Intraoperative Echocardiography in Low-Risk CABG Surgery: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Intraoperative Echocardiography in Low-Risk CABG Surgery (NCT06154265), a randomized na study. The primary outcome is Enrollment and Randomization Feasibility.

2. Clinical Question

The study's stated goal is to better understand when and where intraoperative TEE should or should not be used during CABG surgery. Its randomized comparison assigns participants to a default-use strategy or an as-needed strategy. The registry record describes the intervention as a TEE probe and gives the procedures for each arm, but does not report the ultrasound criteria that would trigger as-needed use or additional details of surgeon decision-making.

The primary outcome is defined as the proportion of patients approached who consented and were successfully randomized. The registry record reports that 72 patients were approached and 40 were randomized. Those figures describe recruitment and randomization activity; they do not, by themselves, establish whether the strategies differ in clinical effects, safety, or resource use. The record does not report arm-specific primary outcome results or a clinical comparison between the strategies.

3. Trial Design

This is a randomized, parallel-group trial with no masking. The registry lists enrollment of 40 and status as completed. The recorded study start date is 2024-01-22, and the primary completion date is 2025-03-15. These dates and the completed status describe the trial record; they do not establish that every planned analysis or outcome has been reported.

Participants were assigned to Default TEE or As-needed TEE. In the Default TEE arm, the probe was placed after induction of general anesthesia and placement of a breathing tube, used to image the heart before and after CABG, and kept in place throughout surgery. In the As-needed TEE arm, the probe was placed only when the surgeon needed information available through ultrasound imaging of the heart. The registry also calls this arm Backup TEE in the adverse-event results.

The primary outcome is enrollment and randomization feasibility at baseline. The record defines it through the proportion of approached patients who consented and were successfully randomized, and reports that 72 were approached and 40 randomized. The listed secondary outcomes are protocol adherence and rescue echocardiography use in the backup TEE arm. The record lists three outcome measures but does not report arm-specific values for those secondary outcomes.

The registry record does not report the random sequence method, allocation concealment, stratification factors, site details, or a sample-size justification. It also does not report masking, consistent with the trial being listed as unmasked. The intervention descriptions do not specify a detailed imaging protocol beyond when the probe is placed and the stated use of imaging. The sponsor is the University of Pennsylvania.

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 Enrollment and Randomization Feasibility, measured over At time of enrollment and randomization (baseline).

The primary endpoint is titled Enrollment and Randomization Feasibility. It measures the proportion of patients approached for enrollment who consented and were successfully randomized. The registry reports that 72 patients were approached and 40 were randomized. It does not give the numerator and denominator as separate arm-specific results, or report the number who declined, were ineligible, or could not be randomized.

This type of endpoint addresses whether recruitment and allocation can be carried out in the intended clinical setting. As a general statistical rationale, feasibility outcomes can help determine whether a study process is workable and identify recruitment barriers before a larger or more definitive investigation. They are not substitutes for outcome measures of clinical benefit, harm, or comparative effectiveness.

The endpoint timeframe is enrollment and randomization at baseline. The registry record does not report a confidence interval for the feasibility estimate or a prespecified threshold for deciding whether recruitment was feasible. It also does not report a comparison of this endpoint by randomized arm. Because the endpoint concerns the enrollment process, the reported overall figures should be interpreted as descriptive recruitment information rather than as evidence that one TEE strategy performed better than the other.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The trial uses a randomized, parallel-group design. Randomization is intended, in general, to allocate participants by chance so that treatment assignment is not determined by patient or clinician preference. Parallel-group trials compare strategies assigned to separate groups. These design features can support a fair comparison, but the strength of that comparison depends on how allocation was generated and implemented, how outcomes were measured, and how the data were analyzed. The registry record does not report the sequence-generation or allocation-concealment methods.

What does the primary outcome measure?

The primary endpoint is a feasibility measure based on approached patients who consented and were successfully randomized. The record gives the approach and randomization counts, 72 and 40, respectively. In general, a proportion describes the number meeting a defined criterion relative to the relevant eligible or approached group. Here, the registry record does not report a separate estimated proportion, confidence interval, or arm-specific breakdown. The record also does not state a threshold that would define adequate feasibility.

A confidence interval, as a general statistical concept, describes the uncertainty around an estimate under a specified method and assumptions. It is useful because a point estimate alone does not show how much the estimate might vary from sampling uncertainty. No confidence interval for the feasibility outcome is reported in the registry record. Without one, and without a prespecified feasibility threshold, the reported counts cannot establish how precisely the recruitment process has been characterized.

What can a randomized comparison tell readers?

For a treatment comparison, an analysis would ordinarily report outcome results for each randomized arm and an estimate of the difference or other prespecified contrast, together with uncertainty. The registry record does not report such an analysis for the primary outcome, nor does it report a comparative estimate for the listed secondary outcomes. It lists zero analyses. Thus, no treatment-effect estimate, hypothesis test, or p-value is available in the registry record for interpretation.

The primary outcome is about recruitment feasibility rather than a clinical outcome. In general, feasibility outcomes answer whether trial processes can be implemented; clinical outcomes address what happens to participants under the compared strategies. The distinction matters because successful enrollment and randomization do not demonstrate that the assigned strategies have similar or different clinical effects.

How should event counts be understood?

The adverse-event information is presented as counts at risk and counts affected, with separate entries for serious events, other events, and deaths. Counts can be informative descriptions, but a count alone is not a comparison of risk. A formal comparison would need clearly defined event and participant-level data, a stated analysis method, and an estimate with its uncertainty. The registry record does not report those elements. The listed serious-event percentages also lack accompanying denominator explanations in the record, so they cannot be interpreted as directly comparable rates.

For count outcomes, a statistical model may need to account for variation beyond what a simple model assumes. In general, over-dispersion means that observed variability exceeds the model's expected variability; ignoring it can make uncertainty estimates misleading. That concept is not evidence that over-dispersion occurred in this trial. The registry record does not identify a count model or report an analysis of event counts.

What do planning calculations mean?

In general, sample-size planning uses assumptions about the target effect, variability, significance level, allocation, and desired power to estimate the amount of information a future study may need. The planning illustration associated with this record is described as based on a fraction of the observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. It is explicitly a planning illustration, not the trial's own design justification. A planning calculation is not observed power and does not show that the study detected or excluded an effect. The registry record does not report the trial's own sample-size justification.

No inferential statistical plan, estimator, model, or method for handling protocol deviations is reported in the registry record. That absence limits how fully the results can be evaluated and prevents attributing any unreported analysis choice to the investigators.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary outcome, Enrollment and Randomization Feasibility, and two secondary outcomes: Protocol Adherence and Rescue Echocardiography Use in the Backup TEE Arm. It also lists three outcome measures in total. The record does not report a hierarchy among outcomes, a multiplicity adjustment, or a plan for controlling the chance of false-positive findings across multiple analyses. Because no analyses are listed, there are no reported inferential results to assess for multiplicity.

The registry record does not describe missing-data handling, the amount of missing outcome information, or reasons for missingness. It does not state how participants with incomplete follow-up or protocol deviations would be treated in an analysis. These details matter because missingness and analysis choices can affect estimates, particularly when comparing randomized groups.

The record does not identify an intention-to-treat, per-protocol, or other analysis population. It reports 40 randomized participants, but does not describe the analysis set used for the primary or secondary outcomes. Nor does it report whether all randomized participants contributed to each listed outcome. Without those definitions and results, readers cannot determine how the randomized assignment was carried through to analysis.

These are omissions from the registry record, not evidence that particular methods were or were not used outside the record. The results available in the record are insufficient to evaluate a statistical analysis plan, missing-data assumptions, or multiplicity control.

11. Safety Results

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

Deaths

Other (non-serious) adverse events

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

Most frequent serious adverse event terms

Serious events with the highest arm-level rate: severe swallowing dysfunction requiring percutaneous gastrostomy tube placement (5.3%), conversion from isolated cabg to cabg + mitral valve replacement (4.8%), tee-related esophageal bleeding requiring endoscopic therapy (4.8%).

The registry lists serious-event counts separately for the two arms. Default TEE has 2 serious events among 21 at risk; Backup TEE has 1 among 19 at risk. Other events are recorded as 0 among 21 at risk in Default TEE and 0 among 19 at risk in Backup TEE. Deaths are recorded as 0 in Default TEE and 1 in Backup TEE.

The record lists severe swallowing dysfunction requiring percutaneous gastrostomy tube placement (5.3%), conversion from isolated CABG to CABG + mitral valve replacement (4.8%), and TEE-related esophageal bleeding requiring endoscopic therapy (4.8%) among its top serious-event terms. It does not provide the denominators or clarify how the listed percentages relate to the arm-specific counts. The terms should therefore be read as reported event descriptions, not as a basis for comparing rates across arms.

These are descriptive registry figures. The record does not report an inferential safety analysis, uncertainty intervals, event adjudication, or causal attribution. The counts alone do not establish whether an event was caused by the assigned TEE strategy or whether the groups differ in safety.

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

The posted information establishes that a randomized trial of Default TEE versus As-needed TEE was conducted and is listed as completed. The primary outcome is recruitment and randomization feasibility. The record reports that 72 patients were approached and 40 were randomized, providing a basic description of enrollment activity.

It does not establish the comparative effect of the two strategies on patient outcomes. There are no arm-specific primary results or comparative estimates in the registry record, and the listed secondary outcomes lack results. The adverse-event counts offer limited descriptive safety information, but no formal comparison or attribution analysis. The record also does not report confidence intervals that would convey the precision of the primary or safety findings.

Accordingly, the results do not demonstrate that either strategy is better, worse, or equivalent. A lack of reported comparative results is not evidence that the strategies have the same effects. Equivalence or non-inferiority would require a suitable design, prespecified margins where relevant, and analyses with estimates and uncertainty; such details are not reported in the registry record.

The study's feasibility endpoint is relevant to the conduct of research in this setting, but it is distinct from the clinical question of when TEE should be used during CABG. The registry's stated goal concerns understanding appropriate use, while the reported primary outcome addresses whether patients could be enrolled and randomized. The available record does not provide enough comparative outcome evidence to answer the broader clinical question.

The trial's randomized design is an important feature, but design labels alone do not determine the reliability or precision of results. Interpretation also depends on complete outcome reporting, analysis methods, and uncertainty estimates. Those elements are not available in the registry record for the primary and secondary comparisons.

13. Why This Trial Matters Statistically

This trial addresses a practical question about how intraoperative TEE is used during low-risk isolated CABG surgery: default use throughout the operation or placement only when the surgeon needs ultrasound information. Comparing these strategies can be difficult because the procedure is embedded in an operation, and the clinical decision to obtain imaging may depend on circumstances during surgery.

Statistically, the registry record makes an important distinction between feasibility and clinical effectiveness. The primary endpoint concerns whether approached patients consented and were randomized. That information can describe recruitment, but it is not a measure of patient outcomes or the comparative effect of the assigned strategies. Keeping those questions separate prevents a feasibility result from being interpreted as a treatment result.

The randomized design could support a comparative analysis, but the record does not report arm-specific primary results or analyses of the listed secondary outcomes. This illustrates why a trial's design and completion status are not enough for statistical interpretation: estimates, measures of uncertainty, outcome definitions, and analysis populations are also needed. Without them, readers cannot assess the magnitude or precision of any difference between strategies.

The adverse-event entries also illustrate the limits of raw counts. Counts are useful for describing what the registry records, but without clear denominators, attribution, and uncertainty, they do not support a comparative safety conclusion. Transparent reporting of these details is essential when decisions concern a procedure used during surgery.

The record therefore matters as a randomized feasibility study, while its reported results leave the comparative clinical question unresolved. The gap between the stated goal and the reported primary endpoint is statistically important: recruitment feasibility and clinical outcomes require different evidence.

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 primary limitation for interpretation is that the registry record reports recruitment counts but no arm-specific primary outcome results or comparative analysis. It does not report an estimate with a confidence interval, a p-value, or another measure of uncertainty. As a result, the feasibility outcome cannot be judged against a stated threshold, and the relative performance of the randomized strategies cannot be assessed.

Although the trial is listed as completed, the registry record does not report results for protocol adherence or rescue echocardiography use in the backup arm. It also does not provide detailed clinical outcomes by arm. The adverse-event information is limited to counts and event terms, with no reported statistical comparison, causal attribution, or explanation of the percentages attached to the top serious-event terms.

The record does not report detailed eligibility criteria, participant characteristics, allocation procedures, or an analysis population. These omissions restrict assessment of how participants entered the trial, whether randomization was implemented as intended, and to whom the findings might apply. No masking was used, which is reported in the design record; the implications for outcome assessment cannot be evaluated without further details about how outcomes were determined.

The record also does not report a statistical analysis plan, sample-size justification, handling of missing data, or methods for addressing multiple outcomes. It lists zero analyses. These omissions make it impossible to assess whether the reported figures follow a prespecified plan or whether outcome reporting is complete. These limitations describe what is not reported in the registry record and should not be taken as evidence about information available elsewhere.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Intraoperative Echocardiography in Low-Risk CABG Surgery — NCT06154265.
• Registry record last updated 2026-05-12; status last verified 2026-04.
• Results first posted 2026-05-12.
• 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.

18. Record Summary

NCT06154265 is a randomized, parallel-group, unmasked trial titled “Intraoperative Echocardiography in Low-Risk CABG Surgery.” It compares Default TEE with As-needed TEE, also described as Backup TEE. The registry lists enrollment of 40, status as completed, a start date of 2024-01-22, and a primary completion date of 2025-03-15. The sponsor is the University of Pennsylvania.

The primary outcome is Enrollment and Randomization Feasibility at baseline, defined as the proportion of approached patients who consented and were successfully randomized. The record reports that 72 patients were approached and 40 randomized. Protocol adherence and rescue echocardiography use in the backup arm are listed as secondary outcomes. No analyses are listed in the registry record, and arm-specific comparative outcome results are not reported.

Safety entries include serious-event counts, other-event counts, deaths, and several serious-event terms. The available information is descriptive and does not include a formal safety comparison or uncertainty estimates.