Chronic Total Occlusion Percutaneous Coronary Intervention Study: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Chronic Total Occlusion Percutaneous Coronary Intervention Study (NCT03988166), a na na study. The primary outcome is Number of Participants With Procedure Success.

2. Clinical Question

This question combines a procedural finding with a short-term safety condition. It is not simply a question about whether a guidewire crossed the occlusion: a participant must also have no in-hospital MACE under the registry definition. MACE includes cardiac death, target lesion revascularization, or post-procedural myocardial infarction (MI), with Q-wave or non-Q-wave MI defined using creatine kinase with Muscle (M)-Brain (B) subunits > 3 ULN.

The study objective is to evaluate angiographic confirmation that a guidewire is positioned in the true vessel lumen beyond the CTO during the specified PCI procedures. The primary outcome therefore addresses both guidewire position and the absence of the listed in-hospital events. The registry record does not report a primary outcome count or proportion, so the endpoint’s observed result cannot be described from this record.

3. Trial Design

The study is titled Chronic Total Occlusion Percutaneous Coronary Intervention Study and is registered as NCT03988166. The registry lists Vascular Solutions LLC as the sponsor, the study status as COMPLETED, and enrollment as 150. The recorded start date is 2020-05-20, and the primary completion date is 2021-02-22. The phase is listed as NA.

The design is recorded as SINGLE GROUP, with allocation listed as NA and masking listed as NONE. Thus, the record describes one group undergoing CTO PCI rather than a randomized comparison between treatment groups. There is no like-for-like control group in the registry record. Without a comparator, the study design does not estimate a difference between the specified procedure and another procedure or device strategy.

The arm description identifies CTO PCI in which at least one Teleflex guidewire and at least one Turnpike catheter are used. The listed interventions include the procedure, Chronic Total Occlusion Revascularization, and the devices GuideLiner® V3 catheter, TrapLiner® catheter, and Turnpike® catheter. The description does not say that each listed device was used in every participant.

The primary endpoint is measured through discharge, up to 24 hours post-procedure. It is a count of participants meeting the registry’s combined definition of procedure success. Five secondary outcomes are named: successful recanalization, in-hospital MACE, clinically significant perforation, procedural success according to crossing technique, and technical success. The record lists six outcome measures in total.

The registry record does not report a detailed protocol, eligibility criteria, recruitment setting, procedure-specific variations, or the rationale for the enrollment figure. It also does not report a statistical analysis plan. Although the study is marked COMPLETED, the primary result and the results for the named secondary outcomes are not reported in the registry information used for this interpretation.

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:

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: Evaluation of procedural and in-hospital outcomes among 150 patients undergoing attempted CTO revascularization utilizing specialized guidewires, microcatheters and guide extensions.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Procedure Success, measured over Through Discharge up to 24 hours post-procedure.

The primary endpoint is the number of participants with procedure success through discharge, up to 24 hours post-procedure. Success has two components: angiographic visualization of any guidewire in a position beyond the occlusion, distal or proximal depending on the route of access, and no in-hospital MACE. A guidewire position alone is therefore not sufficient under the stated definition.

MACE is defined as a serious adverse experience that includes cardiac death, target lesion revascularization, or post-procedural MI. MI may be Q-wave or non-Q-wave and is specified as having creatine kinase with Muscle (M)-Brain (B) subunits > 3 ULN. These details define which events affect the endpoint; they should not be replaced with a broader or narrower clinical definition when interpreting the result.

A binary participant count is useful for describing how many participants satisfy a prespecified outcome definition. It makes the endpoint directly interpretable as a count, while a proportion can describe the count relative to an eligible denominator if the necessary data are available. The registry information for this analysis gives the endpoint definition but does not report the number meeting it, a denominator for the primary outcome, or an estimated proportion.

Because the endpoint combines a technical angiographic criterion and an in-hospital safety criterion, it represents a composite of procedural and clinical conditions. A composite can summarize several requirements in one outcome, but its interpretation depends on knowing which component events occurred and how the endpoint was counted. The primary component-level results are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry lists the primary outcome as a count of participants with a binary event: meeting the specified procedure-success definition. This kind of endpoint assigns each participant to whether the defined condition was met. The reported count is easiest to interpret when accompanied by the number of participants assessed, because the count alone does not convey the fraction of the study group represented. Neither a primary success count nor its denominator is reported in the registry record.

What does a confidence interval describe?

In general, a confidence interval expresses the uncertainty around an estimate under the statistical method used. For a participant proportion, it conveys a range of values compatible with the observed data and method; it is not a guarantee that the true value lies within that interval. The width depends on the amount and pattern of information in the data as well as the method. No primary estimate or confidence interval is reported in the registry record, so the precision of the primary result cannot be assessed.

What can a single-group design estimate?

In general, a single-group study can describe outcomes among participants who underwent the specified procedure. It does not, by itself, estimate a between-group treatment effect because no separate comparator is included. A result from this design is also not automatically a causal estimate: differences in who enters the study, how the procedure is performed, and how outcomes are assessed can shape the observed outcome. For this study, the registry identifies a SINGLE GROUP design and allocation as NA.

The record also lists masking as NONE. Masking concerns whether people involved in a study are kept unaware of assigned interventions or outcomes; with no masking listed, the registry does not describe blinded assessment. The record does not give further details about outcome adjudication or who assessed angiographic guidewire position. Those details can matter for outcomes that involve interpretation of procedural images or clinical events.

Why do endpoint definitions matter?

A binary endpoint depends on a clear rule for classifying participants. Here, the rule combines angiographic evidence of a guidewire beyond the occlusion with no in-hospital MACE through discharge, up to 24 hours post-procedure. The event definition includes cardiac death, target lesion revascularization, and post-procedural MI meeting the stated enzyme criterion. If a participant meets the guidewire criterion but experiences a qualifying MACE, that participant would not meet the complete success definition. This is a general implication of a conjunctive endpoint definition, not a report of any individual participant’s outcome.

Composite endpoints can provide a concise summary of multiple conditions, but the overall count does not show which component most often determines the outcome. Component counts help clarify the clinical and procedural composition of a composite. The registry names secondary outcomes that include MACE and technical success, but it does not report their results or component-level counts in the information available for this interpretation.

How should planning calculations be read?

In general, sample-size calculations depend on assumptions about the target effect, significance level, allocation, and statistical model. A planning calculation is an illustration of the amount of information a future study might require under its stated assumptions; it is not an observed result and is not observed power. The registry record does not report a sample-size justification for the trial’s design. Any calculations based on a stated fraction of an observed effect should be understood as planning illustrations rather than as the study’s original design rationale.

The planning assumptions described in the registry record use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. They define the effect to detect as a stated fraction of the observed effect. Those assumptions describe a two-arm planning framework, while this registry study is recorded as single-group. They therefore should not be mistaken for the trial’s design or for evidence that a two-arm comparison was conducted. The record does not report an observed primary effect estimate on which to base an independent interpretation of such planning scenarios.

For binary outcomes, a comparison between groups would ordinarily require each group’s event count and denominator, along with a defined effect measure and uncertainty estimate. Those quantities are not reported for the primary outcome here, and there is no comparison group. No unadjusted re-calculation or treatment contrast can be supported from the registry information. More generally, a statistical method cannot recover missing outcome results or create a comparator that the design did not include.

Finally, analytic choices such as how to handle missing endpoint observations, which participants are included in each analysis, and whether results are adjusted for other variables can affect interpretation. The registry record does not report these methods. Without such details and without outcome estimates, the central statistical reading is descriptive: the design and endpoint are specified, but the endpoint result and its precision are not reported.

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("Chronic Total Occlusion Percutaneous Coronary Inte")
n      <- c(150)
events <- c(121)
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  Chronic Total Occlusion Percutaneous Coronary Inte  150  121  80.7  73.4  86.7  73.6  86.2  73.6  86.2

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists six outcome measures in total: the primary procedure-success endpoint and five named secondary outcomes. Considering several outcomes can raise a multiplicity question because repeated statistical tests may increase the chance of at least one apparently noteworthy result under a common null hypothesis. In general, a prespecified testing hierarchy or adjustment can address some multiplicity concerns, while clearly labeling secondary or exploratory outcomes can help readers interpret them. The registry record does not report a multiplicity strategy, testing hierarchy, or statistical plan.

The record lists zero analyses. This does not establish that no analyses were performed; it means that analyses are not reported in the registry information available for this interpretation. No outcome estimates, hypothesis tests, or confidence intervals are included for the primary or secondary outcomes. The record therefore does not support an assessment of statistical significance or of how multiple outcomes were handled in any analysis.

Missing-data handling is not reported in the registry record. It does not state whether all participants had endpoint assessments, how unavailable angiographic or clinical information was treated, or whether any imputation or sensitivity analysis was used. For a binary endpoint, missing observations can affect both the event count and the denominator, so the analysis population and missingness rules are important for interpreting a result.

The analysis populations are also not reported. The registry record does not specify whether the primary analysis included all enrolled participants, only participants who received the described procedure, or another defined group. The enrollment entry alone does not identify the number analyzed for the primary outcome. These omissions limit reproducibility and prevent a reader from determining how the endpoint count would relate to all participants entered into the study.

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

Serious events with the highest arm-level rate: myocardial infarction (mi) (18.0%), myocardial infarction (6.0%), death (0.7%), target lesion revascularization (0.7%).

The adverse-event record lists 150 participants at risk for serious adverse events and 38 participants affected in the study group. It separately lists 150 at risk for other adverse events and 0 affected. The record also lists deaths as 1. These are safety entries, not the primary procedure-success result, and they do not provide a comparison with another group.

The serious-event terms listed include Myocardial Infarction (MI) at 18.0%, Myocardial Infarction at 6.0%, Death at 0.7%, and Target Lesion Revascularization at 0.7%. The two myocardial-infarction labels appear separately in the registry record; the information available does not explain how the labels relate or whether their records overlap. They should not be combined or treated as mutually exclusive categories without further information.

Counts of participants affected and listed event terms are not necessarily interchangeable: a participant may have more than one event, and a term-level percentage may use a particular registry denominator or coding convention. The registry information does not explain these details. It also does not provide event timing, severity beyond the serious-event classification, or a breakdown of the primary endpoint by safety component. These figures describe what is recorded, but they do not establish a causal relationship with a device or procedure.

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

The study addresses a specific procedural question: whether angiographic visualization confirms guidewire position beyond a CTO in patients undergoing PCI with at least one Teleflex guidewire and at least one Turnpike catheter. Its primary endpoint adds an in-hospital safety condition to that angiographic criterion. This gives the endpoint a clearly stated procedural and clinical structure.

What the registry record does not establish is the observed frequency of that endpoint. It does not report the primary success count, the endpoint denominator, or an uncertainty interval. The record’s completion status and enrollment entry do not fill those gaps. Accordingly, the outcome cannot be characterized as frequent or infrequent, precise or imprecise, on the basis of the primary results.

The single-group design also defines the scope of any eventual interpretation. Descriptive results could characterize the observed outcomes in this study group, but they would not provide a randomized comparison with another approach. Without a comparator, differences in outcome cannot be attributed to one procedure or device strategy over another using this study alone.

The named secondary outcomes and adverse-event entries provide additional categories of interest, but the secondary outcome results are not reported. The safety information lists serious events and deaths, yet it cannot substitute for the primary endpoint result or establish how events relate to a particular device. The registry does not report enough analytic detail to determine how missing observations, analysis populations, or multiple outcomes were handled.

In general, a registry description can define what investigators intended to measure, while posted results are needed to evaluate what was observed and with what precision. For this study, the outcome definition is available, but the primary result is not reported in the registry record. The strongest defensible interpretation is therefore about the study’s question and design, not about whether the procedure met its stated success criterion at any particular frequency or how it compares with alternatives.

14. Why This Trial Matters Statistically

This study illustrates why a procedural endpoint needs an operational definition. “Procedure success” can otherwise refer to different technical or clinical events. Here, success requires angiographic visualization of a guidewire beyond the occlusion and no in-hospital MACE, with MACE and MI defined in the registry record. The stated rule makes clear that success is not limited to crossing or guidewire position alone.

It also highlights the distinction between describing an outcome and estimating a comparative effect. A single-group study can be relevant for documenting outcomes under specified procedural conditions, but it does not contain a randomized comparator. Readers should therefore distinguish a group’s observed experience, if reported, from evidence that one strategy produces better outcomes than another.

Reporting completeness matters as much as endpoint design. An endpoint definition without an event count, denominator, and uncertainty estimate does not show the observed outcome or its precision. Likewise, named secondary outcomes do not communicate findings unless their definitions and results are reported. In this record, the study status is COMPLETED, but the primary and secondary outcome results are not reported in the available registry information.

The safety entries also demonstrate the need to interpret registry categories cautiously. Affected-participant counts, deaths, and term-level percentages describe different aspects of the record and should not be collapsed into a single summary without clear definitions. Separate event labels may require further coding detail before their relationship can be understood.

Statistically, the central lesson is that design, measurement, and results answer different questions. The record describes a single-group procedural study and a composite success definition. It does not report the primary outcome estimate needed to assess observed success, and its design does not provide a controlled treatment contrast. Clear separation of those points prevents a study objective or registry status from being mistaken for an outcome finding.

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 constrain interpretation. First, the registry records a single-group design, allocation as NA, and masking as NONE. With no control group, the study cannot provide a randomized comparison against another procedure or device strategy. The record does not identify an alternative comparator or report a comparative effect.

Second, the primary endpoint result is not reported in the registry information used for this analysis. The endpoint definition is available, but the number of participants meeting it, the number assessed, and any estimate of precision are not. The secondary outcomes are named but their results are not reported. Consequently, the study’s stated objective cannot be evaluated from the outcome information.

Third, the endpoint is a composite requiring both guidewire visualization beyond the occlusion and absence of in-hospital MACE. The registry does not report component-level primary outcome results or explain which component contributed to any success or non-success classification. The stated timeframe is through discharge, up to 24 hours post-procedure, which limits the endpoint to the specified short-term period.

The information available does not report detailed eligibility criteria, participant characteristics, missing-data rules, analysis populations, outcome-adjudication procedures, or a statistical analysis plan. It also does not report the rationale for enrollment or a sample-size justification for the single-group design. These omissions limit assessment of representativeness, analysis choices, and the intended precision of results.

The safety record includes serious-event counts and listed terms, but it does not explain the relationship between the two myocardial-infarction labels or provide detailed event-level context. These limits do not establish that the study was conducted improperly; they identify information not reported in the registry record and therefore unavailable for a fuller statistical interpretation.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Chronic Total Occlusion Percutaneous Coronary Intervention Study — NCT03988166.
• Registry record last updated 2022-09-28; status last verified 2021-10.
• Results first posted 2022-09-28.
• 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

NCT03988166 is the Chronic Total Occlusion Percutaneous Coronary Intervention Study, sponsored by Vascular Solutions LLC. The registry lists the study as COMPLETED, with enrollment of 150, a start date of 2020-05-20, and a primary completion date of 2021-02-22. Phase is listed as NA.

The design is SINGLE GROUP, allocation is NA, and masking is NONE. The study concerns CTO PCI using at least one Teleflex guidewire and at least one Turnpike catheter. The primary endpoint counts participants with angiographic guidewire visualization beyond the occlusion and no in-hospital MACE through discharge, up to 24 hours post-procedure.

The record names five secondary outcomes and lists six outcome measures overall. It reports no analyses, and the primary and secondary outcome results are not reported in the registry information used. The adverse-event record lists 38 participants affected by serious events, 0 affected by other events, and 1 death; these safety entries do not replace the missing primary endpoint result.