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 Assessment of Coronary Flow Reserve in Heart Failure Patients After Ultrafiltration Versus Diuretics (NCT01457053), a randomized na study. The primary outcome is Myocardial Blood Flow.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01457053 |
| Phase | NA |
| Condition | Acute Decompensated Heart Failure |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 4 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Cincinnati |
| Results posted | Yes |
2. Clinical Question
Population
Patients with acute decompensated heart failure. The registry record reports enrollment of 4 and states that no data were analyzed because enrollment was inadequate.
Intervention
Ultrafiltration, a treatment intended to remove fluid from the body. The registry record identifies ultrafiltration as the intervention but does not describe its delivery protocol.
Comparator
Intravenous loop diuretic therapy, with furosemide, torsemide, and bumetanide named in the record. The record does not give analyzed comparative results.
Primary question
Whether myocardial blood flow and coronary flow reserve, assessed by positron emission tomography, differ between the treatment groups during the stated 1 - 5 days timeframe. No primary outcome comparison was analyzed.
The clinical question is about the effects of two approaches to treatment on measures of cardiac blood flow in acute decompensated heart failure. The primary outcome is titled “Myocardial Blood Flow,” while its description refers to both myocardial blood flow (MBF) and coronary flow reserve (CFR). The record does not report an estimate for either measure, its unit, or its variability.
The trial was randomized and had two parallel treatment groups. Random allocation is generally used to make comparison groups more similar, on average, with respect to factors that could affect outcomes. That design feature does not guarantee balance in a small study, and it cannot produce an interpretable treatment comparison when the primary outcome was not analyzed. The record lists a single masking designation but does not identify who was masked.
The stated timeframe for the primary outcome is 1 - 5 days. The record does not clarify when within that period measurements were intended to occur, how multiple measurements would be handled, or which measure would be used for a primary comparison. Those details are not reported in the registry record. Most importantly, it explicitly attributes the absence of primary outcome data to inadequate enrollment. Consequently, the registry record documents the question the study planned to address, but does not answer it.
3. Trial Design
This was a randomized, single-masked, parallel-group pilot study sponsored by the University of Cincinnati. The trial record lists the phase as NA, enrollment as 4, and status as terminated. The recorded start was 2011-11 and primary completion was 2013-05. The registry record does not give a reason for termination beyond the primary outcome note that no data were analyzed because enrollment was inadequate.
Participants with acute decompensated heart failure were assigned to ultrafiltration or diuretic therapy. The diuretic intervention is described as loop diuretics, naming furosemide, torsemide, and bumetanide. The record does not state which specific drug or dosing schedule each participant received, nor does it describe the ultrafiltration procedure. These treatment details are not reported in the registry record.
The parallel design means the planned comparison was between groups receiving different assigned treatments, rather than a within-person crossover. Randomization describes how assignment was intended to occur; the registry record does not state the sequence-generation method, allocation concealment procedures, or whether any departures from assignment occurred. The single-masked designation does not establish whether participants, treating staff, outcome assessors, or analysts were masked. The identity of the masked group is not reported in the registry record.
The primary outcome timeframe is 1 - 5 days. The outcome description names PET assessment of myocardial blood flow and coronary flow reserve. The registry record does not describe the PET protocol, measurement schedule, or analysis procedure. Although the study is identified as a pilot, the record does not report whether it was designed to assess feasibility, estimate treatment effects, or inform a later trial. A sample-size justification and recruitment targets beyond the recorded enrollment are not reported in the registry record.
Enrollment of 4 is not a basis for judging what the treatment comparison would have shown: the registry explicitly says no data were analyzed because enrollment was inadequate. The status of terminated indicates that the study did not continue as planned, but does not by itself explain why recruitment was insufficient or what operational factors contributed. Those reasons are not reported in the registry record.
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 | Ultrafiltration | Diuretic Therapy |
|---|---|---|
| STARTED | 2 | 2 |
| COMPLETED | 1 | 1 |
| NOT COMPLETED | 1 | 1 |
Reasons for not completing this period:
| Reason | Ultrafiltration | Diuretic Therapy |
|---|---|---|
| Unable to undergo selected treatment | 1 | 1 |
Analysis population for the primary outcome, as defined in the registry: No data analyzed due to inadequate enrollment.
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 | All Study Participants |
|---|---|---|
| Participants analysed | 4 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 4 |
| Age, Categorical: >=65 years | Participants | 0 |
| Gender: Female | Participants | 1 |
| Gender: Male | Participants | 3 |
6. Primary Endpoint
The registry lists the primary outcome as Myocardial Blood Flow, measured over 1 - 5 days.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary outcome is titled myocardial blood flow. Its description says the study aimed to evaluate ultrafiltration compared with intravenous diuretic therapy on myocardial blood flow (MBF) and coronary flow reserve (CFR), assessed by positron emission tomography (PET), in patients with acute decompensated heart failure. The stated timeframe is 1 - 5 days. No units, numerical results, or variability measures are reported.
In general, myocardial blood flow describes blood reaching the heart muscle. Coronary flow reserve is a measure intended to characterize the capacity of coronary blood flow to increase under conditions that call for greater flow. These measures can provide information about cardiac blood-flow physiology. PET is an imaging method used to assess physiological processes, including blood flow. These general descriptions do not establish which exact measurement or calculation the trial planned to use; those procedural details are not reported in the registry record.
Measures of blood flow and reserve are used in research because they can describe physiological outcomes that may change after an intervention. They are not, by themselves, a report of how participants felt or functioned, nor do they establish a clinical benefit. The registry record does not report additional patient-centered outcomes in the primary outcome description.
There is an important distinction between the outcome title and its description: the title names myocardial blood flow, while the description includes both MBF and CFR. The record does not provide an analyzed endpoint value or a treatment contrast. It also states that no data were analyzed because of inadequate enrollment. As a result, there is no posted estimate from which to assess the size, direction, or precision of a difference between the groups.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The principal statistical fact is that the primary outcome was not analyzed. The registry record states, “No data analyzed due to inadequate enrollment.” It therefore does not report a treatment effect for myocardial blood flow or coronary flow reserve, and there is no estimate or uncertainty interval to interpret. The record describes a planned randomized comparison, not a completed statistical comparison of the two treatments.
The enrollment entry is 4, but it should not be mistaken for an analyzed sample for the primary outcome. The record explicitly says no data were analyzed. It does not give participant-level outcome measurements, identify how many participants completed PET assessment, or explain whether any measurements were collected but excluded from analysis. Those details are not reported in the registry record. With no analyzed outcome data, it is not possible to describe the observed direction or magnitude of a group difference.
In general, a treatment-effect estimate gives the observed contrast between groups, and a confidence interval communicates the range of values compatible with the data under the analysis assumptions. Neither is reported for the primary outcome. A p-value would address compatibility with a specified statistical null model; it is also not reported. The absence of these statistics is not evidence that the groups had equal outcomes. It means that this registry record does not contain an analyzed result that can distinguish a difference from no difference.
The record lists a primary outcome timeframe of 1 - 5 days, but it does not report when measurements were made or how values across that period would be handled. The outcome title and description also differ in scope: the title names myocardial blood flow, while the description refers to both MBF and CFR. No single analyzed comparison is available to resolve that distinction. The record notes that the primary outcome has several categories or time points and was not reduced to one comparison. No analysis results are listed.
Enrollment was inadequate according to the outcome note, and trial status is terminated. These registry entries limit what can be learned from the trial record. They do not establish that either treatment changed blood flow, that the treatments had similar effects, or that a treatment effect was absent. They also do not establish why recruitment was inadequate. The registry record does not report a recruitment explanation, a formal stopping rule, or any interim analysis.
Any sample-size planning illustration should be separated from observed evidence. General planning calculations depend on assumptions about the treatment effect to detect, variability, significance level, allocation, and statistical model. The record describes illustration assumptions of a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the effect framed as a stated fraction of an observed effect. However, no analyzed primary effect is available in the registry record. Planning values cannot substitute for missing trial results and are not observed power. The posted data support a description of the design and its recruitment shortfall, but not a conclusion about comparative treatment effects.
9. Statistical Methods Explained
What does randomization contribute?
In general, randomization assigns participants to treatment groups by chance. Its purpose is to reduce systematic differences between groups in factors that are known or unknown at baseline. It supports a causal comparison when the study is conducted and analyzed appropriately, but it does not ensure that groups will be balanced in a small sample. Nor does randomization itself provide an outcome estimate. In this record, the study was randomized, but the primary outcome was not analyzed because enrollment was inadequate. Thus the design intention cannot be translated into a treatment-effect estimate.
The registry identifies a parallel-group model. In a parallel design, each participant is assigned to a treatment group and the planned comparison is between those groups. The record does not report allocation concealment methods, sequence generation, adherence, or treatment switching. It also does not identify who was masked despite listing single masking. Those implementation details matter when assessing possible sources of bias, but they cannot be inferred from the design labels.
What would an outcome comparison ordinarily report?
In general, a comparison of a continuous measurement such as a blood-flow value may report a group-specific summary and a treatment contrast, together with a measure of uncertainty. A confidence interval is an interval estimate expressing the precision of the estimate under specified assumptions. A narrower interval generally indicates greater precision, while a wider one indicates more uncertainty. A p-value, when used, evaluates how compatible the observed data are with a null hypothesis under a statistical model; it is not a measure of clinical importance. No outcome estimate, confidence interval, or p-value for MBF or CFR appears in the registry record.
The record does not give the endpoint unit, planned summary statistic, or model. It is therefore not possible to say whether the planned analysis would compare means, use a transformed measure, adjust for baseline values, or account for repeated measurements. These choices can affect the interpretation of an estimate. They are not reported in the registry record, and an analyst should not reconstruct a protocol from the outcome title alone.
What does the planning language mean?
General sample-size planning asks how many participants or events may be needed to detect an effect under stated assumptions. A planning calculation is not evidence that an effect occurred. The registry describes illustration assumptions: a two-sided significance level of 0.05, equal allocation between groups, and a normal approximation. It also frames the effect to detect as a stated fraction of the observed effect. Those assumptions are not a reported justification for the trial’s actual enrollment, and no sample-size rationale is reported in the registry record.
For a planning illustration based on an observed effect, an effect estimate is needed as an input. Here, the registry reports no analyzed primary outcome data. Any planning output based on an effect that is not available in the record cannot be interpreted as evidence about this trial’s treatment effect. Sample-size illustrations are forward-looking calculations under assumptions, not observed power. The registry also distinguishes planning conventions for time-to-event outcomes from other outcomes, but this primary outcome is not reported as a time-to-event endpoint.
Why does over-dispersion matter in general?
Over-dispersion is a general issue for some count-data models. It occurs when observed variability in counts exceeds what a chosen model assumes. If not addressed, standard errors and uncertainty estimates can be misleading. This trial’s primary outcome is described as PET-assessed myocardial blood flow and coronary flow reserve, not a count endpoint. The registry does not report a count model or an analysis requiring an over-dispersion assessment. This general concept should not be mistaken for a method used in the trial.
How should the missing analysis be understood?
The record’s statement that no data were analyzed because enrollment was inadequate is distinct from a reported null result. A null result would require analyzed data and a defined estimate that happened not to show a clear difference under the chosen method. No such estimate is reported. The registry also records zero analyses. It does not identify a statistical analysis plan, primary model, covariate adjustment, treatment-effect estimand, or handling of repeated or incomplete measurements. These are not reported in the registry record.
In general, a prespecified analysis plan helps clarify which outcomes, populations, models, and comparisons were intended before results are examined. It can also document interim analyses and rules for interpreting multiple tests. The registry record does not report these details. Their absence from this record should be described as unreported, rather than filled in by assuming common practice. The available methodological evidence is therefore limited to the listed randomized, single-masked, parallel design, the planned PET outcome and timeframe, and the statement that inadequate enrollment prevented analysis.
10. Multiplicity, Missing Data and Analysis Populations
The primary outcome description includes myocardial blood flow and coronary flow reserve, and the registry notes that the primary outcome has several categories or time points and was not reduced to one comparison. The record does not specify which measure or time point would govern a single primary treatment comparison. No analyses are reported. The number and structure of planned statistical tests are not reported in the registry record.
In general, multiplicity arises when several outcomes, time points, subgroups, or statistical comparisons are tested. Examining multiple results can increase the chance of finding an apparently notable result by chance, so an analysis plan may specify how comparisons will be prioritized or adjusted. This is a general statistical concern, not evidence that any particular multiplicity adjustment was planned or used in this study. The registry record does not report an adjustment method or a hierarchy among MBF, CFR, categories, and time points.
The primary outcome population note says no data were analyzed because of inadequate enrollment. As a result, there is no analysis population defined by reported outcome availability, and no missing-data method can be assessed. The record does not report participant-level completion, reasons for missing measurements, exclusions, or whether any outcomes were collected but not analyzed. These details are not reported in the registry record.
In general, missing-data methods depend on why observations are missing and on the analysis being conducted. Complete-case analysis, imputation, or other approaches make different assumptions and can yield different results. None should be attributed to this trial without documentation. The record also does not describe an intention-to-treat population, a per-protocol population, or another analysis set. Given the explicit statement that no data were analyzed, the most accurate interpretation is that the registry provides no basis for judging how missing observations or analysis populations were handled.
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 |
|---|---|---|---|
| Ultrafiltration | 0 | 1 | 0.0% |
| Diuretic Therapy | 0 | 1 | 0.0% |
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 |
|---|---|
| Ultrafiltration | 0 of 1 |
| Diuretic Therapy | 0 of 1 |
The registry lists one participant at risk for serious adverse events in each group and zero participants affected in each group. It also lists one at risk for other adverse events in each group and zero affected in each group. These are the posted safety counts; they should be read with their small denominators and alongside the registry’s statement that no primary outcome data were analyzed because enrollment was inadequate.
Zero affected in the listed safety counts does not establish that either treatment is free of risk. With only one participant listed at risk per group for each category, the counts provide very limited information about the frequency of adverse events. They also do not support a meaningful comparative estimate between treatment groups. The registry does not provide event descriptions in the serious adverse event terms list.
Deaths are not reported in the registry record. The record does not clarify the relationship between the listed safety populations and total enrollment of 4, nor does it provide further details on safety follow-up, event collection, or attribution to treatment. Those details are not reported. The safety figures should therefore be described narrowly as the counts recorded, not as proof of no harm or a basis for comparing safety between treatments.
12. What the Result Does, and Does Not, Mean
The registry record establishes that investigators planned a randomized comparison of ultrafiltration and intravenous diuretic therapy in patients with acute decompensated heart failure. It identifies PET-assessed myocardial blood flow and coronary flow reserve as the focus of the primary outcome description, with a stated timeframe of 1 - 5 days. It also records enrollment of 4, a terminated status, and a statement that no data were analyzed because enrollment was inadequate.
Those details do not show whether myocardial blood flow or coronary flow reserve increased, decreased, or remained similar in either group. No treatment-effect estimate, confidence interval, or p-value is reported. The record therefore cannot establish that one treatment produced a greater change than the other, that their effects were alike, or that there was no effect. Lack of an analyzed result is not equivalent to evidence for no difference.
The study’s planned randomized design is relevant to the question it intended to address, but a design cannot replace outcome data. With the primary outcome unanalyzed, the treatment comparison remains unanswered in this registry record. The record also does not report enough detail to assess the intended endpoint calculation, missing-data approach, or analysis populations.
The safety entries are similarly limited. The registry lists zero affected among one participant at risk per group for serious and other adverse events, while deaths are not reported. These small recorded counts do not establish comparative safety. They should not be expanded into a claim that adverse events did not occur beyond what the entries state.
The appropriate conclusion is about the limits of the evidence in the record: the trial documents an intended comparison and an enrollment shortfall, but it does not provide analyzed results capable of estimating comparative effects. Any claim about how the treatments affect cardiac blood flow or safety would go beyond what this record reports.
13. Why This Trial Matters Statistically
This trial is statistically informative mainly because it illustrates the gap between a planned comparison and an analyzable result. Randomization can be an important design feature, but a randomized label does not guarantee that a study will recruit enough participants to produce interpretable estimates. The registry record says enrollment was inadequate and no primary outcome data were analyzed. The primary comparison therefore remains unavailable despite the planned design.
The record also illustrates why endpoint specification matters. The primary outcome title names myocardial blood flow, while the description refers to myocardial blood flow and coronary flow reserve and notes several categories or time points. Without an analyzed comparison or a clearly reported choice among those measures and times, readers cannot identify a single treatment-effect estimate. A transparent endpoint definition and analysis plan can help readers understand what was intended and how results should be interpreted; those details are not reported in the registry record.
Statistically, absence of an estimate is different from an imprecise estimate. A wide confidence interval would indicate that an analysis produced an estimate with substantial uncertainty. Here, there is no reported primary outcome analysis from which to form such an interval. The study consequently supplies no direct estimate of the direction or magnitude of the treatment contrast.
The record is also a reminder to distinguish planning calculations from trial evidence. Planning assumptions may describe hypothetical requirements under selected conditions, but they do not show that an effect was observed. In this case, no analyzed primary effect is reported. A sample-size illustration should not be read as observed power or as a result of the treatment comparison.
Finally, the safety counts require careful attention to denominators. Zero affected among one at risk in each group is a limited record of events, not a strong comparative safety assessment. Taken together, the trial’s statistical importance lies in the clarity of its limitations: an intended randomized experiment was registered, but inadequate enrollment prevented the primary comparison from being analyzed.
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 central limitation is explicit: the registry record states that no data were analyzed because enrollment was inadequate. Although enrollment is recorded as 4, there is no analyzed primary outcome estimate. The trial’s terminated status further indicates that the planned study did not proceed to a reported primary comparison. The record does not explain the causes of recruitment difficulty or termination.
The endpoint is not fully specified in the available description. The title identifies myocardial blood flow, while the description includes coronary flow reserve as well. The record also flags several categories or time points and says the outcome was not reduced to one comparison. Units, measurement procedures, the timing of individual assessments, and the planned summary or model are not reported in the registry record. This prevents assessment of how the endpoint would have been operationalized and analyzed.
Important design and analysis details are also absent. The registry gives a single-masked designation but does not identify who was masked. It does not report allocation concealment, randomization sequence methods, adherence, treatment switching, analysis populations, missing-data procedures, or a statistical analysis plan. These omissions do not establish that such procedures were absent; they mean that they are not reported in the registry record.
The safety data are limited to small listed at-risk groups and zero affected counts, with deaths not reported. The record does not give event-level descriptions or further follow-up details. As a result, these entries cannot support a robust comparison of safety between treatments.
Finally, the registry does not report a sample-size justification or an explanation of the intended role of the pilot beyond its study designation. The planning assumptions described in the record are not evidence that the actual enrollment was adequate. With no analyzed primary outcome and limited methodological detail, conclusions about efficacy, precision, or comparative safety are not supported by the posted results.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Assessment of Coronary Flow Reserve in Heart Failure Patients After Ultrafiltration Versus Diuretics — NCT01457053.
- Registry record last updated 2016-12-05; status last verified 2016-10.
- Results first posted 2015-06-08.
- 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
NCT01457053 is a randomized, single-masked, parallel pilot study sponsored by the University of Cincinnati. It planned to compare ultrafiltration with intravenous loop diuretic therapy in acute decompensated heart failure. The listed primary outcome concerns PET-assessed myocardial blood flow and coronary flow reserve, with a timeframe of 1 - 5 days.
The recorded enrollment is 4, and the trial status is terminated. The registry record states that no data were analyzed because enrollment was inadequate. It reports no primary outcome estimate or statistical comparison. Safety entries list zero affected among one participant at risk per group for serious and other adverse events; deaths are not reported. The record does not establish comparative treatment effects or comparative safety.