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 Study to Evaluate VORTX Rx (Theresa) (NCT03741088), a na na study. The primary outcome is Acute Technical Performance of the VORTX Rx® Medical Device for the Ablation of Primary and Metastatic Liver Tumors.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03741088 |
| Phase | NA |
| Condition | Carcinoma, Hepatocellular, Liver Metastases |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 8 |
| Arms in the primary outcome | n/a |
| Lead sponsor | HistoSonics, Inc. |
| Results posted | Yes |
2. Clinical Question
Population
The study concerns people with primary or metastatic liver tumors. The registry lists hepatocellular carcinoma and liver metastases among the conditions. The enrolled study population was 8; further eligibility details and the number of participants in each condition are not reported in the registry record.
Intervention
The intervention was VORTX Rx treatment, described as focused ultrasound ablation of liver tumors. The record characterizes the study as evaluating acute technical performance and safety of the device.
Comparator
There was no separate comparator group in this single-group study. Allocation is listed as NA, and the study is described as non-randomized and open-labeled. Its observations therefore do not provide a like-for-like comparison with another treatment or with no treatment.
Primary question
The primary question was how many lesions met the protocol-established definition of successful ablation at 1-day post ablation. The registry record names this acute technical-performance outcome but lists no analysis result for it. The posted information therefore states the question being evaluated, but not the observed number of successfully ablated lesions.
3. Trial Design
The registry describes a multicenter, open-labeled, non-randomized, single-group medical-device study. Its intervention was VORTX Rx treatment, specified as focused ultrasound ablation of liver tumors. Enrollment was 8. The record lists the study as completed, with a start date of 2018-03-21 and primary completion date of 2019-05-15. Phase is listed as NA.
A single-group design can describe outcomes among participants treated with the device, but it does not by itself estimate how those outcomes would differ under another treatment. Because there was no randomized allocation or separate comparator group, differences from an external population cannot be interpreted as a randomized treatment effect. Open-label status means masking is listed as none; the registry record does not report further details about who assessed technical success or adverse events.
The primary outcome was acute technical performance, expressed as a count of lesions meeting a protocol-established definition of successful ablation, with a timeframe of 1-day post ablation. Safety and other listed outcomes included device-related serious and non-serious adverse events, local tumor progression, involution of the ablation zone, and liver-panel assessments. The record lists 18 outcome measures but no analyses. Details such as eligibility criteria, participant flow, the number of lesions treated, follow-up schedules beyond the stated primary timeframe, and the statistical analysis plan 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 | VORTX Rx Treatment |
|---|---|
| STARTED | 8 |
| COMPLETED | 5 |
| NOT COMPLETED | 3 |
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 | VORTX Rx Treatment |
|---|---|---|
| Participants analysed | 8 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 5 |
| Age, Categorical: >=65 years | Participants | 3 |
| Age, Continuous | years | 63.1 (SD 13.6) |
| Sex: Female, Male: Female | Participants | 5 |
| Sex: Female, Male: Male | Participants | 3 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 |
| Race (NIH/OMB): White | Participants | 8 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: Spain | participants | 8 |
| Type of live tumors: Hepatocellular carcinoma | Participants | 1 |
| Type of live tumors: Liver metastasis | Participants | 7 |
| Body Mass Index (BMI) | kg/m^2 | 25.1 (18.9 to 28.8) |
| Eastern Cooperative Oncology Group (ECOG) Performance Status: ECOG 0 | Participants | 2 |
| Eastern Cooperative Oncology Group (ECOG) Performance Status: ECOG 1 | Participants | 6 |
6. Primary Endpoint
The registry lists the primary outcome as Acute Technical Performance of the VORTX Rx® Medical Device for the Ablation of Primary and Metastatic Liver Tumors, measured over 1-day post ablation.
| Element | Registry entry |
|---|---|
| Result type | Count Of Units |
| Measure of spread | not applicable |
| Unit | lesions |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the number of lesions that were successfully ablated according to a technical-success definition established in the protocol. The registry assigns this outcome the unit “lesions” and gives its timeframe as 1-day post ablation. It is therefore an acute technical-performance measure, rather than a measure of long-term tumor control or a direct comparison of treatment strategies.
A lesion-level count can describe whether the procedure met a predefined technical criterion for the treated targets. Such an endpoint is used to assess procedural performance close to the time of ablation. Its meaning depends on the precise success criteria, which the registry record says were established in the protocol but does not reproduce. The number of lesions treated and the number meeting the success definition are not reported in the registry record.
No primary-endpoint analysis result is listed. Without the observed count and the relevant denominator, the endpoint cannot be quantified from the posted results. Nor can an acute technical-performance count alone establish longer-term tumor control or comparative benefit. Those questions require suitable outcomes and analyses; the record does not report a primary analysis addressing them.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies an acute technical-performance question: the number of lesions meeting the protocol-defined success criterion at 1-day post ablation. However, it does not list a result or analysis for this primary outcome. The posted information therefore does not establish how many lesions met the criterion, what proportion of treated lesions did so, or how precisely technical success was estimated. The denominator—the number of lesions treated—is also not reported in the registry record.
The study enrolled 8 participants and used a single-group, non-randomized design. Participant enrollment is not interchangeable with the lesion count used by the primary endpoint: the record does not report how many lesions were treated per participant. That distinction matters when interpreting any lesion-level summary, because a participant and a lesion are different units of observation.
The safety record lists 2 participants at risk for serious adverse events and affected, out of 8 at risk; it lists 7 affected for other adverse events, also out of 8 at risk. These are descriptive counts in the VORTX Rx Treatment group. The record also lists FEVER and HYPOCALCEMIA at 12.5% each among the top serious terms, and deaths of 0. These observations describe the registry entries; they do not establish a comparative safety difference. With no separate control group, the study does not estimate how these counts compare with another intervention or with the background occurrence of such events.
The record lists 18 outcome measures and 0 analyses. This means the posted registry results do not include analysis results for the named outcomes. It does not establish that no analyses were conducted outside the registry, nor does it reveal their methods or findings. No confidence interval, hypothesis-test result, or adjustment for participant or lesion characteristics is reported in the registry record.
In general, an estimate describes the observed quantity, while a confidence interval communicates uncertainty around an estimate under its statistical assumptions. Neither an estimate nor an interval for the primary endpoint is reported, so its precision cannot be assessed. The most direct interpretation is consequently limited: the registry describes the design, endpoint, and some safety counts, but does not report an analyzed primary technical-performance result.
9. Statistical Methods Explained
The registry describes the study as multicenter, open-labeled, non-randomized, and single-group. These design terms determine what kinds of conclusions the posted data can support. A single-group study reports observations in one treated group. Without random assignment to a separate comparator, it cannot estimate a randomized between-group treatment effect. Open-labeled status indicates that masking is listed as none. Whether any outcome assessors were separately masked is not reported in the registry record.
What does the primary measure count?
The primary outcome is a count of lesions meeting a protocol-established definition of successful ablation. The unit is lesions, and the stated timeframe is 1-day post ablation. A count is a descriptive summary of how many units meet a defined criterion; interpretation also requires knowing how many units were assessed. Here, the registry does not list either the success count or the lesion denominator. It also does not reproduce the detailed protocol definition, so the operational criteria cannot be evaluated from the record alone.
The enrolled population was 8 participants, but that is not necessarily the denominator for a lesion-level outcome. One participant may contribute information about more than one lesion, and the number treated per participant is not reported. In general, observations from several lesions in one participant may be statistically related. If that dependence is present, an analysis treating every lesion as fully independent could understate uncertainty. Whether the study used a method that accounts for clustering is not reported in the registry record; no primary analysis is listed.
What can a confidence interval tell a reader?
General statistical explanation: a confidence interval expresses the uncertainty associated with an estimate under a specified statistical model and method. Its width reflects both the amount of information and the variability represented by the data. It does not remove design limitations, and it does not make an uncontrolled comparison equivalent to a randomized one. The registry record lists no primary estimate or confidence interval, so neither the endpoint magnitude nor its statistical precision can be assessed.
How should hypothesis tests and significance levels be read?
General statistical explanation: a hypothesis test evaluates compatibility of data with a stated null hypothesis under a particular model. A p-value is not the probability that the null hypothesis is true, and statistical significance does not itself establish clinical importance. The registry record reports no primary test or p-value. It also does not report whether any tests were planned for the secondary outcomes or how such tests would be interpreted.
The sample-size assumptions describe planning illustrations based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The record’s actual design was a single group, so these assumptions describe hypothetical planning rather than the allocation used in this study. Any sample-size illustration is not observed power. The trial’s own sample-size justification and protocol design assumptions are not reported in the registry record.
Why can over-dispersion matter?
General statistical explanation: for count outcomes, a statistical model may assume that variability follows a particular relationship to the expected count. Over-dispersion means the observed variability is greater than that assumed by a model. If it is not accommodated, standard errors and confidence intervals may be too small, and tests may appear more decisive than warranted. Whether the primary endpoint was modeled as a count, whether over-dispersion was assessed, and which model was used are not reported in the registry record. Since no primary analysis result is listed, no model-based uncertainty can be reviewed.
The registry names additional outcomes, including safety events, local tumor progression, involution of the ablation zone, and liver-panel assessments. Different outcome types may require different summaries or models. For example, event counts, continuous laboratory measures, and time-to-event outcomes are not interchangeable statistical quantities. The record does not list analysis methods, estimates, uncertainty intervals, or results for these outcomes. The presence of an outcome name alone does not establish that it was analyzed or that a result was observed.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 18 outcome measures, including the primary technical-performance outcome and secondary measures covering safety, local tumor progression, ablation-zone involution, and several liver-panel assessments. Considering several outcomes creates a multiplicity issue: when many statistical tests are conducted, the chance of at least one apparently unusual result can increase. General statistical approaches can address this by defining a primary testing hierarchy or adjusting significance thresholds, but no such approach is reported in the registry record. Since 0 analyses are listed, there are no posted tests to interpret or adjust.
The record does not report how missing outcome observations were handled, whether any participants or lesions lacked endpoint data, or whether analyses used all enrolled participants. The analysis populations, exclusion rules, and any imputation methods are not reported in the registry record. These omissions matter because the number of observations contributing to an estimate, and the reasons observations are absent, can affect interpretation.
Missing-data methods depend on what is missing and why. General statistical explanation: excluding incomplete records can alter an estimate if the observations available for analysis differ systematically from those not available. Imputation or other modeling methods require assumptions about the missingness process and should be described so readers can assess them. No missingness pattern or method is listed; it is not possible to determine how any missing measurements were treated.
The registry’s sample-size assumptions describe a planning illustration using equal allocation between two arms, although the actual study is single-group and non-randomized. Such illustrations are planning exercises, not observed power. The trial’s own sample-size justification, multiplicity plan, missing-data plan, and analysis-population definitions are not reported in the registry record.
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 |
|---|---|---|---|
| VORTX Rx Treatment | 2 | 8 | 25.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| VORTX Rx Treatment | 0 of 8 |
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 |
|---|---|
| VORTX Rx Treatment | 7 of 8 |
Most frequent serious adverse event terms
| Event term | Organ system | VORTX Rx Treatment |
|---|---|---|
| FEVER | General disorders | 1 of 8 |
| HYPOCALCEMIA | Metabolism and nutrition disorders | 1 of 8 |
Most frequent non-serious adverse event terms
| Event term | Organ system | VORTX Rx Treatment |
|---|---|---|
| ALT increase | Hepatobiliary disorders | 4 of 8 |
| AST increase | Hepatobiliary disorders | 4 of 8 |
| Fatigue | General disorders | 4 of 8 |
| Sciatic pain | Nervous system disorders | 3 of 8 |
| Anorexia | Metabolism and nutrition disorders | 2 of 8 |
| Constipation | Gastrointestinal disorders | 2 of 8 |
| GGT increase | Hepatobiliary disorders | 2 of 8 |
| Nausea | Gastrointestinal disorders | 2 of 8 |
| Transaminase elevation | Hepatobiliary disorders | 1 of 8 |
| Abdominal discomfort | General disorders | 1 of 8 |
Serious events with the highest arm-level rate: fever (12.5%), hypocalcemia (12.5%).
The VORTX Rx Treatment group has 8 participants at risk for serious adverse events, with 2 listed as affected. For other adverse events, 8 were at risk and 7 were listed as affected. The record lists 0 deaths. These are counts of affected participants as represented in the registry record; they should not be confused with the total number of event episodes, which is not reported.
FEVER and HYPOCALCEMIA are the listed top serious terms, each at 12.5%. These terms describe events recorded in the safety results. The registry outcome is worded around serious and non-serious adverse events that are probably or definitely device-related, but the posted figures alone do not describe the event narratives, timing, severity details, or adjudication process. Those details are not reported in the registry record.
With no separate comparator group, these counts are descriptive and cannot establish whether event occurrence differs from another treatment or from an untreated comparison population. The small enrolled group also limits how completely uncommon safety outcomes can be characterized. The figures should be read as the events recorded among this study group, not as a comparative safety estimate.
12. What the Result Does, and Does Not, Mean
The study addresses an important statistical distinction: whether a device meets an acute, predefined technical-performance criterion is not the same question as whether it improves longer-term outcomes or is preferable to another approach. The primary endpoint concerns lesions meeting a protocol definition of successful ablation at 1-day post ablation. That makes it an immediate procedural measure. The registry record does not post the primary result, so the observed technical-performance outcome cannot be evaluated from the available results.
The safety figures provide descriptive information for the enrolled group: serious events affected 2 of 8 at risk, other adverse events affected 7 of 8 at risk, and deaths were 0. The listed serious terms include FEVER and HYPOCALCEMIA, each at 12.5%. These observations do not quantify comparative risks because the study had no control group. They also do not establish how the events relate causally to the device beyond the registry’s outcome framing.
The design can document what was recorded in a treated group, but it cannot separate the effect of treatment from other explanations for observed outcomes as a randomized comparison can. The record does not report a comparison with another device, procedure, or usual care. It also does not provide longer-term primary results or analysis estimates for the listed secondary outcomes.
Accordingly, the registry supports a description of the study design, its acute technical endpoint, and a limited set of safety counts. It does not support a quantitative conclusion about primary endpoint success, a comparative treatment effect, or the precision of an effect estimate. Such conclusions would require results and methods not reported in the registry record.
13. Why This Trial Matters Statistically
This study is statistically notable for the gap between its clearly named primary question and the results available in the registry. The endpoint is specific in broad terms: a count of lesions meeting a protocol-defined technical-success criterion at 1-day post ablation. But the record lists no analysis results. A well-defined question is important, yet a question without an observed result cannot show the measured performance or its uncertainty.
The unit of analysis is also central. The study enrolled 8 participants, whereas the primary endpoint is defined in lesions. Without the number of lesions treated, readers cannot determine the endpoint denominator or how observations may be distributed across participants. General statistical practice requires aligning the unit used in the analysis with the way observations were collected and accounting for within-participant dependence when appropriate. The registry does not report these analytic details.
The single-group design further limits interpretation. Descriptive outcomes may characterize this group, but do not yield a randomized contrast. This is particularly important when readers are tempted to interpret an event count or technical outcome as evidence of a difference versus another approach. No such comparison is reported.
The listed secondary measures span several types of outcomes, while the registry lists 18 outcome measures and 0 analyses. This makes it especially important to distinguish outcomes specified in the record from outcomes with posted estimates. The registry’s sample-size assumptions are planning illustrations and should not be treated as observed power or as a substitute for an outcome estimate. Statistical transparency depends not only on naming endpoints, but also on reporting the analysis population, method, estimate, and uncertainty.
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.
Several study-specific limitations follow from the registry information. The study was open-labeled, non-randomized, and single-group, with no separate comparator. Its observations therefore cannot provide a randomized comparison of VORTX Rx treatment with another intervention. The record lists enrollment of 8, which limits the amount of information available to characterize outcomes in this group, especially for less frequent events.
The primary endpoint is lesion-based, but the number of lesions treated and the number meeting the technical-success definition are not reported in the registry record. Participant enrollment alone does not reveal the lesion denominator. The protocol definition is referenced but not reproduced, making it difficult to assess exactly how technical success was classified. The record also does not report whether multiple lesions from one participant were analyzed with methods that account for their relatedness.
Although the study is listed as completed, the primary outcome has no posted analysis result. The record lists 18 outcome measures and 0 analyses. It does not report confidence intervals, p-values, analysis populations, missing-data handling, multiplicity procedures, or detailed statistical methods. Follow-up details for secondary outcomes and the results of the listed liver-panel assessments are not reported in the registry record.
The safety counts are descriptive and come from a study without a comparator. Event narratives, timing, and additional attribution details are not reported. These limitations restrict both the interpretation of individual events and any broader comparative conclusion. The registry record also does not report the trial’s own sample-size justification or detailed eligibility criteria.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Study to Evaluate VORTX Rx (Theresa) — NCT03741088.
- Registry record last updated 2021-04-20; status last verified 2021-03.
- Results first posted 2021-02-25.
- 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
NCT03741088 is a completed, multicenter, open-labeled, non-randomized, single-group study sponsored by HistoSonics, Inc. It evaluated VORTX Rx focused ultrasound ablation for primary and metastatic liver tumors. Enrollment was 8; the recorded start date was 2018-03-21 and the primary completion date was 2019-05-15.
The primary endpoint was the number of lesions meeting the protocol-defined technical-success criterion at 1-day post ablation. The record lists 18 outcome measures and 0 analyses, and does not report a primary endpoint result. In the VORTX Rx Treatment group, 2 of 8 were affected by serious adverse events, 7 of 8 by other adverse events, and deaths were 0. FEVER and HYPOCALCEMIA are each listed at 12.5% among the top serious terms. Because the study had no comparator, these safety counts are descriptive rather than comparative.