Optical Imaging Measurement of Intravascular Solution Efficacy Trial: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Optical Imaging Measurement of Intravascular Solution Efficacy Trial (NCT01743872), a na na study. The primary outcome is Quality of Images.

2. Clinical Question

3. Trial Design

The registry describes the Optical Imaging Measurement of Intravascular Solution Efficacy Trial, sponsored by University Hospitals Cleveland Medical Center. Its condition is peripheral artery disease. The recorded model is single group, allocation is listed as NA, masking is none, and phase is listed as NA. Enrollment is recorded as 23. The study status is completed, with a start date of 2012-09 and primary completion dated 2015-12.

The procedures listed are contrast injection, dextran injection, CO2 injection, and heparinized normal saline injection. The brief description focuses on using different flush media during iOCT imaging of the lower-extremity arterial system. It frames the question around the quality of image acquisition and the measurement of vessel area and diameter. A secondary outcome is plaque composition in the superficial femoral artery by flush medium.

The record does not describe a randomized allocation, and its single-group designation does not establish that the media were assigned as independent, comparable treatment groups. It also does not report the order in which media were used, whether each participant received each medium, or how the procedure sequence was determined. The arm description is incomplete, so details of the imaging procedure beyond those explicitly stated are not available in the registry record.

The record names image quality as the primary outcome, with a timeframe of 1 month. It does not report outcome estimates, variability, or analyses. The completed status indicates the study is recorded as completed; it does not itself supply evidence about the results or their precision.

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

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 Quality of Images, measured over 1 month.

The primary endpoint is image quality, expressed as the proportion of clear imaging fields (CIF). A CIF is defined as a cross section in which at least 270° of the vessel wall architecture is visualized. The registry says that two independent observers, blinded to the flush medium, reviewed OCT frames in each pullback sequence. Each cross section was classified as having quality or insufficient quality, and a quality-image proportion was generated for each run from the observers’ determinations.

This measure is intended to capture how often a run yields cross sections with adequate visualization of the vessel wall. A proportion gives a run-level summary of the frame classifications, rather than treating every frame as a separate participant-level outcome. Such a summary can make image quality comparable across runs, although interpretation still depends on how runs and media are related in the study design.

The registry lists the endpoint parameter as a mean and its dispersion as a standard deviation. These describe the intended summary and spread across observations; they are not outcome values. No mean CIF proportion, standard deviation, or comparison estimate is reported in the registry record.

The investigators also describe measuring segment area and diameter to assess possible effects of index of refraction. Those measurements are distinct from the primary image-quality endpoint. The record does not report results for them either.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The methods information in the registry describes how image quality was defined and assessed, but it does not give a complete statistical analysis plan. The primary outcome is a mean of a continuous measure: the CIF proportion for each run. The listed dispersion measure is the standard deviation. No analysis results or analysis descriptions are reported in the registry record.

What does the endpoint summarize?

A cross section receives a quality designation when at least 270° of vessel wall architecture is visible. Other cross sections are classified as insufficient quality. The classifications are summarized into a proportion for each run. In general, a proportion summarizes the share of observations meeting a defined criterion. Here, the criterion is image visibility, and the run-level proportion is intended to represent the quality of that imaging sequence.

The registry states that two independent observers, blinded to the flush medium, reviewed all OCT frames in each pullback sequence. Blinding means an observer is not told which medium is associated with the images being assessed. In general, blinding can reduce the chance that expectations about a medium influence subjective classification. The record does not report whether blinding was maintained in practice or provide observer-agreement statistics.

The record says that a disagreement greater than 10% was to be addressed through consensus re-evaluation at a later time by the same reviewers. This is a resolution rule for disagreements, not a report of how often disagreements occurred. The registry does not state how many classifications were disputed or whether the rule was triggered. It also does not report an independent adjudicator or other procedures beyond the consensus re-evaluation described.

How should the mean and standard deviation be read?

In general, a mean summarizes the central value of a set of measurements. A standard deviation describes how spread out measurements are around that mean. For this endpoint, these statistics would describe the run-level CIF proportions across the observations included in an analysis. The registry identifies these summary measures but reports no numeric mean or standard deviation. It is therefore not possible to assess the observed level of image quality or the variation among runs from the record.

A confidence interval, in general, represents a range of values compatible with the data under a specified statistical procedure. Its width conveys precision: a narrower interval indicates greater precision than a wider interval. No confidence interval is reported for this outcome. A p-value, in general, measures how surprising data at least as inconsistent with a specified null model would be if that model held. It does not measure the size or clinical importance of an effect. The registry record reports no p-value or hypothesis-test result.

What design information affects comparison?

The registry records a single-group model and allocation as NA. It also notes that this is not a randomized comparison and that the arms are not a like-for-like control comparison. These details matter because statistical comparisons rely on understanding how observations arise. If media were used within the same participant, the analysis might need to account for that pairing; if observations came from separate groups, the relevant dependence structure could differ. The registry record does not say which arrangement applies, or describe the order of media use. No particular analysis can be inferred from the intervention list alone.

Frames from a pullback sequence may be related to one another, and observations from the same run may not behave like independent measurements. In general, treating correlated measurements as independent can make uncertainty estimates misleading. A sound analysis would need to account for the actual unit of observation and the dependence structure. The registry does not report how these issues were handled, so it is not possible to assess the analysis from the record.

What can the planning assumptions establish?

The registry describes a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It describes the effect to detect as a stated fraction of the observed effect. Such calculations are planning illustrations, not observed power and not trial results. The record also identifies a two-arm allocation assumption, while the trial is flagged as not being a randomized, like-for-like comparison. The assumptions therefore should not be taken as proof that the actual study design had those features. The registry record does not report a sample-size justification for the trial itself.

More generally, sample-size calculations depend on the target effect, variability, design, and analysis assumptions. A calculation based on an observed effect is especially dependent on that effect estimate, which may be uncertain. No sample-size illustration can fill the gap left by missing outcome results or establish what the trial found.

In summary, the registry provides a definition of the image-quality endpoint and a description of observer review, but not the statistical methods needed to reproduce or evaluate a comparison. The analysis population, handling of missing outcomes, model specification, estimates, and uncertainty are not reported in the registry record.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Contrast Injection", "Dextran Injection", "CO2 Injection", "Heparinized Saline")
n   <- c(19, 19, 19, 19)
m   <- c(0.702, 0.872, 0.1, 0.743)
sp  <- c(0.305, 0.12, 0.104, 0.248)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Contrast Injection  19  0.702  0.305  0.555  0.849
CARM  Dextran Injection  19  0.872  0.120  0.814  0.930
CARM  CO2 Injection  19  0.100  0.104  0.050  0.150
CARM  Heparinized Saline  19  0.743  0.248  0.623  0.863

11. Multiplicity, Missing Data and Analysis Populations

The registry describes image quality as the primary outcome and lists area and diameter measurements as quantitative assessments related to index of refraction. It also lists plaque composition by flush medium as a secondary outcome. These are multiple outcome measures, but the registry record does not report whether or how the analysis addressed multiplicity. No hierarchy among secondary measurements, adjustment procedure, or prespecified interpretation of multiple tests is reported. Without that information, any collection of test results, if available elsewhere, would need to be interpreted with care.

Missing-data handling is not reported in the registry record. The record does not state whether all enrolled participants contributed evaluable imaging, how incomplete pullbacks or unclassifiable frames were handled, or whether any observations were excluded. It also does not describe an imputation method or a sensitivity analysis. These details matter because the amount and pattern of missing information can affect both the estimated endpoint and its uncertainty.

The analysis population is also not reported. The registry does not state whether the primary analysis included every enrolled participant, only participants with usable images, or another defined set. The enrollment figure alone does not identify the number of evaluable runs or the number of observations contributing to a particular endpoint.

The record reports zero analyses. It therefore contains no statistical results with which to evaluate multiplicity, missing-data assumptions, or the defined analysis population. These omissions do not show that such procedures were absent from the study; they mean they are not reported in the registry record.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The adverse-event record lists Contrast Injection, Dextran Injection, CO2 Injection, and Heparinized Saline. For each listed group, the registry records 23 at risk, zero serious adverse events, zero other adverse events, and zero deaths. These are the counts entered in the registry’s adverse-event fields.

Zero recorded events should be interpreted as no events recorded in these fields, not as proof that an event is impossible or that a procedure has no risk. Event counts alone do not show how completely participants were followed, how events were defined or collected, or whether all relevant events were entered. Those details are not reported in the registry record.

The registry does not provide confidence intervals or a comparative safety analysis. Nor does its single-group designation establish a randomized safety comparison between the listed media. The adverse-event entries therefore describe the recorded counts, but do not quantify the precision of a risk estimate or establish that one medium is safer than another.

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

The record identifies a focused methodological question: whether image quality during iOCT of lower-extremity arterial disease differs by flush medium, with particular interest in CO2 compared with contrast and dextran. It defines a clear imaging field and explains how observers classified images. These details help readers understand what the investigators intended to measure.

The record does not, however, report the CIF results or comparative estimates. It therefore cannot show whether image quality was similar across media, whether one medium produced a higher proportion of clear fields, or how precise any difference might be. The investigators’ hypothesis and expectation of little difference are not findings. No conclusion about imaging performance can be drawn from those expectations alone.

The registry also does not report results for vessel area, diameter, or plaque composition. The adverse-event entries record zero events in the listed fields, but the record does not provide the follow-up or analysis detail required to interpret those counts as comparative evidence about safety. In particular, absence of recorded events in these fields is not equivalent to proof of no risk.

The design information requires caution as well. The study is registered as single group, with allocation listed as NA, and the registry specifically notes that the study is not a randomized comparison and that the arms are not like-for-like controls. The record does not explain the relationship among observations for each medium. This makes it inappropriate to assume that a direct causal comparison is supported by the study structure.

In practical terms, the registry documents the research question, measurement definition, and some procedural and design information. It does not supply the outcome evidence needed to judge whether the hypothesis was supported. The result is an incomplete statistical record, not evidence that the media are equivalent or different.

14. Why This Trial Matters Statistically

This trial matters statistically because image quality is not a simple count of clinical events; it is a measurement constructed from judgments about visibility in imaging frames. The registry’s CIF definition gives a threshold for classifying a cross section, while the run-level proportion summarizes those classifications. Clear definitions are important when an endpoint depends on interpreting images rather than recording an objectively counted event.

The assessment process also highlights measurement reliability. The registry describes two independent observers blinded to flush medium and a consensus process for disagreements greater than 10%. These features are relevant to reducing observer influence and resolving conflicting classifications. But without reported disagreement rates, agreement measures, or endpoint results, readers cannot evaluate how consistently the measure was applied.

The design record underscores why statistical comparisons depend on more than a list of interventions. The single-group model, allocation marked NA, and statement that the arms are not like-for-like control comparisons leave the relationship among measurements unclear. For repeated or paired imaging observations, analysis should reflect the way those observations are connected. The registry does not report that structure or the analysis used.

Finally, a completed study record without outcome estimates illustrates the difference between a research question and an answer. A defined endpoint and a plausible hypothesis do not establish a treatment or imaging effect. Reporting the estimates, uncertainty, analysis population, and methods would be needed to evaluate the strength and precision of the evidence. In this record, those statistical results are not reported.

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.

The main trial-specific limitation for interpretation is that the registry record does not include primary endpoint results. It reports no CIF mean, standard deviation, comparison estimate, confidence interval, or test result. The intended endpoint is therefore described, but the observed image quality and its precision cannot be assessed.

The record’s design description is limited. It identifies a single-group model and allocation as NA, and explicitly notes that the study is not a randomized, like-for-like comparison. The intervention list names contrast, dextran, CO2, and heparinized saline, but the record does not explain how these procedures were sequenced or how observations were linked to participants and runs. The arm description is incomplete, and the registry does not describe the analysis structure.

Participant eligibility and characteristics are not reported beyond the condition and enrollment entry. The analysis population, number of evaluable images or runs, and handling of missing or unusable data are also not reported. The record describes observer review but does not provide agreement results or the frequency of consensus re-evaluation.

Although the adverse-event fields record zero events, the record does not give detailed event definitions, follow-up completeness, or comparative safety estimates. It also does not report whether multiplicity was addressed for the several outcome measures described. These gaps limit interpretation of both measurement and safety.

These are limitations of the information available in the registry record. They do not establish that the study did not collect additional data or conduct further analyses; those details are simply not reported in the registry record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Optical Imaging Measurement of Intravascular Solution Efficacy Trial — NCT01743872.
• Registry record last updated 2022-09-21; status last verified 2022-08.
• Results first posted 2022-09-21.
• 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

The Optical Imaging Measurement of Intravascular Solution Efficacy Trial is registered for peripheral artery disease and has completed status. The record lists University Hospitals Cleveland Medical Center as sponsor, enrollment of 23, a single-group model, allocation as NA, and no masking. It identifies image quality as the primary outcome, measured using the proportion of clear imaging fields, and lists plaque composition by flush medium as a secondary outcome.

The procedures include contrast, dextran, CO2, and heparinized saline injections. The registry describes observer assessment of OCT frames and a CIF definition based on visualization of at least 270° of vessel wall architecture. It does not report primary outcome estimates, statistical analyses, missing-data methods, or an analysis population. The adverse-event fields record zero serious events, zero other events, and zero deaths in each listed group. The registry record therefore documents the study question and selected methods, but does not report the results needed to determine comparative image quality or safety.