an outcome report that establishes a measured physiological effect. Any interpretation should keep that distinction clear: the study’s question and methods are described, while its primary quantitative findings are not reported in the registry record.

14. Why This Trial Matters Statistically

This study illustrates why the registry description and the outcome results need to be read separately. The record identifies a measurable endpoint, its unit, its intended summary, and the general context of measurement around exercise. Yet the primary endpoint values and analyses are not reported. Knowing what a study intended to measure is not the same as knowing what it found.

The single-group design also matters statistically. Because everyone is assigned to the Exercise arm and no separate control group is described, the design does not supply a like-for-like comparison between groups. A within-person comparison could address how measurements differ across occasions, but the registry record does not report such an estimate or specify its analysis. Design determines the scope of the question an estimate can answer.

The enrollment of 14 gives a sense of study scale, but does not alone convey precision. Precision depends on the observed measurements and their variability, as well as the analysis. Those outcome details are not reported. A planning illustration based on an observed effect is also distinct from an observed result; it cannot fill in missing endpoint findings.

Finally, the safety counts show how registry reporting should be interpreted carefully. Zero affected participants are the counts recorded for the listed categories, not proof that every possible event was absent. Together, these points underscore the value of reporting outcome estimates, uncertainty, analysis populations, and methods alongside study design. Without them, readers can understand the study’s stated aim but cannot evaluate its primary quantitative findings.

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 main trial-specific limitation in the registry record is the absence of primary outcome results. Although pulmonary transit time is identified as the primary measure, no observed mean, standard deviation, before-and-after estimate, or uncertainty interval is reported. The record also lists no analyses. The magnitude and precision of the primary finding therefore cannot be assessed.

The design is single group, with everyone assigned to the Exercise arm and allocation listed as not applicable. There is no separate control group described. This limits the kind of comparison the record can support, even if results were available. The record does not report a comparative estimate or a detailed account of how repeated measurements were analyzed.

The enrolled group is small in scale, with 14 participants, but enrollment alone does not show how many had complete outcome data. Participant characteristics beyond the condition are not reported, nor are eligibility details, missingness, exclusions, or the analysis population. These omissions limit assessment of who contributed to the outcome and how broadly the findings might apply.

Measurement and analysis details are also limited. The record does not report the exercise protocol, imaging procedures, measurement timing beyond the brief description, or the statistical analysis plan. It does not report a sample-size justification for the study, interim analyses, multiplicity handling, or sensitivity analyses. Such information is not reported in the registry record, so no assumptions about these methods should be made.

Finally, the safety entry has limited detail beyond the counts. The record lists no affected participants in the adverse-event categories and no deaths, but does not describe ascertainment or event reporting procedures. These limitations constrain interpretation of both the endpoint and the safety information.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Exercise Pulmonary Transit Time — NCT04336995.
• Registry record last updated 2024-04-09; status last verified 2024-04.
• Results first posted 2022-07-12.
• 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

The registry record describes a completed Phase 4, single-group study titled “Exercise Pulmonary Transit Time.” It lists heart failure with diastolic dysfunction as the condition and reports enrollment of 14 participants. Everyone is in the Exercise arm; allocation is not applicable and masking is none.

The listed intervention is contrast echocardiography. The stated aim is to measure pulmonary transit time before and after exercise. The primary outcome is a continuous measure in seconds, summarized as a mean with standard deviation, and defined as the interval required for pulmonary blood volume to traverse the pulmonary circulation.

The study start date is 2020-08-27, and the primary completion date is 2021-08-25. The registry records 14 participants at risk and zero affected for both serious and other adverse events, with zero deaths. It lists no primary outcome analyses. The observed pulmonary transit time results and statistical uncertainty are not reported in the registry record.