A Prospective, Multi-center Trial to Assess an Everolimus-Eluting Coronary Stent System (PROMUS Element™): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Prospective, Multi-center Trial to Assess an Everolimus-Eluting Coronary Stent System (PROMUS Element™) (NCT00824434), a na phase 3 study. The primary outcome is Cardiac Events (Composite).

2. Clinical Question

The registry describes a prospective, multi-center assessment of the stent system in patients with a single de novo atherosclerotic lesion. Its brief summary identifies acute clinical outcomes at 30 days, alongside angiographic and intravascular ultrasound (IVUS) data at 9 months. The primary endpoint is a composite: a participant meets it if any of its listed events occurs during the specified period.

Because the design is single-group, the clinical question represented by the primary endpoint is descriptive: how often the composite was recorded among participants in the study. It is not a randomized comparison of the stent against another treatment or a control group. The registry record does not report a numerical primary endpoint result, so the frequency of the composite cannot be described from this record. Nor does the record establish a comparative treatment effect.

3. Trial Design

The study is registered as a phase 3, prospective, multi-center, single-group trial of the PROMUS Element device. Its status is completed, and the registry lists enrollment as 100. The listed start and primary completion dates are 2009-03 and 2009-09. Masking is recorded as none, and allocation is recorded as NA. The registry does not describe a control group; its arm description identifies an experimental stent.

The stated purpose was to compile acute clinical outcomes data at 30 days and angiographic and IVUS data at 9 months for patients treated for a single de novo atherosclerotic lesion. The primary endpoint is a percentage of participants with a composite cardiac event at 30 days. The registry also lists secondary outcomes that include in-stent late loss, post-procedure incomplete stent apposition, myocardial infarction, all-cause mortality, target lesion revascularization, and target vessel revascularization. Some listed outcome names occur more than once in the record.

The registry lists 16 outcome measures and 2 analyses. These counts do not specify which results were reported or how outcomes were selected for analysis. Details such as eligibility criteria beyond the lesion description, recruitment procedures, device implantation protocol, and follow-up completeness are not reported in the registry record.

The single-group structure matters when interpreting results. Without a concurrent comparison group, outcomes can describe what was recorded among enrolled participants, but cannot isolate the effect of the device from other explanations. The registry record does not report a randomized allocation process or a masking procedure.

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: Analysis was intention to treat; all patients in the study underwent clinical follow up to provide the information needed for this endpoint.

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 Cardiac Events (Composite), measured over 30 days.

The primary endpoint is the percentage of participants who had a cardiac event within 30 days. It combines myocardial infarction, cardiac death, target lesion revascularization, and stent thrombosis; stent thrombosis is defined using definite or probable Academic Research Consortium criteria. A participant with any listed component qualifies for the composite.

Composite endpoints are used to capture a set of clinically relevant events in one measure. In general, they can summarize whether any component occurred, but the combined percentage does not show which component drove the result. Components may also differ in frequency and clinical importance. Interpreting a composite therefore requires attention to its definition and, where available, its component-specific results.

The registry describes the primary measure as a percentage and says the analysis was intention to treat. It also states that all patients in the study underwent clinical follow-up to provide information for the endpoint. That statement describes the planned or recorded follow-up approach; it does not establish that every endpoint value was complete. The numerical primary endpoint result, component results, and uncertainty around the estimate are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary measure is a binary participant-level outcome: a participant either had at least one qualifying event during the 30-day period or did not. The registry expresses this as a percentage of participants. In general, a percentage is a way to describe the observed frequency in a defined group; interpretation depends on knowing both the numerator and the denominator and how participants with incomplete follow-up were handled. The registry record does not report the primary endpoint value or its event count.

The composite includes myocardial infarction, cardiac death, target lesion revascularization, and definite or probable stent thrombosis. A composite endpoint treats occurrence of any listed component as meeting the endpoint. This can provide a single summary, but it does not imply that the components occur equally often or carry equal clinical meaning. In general, component-level results and a clear definition of each component are needed to understand what a composite percentage represents. The registry gives a definition for the composite and refers to definitions of individual components, but component results are not reported in the registry record.

The stated primary analysis population is intention to treat. In general, intention-to-treat analysis retains participants in the group to which they were assigned or enrolled, according to the study's design, rather than excluding them because of events after entry or deviations from treatment. This approach can help preserve the planned comparison in randomized trials. This study is listed as single-group, so the registry's intention-to-treat statement does not create a comparator. The record does not further explain how the analysis population was implemented or how missing measurements were treated.

A confidence interval, when reported, describes statistical uncertainty around an estimated quantity under the assumptions of the analysis. It is not a guarantee that the true value lies within a particular interval. The registry record does not report a confidence interval for the primary endpoint. Without an estimate and its uncertainty, it is not possible to judge the precision of the endpoint frequency from the record.

General statistical interpretation also distinguishes statistical uncertainty from clinical importance. A p-value, if available, addresses compatibility of data with a specified statistical model and null hypothesis; it does not measure the size or importance of an effect. No primary-endpoint p-value or hypothesis-testing result is reported in the registry record. The record also does not describe a primary hypothesis, statistical test, or prespecified decision threshold.

The registry lists 16 outcome measures and 2 analyses. When several outcomes or analyses are examined, the chance of at least one apparently unusual finding can increase if no adjustment or interpretation plan is used. This is the general reason multiplicity matters. The registry record does not report how outcome multiplicity was addressed, whether analyses were prespecified, or which analysis was considered confirmatory beyond identifying the primary endpoint.

The record includes planning assumptions for sample-size illustrations: two-sided significance level 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a fraction of the observed effect. It specifies that the illustrations are planning exercises rather than the trial's own design. Those assumptions do not match the registered single-group structure as a description of the actual study allocation, and the registry does not report the trial's sample-size justification. The actual illustration values and the effect estimate on which they depend are not reported in the registry record. Such planning calculations are not observed power and should not be read as study findings.

In general, over-dispersion matters when observed variability is greater than a statistical model assumes; ignoring it can make uncertainty appear too small. The primary endpoint is recorded as a binary percentage, and no over-dispersion adjustment or model is described in the registry record. There is therefore no basis for asserting that such an adjustment was used or was needed.

The registry names secondary angiographic, IVUS, and clinical outcomes, but does not provide their numerical results in this record. No conclusions about those outcomes, their precision, or relationships among them can be drawn from their names alone.

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("PROMUS Element")
n      <- c(100)
events <- c(1)
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  PROMUS Element  100  1  1.0  0.0  5.4  0.2  5.4  0.2  5.4

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 16 outcome measures and 2 analyses, alongside one named primary endpoint and several secondary outcomes. With multiple outcomes or analyses, there are generally more opportunities for findings to appear noteworthy by chance. Statistical plans can address this through prespecification, adjustment, or a clear distinction between confirmatory and exploratory analyses. The registry record does not report a multiplicity strategy, specify which secondary outcomes were confirmatory, or explain how the 2 analyses relate to the listed outcomes.

The primary analysis is described as intention to treat. The record states that all patients underwent clinical follow-up to provide information for the primary endpoint, but does not report the number with complete endpoint data, the amount or pattern of missing data, or the method used if endpoint information was unavailable. Follow-up being undertaken does not establish that all data were complete. Missing-data methods and sensitivity analyses are not reported in the registry record.

The record does not explain whether any participants were excluded from analysis, how deviations from the intervention were handled, or whether the analysis population differed from enrollment. It also does not report a protocol-level statistical analysis plan or details about interim analyses. These items are not reported in the registry record, so their absence should not be interpreted as proof that no such procedures existed.

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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: non-cardiac chest pain (8.0%), angina pectoris (4.0%), angina unstable (3.0%), coronary artery dissection (3.0%), musculoskeletal chest pain (3.0%).

The safety summary lists 100 participants at risk for serious adverse events and 27 participants affected. It separately lists 100 at risk for other adverse events and 48 affected. These are distinct registry categories; the record does not explain whether the same participant could be counted in both categories, so the figures should not be added together. The deaths field is not reported in the registry record.

The listed serious adverse event terms include non-cardiac chest pain at 8.0%, angina pectoris at 4.0%, unstable angina at 3.0%, coronary artery dissection at 3.0%, musculoskeletal chest pain at 3.0%, and myocardial infarction at 2.0%. These term-specific percentages describe the entries as recorded; the registry record does not provide additional detail about event severity, timing, relatedness to the device, or whether categories overlap.

Adverse-event summaries are descriptive. They do not establish that an event was caused by the device, and the single-group design offers no concurrent comparison for estimating relative safety. The listed figures should be read with those limits in mind.

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

The registry record establishes the study's purpose, design, endpoint definition, and selected safety summaries. It describes a completed prospective, multi-center, single-group phase 3 assessment of the PROMUS Element stent system, with a 30-day composite cardiac endpoint and planned 9-month angiographic and IVUS data collection. These design details explain what the study set out to examine.

They do not reveal the primary endpoint result. The percentage of participants with the composite, the number of events for its individual components, and an estimate of statistical precision are not reported in the registry record. Accordingly, the record cannot establish how frequently the primary event occurred among participants or how uncertain that frequency is.

Even if a single-group event percentage were available, it would describe outcomes in that study group rather than the difference between the device and a comparator. No comparator is described. A before-and-after or cross-study contrast is also not reported and should not be inferred. The study's enrollment figure is not an outcome and cannot substitute for an event count.

In general, a study's endpoint is a defined measurement, not by itself a conclusion about benefit, harm, or causation. Interpretation depends on observed results, uncertainty, the comparison design, and the completeness and conduct of follow-up. The registry record gives some of the design and endpoint information but does not report the primary result, its uncertainty, or enough detail to assess missingness and analysis decisions.

The safety entries provide counts of participants affected and several term-specific percentages, but do not establish cause or comparative risk. They should be considered descriptive reports, not proof that the device caused or prevented any listed event. Overall, this record supports a description of the planned assessment and selected safety entries, not a quantified efficacy claim or comparative safety conclusion.

14. Why This Trial Matters Statistically

This trial is statistically notable as a prospective, multi-center, single-group evaluation of a coronary stent system with a prespecified 30-day composite cardiac endpoint. Its registry record illustrates why design and result reporting must be read together: a clearly defined outcome helps identify what was to be measured, but without the numerical result a reader cannot assess the event frequency or precision.

The composite definition also highlights a common interpretive issue. Combining myocardial infarction, cardiac death, target lesion revascularization, and stent thrombosis yields one endpoint, while leaving open how much each component contributes. Component-specific data are important for understanding the composition of a composite and should be reported alongside the overall measure where available. Those results are not reported in the registry record.

The single-group design makes the distinction between description and comparison especially important. A rate in participants treated with the device would be a description of that group. It would not alone estimate what would have happened under an alternative intervention. Readers should not treat a phase designation or a completed status as substitutes for a comparative design or a reported treatment effect.

The record also lists numerous outcome measures and analyses without reporting the multiplicity approach. This makes transparent analysis planning relevant: readers need to know which outcome was primary, how secondary outcomes were interpreted, and whether adjustments or sensitivity analyses were used. The registry identifies the primary endpoint but does not report those additional statistical details.

These features make the record a useful example of how to separate the clinical question, outcome definition, study structure, and available evidence. Each contributes to interpretation, but none can fill the gap left by an unreported primary result.

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 principal limitation for interpretation is that the numerical primary endpoint result is not reported in the registry record. The record also does not report a confidence interval, component-specific primary endpoint results, or a primary-endpoint test result. This prevents assessment of the event frequency, its precision, and the contribution of each component.

The study is listed as single-group with no comparator. Consequently, the design described in the registry does not provide a concurrent basis for estimating a treatment contrast. The record also does not report detailed eligibility criteria, the intervention protocol, device deployment information, or participant-level follow-up completeness. These details are not reported in the registry record.

Although the primary analysis is described as intention to treat and all patients are said to have undergone clinical follow-up, the record does not state how missing outcome information was handled or how many endpoint assessments were evaluable. It does not describe an analysis plan, multiplicity handling, or interim analyses. These omissions limit assessment of the statistical methods and should not be taken as evidence that any particular method was or was not used.

The registry lists secondary outcomes and safety terms, but detailed results and context are limited. The adverse-event summary does not report event relatedness, timing, or overlap between categories, and the deaths field is not reported in the registry record. These limitations constrain interpretation of both efficacy-related endpoints and safety descriptions.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Prospective, Multi-center Trial to Assess an Everolimus-Eluting Coronary Stent System (PROMUS Element™) — NCT00824434.
• Registry record last updated 2012-08-30; status last verified 2012-08.
• Results first posted 2012-03-07.
• 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 describes NCT00824434, a completed phase 3, prospective, multi-center, single-group study of the PROMUS Element everolimus-eluting coronary stent system. Enrollment is listed as 100. The study aimed to compile 30-day clinical outcomes and 9-month angiographic and IVUS data for patients with a single de novo atherosclerotic lesion.

The primary endpoint was the percentage of participants with myocardial infarction, cardiac death, target lesion revascularization, or definite or probable stent thrombosis within 30 days. The analysis is described as intention to treat. The numerical primary endpoint result and its statistical precision are not reported in the registry record.

The record lists 16 outcome measures and 2 analyses. It also reports serious adverse events in 27 of 100 participants at risk and other adverse events in 48 of 100 at risk. The study has no listed comparator, so the record does not provide a randomized treatment comparison.