XIENCE Xpedition Everolimus-Eluting Coronary Stent Japan Post Marketing Surveillance (XIENCE Xpedition SV Japan PMS): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for XIENCE Xpedition Everolimus-Eluting Coronary Stent Japan Post Marketing Surveillance (XIENCE Xpedition SV Japan PMS) (NCT02513732), a registered phase not stated study. The primary outcome is Number of Participants With Stent Thrombosis: Late.

2. Clinical Question

In statistical terms, the main question is descriptive: how many participants in the named population experienced late stent thrombosis during the defined follow-up interval? A single-arm count can describe events in the observed group, but without a comparator it cannot by itself estimate a difference between treatment strategies. The registry record includes safety reporting and multiple secondary outcomes, including percent diameter stenosis and use of antiplatelet therapy. Those measures broaden the topics recorded, but their presence does not substitute for a reported primary endpoint result or a comparative analysis.

3. Trial Design

This is a completed post-marketing surveillance study of the XIENCE Xpedition Everolimus-Eluting 2.25 mm stent. Its stated objective is to evaluate safety and efficacy in real-world practice in Japanese hospitals. The registry identifies Abbott Medical Devices as the sponsor and lists an enrollment of 100. The study start is recorded as 2014-07 and primary completion as 2020-09.

The record describes one arm: patients receiving the XIENCE Xpedition 2.25 mm stent. The intervention is classified as a device. No comparator arm is described, and allocation is not stated. The registry also identifies the study as not being a randomized comparison. Therefore, the design recorded is a single-arm surveillance study rather than a randomized, controlled comparison. The record does not state whether any external comparator or historical control was used.

The primary endpoint is the number of participants with late stent thrombosis. Its stated interval is 30 days to 1 year after implantation, and the timeframe is also labeled Day 212. The named analysis population is the Intend To Treat population. The registry lists 127 outcome measures, including secondary measures for percent diameter stenosis and antiplatelet therapy use. However, it lists 0 analyses. The primary endpoint result and analysis details are not reported in the registry record.

Further design details, including eligibility criteria, recruitment procedures, follow-up completeness, the planned sample-size justification, and any protocol-defined analysis plan, are not reported in the registry record. The enrollment figure describes the registered study size; it does not explain how that size was chosen or how many participants contributed data to each outcome. The study’s completed status indicates its registry status, but does not by itself provide evidence about endpoint results or the completeness of follow-up.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Intend To Treat population(ITT population)

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.

Population: A total of 100 patients were treated with Xience Xpedition 2.25 mm stent

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Stent Thrombosis: Late, measured over 30 days to 1 year post stent implantation-Day 212.

The primary endpoint counts participants with late stent thrombosis. The registry defines late thrombosis as occurring from 30 days to 1 year after stent implantation and identifies the endpoint timeframe as Day 212. Its description distinguishes acute events, from 0 to 24 hours; subacute events, from >24 hours to 30 days; late events, from 30 days to 1 year; and very late events, after 1 year. These categories clarify that the primary endpoint concerns a specific post-implantation interval rather than every event category listed in the definition.

A participant count is a binary outcome summarized as the number who did or did not meet the event definition. Such outcomes are useful for describing how often a defined event was recorded in a study population. Interpretation depends on a clear event definition, the follow-up interval, the population included, and the number of participants with ascertainable outcome data. The registry names the Intend To Treat population, but does not report the primary endpoint count or an analysis denominator.

The endpoint is relevant to the study’s stated safety and efficacy evaluation, but the registry record does not report its result. No conclusion about the observed frequency of late stent thrombosis can therefore be drawn from the endpoint entry alone. The listed definition also does not provide event adjudication procedures or further detail about how events were assessed; those details are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a participant count represent?

The primary outcome is a count of participants meeting an event definition. In general, a binary outcome classifies each participant as having or not having the event during the specified period. The count is then interpreted in relation to the population and follow-up used to assess it. This study names the Intend To Treat population, but the registry record does not report the primary event count or the number with evaluable follow-up for that endpoint. Without those details, an event proportion, confidence interval, or other estimate cannot be read from the posted primary result.

In general, a confidence interval describes the range of values compatible with an estimate under a statistical model and its assumptions. A narrower interval indicates greater precision, while a wider interval indicates greater uncertainty. No confidence interval for the primary endpoint is reported in the registry record. It would therefore be inappropriate to characterize the precision of the primary estimate.

What can a single-arm study estimate?

In general, a single-arm study can describe outcomes among people in the observed group. A comparison of outcomes between treatments requires a suitable comparator and an analysis that accounts for how participants entered each group. The registry describes one stent arm, states that the study is not a randomized comparison, and does not state an allocation procedure. As a result, the record does not support a randomized estimate of a difference between treatments. Even if outcomes were available, differences from another population or study would not automatically establish that the device caused the difference.

Random allocation, when used, aims to make treatment groups comparable on average with respect to measured and unmeasured baseline factors. That general benefit cannot be attributed to this study: randomization is not reported, and the registry explicitly characterizes the study as non-randomized. The record also does not identify a control group. The main statistical focus available from its design is therefore descriptive surveillance, rather than a controlled treatment-effect comparison.

Why does the endpoint window matter?

Event definitions and follow-up windows determine which observations count toward an endpoint. The primary endpoint is late stent thrombosis, defined for the period from 30 days to 1 year after implantation, with Day 212 also stated as the timeframe. The description separately names acute, subacute, late, and very late categories. In general, keeping these intervals distinct prevents events from different stages of follow-up from being treated as though they answered the same question. The registry does not report the primary count, event dates, or details of how event timing was established.

Time-to-event methods can incorporate both the timing of an event and incomplete follow-up, but the record does not report a time-to-event analysis for the primary outcome. General statistical methods should not be assumed to have been used just because they could be appropriate for a particular outcome. The posted analysis count is 0, and the analysis method for the primary endpoint is not reported in the registry record.

How should the sample-size illustrations be understood?

General sample-size planning asks how much information a study would need to detect a specified effect under stated assumptions. The planning illustrations associated with this study use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is expressed as a stated fraction of the observed effect. For time-to-event outcomes, the illustration is based on the total number of events using the Schoenfeld method; other illustrations are expressed as participants per arm.

These are planning calculations, not a report of the study’s original design rationale. The registered study has one described arm, and its allocation is not stated. The registry does not report a sample-size justification or say that these assumptions governed the study design. Such illustrations are hypothetical planning aids and are not observed power. No numerical illustration values are reported in the registry record, so none can be interpreted as a required or achieved study size.

What do the safety summaries convey?

In general, a count of participants affected by an adverse event is a descriptive summary. A count of participants and a list of event terms do not by themselves show whether an event was caused by an intervention. Causal attribution requires information and assessment beyond the fact that an event occurred during a study. The registry provides serious and other adverse-event counts and several serious-event terms with percentages, but does not report event-level timing, relatedness assessments, or rules for handling multiple events in one participant. The terms and counts should therefore be read as recorded safety information, not as causal estimates.

When several outcomes are examined, multiplicity can arise because repeated statistical tests increase the chance of at least one result appearing notable by chance. General approaches to multiplicity include prespecifying a primary hypothesis or adjusting interpretation for multiple tests. The registry lists 127 outcome measures, but does not report an analysis plan, a multiplicity strategy, or any analyses. No particular method for controlling multiplicity can be attributed to this study from 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("XIENCE Xpedition 2.25 mm Stent Arm")
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  XIENCE Xpedition 2.25 mm Stent Arm  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 127 outcome measures, including repeated entries for percent diameter stenosis and antiplatelet therapy use, but reports 0 analyses. The primary endpoint is identified, yet its analyzed result is not reported in the registry record. No statistical analysis plan, testing hierarchy, or approach to multiplicity is reported. In general, examining many outcomes can create multiplicity concerns because repeated testing can increase the chance of a result appearing notable by chance. The record does not establish whether or how this issue was addressed.

The primary outcome specifies the Intend To Treat population. The registry does not report how many participants had complete primary endpoint follow-up, how missing observations were handled, whether any participants were excluded from an analysis, or whether imputation or sensitivity analyses were used. These details are not reported in the registry record. The enrollment of 100 should not be treated as the denominator for every outcome without a reported analysis population and outcome-specific follow-up information.

The registry’s completed status and its enrollment figure do not reveal whether all planned observations were collected or analyzed. The record also does not report a protocol-based definition of analysis populations beyond naming the population for the primary endpoint. Missing-data assumptions and the effect of incomplete follow-up therefore cannot be assessed from the posted information.

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.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: coronary artery stenosis (23.0%), coronary artery restenosis (20.0%), angina pectoris (12.0%), peripheral arterial occlusive disease (7.0%), pneumonia aspiration (7.0%).

For the XIENCE Xpedition 2.25 mm Stent Arm, the registry reports 63 participants affected by serious adverse events among 100 at risk and 67 participants affected by other adverse events among 100 at risk. It also reports 9 deaths. The record does not describe the causes or timing of the deaths, or whether they were considered related to the device. These counts should be read as safety entries, not as evidence that the device caused an event.

The listed serious adverse-event terms include coronary artery stenosis (23.0%), coronary artery restenosis (20.0%), angina pectoris (12.0%), peripheral arterial occlusive disease (7.0%), pneumonia aspiration (7.0%), and pneumonia (4.0%). The registry does not specify whether these percentages refer to participants or events, whether categories overlap, or how event relatedness was assessed. They should not be added together or interpreted as mutually exclusive categories. A comparator is not reported, so the figures do not provide a comparative safety estimate. They also do not replace the unreported primary endpoint result.

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

The registry record establishes the study’s stated purpose, the device used, the enrolled population size, the single described arm, and the definition of the primary endpoint. It also reports selected safety counts and serious-event terms. These registry entries describe what the study set out to monitor and what safety information appears in the record. They do not establish the frequency of late stent thrombosis, because the primary endpoint count is not reported in the registry record.

The 100 enrolled participants do not, by themselves, show how many had complete follow-up or contributed data to each outcome. The listed safety counts are descriptive and lack a comparator. They cannot show whether event frequency differed from what would have occurred under another treatment or in another population. The registry also does not report enough information to determine whether reported adverse events were attributed to the device.

The study’s stated objective includes evaluating safety and efficacy, but an objective is not a result. The registry lists 127 outcome measures and 0 analyses, leaving the primary outcome and the analysis of secondary outcomes unavailable in the posted record. Without those results, readers cannot assess the magnitude of any observed effect or the statistical precision of an estimate. There is no reported basis for a quantitative treatment-effect claim.

More generally, a single-arm surveillance study can contribute descriptive information about outcomes observed in routine practice, but it does not provide the protection against confounding that random allocation can offer. Here, allocation is not stated and the registry says the study is not a randomized comparison. The record therefore cannot support a randomized comparison or an unqualified causal conclusion. It is most appropriately read as a registry description of a surveillance study with selected safety reporting and an unreported primary endpoint result.

14. Why This Trial Matters Statistically

Post-marketing surveillance addresses outcomes recorded after a device enters real-world practice. A registry entry can help readers understand the intended population, intervention, follow-up window, and outcomes the study set out to monitor. In this study, the primary endpoint is a defined count of participants with late stent thrombosis, and the record identifies a Japanese hospital setting and a single device arm.

The record also illustrates why endpoint definitions and result availability matter. The primary event interval is distinguished from acute, subacute, and very late thrombosis, but the endpoint count is not reported. Without the count and its analysis, the central outcome cannot be quantified or assessed for precision. The completed status and the presence of many outcome measures do not fill that gap.

Statistically, the non-randomized, single-arm design shapes what can be concluded. Descriptive surveillance can record events in the observed group, while a treatment comparison requires a suitable comparator and analysis. No comparator is described, and the registry says allocation is not stated. The posted safety summaries are useful as descriptive entries, but they do not establish causal attribution or comparative safety.

The study is therefore important to interpret with attention to the distinction between a registered objective and a reported result. It supplies design context and selected safety information, but not a reported primary endpoint analysis. That distinction is central when reading any clinical registry: an outcome’s definition, a study’s completion status, and the availability of analyzed results are separate aspects of the evidence.

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.

Several trial-specific limitations restrict interpretation of this record. It describes only one arm and identifies the study as not randomized; allocation is not stated. A comparator is not reported, so there is no like-for-like control comparison in the registry. The primary endpoint count is also not reported, preventing a direct description of the primary outcome’s observed frequency.

The registry records 100 enrolled participants, but does not report outcome-specific denominators, follow-up completeness, or missing-data handling. It is therefore not possible to determine from the record whether all enrolled participants contributed to every outcome. Although the endpoint names an Intend To Treat population, further details about analysis populations and implementation are not reported in the registry record.

The record lists 127 outcome measures and 0 analyses. It does not report a statistical analysis plan, multiplicity approach, sample-size justification, confidence intervals, or inferential results. These gaps prevent evaluation of the precision of the primary estimate and of how secondary outcomes were analyzed. The registry does not report details of event adjudication or the assessment of adverse-event relatedness, which also limits interpretation of the safety entries.

The serious and other adverse-event counts and the listed event percentages are descriptive, with no comparator. The record does not clarify whether listed terms overlap or whether percentages describe participants or events. Causes and timing of the 9 deaths are not reported in the registry record. These limitations apply to the posted registry information; the record does not establish whether additional information exists outside it.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: XIENCE Xpedition Everolimus-Eluting Coronary Stent Japan Post Marketing Surveillance (XIENCE Xpedition SV Japan PMS) — NCT02513732.
• Registry record last updated 2021-05-13; status last verified 2021-04.
• Results first posted 2019-02-21.
• 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

This completed post-marketing surveillance study evaluated the XIENCE Xpedition 2.25 mm stent in Japanese hospitals. The registry records 100 enrolled participants, one device arm, and a study start of 2014-07 with primary completion in 2020-09. The stated primary endpoint is the number of participants with late stent thrombosis from 30 days to 1 year after implantation, with Day 212 also stated as the timeframe.

The registry lists 127 outcome measures and 0 analyses. The primary endpoint result is not reported in the registry record. Safety entries include 63 participants affected by serious adverse events, 67 affected by other adverse events, and 9 deaths, with 100 at risk for each adverse-event category. The record does not report a comparator or randomized allocation. These details support a descriptive reading of the registry, but not a primary endpoint estimate or a comparative treatment conclusion.