REPAIR - transcatheteR rEPair of mitrAl Insufficiency With caRdioband System: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for REPAIR - transcatheteR rEPair of mitrAl Insufficiency With caRdioband System (NCT02703311), a na na study. The primary outcome is Reduction in Severity of MR at 30 Days of at Least One Category on a 0-4 Scale..

2. Clinical Question

The study objectives also included assessing heart failure symptoms and safety in the post-marketing setting. The listed secondary outcomes include change in distance walked on the 6 Minute Walk Test and change in mitral regurgitation severity. These objectives describe what the study set out to evaluate; they do not establish that an improvement occurred. The record reports enrollment of 11 and a terminated status, but does not report why the study was terminated or provide results for the primary question.

3. Trial Design

REPAIR is registered as a single-group, interventional device study of Cardioband for mitral regurgitation. The registry lists allocation as NA and masking as NONE. There is no randomized control arm described, so the design does not support a like-for-like comparison between Cardioband and another treatment. Instead, the primary endpoint compares mitral regurgitation severity within participants, from baseline to 30 days.

The record lists enrollment of 11 and gives a study start of 2016-08 and primary completion of 2017-11. Its current status is TERMINATED. These record details do not explain the reason for termination, whether the planned enrollment was reached, or whether the planned study activities were completed. Those details are not reported in the registry record.

The brief summary places the investigation in a post-marketing setting and describes a population with symptomatic, severe mitral regurgitation. The intervention was mitral valve repair with the Cardioband system through a transcatheter procedure, using transesophageal echocardiography and fluoroscopy guidance. The record lists the study phase as NA.

A single-group design can describe changes observed among participants over time. Without a concurrent comparator, however, a before-and-after difference cannot by itself separate a treatment-associated change from other influences, such as the natural course of illness, changes in care, or measurement variation. This is a general design consideration, not a finding about what occurred in this study.

The record lists 13 outcome measures and 0 analyses. It does not report a statistical analysis plan, a sample-size justification, an interim analysis plan, or a detailed account of the analyses performed. The sample-size material associated with the record is explicitly a planning illustration based on the observed effect, not a description of the trial’s own design. It assumes a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; those assumptions do not change the fact that the registered study itself is single-group.

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: Intra-subject comparison of patients with paired data at baseline and 30 days

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 Reduction in Severity of MR at 30 Days of at Least One Category on a 0-4 Scale., measured over 30 days.

The primary endpoint is reduction in mitral regurgitation (MR) severity at 30 days of at least one category on a 0-4 scale. It compares each participant’s severity at 30 days with that participant’s baseline severity. The outcome description expresses the target as a percentage of patients whose severity fell by at least one grade. The stated population is participants with paired data at baseline and 30 days.

This kind of endpoint translates a change on an ordered clinical scale into a responder measure: participants either meet the specified reduction threshold or do not. It can make the clinical meaning of a change easier to describe than a scale average alone. It also depends on how the categories are assigned and on having measurements at both time points. A participant without a paired measurement cannot be classified using the stated within-person comparison unless an analysis rule is specified.

The endpoint’s threshold does not tell readers how large changes were among participants who met it, how many categories changed, or whether any change persisted beyond 30 days. Nor does it show what would have happened over the same period without the procedure. These are general limits of a short-term responder endpoint in a single-group study.

The registry record does not report the number or percentage of participants meeting the threshold, the distribution of changes in MR severity, or an uncertainty estimate for the result. It therefore describes the endpoint being assessed, but does not report the primary endpoint result.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registered primary outcome is a binary responder measure based on an ordered MR severity scale. A participant meets the endpoint if severity is reduced by at least one category at 30 days compared with baseline. The result could be expressed as a count or a percentage of participants meeting that definition. The registry identifies the outcome unit as participants and states that the analysis population is participants with paired baseline and 30-day data. It does not report the observed count or percentage.

What does a paired comparison mean?

A paired comparison uses measurements from the same participant at two time points. The baseline measurement is not treated as an independent control group; rather, it provides the reference for assessing that participant’s later measurement. This approach accounts for the fact that each participant serves as their own baseline reference. It does not remove changes over time that might have occurred for reasons other than the intervention, and it does not provide the counterfactual comparison that a concurrent control group could offer.

For this endpoint, the underlying scale is ordered: its categories indicate levels of MR severity, but the distance between adjacent categories need not be assumed equal. Defining a responder by a minimum category reduction avoids treating the scale as though each step necessarily represents the same quantitative amount of change. At the same time, a responder threshold discards detail: it does not distinguish a participant whose severity fell by the minimum qualifying amount from one whose severity fell by more categories. The registry record does not report analyses of the full category distribution or individual change scores.

How should uncertainty be understood?

In general, an effect estimate describes the observed result in a study, while a confidence interval describes the range of values reasonably compatible with the data and the statistical method. A narrower interval indicates greater precision; a wider interval indicates less precision. A p-value, when reported, addresses compatibility between the data and a specified null hypothesis under the assumptions of the test. It does not measure the probability that a treatment works, and it does not replace an estimate of the effect and its uncertainty.

No confidence interval, p-value, or primary endpoint estimate is reported in the registry record. There is consequently no reported inferential result to interpret. The registry also does not report the statistical test, model, or estimation method used for the primary endpoint. Those methods are not reported in the registry record.

What does the sample-size illustration represent?

The stated sample-size assumptions describe a planning illustration computed from the observed effect, not the design justification for this trial. The illustration assumes a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; it considers effects defined as stated fractions of the observed effect. The record states that non-time-to-event illustrations give participants per arm for 80% or 90% power, while time-to-event illustrations give a total number of events. These are hypothetical planning quantities. They are not observed power, and they do not turn this single-group study into a two-arm comparison.

In general, a sample-size calculation depends on assumptions about the target effect, variability or event frequency, error rates, allocation, and analysis. A planning illustration cannot establish that a completed study had a particular level of power, especially when it is based on an observed effect rather than the trial’s original design assumptions. The original sample-size justification is not reported in the registry record.

Why can over-dispersion matter?

In general, over-dispersion occurs when variation in count data is greater than a model assumes. If a model understates the true variability, its standard errors may be too small and its confidence intervals too narrow. Appropriate modeling may require accounting for that extra variation. This is a general statistical consideration; the registry record does not report an over-dispersion analysis or a count model for the primary endpoint.

Finally, statistical interpretation depends on knowing which participants were analyzed, how missing measurements were handled, and whether the planned analysis was changed. The registry record does not report the detailed analysis population, missing-data method, or statistical analysis plan. The design and endpoint can therefore be described, but the method used to estimate the primary result and its precision cannot be reconstructed 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("Cardioband")
n      <- c(7)
events <- c(4)
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  Cardioband  7  4  57.1  18.4  90.1  25.0  84.2  24.5  84.3

11. Multiplicity, Missing Data and Analysis Populations

The record lists 13 outcome measures, including the primary MR severity endpoint and secondary outcomes concerning change in distance walked on the 6 Minute Walk Test and change in MR severity. It reports 0 analyses. A multiplicity adjustment or other strategy for interpreting multiple outcomes is not reported in the registry record. Without a reported analysis plan, it is not possible to determine whether the study treated these outcomes as confirmatory, exploratory, or in some other way.

In general, testing multiple outcomes can increase the chance of finding an apparently notable result by chance if each test is interpreted separately. Prespecified priorities and a stated multiplicity strategy help readers understand how to interpret a family of results. This is a general statistical consideration, not a claim that any particular analysis was conducted in this study.

The primary endpoint population is participants with paired baseline and 30-day data. The registry record does not report how many participants had paired data, the extent or reasons for missing measurements, or how missing data were handled. It also does not describe whether any participants were excluded from the endpoint analysis or how the analysis population was defined beyond the paired-data requirement.

Those omissions limit assessment of potential bias from incomplete follow-up. In general, a paired analysis can include only participants with measurements at both time points unless a specified method handles missing values. If follow-up availability is related to health status or outcome, the analyzed participants may differ from those without paired measurements. Whether that occurred is not reported in the registry record.

The registry record does not describe an intention-to-treat analysis, a per-protocol analysis, or another named analysis population. It also does not report interim analyses, a prespecified statistical analysis plan, or the handling of protocol deviations. These details are not reported in the registry record.

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: cardiac failure (54.5%), ventricular tachycardia (18.2%), pneumonia (18.2%), arrhythmia (9.1%), atrial fibrillation (9.1%).

The adverse-event record lists the Cardioband group with 11 participants at risk and 9 participants affected by serious adverse events. It also lists 11 at risk and 9 affected in the other adverse-event fields. The record lists 5 deaths. It does not explain the relationship, if any, between these deaths and serious adverse events, nor does it report causes of death in the information. These counts should not be interpreted as establishing causation.

The listed top serious-event terms include Cardiac Failure at 54.5%, Ventricular Tachycardia at 18.2%, Pneumonia at 18.2%, Arrhythmia at 9.1%, Atrial Fibrillation at 9.1%, and Cardiac Failure Acute at 9.1%. The denominator and counting rules for these percentages are not reported in the registry record. Event terms may also describe overlapping experiences; the record does not say whether the listed categories are mutually exclusive.

In general, adverse-event summaries describe events recorded during a study and require context about definitions, follow-up duration, attribution, and the population assessed. A single-group safety summary cannot by itself distinguish events related to the procedure from events arising for other reasons. The registry record does not provide a concurrent control comparison or further detail on attribution and event timing.

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

The record establishes that REPAIR was a post-marketing, single-group study of the Cardioband system with a planned primary assessment of MR severity at 30 days. It also establishes the endpoint’s responder definition: a reduction of at least one category on a 0-4 scale compared with baseline, among participants with paired measurements. It does not report how many participants met that definition or the estimated percentage. The primary efficacy result is therefore not reported in the registry record.

This means the endpoint definition must not be mistaken for an observed finding. The stated study objective and the brief summary describe what investigators intended to evaluate. They do not show whether MR severity changed, how often a change occurred, or how precisely any change was estimated. No efficacy conclusion can be drawn from the objective alone.

Even if a baseline-to-follow-up change were reported, a single-group design would describe change over time rather than provide a randomized comparison. General factors besides the intervention can influence measurements taken at different times. Without a concurrent comparator, those influences cannot be separated confidently from an intervention-associated change using the design alone.

The safety record gives event counts and listed event-term percentages, but those data are separate from the primary endpoint and do not establish whether the device caused an event. The record does not report enough detail about timing, attribution, or the denominator for the listed serious-event percentages to support a more detailed comparison. The listed deaths also cannot be attributed to the intervention based on these data alone.

The study is marked TERMINATED, but the reason for termination is not reported in the registry record. The record’s enrollment figure does not establish how many participants contributed paired primary endpoint data. The number with paired data, missing-data handling, analysis methods, and uncertainty estimates are not reported in the registry record.

Accordingly, the record supports a description of the study question, design, and some safety counts. It does not support a quantitative conclusion about the primary MR endpoint, the precision of any efficacy estimate, or a causal claim about outcomes. These limits concern what is reported in the registry record; they do not determine what may be available from other sources.

14. Why This Trial Matters Statistically

This study illustrates an important distinction between defining an outcome and reporting its result. The registry specifies a clinically interpretable responder threshold for MR severity at 30 days, based on a paired comparison with baseline. Yet the observed count or percentage meeting that threshold is not reported in the registry record. Without the result, neither the size of the observed change nor its precision can be assessed.

Its single-group structure also highlights the difference between within-person change and a controlled treatment comparison. Paired measurements can show how participants’ status changed over time, but they do not supply an untreated counterfactual. This is a general limitation of before-and-after designs and is especially important when readers are considering whether a change can be attributed to an intervention.

The record also makes clear why analysis-population details matter. The primary endpoint applies to participants with paired data, but the paired-data count and missing-data handling are not reported. Readers therefore cannot evaluate how complete the endpoint assessment was or whether the participants included in that assessment might differ from those without paired measurements.

Finally, the study status and safety counts need to be kept distinct from efficacy conclusions. TERMINATED does not explain why the study stopped, and the serious adverse-event information does not supply a primary endpoint result or establish causal attribution. The posted record is useful for identifying the intended question and design, but its missing analysis details and primary outcome result constrain statistical interpretation.

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 limitations specific to this trial follow from the information recorded. First, the study is registered as single-group, with no randomized comparator described. The baseline-to-30-day endpoint is therefore an intra-subject comparison, not a comparison against a concurrent control. Any observed change would need to be interpreted as change over time, with causal attribution limited by the design.

Second, the record lists enrollment of 11 but does not report the number of participants with paired baseline and 30-day MR assessments. Because the endpoint is defined for participants with paired data, the size and composition of the endpoint analysis population cannot be established from the record. Missing measurements and their handling are not reported in the registry record.

Third, the primary endpoint result is absent. The record does not report the number or percentage meeting the one-category reduction threshold, an uncertainty interval, or an inferential result. It also does not report the detailed statistical method or analysis plan. The number of outcome measures is listed as 13, but the record reports 0 analyses and does not describe multiplicity handling.

Fourth, the study is marked TERMINATED, but the reason is not reported. The record does not establish whether termination affected enrollment, follow-up, or analysis. The listed serious adverse-event counts and percentages also lack reported detail on attribution, timing, and the denominator for the event-term percentages. These limits prevent a fuller assessment of the outcome and safety records from the registry information alone.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: REPAIR - transcatheteR rEPair of mitrAl Insufficiency With caRdioband System — NCT02703311.
• Registry record last updated 2020-11-09; status last verified 2020-10.
• Results first posted 2020-11-09.
• 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

REPAIR is a terminated, single-group study of the Cardioband transcatheter system for symptomatic, severe MR in the post-marketing setting. The registry lists enrollment of 11, masking as NONE, allocation as NA, and study dates of 2016-08 to primary completion in 2017-11.

The primary endpoint is a reduction in MR severity of at least one category on a 0-4 scale at 30 days compared with baseline, among participants with paired data. The registry record does not report the primary endpoint result, the paired-data count, or its statistical analysis. It lists 13 outcome measures and 0 analyses.

The safety record lists 9 participants affected by serious adverse events among 11 at risk and 5 deaths. The reason for termination, the primary result, and further details about missing data and analysis methods are not reported in the registry record.