This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for NeoChord TACT Post-Market Surveillance Registry (NCT01784055), a registered phase not stated study. The primary outcome is Procedure Success.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01784055 |
| Phase | Phase not stated |
| Condition | Mitral Valve Insufficiency, Heart Valve Diseases, Heart Diseases |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 126 |
| Arms in the primary outcome | n/a |
| Lead sponsor | NeoChord |
| Results posted | Yes |
2. Clinical Question
Population
The registry concerns mitral valve insufficiency and lists heart valve diseases, heart diseases, and cardiovascular diseases among its conditions. The registry record gives an enrollment of 126, but does not report detailed eligibility criteria or a more specific description of the population assessed for the primary outcome.
Intervention
The intervention under monitoring is the NeoChord DS1000 System, described in the registry record as a CE Marked NeoChord Artificial Chordae Delivery System. The record’s stated purpose is to monitor its long-term performance. The primary outcome, however, is assessed from the procedure through hospital discharge, approximately 1 day.
Comparator
No comparator is specified in the posted record. Allocation is not stated, and the registry entry does not describe a randomized comparison. The record therefore does not establish a like-for-like control group against which to compare procedure success or safety.
Primary question
The registered primary question is whether a participant has at least one neochord placed using the DS1000 System and has mitral regurgitation reduced to at most 2+ at the time of the procedure. Both conditions are part of the definition. The registry record does not report an analysed success count or rate, so the question is registered but its result cannot be assessed from the posted outcome data.
3. Trial Design
The NeoChord TACT Post-Market Surveillance Registry, NCT01784055, is a post-market registry for the NeoChord DS1000. Its stated purpose is to monitor long-term performance of the CE Marked system. The record lists NeoChord as sponsor, an enrollment of 126, a start date of 2013-03, primary completion in 2016-07, and status as completed.
The record lists one primary outcome measure: procedure success. Its assessment window runs from the procedure through hospital discharge, described as approximately 1 day. That short outcome window should be distinguished from the registry’s stated broader aim of monitoring long-term performance. The available primary-outcome description does not report a long-term endpoint or a long-term result.
The registry record does not state allocation, and it does not describe a randomized comparison. It lists an overall safety group rather than treatment and control groups. No like-for-like control comparison is reported, so the record cannot by itself separate outcomes associated with the procedure from other influences or support a comparative treatment effect.
Enrollment is a registry characteristic, not a reported count of participants who met the primary outcome definition or were included in a particular analysis. The registry record does not report the primary-outcome analysis population, the number assessed, or how missing assessments were handled. It also does not report a statistical analysis plan or sample-size justification. The completed status and completion date describe the registry record, but do not establish that every planned analysis or follow-up result is posted.
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
| Stage | Overall |
|---|---|
| STARTED | 126 |
| COMPLETED | 100 |
| NOT COMPLETED | 26 |
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.
| Characteristic | Unit | Overall |
|---|---|---|
| Participants analysed | 126 | |
| Age, Continuous | years | 66 (SD 14) |
| Sex: Female, Male: Female | Participants | 34 |
| Sex: Female, Male: Male | Participants | 91 |
| Race and Ethnicity Not Collected | Participants | — |
6. Primary Endpoint
The registry lists the primary outcome as Procedure Success, measured over The patient will be evaluated from the procedure through the hospital discharge. Approximately 1 day..
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is titled Procedure Success and is recorded as a count of participants. Success is defined by two conditions: at least one neochord must be placed using the DS1000 System, and mitral regurgitation must be reduced to at most 2+ at the time of the procedure. A participant must satisfy both elements to meet the stated definition. The registry specifies assessment from the procedure through hospital discharge, approximately 1 day.
A binary endpoint turns a participant’s outcome into a category: the definition is met or it is not. Counting participants who meet a clear procedural definition can make the outcome straightforward to describe. Combining device placement with a specified degree of regurgitation reduction also makes clear that placement alone is not sufficient for success under this definition.
This endpoint addresses an immediate procedural result. It does not, by itself, measure durability, later symptoms, longer-term function, or other outcomes. Although the registry’s overall purpose refers to long-term performance, the listed primary outcome has the short assessment window. The registry record does not report the observed count or rate meeting the definition, nor an estimate of its precision. Therefore, the endpoint’s definition can be interpreted, but its observed result cannot be evaluated from the posted primary-outcome information.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The record identifies procedure success as the primary outcome but does not report an analysed result for it. In particular, no number of participants meeting the definition, rate, confidence interval, or statistical test is reported in the registry record. The endpoint can therefore be described, but the posted primary-outcome information does not show how often it was met or how precisely that frequency was estimated.
The definition requires both at least one neochord placement using the DS1000 System and mitral regurgitation reduced to at most 2+ at the time of the procedure. This matters for interpretation: a result based on placement alone would not answer the registered question. The stated assessment window extends through hospital discharge and is approximately 1 day. It is not a long-term measure, even though the registry’s stated purpose is to monitor long-term performance.
The posted safety information reports an overall group with 126 participants at risk for serious adverse events and 37 affected. For other adverse events, the record reports 126 at risk and 9 affected. It also records 7 deaths. These are descriptive registry counts. The record does not provide a randomized comparator, an allocation method, or a like-for-like control comparison. Consequently, these figures do not establish whether an event was caused by the device or procedure, and they do not quantify a comparative risk.
The serious adverse-event terms listed include Other cardiac complication at 11.9%, Valve intervention at 10.3%, Procedural complication at 4.8%, Renal dysfunction at 3.2%, Respiratory complication at 3.2%, and Infection at 2.4%. The registry record does not explain in the posted information how these categories relate to one another, whether participants could appear in more than one category, or the denominator used for each percentage. They should be read as reported descriptive entries, not combined into a new total.
Any sample-size figures associated with the posted material are planning illustrations, not observed power. The stated illustration uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a fraction of the observed effect. The record does not report a randomized comparison or a primary-outcome effect estimate that would support a substantive comparison. The illustration should not be mistaken for evidence that a comparison was conducted or that the chosen assumptions were part of the registry’s design.
Overall, the record establishes the registered question, the follow-up window, and some safety counts, but it does not report a primary-outcome analysis. That distinction limits interpretation: an endpoint definition is not a result, and a completed registry status does not fill in the missing outcome estimate.
9. Statistical Methods Explained
What does a count of participants mean?
The primary outcome is recorded as a count of participants. For a binary endpoint, each participant is classified according to whether the registered definition is met. A count describes how many participants meet the definition; a rate or proportion relates that count to an appropriate analysis denominator. The registry record reports neither a primary-outcome count nor a rate or denominator for an analysis. Enrollment of 126 should not be substituted for an analysis denominator without a report stating that all enrolled participants were assessed and included.
The definition combines two conditions. At least one neochord must be placed using the DS1000 System, and mitral regurgitation must be reduced to at most 2+ at the time of the procedure. This is a conjunctive rule: meeting just one condition does not satisfy the registered endpoint. For the result to be reproducible, the record would ideally make clear how each component was assessed and how participants with incomplete assessments were classified. Such details are not reported in the registry record.
What does the time window imply?
The primary outcome is assessed from the procedure through hospital discharge, approximately 1 day. The window defines when the endpoint is evaluated and helps prevent an immediate procedural outcome from being confused with later follow-up. A short window can answer a question about the procedure and discharge period, but it cannot by itself describe durability or outcomes beyond that period. Although the registry’s stated aim refers to long-term performance, the posted primary outcome is limited to this immediate window.
How should a confidence interval be read?
General statistical explanation: a confidence interval expresses uncertainty around an estimated quantity under the method used to construct it. For a binary outcome, an interval around a proportion can show how compatible the data are with a range of underlying rates. A narrow interval indicates greater precision than a wide interval, but neither width nor the point estimate alone establishes causation. The registry record does not report a primary-outcome estimate or confidence interval, so no precision assessment for procedure success can be made from the posted outcome information.
General statistical explanation: precision depends on the amount of usable information and on the outcome’s variability. The enrolled count alone is not enough to establish precision when the analysis population, outcome count, and handling of missing observations are not reported. No confidence limits should be inferred from enrollment alone.
What do the adverse-event counts tell the reader?
The overall safety group reports 126 at risk and 37 affected for serious adverse events, alongside 126 at risk and 9 affected for other adverse events. The record also reports 7 deaths. These entries are descriptive counts; the posted information does not give a comparison group or explain the relationship between the categories. The listed serious adverse-event terms are accompanied by reported percentages, but the record does not state the denominator for each term or whether categories overlap. It would therefore be inappropriate to add the categories or reinterpret them as mutually exclusive participant outcomes.
General statistical explanation: an event rate needs a clearly defined numerator and denominator. Comparisons of rates also require compatible definitions, follow-up periods, and populations. Without a suitable comparator, descriptive event counts cannot show whether event frequency differs from what would have occurred under another treatment or without the procedure. Nor do counts alone establish that the procedure caused an event.
What is the role of the sample-size illustration?
The stated sample-size assumptions describe a planning illustration, not an observed-power calculation. They specify a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect to detect expressed as a stated fraction of the observed effect. The stated convention is participants per arm for outcomes other than time-to-event outcomes, for which the illustration gives a total number of events.
General statistical explanation: a planning calculation asks what amount of information might be needed to detect an assumed effect under specified assumptions. It does not show that the effect is true, that the study was designed around it, or that a study had a particular probability of success after its results were observed. Here, the registry record does not report a primary-outcome effect estimate or a randomized comparison. The record also does not report its own sample-size justification. The planning assumptions should therefore remain separate from the registry’s design and from the unreported primary-outcome result.
What can be inferred from the analysis record?
The record lists one outcome measure and zero analyses. This supports a narrow conclusion: the registry record describes an outcome but does not post an analysis for it. It does not establish why the analysis is absent, whether analyses were performed outside the record, or whether additional analyses were planned. Those details are not reported in the registry record. In general, an outcome definition, a completed status, and an analysis result are distinct kinds of information; one should not be taken as a substitute for another.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists one outcome measure and zero analyses. It identifies procedure success as the primary outcome, but does not report an analysed result for that endpoint. The record does not state whether additional outcomes were assessed outside the posted record, whether there were planned interim analyses, or what multiplicity strategy was used. These details are not reported in the registry record.
Multiplicity concerns arise when several outcomes, time points, subgroups, or statistical tests are examined. General statistical explanation: conducting many tests can increase the chance that at least one result appears noteworthy by chance unless the analysis plan accounts for the testing structure. The record does not provide enough information to determine whether such adjustments were relevant or made. The presence of one registered outcome measure does not establish that only one analysis was contemplated.
The record does not describe missing-data handling for the primary outcome. It does not state how many participants had an assessable procedure-success outcome, how incomplete assessments were treated, or whether any analysis population differed from enrollment. Enrollment of 126 is therefore not an adequate substitute for the missing analysis denominator. General statistical explanation: missing outcome information can affect an estimate if participants with missing data differ from those with observed data, and the direction or size of that effect depends on the missingness pattern and analytic approach. Neither is described in the registry record.
The registry record also does not identify an intention-to-treat, per-protocol, or other named analysis population for procedure success. It does not report protocol deviations or rules for including participants in the endpoint analysis. These omissions prevent assessment of how the analysis population was defined, not just how large it was.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Overall | 37 | 126 | 29.4% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Overall | 7 of 126 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Overall | 9 of 126 |
Most frequent serious adverse event terms
| Event term | Organ system | Overall |
|---|---|---|
| Other cardiac complication | Cardiac disorders | 15 of 126 |
| Valve intervention | Surgical and medical procedures | 13 of 126 |
| Procedural complication | Injury, poisoning and procedural complications | 6 of 126 |
| Renal dysfunction | Renal and urinary disorders | 4 of 126 |
| Respiratory complication | Respiratory, thoracic and mediastinal disorders | 4 of 126 |
| Infection | Infections and infestations | 3 of 126 |
| Neurological complication | Nervous system disorders | 3 of 126 |
| Regurgitation | Cardiac disorders | 2 of 126 |
| Dyspnea | General disorders | 2 of 126 |
| Peripheral vascular complication | Vascular disorders | 2 of 126 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Overall |
|---|---|---|
| Regurgitation | Cardiac disorders | 9 of 126 |
Serious events with the highest arm-level rate: other cardiac complication (11.9%), valve intervention (10.3%), procedural complication (4.8%), renal dysfunction (3.2%), respiratory complication (3.2%).
The overall safety group reports 126 participants at risk for serious adverse events and 37 affected. For other adverse events, it reports 126 at risk and 9 affected. The record separately reports 7 deaths. These are descriptive figures from the registry record; they do not provide a comparison with a control group or establish that an event was caused by the device or procedure.
The listed serious adverse-event terms and reported percentages are Other cardiac complication, 11.9%; Valve intervention, 10.3%; Procedural complication, 4.8%; Renal dysfunction, 3.2%; Respiratory complication, 3.2%; and Infection, 2.4%. The record does not state the denominator for each percentage or whether a participant could be represented in more than one term. The terms should not be added or interpreted as mutually exclusive categories.
General statistical explanation: adverse-event counts describe what was recorded during the defined observation process. Interpreting them as risks or comparing them with another group requires clear definitions, denominators, follow-up periods, and comparable populations. The posted safety entries do not supply a like-for-like control comparison, so they describe reported events rather than a comparative safety effect.
12. What the Result Does, and Does Not, Mean
The record’s main statistical contribution is to define a procedure-success outcome for the NeoChord DS1000 System and to post descriptive safety information. Procedure success requires both at least one neochord placed and mitral regurgitation reduced to at most 2+ at the time of the procedure. The assessment period is from the procedure through hospital discharge, approximately 1 day. Those details clarify what the endpoint would count and when it would be assessed.
The record does not report an analysed result for the primary outcome. It therefore does not show the number or rate of participants meeting the success definition, nor the uncertainty around such an estimate. Without that information, readers cannot use the posted primary outcome to judge the observed frequency of the defined result. The registry’s completed status does not provide the missing estimate.
The safety counts and adverse-event terms are descriptive. With allocation not stated and no like-for-like control comparison, they cannot establish comparative risks or attribute events to the device or procedure. The registry record does not report the relationship among the listed adverse-event categories or the denominator for each listed percentage. These limitations constrain interpretation of the safety entries.
The record also does not establish long-term performance from the primary endpoint, because the stated primary-outcome window is approximately 1 day. Its broader monitoring purpose should not be mistaken for evidence that longer-term outcomes are posted in the available record. Nor can the posted information establish a causal effect: a registry description and a set of counts do not, without an appropriate comparison and analysis, show what would have happened under an alternative approach.
In short, the registry record supports interpretation of the registered endpoint definition, timing, enrollment, status, and reported safety entries. It does not support a conclusion about the observed primary-outcome result, its precision, or comparative effectiveness or safety. Those are not reported in the registry record.
13. Why This Trial Matters Statistically
This registry illustrates why outcome definitions and outcome results must be read separately. Procedure success has a specific operational definition: at least one neochord placed using the DS1000 System together with mitral regurgitation reduced to at most 2+ at the time of the procedure. The definition says what would count as success, but the record does not report how many participants met it. Statistical interpretation depends on both a well-defined measure and a result with a denominator and an assessment of uncertainty.
The timing also matters. The registered endpoint runs from the procedure through hospital discharge, approximately 1 day, while the stated purpose refers to long-term performance. Keeping those concepts distinct prevents an immediate procedural outcome from being read as evidence about longer-term performance. The posted primary outcome cannot answer questions beyond its stated window.
The safety entries show another important distinction: descriptive event counts are not comparative effects. The record gives overall counts and selected serious adverse-event terms, but does not describe a randomized comparator or allocation method. Without a like-for-like comparison, counts can describe what was recorded but cannot isolate the contribution of the device or procedure.
Finally, the record reports a completed registry but zero analyses. Completion status, enrollment, outcome definitions, and analysed findings are separate record elements. A completed status does not ensure that every endpoint result is posted. For readers assessing clinical evidence, recognizing which elements are present and which are not is essential to avoid overstating what a registry record can establish.
14. 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 primary limitation is that the registry record does not report an analysed result for its primary outcome. No procedure-success count, rate, analysis denominator, or confidence interval is posted. This prevents an assessment of the observed endpoint frequency and its precision, despite the outcome being clearly named and defined.
The record’s primary outcome is short-term: assessment runs from the procedure through hospital discharge, approximately 1 day. The registry’s stated aim is to monitor long-term performance, but the posted primary outcome does not itself establish long-term performance. The record does not report a long-term primary outcome result.
Allocation is not stated, and the record does not describe a randomized comparison or a like-for-like control group. This limits interpretation of safety counts and prevents a comparative estimate from being inferred. The record also does not report the analysis population, missing-data approach, detailed eligibility criteria, or how the adverse-event category percentages were calculated. It does not explain whether the listed safety categories can overlap.
The registry record lists an enrollment of 126, but does not show how many participants contributed data to a primary-outcome analysis. The record does not report a sample-size justification, statistical analysis plan, multiplicity approach, or details of interim analyses. Such details are not reported in the registry record; their absence from the posted information should not be filled by assumptions.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: NeoChord TACT Post-Market Surveillance Registry — NCT01784055.
- Registry record last updated 2018-04-02; status last verified 2017-08.
- Results first posted 2018-04-02.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT01784055 is the NeoChord TACT Post-Market Surveillance Registry, sponsored by NeoChord. The record describes monitoring of the CE Marked NeoChord DS1000 System, lists an enrollment of 126, and is marked completed. Its start date is 2013-03 and its primary completion date is 2016-07.
The registered primary outcome is Procedure Success, defined by at least one neochord placed using the DS1000 System and mitral regurgitation reduced to at most 2+ at the procedure. The assessment window is through hospital discharge, approximately 1 day. The registry record lists one outcome measure and zero analyses, and does not report a primary-outcome result.
The overall safety entries report 37 affected among 126 at risk for serious adverse events, 9 affected among 126 at risk for other adverse events, and 7 deaths. No randomized comparison or allocation method is reported. The safety entries are descriptive and do not establish comparative or causal effects.