The OMEGA Clinical Trial: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for The OMEGA Clinical Trial (NCT01419171), a na na study. The primary outcome is 9-month Target Lesion Failure (TLF) Rate.

2. Clinical Question

3. Trial Design

OMEGA was a prospective, multicenter, single-arm trial of the OMEGA™ Monorail Coronary Stent System. Its stated purpose was to evaluate the device’s safety and effectiveness for subjects with a de novo atherosclerotic coronary artery lesion. The registry lists an enrollment of 328 and a completed study status. The recorded study start is 2011-10, and primary completion is recorded as 2013-10.

With a single group, participants received the study device; the design did not include a randomized allocation or a control arm. Masking is listed as none. The phase is listed as NA. These design characteristics matter when interpreting the results: outcome frequencies describe the enrolled study group, but there is no concurrent group to provide a direct comparison under the same study conditions.

The primary endpoint was assessed at nine months. Its analysis population is reported as N=323. The record says five patients were not evaluable because follow-up was < 240 days and they were event-free. The record does not report additional details about follow-up procedures, handling of other missing observations, eligibility criteria, or a sample-size justification.

The registry lists 14 outcome measures and names secondary measures at 12 months, including target lesion revascularization, target vessel revascularization, target vessel failure, myocardial infarction, cardiac and non-cardiac death, all death, and cardiac death or myocardial infarction. It reports no analysis entries. The outcome names describe what was intended to be measured; they do not establish that numerical results for those outcomes are available in the registry record.

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

Analysis population for the primary outcome, as defined in the registry: N=323 (5 patients were not evaluable for the endpoint: Follow-up \< 240 days and event-free)

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 9-month Target Lesion Failure (TLF) Rate, measured over Nine Month.

The primary endpoint, nine-month target lesion failure (TLF), combines three types of events: ischemia-driven revascularization of the target lesion, myocardial infarction related to the target vessel (Q-wave or non-Q-wave), and cardiac death. A participant meeting any of these criteria would meet the composite endpoint definition. The registry identifies the measure as a percentage of participants and reports an analysis population of N=323.

As a general statistical concept, a composite endpoint can capture several clinically important events in a single outcome measure. It can also make interpretation less direct: a combined rate does not, by itself, show how much each component contributed. Component-specific results are needed to understand the pattern of events. The registry record does not report a numerical TLF result or component-specific primary-endpoint results.

The endpoint is used to assess a defined set of outcomes over a specified follow-up period. Its interpretation depends on the event definition, the population included in the analysis, and the completeness of follow-up. Here, the record states that five patients were not evaluable because follow-up was < 240 days and they were event-free. It does not report an observed TLF percentage or confidence interval, so neither the event frequency nor its statistical precision can be read from the primary-endpoint entry.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies the primary measure as a percentage of participants and gives a 95% confidence interval as its dispersion measure. The endpoint itself is binary at the participant level: a participant either meets the stated TLF definition during the specified period or does not. As a general statistical concept, a percentage for a binary outcome represents the share of the defined analysis population meeting that outcome. The registry record does not provide the observed percentage or the interval limits for this endpoint.

What does a confidence interval convey?

In general, a confidence interval describes the uncertainty associated with an estimate under a specified statistical method. A narrow interval indicates greater precision under that method than a wider interval; it does not establish that an estimate is clinically important, nor does it correct problems in study design or measurement. Interpretation also depends on what population and follow-up period the estimate concerns. Here, the record names a 95% confidence interval but does not report its values, so its width and implications cannot be evaluated.

A confidence interval is distinct from a test result. A p-value, when reported, addresses compatibility between data and a specified statistical model or null hypothesis; it does not measure the size or importance of an effect. The registry record reports no analysis entries and does not give a primary-endpoint p-value. It also does not report the testing procedure or a statistical analysis plan. The absence of those details means that no inferential method beyond the stated endpoint and dispersion measure can be attributed to the trial.

Why does the single-group design matter?

As a general principle, a single-group study estimates outcomes within the observed group. It does not estimate a randomized between-group contrast because there is no control arm. Outcomes may reflect the device, participant characteristics, other care, follow-up practices, or factors not captured in the registry entry. Without a concurrent comparator, the observed frequency cannot isolate the effect of the device from those influences. The record lists allocation as NA, masking as none, and the model as single group.

This design can describe what was observed among enrolled participants, if the outcome results are available. It cannot by itself establish what would have happened to comparable participants under another intervention or no intervention. That limitation is not resolved by having a multicenter study: multiple centers may broaden the setting in which participants were treated, but they do not create a randomized comparison.

How should the analysis population be read?

The primary endpoint population is reported as N=323. The registry notes that five patients were not evaluable because follow-up was < 240 days and they were event-free. This is a specific reason for non-evaluability, not evidence that those patients experienced TLF. The record does not explain whether other missing observations occurred, how the analysis treated them, or whether any sensitivity analyses were conducted. Those procedures are not reported in the registry record.

In general, the population used in an analysis determines what the resulting estimate describes. Excluding participants with incomplete follow-up can change the population represented by an estimate, particularly if evaluability is related to outcome risk. Assessing that possibility requires information about the participants, follow-up, and analysis rules; those details are not reported in the registry record. The participant count alone cannot show whether the analysis population was prespecified or whether the treatment of missing data was appropriate.

What can be inferred from the planning assumptions?

The record describes a planning illustration based on a fraction of the observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. These are assumptions for a planning illustration, not evidence that the trial used that design or analysis. The OMEGA study itself is listed as single-group, so the illustration’s equal-allocation assumption does not describe its trial allocation. The record does not report the resulting sample-size values. Any such planning values are illustrations rather than observed power, and the record does not provide a trial-specific sample-size justification.

As a general concept, power calculations estimate the chance that a planned analysis will detect a specified effect under stated assumptions. They are prospective planning tools, not a measure of how persuasive a completed study’s results are. A planning calculation tied to a fraction of an observed effect also depends on that effect estimate; no primary TLF estimate is reported in the registry record. No sample-size illustration should therefore be interpreted as an observed result for this trial.

Why can event-count variation matter?

For count outcomes, statistical methods may need to account for over-dispersion: variability greater than a chosen model expects. As a general explanation, ignoring over-dispersion can make uncertainty appear smaller than it is and can make inferential results too optimistic. This is a general consideration, not a claim about the OMEGA analysis. The listed primary outcome is a percentage of participants, and the registry record does not report use of a count model or an over-dispersion adjustment.

Overall, the methods information establishes the endpoint definition, follow-up time, analysis population, and stated confidence-interval type. It does not establish the actual calculation method, the treatment of all missing data, a hypothesis-testing plan, or the numerical endpoint result. Those details are not reported in the registry record.

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("OMEGA™ Monorail Coronary Stent System")
n      <- c(323)
events <- c(37)
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  OMEGA™ Monorail Coronary Stent System  323  37  11.5  8.2  15.4  8.4  15.4  8.4  15.4

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 14 outcome measures, including the nine-month primary TLF endpoint and secondary outcomes at 12 months. Testing or interpreting multiple outcomes can raise a multiplicity issue: as a general statistical concept, the more questions examined, the greater the chance of at least one apparently notable result arising by chance when each is considered separately. Whether and how that issue is addressed depends on a prespecified analysis strategy. A multiplicity adjustment, hierarchy, or other strategy is not reported in the registry record.

The registry reports zero analysis entries. It gives no numerical result for the primary endpoint and no numerical results for the listed secondary outcomes. It also does not report interim analyses, stopping rules, or a statistical analysis plan. Their presence or absence in the actual conduct of the study cannot be inferred beyond what is recorded.

For the primary analysis, N=323 is reported. Five patients were not evaluable because follow-up was < 240 days and they were event-free. This tells readers why those five were not considered evaluable, but it does not specify the complete missing-data strategy. The record does not state whether other data were missing, how incomplete follow-up was handled in secondary outcomes, or whether sensitivity analyses were performed. These details are not reported in the registry record.

As a general matter, missing outcome information can affect both the population represented by an estimate and its uncertainty. The direction and size of any effect depend on why information is missing and on the analysis approach. No conclusion about bias or its magnitude can be drawn from the count of non-evaluable patients alone.

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 1% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: angina pectoris (8.5%), angina unstable (4.9%), non-cardiac chest pain (3.0%), atrial fibrillation (1.5%), acute myocardial infarction (1.2%).

The safety entry lists 328 participants at risk for the OMEGA™ Monorail Coronary Stent System group. It lists 108 affected in the serious-adverse-event grouping and 118 affected in the other-adverse-event grouping. These are registry counts, not a comparison between treatment arms. The record also lists serious-event terms with percentages: angina pectoris, 8.5%; angina unstable, 4.9%; non-cardiac chest pain, 3.0%; atrial fibrillation, 1.5%; acute myocardial infarction, 1.2%; and coronary artery stenosis, 1.2%.

These entries should be read as safety descriptions within a single-arm study, not as evidence that the device caused each event or that the event frequency differs from another treatment. A like-for-like control group is not reported. The registry record does not report deaths in the safety entry, and a death count cannot be inferred from the separate list of secondary mortality outcomes.

As a general statistical caution, event-term percentages may not sum to a total because participants can experience more than one event, depending on how events are tabulated. The record does not provide enough detail to determine the overlap among these terms. Serious and other adverse-event groupings also do not replace the primary TLF result: they are separate safety summaries, with different definitions and purposes.

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

The registry record establishes that OMEGA was a completed, prospective, multicenter, single-arm study enrolling 328 participants to evaluate the OMEGA™ Monorail Coronary Stent System. It defines a nine-month primary endpoint, TLF, as ischemia-driven target lesion revascularization, target-vessel-related myocardial infarction (Q-wave or non-Q-wave), or cardiac death. The primary analysis population is reported as N=323, with five patients not evaluable because follow-up was < 240 days and they were event-free.

That information describes the study question and its measurement framework. It does not report the observed TLF percentage or 95% confidence interval. Therefore, the registry record does not allow a numerical assessment of how often the primary endpoint occurred or how precisely its rate was estimated. The secondary outcomes are named, but their numerical results are not reported in the registry record either.

A result from a single-arm study, if available, would describe outcomes in the studied group. It would not provide a randomized estimate of a difference between the device and another treatment. As a general principle, an outcome rate without a concurrent comparator cannot separate the intervention’s contribution from other influences on outcomes. The single-arm design is therefore an important limit on what can be concluded, independent of how large or small an event rate might be.

The safety counts and listed event terms provide additional descriptive information, but they are not proof of causation and do not supply a comparative risk estimate. The record does not report a control group or mortality count in the safety entry. It also does not provide the statistical analysis details needed to assess unreported outcomes or the handling of all missing data.

In short, the registry record supports a description of the trial’s design, endpoint definition, analysis population, and recorded safety counts. It does not support a quantitative conclusion about the primary endpoint, a comparative treatment effect, or the numerical secondary outcomes. Those distinctions are essential when separating what a study set out to measure from what its posted results actually establish.

14. Why This Trial Matters Statistically

This trial is statistically instructive because its design and endpoint definition are reported more fully than its primary outcome result. Readers can identify the study as prospective, multicenter, and single-arm, see the intended nine-month TLF definition, and note the primary analysis population. But without the observed rate and confidence interval, they cannot assess the frequency or precision of the central endpoint from the registry record.

The single-group design also illustrates the difference between describing outcomes and estimating a comparative effect. In general, a frequency measured in one group does not answer how outcomes would differ under another treatment. A randomized comparator can support a direct contrast under the study design; this registry record reports no such group. That distinction matters even when a study is completed and has a substantial enrollment.

The record also demonstrates why outcome definitions and follow-up populations should be read together. TLF is a composite outcome, so an overall rate would need component-specific information for a fuller account of which events contributed. The primary population excludes five patients who were not evaluable because follow-up was < 240 days and they were event-free. The registry does not report further missing-data procedures or component-level results.

Finally, the separation between safety summaries and primary outcomes is important. Serious adverse-event counts and event-term percentages describe a different set of observations from the defined TLF endpoint. They do not provide a control comparison or replace the absent primary result. Statistically, this record is therefore useful for clarifying what was planned to be measured and what design limits apply, while also showing that a completed study record may not provide enough posted numerical results for readers to evaluate its central estimate.

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 immediate limitation for interpreting the registry entry is that the primary TLF result and its 95% confidence interval are not reported in the registry record. Without them, the primary endpoint’s observed frequency and precision cannot be assessed. Numerical results for the listed secondary outcomes are also not reported in the registry record.

The study is single-arm and has no reported concurrent comparator. Consequently, the design does not estimate a randomized difference between the device and another treatment. Any outcome frequency, if reported, would be descriptive of the study group and would not by itself identify the cause of an event or isolate an intervention effect.

The primary analysis population is N=323, and five patients were not evaluable because follow-up was < 240 days and they were event-free. The registry does not report whether other data were missing, how missing observations were handled across outcomes, or whether sensitivity analyses were conducted. The record also does not report eligibility details beyond the study’s stated focus on a single de novo atherosclerotic coronary artery lesion.

The registry lists 14 outcome measures but no analysis entries. It does not report a statistical analysis plan, multiplicity procedures, interim analyses, or a trial-specific sample-size justification. The safety entry supplies counts and selected event-term percentages, but does not provide a comparator or enough detail to determine overlap among event terms. These limitations concern what can be concluded from the registry record; they do not establish how the trial was conducted beyond the information recorded.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: The OMEGA Clinical Trial — NCT01419171.
• Registry record last updated 2014-09-25; status last verified 2014-09.
• Results first posted 2014-08-15.
• 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

OMEGA was a completed, prospective, multicenter, single-arm trial of the OMEGA™ Monorail Coronary Stent System. The registry lists 328 enrolled participants and a primary endpoint of nine-month target lesion failure, defined as ischemia-driven target lesion revascularization, target-vessel-related myocardial infarction (Q-wave or non-Q-wave), or cardiac death.

The primary analysis population is reported as N=323; five patients were not evaluable because follow-up was < 240 days and they were event-free. The primary endpoint result and confidence interval are not reported in the registry record. The registry lists 14 outcomes and no analysis entries. Its safety entry lists 108 affected in the serious-adverse-event grouping and 118 affected in the other-adverse-event grouping, with selected serious-event terms and percentages. The single-arm design does not provide a concurrent treatment comparison.