PROMUS Element Plus US Post-Approval Study: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for PROMUS Element Plus US Post-Approval Study (NCT01589978), a na phase 4 study. The primary outcome is Cardiac Death or Myocardial Infarction Rate in PLATINUM-like Patients.

2. Clinical Question

3. Trial Design

The PROMUS Element Plus US Post-Approval Study is a phase 4, prospective, open-label, consecutively enrolling, single-group study. Its stated purpose is to observe clinical outcomes among patients receiving the PROMUS Element Plus coronary stent in routine clinical practice. The registry lists coronary artery disease as the condition under study. The study is marked completed, with a listed start of 2012-05 and primary completion of 2014-08.

The registry lists enrollment of 2681. Its brief summary describes an approximate planned enrollment of 2,689 patients at up to 65 centers in the United States. These are different enrollment figures as stated in the record; the registry does not explain the distinction. The summary describes follow-up through 5 years. The primary endpoint, however, is defined at 12 months and in a PLATINUM-like population.

Because the study has a single group and no masking, treatment assignment is not concealed through a randomized comparison. The consecutive-enrollment description indicates how enrollment was intended to proceed, but the registry record does not provide enough detail to assess how completely that approach was implemented or how representative the enrolled patients were. The study is observational in its clinical setting, even though the primary endpoint specifies a performance-goal test.

The registry lists 21 outcome measures and 2 analyses. It names secondary outcomes including stent thrombosis, longitudinal stent deformation, major adverse cardiac events, myocardial infarction, and cardiac death. It does not report a detailed statistical analysis plan, outcome-adjudication procedures, or the handling of follow-up beyond the broad summary. Those details are not reported 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: Note: PLATINUM-like population for the Primary Endpoint at 12 months includes PROMUS Element patients from the PLATINUM trials (WH and SV) (N=862), PLATINUM-like patients from PE-Prove (N=269), and PLATINUM-like patients from PROMUS Element Plus US Post-Approval Study (N=776) (as stated as a subgroup in the Participant Flow Module.

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 Death or Myocardial Infarction Rate in PLATINUM-like Patients, measured over 12 months.

The primary endpoint is the percentage of PLATINUM-like patients experiencing cardiac death or myocardial infarction by 12 months after stent implantation. It combines two clinically important event types into a single binary outcome: a patient either meets the composite endpoint during the specified period or does not. The registry states that the rate will be tested against a performance goal of 3.2%.

A composite endpoint can capture more than one kind of clinically important event and can provide a single summary measure. Its interpretation depends on knowing how each component contributes to the total. The registry record does not report the separate primary-endpoint counts for cardiac death and myocardial infarction, nor does it provide the observed composite rate in the information. It therefore does not allow readers to determine which component, if either, accounts for the endpoint result.

The endpoint is defined for a restricted PLATINUM-like group rather than all patients enrolled in the post-approval study. The registry describes that group using clinical exclusions and lesion criteria. It also states that the primary endpoint population incorporates PROMUS Element patients from the PLATINUM trials, PLATINUM-like patients from PE-Prove, and PLATINUM-like patients from this study. The size and composition of those contributing groups matter when interpreting the endpoint, but the record does not provide the endpoint result or all analysis details needed to assess it.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a single-group study estimate?

In general, a single-group study estimates outcomes observed among participants who received the intervention under the study conditions. It has no concurrent randomized control arm, so it cannot directly estimate a treatment contrast protected by random assignment. Patient characteristics, clinical decisions, and follow-up can all influence observed outcomes. In this study, the registry describes prospective observation in routine clinical practice and no masking. These design features help define what the results could describe, but they do not remove confounding or create a counterfactual comparison.

The endpoint description adds a performance-goal comparison. In general, such a test evaluates an observed rate against a prespecified benchmark. The benchmark is not a group enrolled and followed alongside the study participants. Its relevance depends on the way it was selected and on whether its underlying population and outcome definitions are sufficiently comparable. The registry states the performance goal as 3.2%, but its justification and statistical assumptions are not reported in the registry record.

How should a percentage endpoint be understood?

In general, a binary percentage endpoint represents the proportion of an analysis population with the event defined by the endpoint during the stated period. The primary endpoint is cardiac death or myocardial infarction by 12 months in PLATINUM-like patients. A percentage is easier to interpret when its analysis denominator, event definition, and follow-up completeness are clear. The registry information does not report the observed percentage, the number of events, or a confidence interval for this endpoint. Those omissions prevent assessment of the estimate's precision.

A confidence interval, in general, describes a range of values compatible with the observed data under a specified statistical procedure. It communicates uncertainty around an estimate rather than guaranteeing that the true value lies within a particular range. Because no primary-endpoint confidence interval is reported in the registry record information, readers cannot judge the precision of the primary estimate or how its uncertainty relates to the 3.2% performance goal.

Why does the endpoint population matter?

The registry defines the primary analysis population using clinical exclusions and lesion measurements, and describes it as including participants from several study sources. This restricts the interpretation to the specified PLATINUM-like population. It should not be treated as an estimate for every patient in the post-approval study or for all patients with coronary artery disease. In general, subgroup definitions can improve comparability with a target population but may also limit generalizability. The record does not report the detailed analysis procedures used to combine the contributing patient groups.

The stated lesion criteria include lesion length and reference vessel diameter limits. For example, the description includes lesion length no greater than 28 mm with reference vessel diameter at least 2.25 mm and less than 2.5 mm, or lesion length no greater than 24 mm with diameter at least 2.5 mm and no greater than 4.25 mm. The registry also lists a range of clinical exclusions. These criteria are part of the endpoint definition, not evidence that every enrolled participant met the primary analysis criteria.

What can significance testing establish?

In general, a statistical test evaluates how compatible the data are with a specified null hypothesis under the test's assumptions. A result relative to a performance goal does not establish a causal comparison with another treatment. Statistical significance also does not describe the size or clinical importance of an effect on its own; the estimate and its uncertainty are needed for that assessment. Here, the registry says the primary test will assess whether the rate meets the 3.2% goal, but it does not report the test statistic, p-value, or result in the information.

Sample-size calculations are planning illustrations, not observed power. The registry's sample-size assumptions describe a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with effects expressed as fractions of an observed effect. The record information does not give the resulting planning values. These assumptions do not describe the design of this single-group study, and no planning illustration can substitute for the observed endpoint estimate and its uncertainty.

What is not documented?

The registry record does not report the detailed statistical analysis plan, the method for handling missing endpoint data, the exact analysis population rules, or any interim-analysis procedures. It also does not report whether adjustments were made for covariates or how the contributing study populations were combined statistically. These omissions limit independent evaluation of the planned and completed analyses. General statistical principles can clarify what such information would help establish, but they cannot fill in procedures that 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("PROMUS Element")
n      <- c(1907)
events <- c(34)
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  1907  34  1.8  1.2  2.5  1.3  2.5  1.3  2.5

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 21 outcome measures and 2 analyses, including the primary composite endpoint and secondary outcomes such as stent thrombosis, major adverse cardiac events, myocardial infarction, cardiac death, and longitudinal stent deformation. When multiple outcomes or analyses are examined, the chance of obtaining an apparently notable result by chance can increase if each is tested separately without a plan for multiplicity. In general, a prespecified hierarchy, adjustment procedure, or clear designation of descriptive analyses can help readers understand how multiple tests are interpreted.

The multiplicity strategy is not reported in the registry record. The record information also does not specify which outcomes were considered confirmatory, whether secondary outcomes were adjusted for multiple testing, or how the 2 listed analyses relate to the outcome measures. No conclusion about multiplicity control should be inferred from the number of listed outcomes alone.

Missing-data methods are also not reported in the registry record. For a 12-month endpoint, interpretation can depend on whether participants have complete follow-up, how loss to follow-up is handled, and whether event status can be determined for participants without a visit or assessment. The brief summary describes clinical follow-up through 5 years, but it does not provide completion rates or endpoint-specific missingness. The primary endpoint denominator and missing-data assumptions are therefore not available in the registry information.

The primary analysis population is restricted to PLATINUM-like patients and includes participants from multiple study sources according to the endpoint description. Detailed inclusion rules for the analysis, treatment of participants with incomplete information, and any sensitivity analyses are not reported in the registry record. These details would be needed to assess how robust the estimated rate is to analysis-population decisions.

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 0.1% 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 (4.5%), angina unstable (3.5%), non-cardiac chest pain (2.9%), coronary artery disease (1.8%), cardiac failure congestive (1.7%).

The registry reports a PROMUS Element group with 2681 participants at risk for serious adverse events and 780 affected by serious events. It also reports 2681 at risk for other adverse events and 5 affected. These are registry counts. The record information does not specify the full event-collection window, whether participants could contribute more than one event, or the criteria used to classify events as serious.

The most frequently listed serious-event terms are angina pectoris at 4.5%, unstable angina at 3.5%, non-cardiac chest pain at 2.9%, coronary artery disease at 1.8%, congestive cardiac failure at 1.7%, and pneumonia at 1.3%. These terms are reported as event categories with percentages; the registry information does not establish that they were caused by the stent. A term appearing in a safety listing is not, by itself, evidence of treatment attribution.

Deaths are not reported in the registry record. The listed safety information should be read as a descriptive report of adverse events, not as a comparison with another treatment or a complete causal assessment. Because this is a single-group study, these figures do not establish how event rates would compare under another treatment or in another population.

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

The record describes a prospective, open-label study observing outcomes after receipt of the PROMUS Element Plus coronary stent in routine clinical practice. The primary endpoint is a 12-month composite of cardiac death or myocardial infarction in PLATINUM-like patients, evaluated against a stated performance goal of 3.2%. The record also describes longer-term follow-up through 5 years and lists several secondary outcomes.

The primary endpoint result is not reported in the registry information. There is no observed rate, event count, confidence interval, or test result available in the registry record. Consequently, it is not possible to state whether the observed rate met the performance goal or how precisely it was estimated. A benchmark and an endpoint definition describe the planned question, not its answer.

Even if an observed rate and test result were available, the single-group design would remain important to interpretation. It can describe outcomes among the patients studied, but it does not provide a randomized treatment comparison. The performance goal is not a concurrent control, and the registry information does not explain how the goal was derived or how closely its source population and methods align with this study.

The safety listings likewise describe reported events without establishing causal attribution. The study's open-label, routine-practice setting may be informative about observed clinical outcomes, while the absence of a control group and the lack of detailed reporting on follow-up completeness, missing data, and event adjudication limit what can be inferred. The record does not support a claim that the device causes or prevents any listed event, or that its outcomes are better or worse than those of another treatment.

14. Why This Trial Matters Statistically

This study is statistically notable for combining post-approval observation in routine clinical practice with a performance-goal question for a narrowly defined primary endpoint population. That distinction matters: descriptive follow-up in a single group and testing against an external benchmark answer different questions from a randomized comparison. Keeping those questions separate prevents a performance-goal test from being mistaken for evidence of comparative treatment effect.

The primary endpoint population is not simply the full enrolled cohort. The registry describes PLATINUM-like patients drawn from the PLATINUM trials, PE-Prove, and this study. That feature makes clear why analysis-population definitions are central: a result for this selected population would not automatically describe all patients enrolled in the post-approval study. The record's endpoint criteria also show how clinical and anatomical restrictions shape the population being analyzed.

The registry states a performance goal of 3.2%, but does not report the primary endpoint estimate or its uncertainty in the information. This highlights a basic statistical principle: an endpoint definition and a planned benchmark are not enough to assess a finding. Readers need the observed estimate, precision, analysis population, and testing result to understand what the data say.

The registry also lists multiple outcomes and analyses without reporting the multiplicity strategy, missing-data methods, or detailed statistical plan. Those omissions are relevant because they affect how confidently individual results can be interpreted. The study therefore illustrates the value of reporting both clinical context and the analytical details needed to evaluate uncertainty, selection, and the scope of inference.

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 central limitation in the registry information is that the primary endpoint result is not reported. The record gives the endpoint definition and performance goal but not the observed rate, event count, confidence interval, or test result. This prevents evaluation of the primary statistical question and its precision.

The single-group design has no concurrent control arm. As a result, observed outcomes cannot be used as a randomized estimate of the effect of the stent relative to another treatment. The registry does not explain the origin or justification of the 3.2% performance goal, which limits assessment of the benchmark's suitability.

The primary endpoint uses a PLATINUM-like population that draws on several study sources and is narrower than the full post-approval study population. The registry record does not give the detailed combination method, all analysis-population rules, or the endpoint-specific denominator. The criteria may also limit generalizability beyond the defined population.

Additional limitations include the absence of reported details on missing data, follow-up completeness at 12 months, endpoint adjudication, multiplicity control, covariate adjustment, and interim analyses. The registry's safety information does not describe event attribution or the full collection period, and deaths are not reported in the registry record. These gaps should not be filled by assumptions about the protocol or statistical plan.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: PROMUS Element Plus US Post-Approval Study — NCT01589978.
• Registry record last updated 2018-07-26; status last verified 2018-06.
• Results first posted 2016-05-03.
• 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 PROMUS Element Plus US Post-Approval Study is listed as a completed phase 4, prospective, open-label, consecutively enrolling, single-group study. It observes clinical outcomes after use of the PROMUS Element Plus everolimus-eluting platinum chromium coronary stent system in routine clinical practice. The registry lists enrollment of 2681 and describes follow-up through 5 years.

The primary endpoint is the percentage of PLATINUM-like patients experiencing cardiac death or myocardial infarction at 12 months, with a stated performance goal of 3.2%. The endpoint population description includes patients from the PLATINUM trials, PE-Prove, and this study. The registry information does not report the observed primary endpoint result or its precision.

Reported safety information includes serious and other adverse-event counts and frequently listed serious-event terms. The record does not provide detailed methods for missing data, multiplicity, or the statistical analysis plan. The single-group design supports descriptive interpretation, not a randomized comparison.