Rapid Renal Sympathetic Denervation for Resistant Hypertension: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Rapid Renal Sympathetic Denervation for Resistant Hypertension (NCT01520506), a na na study. The primary outcome is Acute Procedural Safety.

2. Clinical Question

This is a focused safety question about events around the procedure, not a comparative question about whether the device changes blood pressure relative to another treatment. The record also lists chronic procedural safety and renal denervation procedure effectiveness as secondary outcomes, but numerical results for those outcomes are not reported in the registry record. The available descriptions establish what the investigators intended to assess; they do not establish the observed frequency of the primary endpoint or the magnitude of any effectiveness outcome.

3. Trial Design

The registry record describes Rapid Renal Sympathetic Denervation for Resistant Hypertension Using the OneShot™ Ablation System, sponsored by Medtronic Endovascular. The study is marked completed, with a start date of 2012-05 and primary completion in 2013-11. The record lists enrollment as 50. Phase is recorded as NA, allocation as NA, masking as NONE, and the model as SINGLE GROUP.

The intervention is the Covidien OneShot™ System, classified as a device. The listed group is Rapid Renal Denervation. Because this is a single-group design without a listed comparator, the study does not provide a randomized, concurrent comparison between the device and another intervention. The registry record does not describe a control condition or an allocation procedure.

The single-group structure is important when interpreting both safety and effectiveness. Events observed after a procedure can be described, but without a concurrent comparison they cannot by themselves identify how event frequency differs from another treatment or from the course that would have occurred without the procedure. Likewise, any change in an outcome over time would not alone isolate the device's contribution. Numerical results for the listed primary and secondary outcomes are not reported in the registry record.

The record identifies resistant hypertension as the condition and describes the device as delivering low-level radio frequency energy through the wall of the renal artery to denervate the kidney. Further details about eligibility, the procedure, follow-up assessments, and analysis populations are not reported in the registry record. The design and intervention description should therefore be read as a limited account of the study structure, rather than a complete protocol.

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

Reasons for not completing this period:

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Acute Procedural Safety, measured over One Week.

The primary endpoint is titled Acute Procedural Safety. It is defined as the overall rate of serious adverse events and adverse device effects at discharge, with a timeframe of one week. The description specifies serious events related to groin and vascular access complications and serious events related to renal artery injury. The unit is percentage of participants, and the listed measure type is NUMBER.

Safety endpoints of this kind are used to describe complications associated with a procedure and its device, particularly during the period named in the endpoint. They are clinically and statistically different from an effectiveness endpoint: they concern harms or adverse effects rather than a change in the condition being treated. A percentage can describe the frequency of participants meeting an event definition only when its numerator, denominator, and ascertainment are clear.

The endpoint definition is present, but its observed numerical result is not reported in the registry record. The adverse-event figures listed elsewhere in the record do not establish the result for this specific endpoint: the record does not show that those counts correspond to the endpoint's restricted definition, discharge assessment, or one-week timeframe. As a result, the primary safety rate and its precision cannot be interpreted from the available record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Interpreting a clinical endpoint starts with identifying what is counted, who is included, and when events are assessed. Here, the primary endpoint is a percentage of participants and concerns acute procedural safety at discharge within a One Week timeframe. Its definition specifies serious events related to access complications or renal artery injury, along with adverse device effects. The registry record does not report an observed value for this endpoint, its numerator and denominator, or an interval estimate. Without those elements, its magnitude and precision cannot be evaluated.

What does a percentage endpoint mean?

In general, a percentage endpoint expresses the proportion of an analysis population that meets a stated event definition. Its interpretation depends on the definition, observation period, and population included. For a safety endpoint, the event criteria also matter: an all-cause adverse-event count is not necessarily equivalent to a narrower endpoint that includes specified serious events or device effects. The registry record gives the primary definition, but it does not report a result that can be matched to that definition.

In general, an interval estimate communicates the uncertainty around an estimated percentage. It depends on the observed data and the method used to calculate it. Reporting the estimate alone would not fully communicate precision; an interval would help readers assess the range of values compatible with the data and method. No such primary-endpoint estimate or interval is reported in the registry record. A formal significance test would answer a different question and would also require a stated analysis and comparison or reference value, neither of which is reported for the primary endpoint.

Why does the single-group design matter?

In general, a single-group study can describe events observed among participants receiving an intervention. It cannot directly estimate a treatment contrast against a concurrent control group because no such group is included. A before-and-after change, if reported, would also need cautious interpretation: changes can reflect factors other than the intervention, and the registry record does not provide results or an analysis for the secondary effectiveness outcome. The listed study model is SINGLE GROUP, and no comparator is listed.

The record lists allocation as NA and masking as NONE. These entries describe the registry's design classifications; they do not supply further information about participant selection, outcome assessment, or procedures for reducing bias. Additional protocol details are not reported in the registry record. Phase is also recorded as NA, which does not provide a statistical analysis plan.

How should the planning assumptions be read?

The registry record 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 also states that the effect to detect is a stated fraction of the observed effect. These are planning assumptions, not evidence that the trial itself used that design or analysis. They do not override the recorded single-group model or establish a control group in this study. The effect fractions and resulting sample-size values are not reported in the registry record.

In general, a planning sample size estimates how many participants a future design may require under specified assumptions. It is not an observed study result and is not observed power. The registry's planning description cannot establish how the trial's enrollment was chosen because the trial's own sample-size justification is not reported in the registry record. The record also does not report an interim-analysis plan or a statistical analysis plan.

Why can over-dispersion matter?

In general, over-dispersion occurs when observed variability exceeds what a statistical model assumes. It can make standard errors too small if the model does not account for that extra variability, leading to intervals that are too narrow or tests that appear more decisive than warranted. This concept is relevant to some count and rate outcomes, but the primary endpoint is described as a percentage of participants. The registry record does not report a model, dispersion estimate, or analysis that would allow readers to assess whether over-dispersion was relevant to any outcome.

More broadly, sound interpretation requires matching the method to the endpoint and design. The registry record names the primary measure and its timing, but provides no analysis results, confidence intervals, or methods for handling repeated observations or event ascertainment. Those methods are not reported in the registry record. The adverse-event fields can be read descriptively as posted, but they do not replace the missing endpoint-specific analysis.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Rapid Renal Denervation")
n      <- c(50)
events <- c(2)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Rapid Renal Denervation  50  2  4.0  0.5  13.7  1.1  13.5  1.2  13.5

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists three outcome measures and records zero analyses. It does not report a multiplicity adjustment, a hierarchy of outcomes, or a prespecified strategy for controlling the chance of false-positive findings across multiple statistical tests. Without an analysis plan or reported tests, it is not possible to determine whether multiplicity was considered or how it would affect interpretation. General statistical practice recognizes that conducting multiple tests can increase the chance of at least one apparently positive finding, but no such inferential findings are reported.

Missing-data methods are also not reported in the registry record. There is no reported account of participants with missing endpoint assessments, withdrawals, exclusions from analysis, or how missing values were handled. The primary endpoint's analysis population is not reported in the registry record. Enrollment is listed as 50, but that entry alone does not specify how many participants had an endpoint assessment or were included in a particular analysis.

Likewise, the record does not describe whether analyses were based on all enrolled participants, those who received the procedure, or a defined subset. It does not report an approach to incomplete follow-up or the handling of participants whose event status could not be determined. These are important details for a one-week safety measure because the interpretation of a percentage depends on both the event definition and the participants contributing to its denominator.

These omissions do not prove that missing information or multiplicity affected the findings. They mean that the record does not permit assessment of those issues. The reported adverse-event figures should be interpreted as descriptive entries, without inferring a complete analysis population or an adjustment procedure.

12. Safety Results

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

Other (non-serious) adverse events

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

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: cardiac disorders (14.0%), vascular disorders (6.0%), infections and infestations (4.0%), respiratory, thoracic and mediastinal disorders (4.0%), blood and lymphatic system disorders (2.0%).

The adverse-event record lists the Rapid Renal Denervation group with 50 at risk for serious events and 16 affected; it also lists 50 at risk for other adverse events and 32 affected. These are the figures posted for the group, not the reported result of the primary Acute Procedural Safety endpoint. The record does not clarify whether these counts use the same event criteria, timing, or analysis population as that endpoint.

The serious-event categories are listed as Cardiac disorders, 14.0%; Vascular disorders, 6.0%; Infections and infestations, 4.0%; Respiratory, thoracic and mediastinal disorders, 4.0%; Blood and lymphatic system disorders, 2.0%; and General disorders and administrative site conditions, 2.0%. Denominators and the relationship between these categories and the affected-participant count are not reported in the registry record. The categories should not be added together or assumed to represent separate participants.

The death field has no reported value; that is not evidence of zero deaths. Overall, these entries describe the adverse-event information as recorded, but they do not establish the acute endpoint rate or explain causal attribution.

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

The record establishes that the study was completed and that it evaluated the Covidien OneShot™ System in a single group with resistant hypertension. It also defines a primary safety endpoint focused on serious adverse events and adverse device effects associated with specified procedural complications at discharge, within One Week. These are relevant features for understanding the study's purpose and the kind of safety question it was designed to address.

However, the primary endpoint's numerical result is not reported in the registry record. The adverse-event figures listed for the Rapid Renal Denervation group are not explicitly linked to the endpoint's definition or timeframe. The record therefore does not show the observed primary safety rate, its precision, or an analysis of that endpoint. The secondary outcomes, including chronic procedural safety and renal denervation procedure effectiveness, also lack numerical results in the registry record.

The study's single-group design is another limit on what can be inferred. Descriptive event information can characterize what was recorded in the group, but it cannot by itself determine how event frequency compares with an alternative intervention or what would have happened without the device. No concurrent comparator is listed. The record also does not report enough information about analysis populations, missing data, or endpoint ascertainment to resolve those concerns.

Thus, the posted record supports a description of the study design, the endpoint definitions, and the adverse-event entries. It does not support a quantified conclusion about the primary endpoint or a comparative conclusion about safety or effectiveness. Those distinctions are important: absence of a reported result is not evidence that no events occurred, and a listed adverse-event count is not automatically an estimate of the endpoint the study identified as primary.

14. Why This Trial Matters Statistically

This trial is statistically instructive because the registry record distinguishes a defined endpoint from an endpoint result. Acute Procedural Safety has a named measure, specified event types, and a one-week timeframe. Yet no numerical result for that endpoint is reported. A clear definition is essential for interpretation, but it does not substitute for an estimate, denominator, or measure of uncertainty.

The study also illustrates why design shapes the questions that results can answer. The record identifies a single group and no comparator. That structure can support descriptive reporting of events in the treated group, but it does not create a direct treatment contrast. Any comparative claim would require a suitable comparison and analytic assumptions not reported in the registry record.

Another statistical lesson is the importance of separating general adverse-event summaries from a narrowly defined primary outcome. The record lists counts and serious-event categories, but does not establish that these entries correspond to the primary endpoint's event criteria and assessment time. Treating them as interchangeable would obscure the distinction between broad safety reporting and the specific outcome selected for primary evaluation.

Finally, a completed status and an enrollment entry do not answer questions about analysis methods, missingness, or precision. Those details are needed to understand how an estimate was constructed and how much uncertainty surrounds it. Here, the record lists three outcome measures and zero analyses, while the primary endpoint's result is not reported. The case demonstrates why transparent endpoint-level reporting matters for clinical interpretation.

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 principal limitation for interpreting this trial from the registry record is that the numerical primary endpoint result is not reported. There is no endpoint estimate, confidence interval, or statistical test for Acute Procedural Safety. The secondary outcomes are named, but their numerical results are not reported in the registry record either.

The adverse-event information is not accompanied by enough detail to connect it to the primary endpoint. The record does not report whether the serious and other event counts reflect the endpoint's specified event types, its discharge assessment, or the One Week timeframe. It also does not report the denominators for the serious-event category percentages or explain whether categories can overlap. The death field has no reported value, which should not be interpreted as a zero count.

Design and analysis information is limited. The model is single group, allocation is NA, and no comparator is listed, so a direct comparison is unavailable. Masking is recorded as NONE. Eligibility criteria beyond the condition, endpoint ascertainment procedures, analysis populations, missing-data handling, and a statistical analysis plan are not reported in the registry record. The sample-size justification and any interim-analysis plan are also not reported in the registry record.

These gaps limit assessment of precision, bias, and the relationship between the posted event entries and the primary question. They do not establish that the study lacked procedures or analyses; they indicate that those details are not reported in the registry record. Interpretation should remain within what the posted record documents.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Rapid Renal Sympathetic Denervation for Resistant Hypertension — NCT01520506.
• Registry record last updated 2019-03-01; status last verified 2019-02.
• Results first posted 2015-09-16.
• 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 registry record describes a completed, single-group device study of rapid renal denervation for resistant hypertension. It lists enrollment as 50 and the Covidien OneShot™ System as the intervention. The primary outcome is Acute Procedural Safety, defined around specified serious procedural events at discharge within One Week.

The record does not report a numerical result for the primary endpoint, nor numerical results for the listed secondary outcomes. It includes serious and other adverse-event counts and serious-event category percentages, but does not establish that these are the primary endpoint results. With no listed comparator and no reported endpoint analysis, the record supports a limited descriptive account rather than a comparative assessment of safety or effectiveness.