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 Coronal Mode Ultrasound Guided Hemodialysis Cannulation: Comparison With Standard Cannulation Technique (NCT02814721), a randomized na study. The primary outcome is Infiltration Due to Dialysis Access Cannulation.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02814721 |
| Phase | NA |
| Condition | Arteriovenous Fistula, Cannulation |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 10 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Henry Ford Health System |
| Results posted | Yes |
2. Clinical Question
Population
People undergoing hemodialysis through a new arteriovenous fistula. The registry describes the study as a single-center pilot, but further eligibility criteria and participant characteristics are not reported in the registry record.
Intervention
Pre-cannulation assessment of the fistula with the Sonic Window coronal-mode ultrasound device, used to evaluate the fistula and identify a cannulation site. The registry describes needle-size escalation over a 3-week period, but the remaining details of the ultrasound-guided protocol are not reported in the registry record.
Comparator
The center’s standard cannulation protocol. It used 17 gauge needles for the first 3 dialysis sessions, 16 gauge for the next 3, and 15 gauge for subsequent sessions.
Primary question
How many infiltration events occurred during 3 weeks from use of the fistula in each randomized group? Infiltration is defined as blood escaping from the fistula because of problems inserting the dialysis needle. The record gives group-level event counts but does not provide an estimable two-arm comparison.
3. Trial Design
This was a prospective, randomized pilot study with a parallel-group design and no masking. The registry describes it as single-center and compares standard cannulation with ultrasound-guided cannulation of new arteriovenous fistulas. The study status is completed. Enrollment is listed as 10; the arm entries report n=4 for standard cannulation and n=5 for ultrasound-guided cannulation. The reason for the difference between the enrollment figure and arm entries is not reported in the registry record, so they should not be treated as interchangeable denominators.
The standard group followed the center’s needle-size escalation protocol: 17 gauge needles for the first 3 dialysis sessions, 16 gauge for the next 3, and 15 gauge for subsequent sessions. The ultrasound-guided group followed a similar up-titration over a 3-week period, with a pre-cannulation fistula evaluation using the Sonic Window device to identify an optimal cannulation site. The available intervention description is incomplete, so further procedural detail is not reported in the registry record.
The primary outcome was the number of infiltration events over 3 weeks from use of the fistula. Patient Pain Scale is listed as a secondary outcome. The method used to generate the randomized allocation, allocation concealment, participant flow, and the analysis population are not reported in the registry record. The record lists 0 analyses, and a statistical analysis plan is not reported. Those omissions limit assessment of how the randomized design was implemented and how the posted counts were selected or analyzed.
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 | Standard Cannulation | Ultrasound Guided Cannulation |
|---|---|---|
| STARTED | 5 | 5 |
| COMPLETED | 4 | 5 |
| NOT COMPLETED | 1 | 0 |
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 | Standard Cannulation | Ultrasound Guided Cannulation | Total |
|---|---|---|---|---|
| Participants analysed | 4 | 5 | 9 | |
| Age, Continuous | years | 52.5 (32.5 to 67.5) | 66 (57 to 70) | 61.5 (35.25 to 68.25) |
| Sex: Female, Male: Female | Participants | 2 | 2 | 4 |
| Sex: Female, Male: Male | Participants | 2 | 3 | 5 |
6. Primary Endpoint
The registry lists the primary outcome as Infiltration Due to Dialysis Access Cannulation, measured over 3 weeks from use of fistula.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | infiltration events |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the number of infiltration events attributed to dialysis access cannulation during 3 weeks from use of the fistula. The registry defines infiltration as extravasation of blood from the fistula due to problems with needle insertion. It is therefore an event-count outcome, rather than a measure of the proportion of participants who experienced at least one infiltration or the time until an event.
Counting events can capture repeated occurrences in the same participant, which may be relevant when assessing a cannulation procedure. However, the registry does not report whether the posted counts represent repeated events per participant, how events were identified or verified, or how multiple events in one participant were handled in an analysis. It also does not report an event definition beyond the description of blood escaping from the fistula because of needle-insertion problems.
The endpoint is relevant to the stated study question because it records a complication associated with cannulation difficulty. Its interpretation depends on consistent observation and recording in both groups and on knowing the observation period and population contributing to each count. The record specifies the 3-week timeframe, but details about monitoring, missing event data, and the analysis method are not reported in the registry record. The posted counts should therefore be read as descriptive group summaries, not as a complete estimate of a treatment effect.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry reports 5 infiltration events for standard cannulation, with n=4, and 7 for ultrasound-guided cannulation, with n=5. These are group-level counts for the primary endpoint. The outcome is not reduced to one comparison in the registry record, and values are missing or not estimable for a two-arm comparison. Consequently, the posted results do not provide a comparative effect estimate or its uncertainty. The counts alone do not establish whether the groups differ in a way that can be attributed to the cannulation approach.
These event counts are not equivalent to counts of participants who experienced infiltration. The record does not say whether an individual could contribute more than one event, nor does it report participant-level outcomes. It also does not explain the difference between the registry enrollment of 10 and the arm entries of n=4 and n=5. Without a reconciled account of the analysis population and event recording, the denominators and the relationship between participants and events remain uncertain.
Random allocation is a useful design feature because, in general, it aims to make comparison groups similar with respect to factors that might influence outcomes. But a randomized label does not itself show how the allocation was generated or concealed, and those details are not reported in the registry record. The study was unmasked, so knowledge of the assigned procedure could potentially affect event detection or reporting. Whether that happened cannot be determined from the posted information.
The pilot scale and limited reported information call for a descriptive reading rather than a definitive comparative conclusion. The registry does not report a statistical analysis for the primary endpoint, an interval estimate, or a prespecified decision threshold. No conclusion about a treatment effect’s direction, size, or precision can be drawn from the counts alone. The sample-size rationale and any interim analyses are not reported in the registry record.
Safety entries are also descriptive. The registry lists no serious adverse events, other adverse events, or deaths in either arm. With the limited group sizes and absent detail about surveillance and reporting, those entries do not establish that adverse events are impossible or that safety is equivalent. They state what was recorded for this study.
9. Statistical Methods Explained
The primary outcome is a count: the number of infiltration events recorded during the specified observation period. Counts differ from continuous measurements, such as a pain score, and from binary outcomes, such as whether a participant ever had an event. The correct statistical approach depends on what the count represents, how events arise, whether participants can have repeated events, and whether each participant has the same observation time. The registry identifies the count and timeframe, but does not report the event-level data or analysis method.
What does a count outcome represent?
A group count can be the total of repeated events across participants. It does not reveal how events are distributed: the same total could arise from a small number of participants with repeated events or from more participants with isolated events. Participant-level data would be needed to distinguish those patterns. The registry does not report whether the posted counts are totals of recurrent events or how events were assigned to participants.
In general, count analyses may use models that relate expected event counts to a comparison group. Some approaches account for differences in observation time, and some allow for extra variability beyond a basic count model. Over-dispersion is the general term for count data varying more than a model’s assumptions predict; ignoring it can make uncertainty estimates too narrow. These are general statistical considerations, not methods reported for this trial. The registry does not report a model, an adjustment for exposure time, or an assessment of over-dispersion.
Why is an effect estimate important?
A group count describes what was recorded in that group. A comparative effect estimate expresses how the outcome differs between groups under a defined statistical approach. An uncertainty interval around such an estimate communicates the range of values compatible with the data and method; it is not a guarantee that the true effect falls within that range. The registry record does not provide an estimable two-arm comparison or an interval for the primary outcome. The separate event counts therefore cannot substitute for a comparative estimate with quantified uncertainty.
Nor should the event counts be converted into a participant-level risk without knowing how many participants experienced at least one event. A total event count can include repeated events, and the registry does not say whether that occurred. No risk, rate, ratio, or difference is calculated in this interpretation.
What can randomization contribute?
In general, random assignment is intended to reduce systematic differences between groups at the start of a study. It supports a causal comparison when allocation is implemented appropriately, outcomes are measured consistently, and follow-up and analysis preserve the randomized groups. The record labels the study randomized but does not report the sequence-generation procedure, allocation concealment, or analysis population. The lack of masking is reported. Whether outcome assessment was independent of assignment is not reported in the registry record.
Randomization does not remove uncertainty in a small pilot study, guarantee balance on every characteristic, or compensate for missing outcome information. Baseline characteristics, participant flow, and reasons for any differences between enrollment and arm entries are not reported. These omissions make it difficult to evaluate whether the group summaries represent comparable follow-up and populations.
What does the registry say about analysis?
The record lists 0 analyses and indicates that values are missing or not estimable for a two-arm comparison of the count outcome. It does not report a test statistic, p-value, confidence interval, model, covariate adjustment, or analysis plan. Their absence should not be read as evidence that the groups are the same; it means that an inferential comparison is not available in the registry record.
General principles for interpreting an analysis still apply: the statistical method should match the outcome and design, uncertainty should be reported alongside an effect estimate, and analysis choices should be specified transparently. For an event count, readers would need to know the unit of analysis, whether repeated events were included, how follow-up was handled, and how missing observations were treated. Those details are not reported in the registry record. The posted results are consequently best understood as descriptive counts with substantial limits on comparative interpretation.
10. Multiplicity, Missing Data and Analysis Populations
The record lists Patient Pain Scale as a secondary outcome and reports 2 outcome measures. It does not report whether the primary and secondary outcomes were tested under a prespecified hierarchy, whether any adjustment for multiple testing was planned, or which secondary outcome analyses were completed. Multiplicity is a general concern when many outcomes or analyses are considered: the chance of a seemingly notable result can rise when results are examined repeatedly. No multiplicity procedure is reported in the registry record, so the intended interpretation of any secondary findings cannot be assessed.
For the primary endpoint, the record lists the group counts but says values are missing or not estimable for a two-arm comparison. It does not report an analysis of missing outcomes, the amount or pattern of missing data, or whether all randomized participants contributed to the posted results. The enrollment entry of 10 and arm entries of n=4 and n=5 are not reconciled. Reasons for non-participation, withdrawal, or exclusion are not reported in the registry record.
The record does not identify an intention-to-treat, per-protocol, or other analysis population. In general, an intention-to-treat analysis retains participants in their randomized groups, while other analysis populations may depend on treatment received or protocol adherence. These are general distinctions; no population definition is reported for this trial. Without participant flow, missing-data information, or a specified analysis population, it is not possible to determine how complete the outcome summaries are or how well they preserve the randomized comparison.
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 |
|---|---|---|---|
| Standard Cannulation | 0 | 4 | 0.0% |
| Ultrasound Guided Cannulation | 0 | 5 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Standard Cannulation | 0 of 4 |
| Ultrasound Guided Cannulation | 0 of 5 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Standard Cannulation | 0 of 4 |
| Ultrasound Guided Cannulation | 0 of 5 |
For standard cannulation, the registry lists 0 serious adverse events among 4 at risk, 0 other adverse events among 4 at risk, and 0 deaths. For ultrasound-guided cannulation, it lists 0 serious adverse events among 5 at risk, 0 other adverse events among 5 at risk, and 0 deaths. These entries describe what the registry records for the study; they are not estimates of the frequency of events in a broader population.
A report of no recorded events does not demonstrate that the risk is absent. Interpretation depends on how adverse events were defined, monitored, and collected, and on whether follow-up was complete. Those details are not reported in the registry record. The record also does not provide a comparative safety analysis or uncertainty estimates. The groups’ entries should therefore be read as descriptive safety information, not as evidence that the procedures have identical safety profiles.
Serious adverse events and other adverse events are listed separately from the primary infiltration endpoint. The registry does not report whether infiltration events were also considered adverse events or how the outcome categories were coordinated. No assumption about overlap between endpoint and safety reporting is warranted.
12. What the Result Does, and Does Not, Mean
The posted results show the recorded primary-outcome counts by randomized group: 5 infiltration events for standard cannulation and 7 for ultrasound-guided cannulation. They also show the reported arm entries, n=4 and n=5, respectively, and the registry enrollment of 10. These numbers describe the record; they do not by themselves quantify a treatment effect. The record does not provide a comparative estimate or its precision, and it does not explain the difference between the enrollment figure and the arm entries.
The trial’s randomized, parallel design addresses a relevant procedural question: whether pre-cannulation use of a coronal-mode ultrasound device is associated with different infiltration counts than the center’s standard approach during the stated period. But the available report does not include enough analysis detail to answer that comparative question statistically. Event counts cannot be interpreted as the number of affected participants unless participant-level event information is available.
The findings do not establish that either approach causes more or fewer infiltrations, and they do not establish equivalence. A missing comparative estimate is not a null finding. The record also does not permit conclusions about how precisely the groups’ outcomes were measured or whether follow-up and event ascertainment were complete.
The safety entries report no serious events, other adverse events, or deaths in either group. Those descriptive entries do not prove that the procedures are free of risk, particularly without further reporting about monitoring and follow-up.
As a pilot randomized study, this record offers a small-scale comparison and identifies outcomes of interest, but it does not report a complete inferential analysis. Further details about participant flow, event recording, allocation procedures, and statistical methods would be necessary for a more complete assessment. No clinical recommendation follows from these registry results alone.
13. Why This Trial Matters Statistically
This study is statistically interesting because its primary outcome is an event count rather than a simple participant-level yes-or-no result. Counts can preserve information about repeated events, but they also require clarity about what counts as an event, whether repeat events are included, and how observation time is handled. The registry reports the endpoint definition and timeframe but does not provide those additional details.
It also illustrates why group summaries and treatment comparisons are not the same thing. The record gives a count for each group, but does not provide an estimable two-arm comparison or uncertainty interval. Without an effect estimate and its precision, the counts cannot show how compatible the data are with different possible group differences. This is especially important when the study is described as a pilot and the arm entries are limited.
Randomization is valuable in principle, but its interpretation depends on implementation and reporting. The record identifies randomized allocation, yet does not report sequence generation, concealment, or the population used for analysis. The enrollment and arm figures are also unreconciled. These are not merely administrative details: they help readers understand who contributed outcomes and whether the comparison follows the assigned groups.
Finally, the study demonstrates the value of distinguishing absence of an analysis from evidence of no difference. The registry reports descriptive event counts and no estimable comparison. That is a limitation in what can be concluded, not a finding that the approaches have the same outcome. Clear reporting of participant flow, event-level data, analysis methods, and uncertainty would make a pilot comparison more informative for statistical learning and future study planning.
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 registry record contains limited information for evaluating the primary outcome. It reports group-level infiltration counts but does not describe whether repeat events within a participant were included, how events were verified, or how missing event data were handled. It does not provide participant-level results or a comparative estimate with uncertainty. These gaps prevent assessment of the distribution of events and the precision of any group contrast.
The study is described as a single-center pilot, which limits the information available about performance in other settings. Eligibility criteria and participant characteristics are not reported in the registry record. The registry enrollment is 10, while the arm entries list n=4 and n=5; the discrepancy is not explained. Participant flow and the analysis population are also not reported, making it difficult to establish which randomized participants contributed to the reported counts.
The allocation procedure is described as randomized, but sequence generation and allocation concealment are not reported. Masking is listed as none, while independent outcome assessment is not described. The available ultrasound-guided intervention description is incomplete, so its full implementation cannot be evaluated or reproduced from the record.
The registry lists 0 analyses and does not report a statistical analysis plan, handling of missing data, multiplicity procedures, or interim analyses. It also does not report details of adverse-event collection. These are limitations of the available registry information; they do not establish that procedures were absent from the conduct of the study.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Coronal Mode Ultrasound Guided Hemodialysis Cannulation: Comparison With Standard Cannulation Technique — NCT02814721.
- Registry record last updated 2024-03-01; status last verified 2024-02.
- Results first posted 2024-03-01.
- 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.
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18. Record Summary
The registry record describes a completed, randomized, unmasked, parallel pilot study comparing standard cannulation with Sonic Window ultrasound-guided cannulation for new arteriovenous fistulas. The primary endpoint is the number of infiltration events during 3 weeks from use of the fistula. Patient Pain Scale is listed as a secondary outcome.
The posted primary-outcome counts are 5 for standard cannulation, with n=4, and 7 for ultrasound-guided cannulation, with n=5. The registry lists enrollment of 10 but does not explain the difference from the arm entries. Values are missing or not estimable for a two-arm comparison, and the record lists 0 analyses. No comparative effect estimate or uncertainty interval is reported.
The safety entries list 0 serious adverse events, 0 other adverse events, and 0 deaths in each group. The registry does not report the allocation procedure, analysis population, missing-data approach, or statistical analysis plan. These results are descriptive and do not establish a comparative treatment effect.