A Feasibility Study of the Cordis Neurovascular Self Expanding Stent System in Intracranial Arteries: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Feasibility Study of the Cordis Neurovascular Self Expanding Stent System in Intracranial Arteries (NCT00349908), a non-randomized phase 1 study. The primary outcome is Technical Feasibility- Successful Stent/Coil Placement (Post Procedure).

2. Clinical Question

The study’s stated purpose was to assess the safety of treating patients with a self-expanding stent in intracranial arteries. Its primary outcome focused on technical feasibility: successful placement of the product assessed immediately after the procedure. The record also lists evaluation of adverse events as a secondary outcome for each group, analyzed separately.

These questions describe feasibility and safety monitoring rather than a comparison of the device against another treatment. Because both groups received the same device and were defined by different conditions, any difference between their results would not isolate a treatment effect. The registry record does not report a comparative analysis or a result for the primary endpoint.

3. Trial Design

This was a Phase 1, completed study with a nonrandomized, parallel-group design and no masking. The registry lists enrollment of 20 participants. The two arms were the Atherosclerosis Arm and the Aneurysm Arm, and each arm description specifies implantation of the Cordis Neurovascular ENTERPRISE Self Expanding Stent System. The sponsor was Codman & Shurtleff.

The listed study start was 2006-09 and the primary completion was 2008-10. The status is completed. These dates describe the registry record; additional details about recruitment, follow-up duration, or the timing of all study activities are not reported in the registry record.

The groups were organized by condition, not by randomized assignment to alternative treatments. There is no listed untreated, standard-care, or alternative-device arm. Although the record lists adverse-event data separately for each group, these are not like-for-like control groups: their defining conditions differ, and both received the same device. Any contrast between group counts would therefore be descriptive rather than a randomized estimate of a treatment effect.

The record lists seven outcome measures and zero analyses. It names technical feasibility as the primary outcome and evaluation of adverse events as a secondary outcome in both groups. The primary outcome is assessed immediately postprocedure; the registry does not specify the timing or duration for the secondary adverse-event evaluation in the registry record. The protocol’s detailed eligibility criteria, recruitment approach, follow-up schedule, and statistical analysis plan are not reported in the registry record.

The reported enrollment and the group-specific adverse-event populations indicate a small feasibility study. Such a design can describe whether procedures were attempted and what events were recorded, but its interpretation depends on complete outcome reporting and clear definitions. The registry record does not give enough information to establish how the study population was selected, how outcome assessments were performed, or whether additional participants or outcome data were excluded from analyses.

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.

Before assignment: This is a device study, there was no wash out or run-in phase for transition.

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.

6. Primary Endpoint

The registry lists the primary outcome as Technical Feasibility- Successful Stent/Coil Placement (Post Procedure), measured over post procedure.

The primary endpoint is titled Technical Feasibility—Successful Stent/Coil Placement (Post Procedure). It measures whether successful placement of the product was achieved, with assessment immediately after the procedure. The stated unit is percentage of stable placement. The endpoint therefore concerns an immediate procedural result, rather than a later clinical outcome.

As a general statistical concept, a technical-feasibility endpoint can describe whether a device procedure reaches its intended procedural milestone. It can help characterize whether placement was achieved in the study setting. It does not, by itself, describe the durability of placement, later health outcomes, or the frequency of complications over a defined follow-up period. Those questions require separately defined outcomes and timeframes.

The registry record does not report the observed value for successful placement, the number of participants included in its calculation, or a confidence interval. It also does not provide a detailed operational definition of stable placement beyond the endpoint wording. Thus, the endpoint’s intended focus is clear, but the posted results do not establish how often the criterion was met or how precisely that frequency was estimated.

The record separately lists evaluation of adverse events as a secondary outcome in both groups. That safety information should not be treated as a substitute for the missing primary-endpoint result: adverse-event counts address a different question from successful placement.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The study is listed as nonrandomized, unmasked, and parallel. These design features shape what statistical conclusions are available. In a randomized comparison, assignment is intended to make treatment groups comparable on average. Here, the groups were defined as an atherosclerosis arm and an aneurysm arm, and both received the same device. The record therefore does not describe a randomized contrast of treatments. Any group-by-group event counts are descriptive, not an estimate of the effect of one treatment versus another.

What does a feasibility endpoint describe?

The primary outcome concerns successful stent or coil placement immediately after the procedure. In general, a feasibility endpoint asks whether a specified procedural task can be accomplished under the study conditions. The registry gives the unit as percentage of stable placement, but does not post the result, the numerator and denominator, or a confidence interval. Without those items, readers cannot assess either the observed frequency or its precision. The word feasibility in the study title does not itself establish that the technical objective was met.

A percentage is a proportion expressed on a percentage scale. In general, its interpretation depends on a clear event definition and a stated analysis population. The record’s endpoint description says successful placement was assessed immediately postprocedure, but additional operational details are not reported in the registry record. It is not stated how borderline or unsuccessful placements were classified, or how participants without an evaluable procedure were handled.

Why does the design limit comparison?

The Atherosclerosis Arm and Aneurysm Arm have different condition labels. Both received implantation of the same named device. Since allocation was not randomized and no alternative-treatment group is listed, differences in event counts could reflect differences between the groups, differences in clinical circumstances, or other factors; the registry record does not provide information to separate these possibilities. General statistical reasoning therefore supports describing each group separately rather than interpreting their contrast as a device effect.

Masking is listed as none. In general, lack of masking can matter when outcomes involve judgment, because knowledge of treatment or group assignment may affect assessment or reporting. The primary outcome is described as placement assessed after the procedure, but the record does not explain who assessed it or whether the criterion was adjudicated. It would be inappropriate to assume either that assessment was subjective or that assessment bias occurred; the relevant procedures are not reported in the registry record.

What can the adverse-event counts tell readers?

The registry lists participants at risk and participants affected by serious and other adverse events for each group. These counts describe the posted safety information. In general, a participant count answers how many people were recorded with an event under the registry’s definitions; it does not necessarily equal the number of individual event episodes. The record does not describe whether participants could contribute more than one event, how recurring events were counted, or the event-collection window. The listed event terms and percentages also lack a reported denominator definition.

For event frequencies, uncertainty is important. General statistical methods can express uncertainty with confidence intervals, which describe a range of estimates compatible with the data under the method’s assumptions. No such intervals are reported for the primary endpoint or adverse-event figures. Without intervals or a stated analysis, the counts should not be treated as precise estimates of the corresponding rates beyond the study participants.

How should planning calculations be understood?

The stated sample-size assumptions describe planning illustrations based on an observed effect, not the trial’s own design justification. The assumptions include a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is described as a fraction of the observed effect. General statistical interpretation is that such calculations explore how a hypothetical future study might be sized under specified assumptions. They are not observed power and do not show that the completed study had a particular probability of detecting an effect.

The registry record does not report a sample-size justification for the trial itself. The primary endpoint result and its observed effect are also not reported in the registry record, so the planning assumptions should not be mistaken for evidence about the trial’s outcomes. No additional sample-size values or analysis outputs are reported in the registry entries.

What methods remain unknown?

The record lists seven outcome measures and zero analyses, but does not describe the analysis model, estimation method, confidence-interval method, or any hypothesis tests. It does not report how missing data were handled or define analysis populations beyond the adverse-event counts at risk. Details such as prespecified subgroup analyses, interim analyses, stopping rules, and multiplicity procedures are not reported in the registry record. These absences limit reproducibility and make it impossible to determine whether the posted adverse-event summaries represent all enrolled participants under a prespecified approach.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists seven outcome measures, including the primary technical-feasibility outcome and secondary adverse-event evaluation for the two groups, and lists zero analyses. It does not report a statistical analysis plan, a hierarchy of outcomes, or a method for controlling multiplicity. It is therefore not possible to determine whether any outcome was designated for confirmatory inference beyond the primary label, or how multiple comparisons were intended to be handled.

As a general statistical concept, multiplicity arises when several outcomes or tests are considered: the chance of at least one apparently notable result can increase if many tests are conducted without an appropriate plan. This is a general concern, not evidence that such testing occurred in this study. The posted record does not provide analysis results from which to assess it.

Missing-data methods and analysis populations are also not reported in the registry record. The adverse-event summaries identify 10 participants at risk in each group, but do not explain whether every enrolled participant contributed to the primary endpoint, whether any endpoint observations were unavailable, or how any unavailable data were handled. The denominator for the primary endpoint is not reported.

In general, analysis populations define which participants contribute to a particular outcome estimate, while missing-data methods describe how unavailable measurements are treated. Those details affect interpretation and reproducibility. Without them, readers cannot establish whether the outcome summaries include all participants, only those with evaluable procedures, or another population. No assumptions about these methods can be made from the posted record.

11. 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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: myocardial infarction (100.0%), lung tumor (100.0%), ischemic stroke (100.0%), hip fracture (100.0%), stroke/cva: ischemic stroke (100.0%).

The adverse-event record reports serious events affecting 3 of 10 participants at risk in the Atherosclerosis Arm and 3 of 10 in the Aneurysm Arm. Other adverse events affected 8 of 10 participants at risk in the Atherosclerosis Arm and 9 of 10 in the Aneurysm Arm. These are group-specific descriptive counts, and the record says the groups were analyzed separately. It does not report a comparative statistical analysis.

The record also lists serious-event terms with percentages: Myocardial Infarction, Lung Tumor, Ischemic Stroke, Hip Fracture, and Stroke/CVA: Ischemic stroke are each listed as 100.0%; Other: Primitive Left Carotid Ligation is listed as 10.0%. The denominator and the precise meaning of those percentages are not reported in the registry record. The terms should not be interpreted as participant-level risks without that information, and some event labels may describe overlapping concepts.

Deaths are not reported in the registry record. That is different from a reported finding of zero deaths. The adverse-event counts do not establish causation, and the condition-specific, nonrandomized groups cannot serve as a like-for-like control comparison. As a general statistical principle, safety counts from a small feasibility study are descriptive and do not by themselves establish the frequency of events in a broader population.

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

The registry record describes a Phase 1 feasibility study of a self-expanding intracranial stent system in two groups: one with atherosclerosis and one with aneurysm. Both groups received the same device. The study’s stated purpose was to assess safety, and its primary endpoint addressed successful placement immediately after the procedure. The record lists 20 participants overall and reports adverse-event counts for each group.

The primary endpoint result is not reported in the registry record. As a result, the posted information cannot establish the proportion of successful stable placements or the precision of that proportion. The adverse-event summaries document participants affected in each group, but they do not establish whether events were caused by the device. The serious-event term percentages lack a reported denominator definition, and deaths are not reported.

As a general statistical principle, feasibility studies can provide descriptive information about procedures and identify issues for further study. Their interpretation depends on outcome definitions, complete reporting, and clarity about who was analyzed. The record does not supply the primary outcome estimate, confidence intervals, detailed analysis methods, or a randomized treatment comparison. It therefore cannot support a claim that the device improves outcomes, is equivalent to another approach, or has a particular comparative safety profile.

The two groups should not be read as treatment and control. They represent different conditions, both receiving the device, with nonrandomized allocation. A difference in their adverse-event counts would not isolate the influence of the device. Nor should the absence of a posted primary result be treated as a negative result: it means the registry record does not state that result.

The defensible interpretation is narrow. The record describes the study design, identifies the intended procedural endpoint, and supplies group-specific adverse-event counts. It leaves important questions unresolved, including the primary placement result, event definitions and denominators, follow-up, missing data, and analysis methods. Those limits constrain conclusions about both feasibility and safety.

13. Why This Trial Matters Statistically

This study is statistically relevant because it illustrates the difference between defining a feasibility outcome and reporting an interpretable estimate for that outcome. The registry specifies immediate postprocedure successful placement as the primary endpoint and gives its unit as percentage of stable placement. Yet the result itself is not reported in the registry record. A clearly named endpoint is useful, but readers also need the observed result, its denominator, and information about uncertainty to evaluate what the study found.

The design also demonstrates why group labels matter. The atherosclerosis and aneurysm groups are not randomized treatment arms, and both received the same device. Describing adverse events separately is appropriate to the record’s stated setup, but a contrast between those groups would not be a controlled estimate of device effects. Statistical interpretation must follow the design rather than treating any two listed groups as interchangeable comparison arms.

The safety figures show another important reporting issue: participant counts, event terms, and percentages do not necessarily have the same denominator or unit of analysis. The record gives counts of participants affected, lists serious-event terms with percentages, and does not define the percentages’ denominators. Clear definitions are needed to distinguish participants from event episodes and to understand whether a person could contribute more than one event.

More broadly, the record lists multiple outcomes but no analyses. The absence of a reported analysis plan, missing-data approach, or precision estimates limits reproducibility and the strength of statistical interpretation. These are not merely technical details: they determine what the estimates mean, which observations contribute, and how uncertainty should be understood. The study is a useful example of why transparent outcome reporting and design-aware interpretation are essential in clinical research.

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 for interpreting the study’s main question is that the registry record does not report the primary endpoint result. The record identifies immediate postprocedure successful placement and its stated unit, but gives no estimate, denominator, or confidence interval. The definition of stable placement is not elaborated beyond the endpoint description.

The study is nonrandomized and has no masking. Its two groups differ by condition and both received the same device, so they do not provide a like-for-like control comparison. The record does not give detailed eligibility criteria, baseline characteristics, or information that would allow readers to assess how comparable participants were within or between groups.

Safety interpretation is limited by the absence of event definitions, follow-up duration, and denominator details for the listed serious-event percentages. The record does not explain whether the event summaries count participants, event episodes, or both, nor how repeated or overlapping events were handled. Deaths are not reported in the registry record, which cannot be interpreted as a finding of no deaths.

The analysis methods, analysis populations, missing-data procedures, and multiplicity plan are not reported in the registry record. Although seven outcome measures and zero analyses are listed, the record does not explain how outcomes were prioritized or whether all intended results were posted. The registry information also does not report the trial’s sample-size justification. These limitations leave uncertainty about outcome completeness, precision, and the scope of any conclusions drawn from the study.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: A Feasibility Study of the Cordis Neurovascular Self Expanding Stent System in Intracranial Arteries — NCT00349908.
• Registry record last updated 2014-06-30; status last verified 2014-05.
• Results first posted 2013-10-11.
• 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.

18. Record Summary

The registry describes NCT00349908, A Feasibility Study of the Cordis Neurovascular Self Expanding Stent System in Intracranial Arteries. It is listed as a completed Phase 1, nonrandomized, unmasked, parallel-group study sponsored by Codman & Shurtleff. The listed study start was 2006-09, primary completion was 2008-10, and enrollment was 20.

The Atherosclerosis Arm and Aneurysm Arm both received implantation of the Cordis Neurovascular ENTERPRISE Self Expanding Stent System. The primary outcome was successful stent or coil placement assessed immediately postprocedure, expressed as percentage of stable placement. Its result is not reported in the registry record. Secondary outcomes addressed adverse events by group. Serious adverse events affected 3 participants in each group; other adverse events affected 8 in the Atherosclerosis Arm and 9 in the Aneurysm Arm. The record lists seven outcome measures and zero analyses. Deaths, detailed statistical methods, missing-data handling, and analysis populations are not reported in the registry record.