Evaluation of Coronary Luminal Diameter Enlargement With Emerge™ 1.20 mm PTCA Dilatation Catheter: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Evaluation of Coronary Luminal Diameter Enlargement With Emerge™ 1.20 mm PTCA Dilatation Catheter (NCT01635881), a na phase 3 study. The primary outcome is Device Procedural Success.

2. Clinical Question

In practical terms, this is a descriptive question about procedural performance in the participants treated with the study catheter. The single-group design can summarize outcomes observed in that group, but it cannot by itself compare those outcomes with what would have happened under another device or treatment. The registered secondary outcome is in-hospital Major Adverse Cardiac Events (MACE); a numerical result for that outcome is also not reported in the registry record.

3. Trial Design

The registry record describes a completed, Phase 3, single-group device study sponsored by Boston Scientific Corporation. It lists an enrollment of 60 and one arm, Emerge, using the Emerge™ 1.20 mm PTCA dilatation catheter. The intervention is classified as a device. The study’s stated purpose was to evaluate acute safety and device procedural success when the catheter was used for pre-dilatation in a stenotic portion of a coronary artery or bypass graft.

The record lists allocation as NA and masking as none. This is therefore not a randomized, masked comparison: there is no separate control arm in the registry description. The design supports a description of outcomes among participants treated with the catheter, but it does not provide a concurrent group for estimating a comparative treatment effect. The record does not report a protocol-level explanation for the choice of this design.

The listed start is 2012-07, and primary completion is listed as 2012-12. The status is completed. These record dates describe the study’s administrative timeline; they do not establish when every participant was assessed or when each outcome was collected. The primary endpoint timeframe is peri-procedural, and the secondary outcome is in-hospital MACE.

The primary endpoint’s stated population is the intent-to-treat subject population. The registry record does not specify how that population was operationalized for this single-group study, whether all enrolled participants were included in the endpoint denominator, or how participants with unavailable measurements were handled. It lists two outcome measures and zero analyses, but provides no numerical primary endpoint result or secondary outcome analysis.

The record does not report detailed eligibility criteria, recruitment procedures, site information, baseline characteristics, or the sample-size justification used to plan the study. The sample-size material elsewhere on this page is a planning illustration based on the observed effect and stated assumptions; it is not the trial’s own design rationale or an estimate of observed power. The study should be read as a single-arm procedural evaluation, not as evidence from a controlled comparison.

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 population consists of intent-to-treat subject 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.

6. Primary Endpoint

The registry lists the primary outcome as Device Procedural Success, measured over Peri-procedural.

The primary endpoint is Device Procedural Success, expressed as a percentage of participants and assessed during the peri-procedural period. The registry defines success through a set of procedural conditions: successful delivery, inflation, deflation and withdrawal of the study balloon; no study-balloon-related vessel perforation, flow-limiting dissection of grade C or higher, or reduction in TIMI flow from baseline; and final TIMI flow grade of 3 at the conclusion of the percutaneous coronary intervention procedure.

Combining these conditions makes the endpoint a composite measure: a participant must meet the stated procedural criteria rather than simply one isolated technical milestone. In general, such endpoints can summarize several aspects of device performance in a single measure. Their interpretation depends on the definition, the way each component is assessed, and how the components are combined. Here, the registry description gives the criteria, but does not report component-specific results or explain assessment procedures beyond those criteria.

The percentage format is intended to describe the share of the analysis population meeting the endpoint definition. A confidence interval is also specified at 95%. In general, a confidence interval communicates the statistical uncertainty around an estimated percentage; it does not eliminate uncertainty about how well the study participants represent other settings or patients.

The primary endpoint’s analysis population is described as intent-to-treat. However, the numerical percentage, the confidence interval, the denominator actually analyzed and any component-level results are not reported in the registry record. Consequently, readers can identify what success was supposed to mean, but cannot use this record to quantify how often that definition was met.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical information in the registry record is limited. It identifies the primary endpoint as a percentage of participants, specifies a 95% Confidence Interval, names an intent-to-treat subject population and gives a peri-procedural timeframe. It does not report a numerical estimate, interval, analysis output or detailed statistical plan. The explanations below describe general statistical ideas and distinguish those ideas from what can be established about this study.

What does a percentage endpoint represent?

In general, a percentage for a binary endpoint summarizes the proportion of participants classified as having or not having the defined event. For this study, the event is meeting the complete Device Procedural Success definition. The registry definition has multiple conditions, so the endpoint is not simply successful balloon delivery or a single blood-flow measure. The reported percentage would depend on how many participants met all listed criteria and the denominator used in the analysis.

The registry record does not provide either the primary endpoint count or the analyzed denominator. Although enrollment is listed as 60, that number cannot be substituted for the endpoint denominator without confirmation that all enrolled participants were included and had an assessable outcome. Neither that confirmation nor a numerical result is reported in the registry record. The tables or plots should therefore not be read as a substitute for a missing primary endpoint result unless they display a result explicitly; no such result is present in this record.

What does a confidence interval add?

In general, a confidence interval expresses statistical uncertainty around an estimate. For a percentage endpoint, it gives a range of values compatible with the data under the method used to construct the interval. A wider interval indicates less precision than a narrower interval, all else being equal. The interval does not describe every source of uncertainty: it does not correct limitations in study design, measurement, representativeness or missing data.

The registry record specifies a 95% Confidence Interval for the primary outcome but does not report its limits or the method used to calculate it. It is therefore not possible to assess the precision of the primary endpoint estimate or reproduce the interval from the record. The confidence level alone is not a result.

What does the single-group design permit?

In general, a single-group study can summarize the frequency of an outcome in the group observed. Without a concurrent comparator, it cannot directly estimate a difference between the device and an alternative. This record lists one Emerge arm, allocation as NA and masking as none. It does not describe a randomized comparison. Consequently, the study design does not support a like-for-like treatment contrast in the registry record.

That distinction matters even when the measured endpoint is procedural and occurs close to device use. A descriptive rate answers how often the defined outcome was recorded in the observed group. A comparative effect asks how that rate differs from an appropriate alternative group. These are different statistical questions. Here, the record supplies the design description but does not supply the primary rate.

What does intent-to-treat mean?

In general, an intent-to-treat analysis aims to analyze participants according to the group to which they were assigned, rather than excluding them because of events after assignment. The registry describes the primary endpoint population as the intent-to-treat subject population. However, the record does not explain how that principle was applied in this single-group device study, what constituted inclusion in the analysis population, or how missing endpoint assessments were handled. It also does not report the number analyzed.

When outcomes are unavailable, the analysis approach can affect an estimated percentage. Different assumptions about unavailable outcomes can lead to different estimates. The record does not report whether endpoint data were missing, how much data were missing, or what method, if any, was used to address them. No missingness assumption should be inferred.

What can be inferred from the posted safety summaries?

The record lists 2 participants affected by serious adverse events and 6 affected by other adverse events, each with 60 at risk in the Emerge group. These are safety summaries, not the primary endpoint analysis. The record also lists serious adverse-event terms with percentages. In general, adverse-event summaries depend on how events and participants are counted, the observation period, coding and attribution rules. The registry record does not provide all those details here, so the counts should be read as the posted summaries rather than as a full safety analysis.

The secondary outcome is in-hospital MACE, but no numerical analysis for it is reported. Serious adverse events and MACE are not interchangeable labels: the record gives them in different parts of the outcome and safety information, and it does not report a numerical MACE result. A reader should not infer that the listed serious-event count represents the MACE outcome.

What is the role of the sample-size illustration?

The sample-size section on this page is a planning illustration, not a report of the trial’s original planning rationale. Its stated assumptions are a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation and an effect to detect expressed as a fraction of the observed effect. For time-to-event tables, the stated convention is total events; for other tables, participants per arm. These are assumptions for the illustration and do not describe the study design, which has a single group.

In general, a planning calculation asks how much information might be needed to detect a specified effect under stated assumptions. It is distinct from observed power, which should not be used to reinterpret a study’s results after the fact. The illustration does not supply a missing primary endpoint estimate, does not establish the original sample-size justification, and does not show that the single-group study had the two-arm comparison assumed in the planning calculation. The original sample-size justification is not reported in the registry record.

Finally, the registry record does not report whether interim analyses were planned or conducted, the statistical procedures used for the primary endpoint, or a broader statistical analysis plan. These omissions prevent a fuller appraisal of analytic choices. The numerical displays should be understood only in light of the specific results and assumptions they show, and should not be used to infer unreported methods or outcomes.

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("Emerge")
n      <- c(60)
events <- c(59)
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  Emerge  60  59  98.3  91.1  100.0  91.1  99.7  91.2  99.6

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists Device Procedural Success as the primary outcome and in-hospital MACE as a secondary outcome. It does not report numerical analyses for either outcome, and the record lists zero analyses. The presence of more than one outcome raises a general multiplicity question: when several outcomes or comparisons are tested, the chance of obtaining at least one apparently notable result can increase. In general, study plans may address this through a prespecified hierarchy, adjustment, or other approach. No multiplicity strategy is reported in the registry record, so readers cannot determine whether or how multiple outcomes were handled.

The record does not state whether interim analyses were planned or conducted. It also does not describe a detailed statistical analysis plan, testing procedure or rules for interpreting the primary and secondary outcomes. These details are not reported in the registry record and should not be inferred from the fact that a primary outcome and a secondary outcome are listed.

For the primary endpoint, the registry names an intent-to-treat subject population, but does not report the number analyzed or how missing endpoint data were handled. The registry does not report whether any participants lacked an assessable peri-procedural outcome, whether any data were excluded, or what assumptions were used if outcomes were unavailable. In general, missing-data handling can influence the denominator and the estimated percentage, so these are relevant details for interpreting a binary endpoint.

The enrollment of 60 is not enough to establish that 60 participants were included in every analysis. The actual endpoint denominator and missingness information are not reported in the registry record. As a result, neither the completeness of the primary outcome data nor the sensitivity of an analysis to missing outcomes can be assessed from this record.

The single-group design also means that there is no randomized between-group comparison whose multiplicity or missing-data handling could be evaluated. The record provides no basis for concluding that an adjustment was or was not necessary; it simply does not report the relevant analytic details. These absences constrain interpretation and reproducibility, rather than demonstrating that a particular method was used.

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 1.0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: melaena (3.3%), anaemia (1.7%), haematochrezia (1.7%), vascular pseudoaneurysm (1.7%).

The registry safety summary lists an Emerge group with 60 participants at risk for serious adverse events and 2 affected. For other adverse events, it lists 60 at risk and 6 affected. These are participant counts in the posted summary. The record does not provide a numerical result for deaths; the deaths entry is null, so deaths are not reported in the registry record.

The listed serious adverse-event terms are Melaena at 3.3%, Anaemia at 1.7%, Haematochrezia at 1.7%, and Vascular pseudoaneurysm at 1.7%. These are the terms and percentages shown in the registry record. The record does not provide accompanying event counts for each term here, nor does it explain whether participants could contribute more than one term. The percentages should therefore be read as posted, not used to reconstruct a new count or an overall event rate.

In general, serious adverse events and other adverse events are categories in a safety summary; their definitions and collection rules matter. The record does not report detailed definitions, observation duration for this summary, attribution procedures or whether events were considered related to the device. The figures do not by themselves establish causation, and they are not the primary Device Procedural Success result. Nor should they be treated as the numerical result for the separately listed in-hospital MACE outcome, which is not reported in the registry record.

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

This record gives a clear description of the intended procedural endpoint and identifies the device and study group. It also provides limited safety summaries. It does not, however, report the numerical result for the primary endpoint, its 95% Confidence Interval, or an analysis of the secondary in-hospital MACE outcome. Without those results, readers cannot quantify the frequency of Device Procedural Success or assess its statistical precision from the registry record.

The endpoint definition tells readers what investigators intended to count as success: a set of balloon-handling requirements, absence of specified study-balloon-related vessel or flow complications, and final TIMI flow grade of 3. That definition helps clarify the target of measurement, but it is not itself evidence about how often the outcome occurred. The missing numerical result also prevents a review of the distribution across endpoint components or the number of participants included in the analysis.

The study’s single-group design means it can, in principle, describe what was observed among participants treated with the Emerge catheter. It does not provide a randomized comparator or a like-for-like control group. Therefore, even if a numerical rate were available, it would not by itself establish how that rate compares with another device or approach. A comparison requires a suitable comparison group and an analysis designed to estimate the contrast.

The safety summaries show that the registry records 2 participants affected by serious adverse events and 6 affected by other adverse events, with 60 at risk for each category. They also list serious adverse-event terms and percentages. These registry entries should be read narrowly: they do not supply the missing primary endpoint result, establish a relationship to the device, or stand in for the in-hospital MACE result.

The sample-size section is a planning illustration based on stated assumptions, not observed power and not the study’s original design rationale. It cannot resolve the missing outcome information or turn a single-group study into a comparative trial. Overall, the registry record establishes what was studied and how the primary endpoint was defined, while leaving the central numerical outcome and several analytic details unreported.

14. Why This Trial Matters Statistically

This study is statistically instructive because its registry entry separates the definition of an outcome from the reporting of its result. Device Procedural Success is described in procedural terms, including balloon handling, specified vessel and flow events, and a final TIMI flow criterion. That definition allows readers to understand what the endpoint was intended to represent. But a detailed definition cannot replace a numerical estimate, denominator or interval. Those primary results are not reported in the registry record.

The study also illustrates the distinction between descriptive and comparative evidence. With one Emerge arm and no separate control group, the design is suited to describing outcomes in the observed group, not to estimating a direct treatment contrast. Allocation is listed as NA and masking as none. This matters when readers encounter broad claims about performance: the registry record does not contain a randomized like-for-like comparison from which a comparative effect could be estimated.

Another important statistical issue is the relationship between enrollment and analysis. The record lists enrollment of 60 and identifies an intent-to-treat subject population for the primary endpoint, but does not report the analyzed denominator or missing-data handling. In general, a reader needs both a clearly defined event and a clear account of who contributed data to interpret a percentage. Enrollment alone does not establish the endpoint denominator.

The record further distinguishes a primary endpoint from a secondary outcome and safety summaries. It lists in-hospital MACE as secondary, while the adverse-event section reports participant counts and selected serious-event terms. These measures should not be collapsed into one result: their definitions and purposes differ, and the registry does not provide an analysis of MACE.

Finally, the planning illustration shows why sample-size calculations require careful context. Its stated assumptions describe a two-arm planning exercise, whereas the trial record describes a single-group study. As a planning illustration, it is not observed power and does not explain the original study’s sample-size rationale. Keeping the estimand, design, analysis population and reported result distinct is essential to reading the record accurately.

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 statistical interpretation is the absence of a reported primary endpoint estimate. The registry defines Device Procedural Success and specifies a 95% Confidence Interval, but neither the percentage nor the interval appears in the record. It also lists zero analyses. Thus, the primary study question cannot be answered quantitatively from this registry entry.

The design is single-group, with allocation listed as NA and masking as none. There is no separate control group for a like-for-like comparison. This limits inference to description of outcomes in the treated group, even if an outcome rate were reported. The record does not establish how outcomes would compare under another device or approach.

The record lists enrollment of 60 and an intent-to-treat subject population for the primary endpoint, but does not state the actual analysis denominator, the number with assessable peri-procedural outcomes, or the handling of missing data. It also does not provide component-level results for the composite primary endpoint. These omissions make it impossible to assess data completeness or identify which endpoint criterion may have been most influential.

Further trial details that would support appraisal are not reported in the registry record, including detailed eligibility criteria, baseline characteristics, the original sample-size justification, the statistical methods for the primary outcome, any interim analyses, and the multiplicity approach. The registry lists in-hospital MACE as a secondary outcome but does not report its numerical result or analysis. Safety summaries are available, but detailed event definitions, attribution procedures and observation details are not reported.

The record identifies the study as completed and provides its listed start and primary completion dates, but those administrative details do not resolve the missing outcome and analysis information. The sample-size material elsewhere on the page is a planning illustration, not a substitute for the original protocol rationale, an outcome analysis, or observed power. These limitations are specific to what this registry record reports; they do not establish that unreported procedures or data were absent from the study itself.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Evaluation of Coronary Luminal Diameter Enlargement With Emerge™ 1.20 mm PTCA Dilatation Catheter — NCT01635881.
• Registry record last updated 2013-11-06; status last verified 2013-10.
• Results first posted 2013-11-06.
• 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 record describes NCT01635881, titled “Evaluation of Coronary Luminal Diameter Enlargement With Emerge™ 1.20 mm PTCA Dilatation Catheter.” It is listed as a completed Phase 3, single-group device study sponsored by Boston Scientific Corporation, with enrollment of 60. The listed start is 2012-07 and primary completion is 2012-12.

The single Emerge arm used the Emerge™ 1.20 mm PTCA dilatation catheter as a pre-dilatation device. The primary outcome was peri-procedural Device Procedural Success, defined using balloon handling, vessel and flow criteria. The record specifies a percentage of participants and a 95% Confidence Interval, but reports no numerical endpoint result or interval. It lists in-hospital MACE as a secondary outcome without a numerical analysis.

The safety summary lists 2 of 60 affected by serious adverse events and 6 of 60 affected by other adverse events. Serious-event terms and percentages are also listed; deaths are not reported in the registry record. The study has no separate comparator group, and the registry does not report a detailed statistical analysis plan, missing-data handling or original sample-size justification.