Comparison of Two Pulmonary Embolism Treatments: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Comparison of Two Pulmonary Embolism Treatments (NCT05684796), a randomized na study. The primary outcome is Change in RV/LV Ratio.

2. Clinical Question

3. Trial Design

STORM-PE is described in the registry as a prospective, multicenter, randomized controlled trial. It uses a parallel-group design and is unmasked. Randomization assigns participants to anticoagulation alone or to anticoagulation plus mechanical aspiration thrombectomy with the Indigo Aspiration System. The registry record lists the enrollment as 100 and the status as completed. The start date is 2023-11-27, and the primary completion date is 2025-06-12. The phase is listed as NA.

The registry describes the anticoagulation group as receiving anticoagulants without a procedure. The Indigo group receives anticoagulants and mechanical aspiration thrombectomy. Because the trial is unmasked, participants and study personnel are not described as blinded to assignment. The registry record does not report additional details about allocation concealment, the randomization sequence, or procedures used to reduce assessment bias. Those aspects of the protocol are not reported in the registry record.

The primary endpoint is the change in RV/LV ratio at 48 hours post-randomization, assessed by computed tomography pulmonary angiography. Secondary outcome areas include major adverse events; walking capacity; functional status and dyspnea measures; and quality of life. The registry lists 12 outcome measures and indicates that 11 secondary outcomes are posted. The number of formal analyses is listed as zero; formal analysis details are not reported in the registry record.

The registry record does not report the trial’s original sample-size justification, its planned analysis population, or whether interim analyses were planned. Nor does the record explain how missing outcome measurements were handled. The sample-size figures associated with the posted results are planning illustrations based on observed effects, not the trial’s original design rationale. The sponsor is Penumbra Inc.

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 Change in RV/LV Ratio, measured over 48 hours post-randomization.

The primary endpoint is change in the RV/LV ratio at 48 hours after randomization, measured on original therapy using computed tomography pulmonary angiography. The ratio compares right ventricular and left ventricular diameter. The registry description states that negative change values represent a reduction in the ratio and are consistent with improvement in right ventricular dilation.

This endpoint is used to quantify a change in cardiac structure on imaging rather than to directly measure symptoms, exercise capacity, quality of life, or survival. Such a measure can provide an objective way to compare the groups’ average imaging changes over the specified timeframe. It is one dimension of the treatment comparison and should be interpreted alongside other outcomes, including adverse events and functional measures.

The registry reports a mean change of -0.24 with a standard deviation of 0.4 for anticoagulation, and a mean change of -0.52 with a standard deviation of 0.37 for Indigo. The negative values in both groups indicate a reduction in the ratio on average. These summaries describe the posted measurements; they do not establish that every participant had the same direction or magnitude of change.

The endpoint is specifically the change at 48 hours, not a direct measure of longer-term recovery. The registry record does not report additional information about the clinical interpretation threshold for the RV/LV ratio or the importance assigned to a particular size of change. Consequently, the estimate describes a group-level imaging contrast and should not be treated as a complete account of benefit or risk.

7. Results Posted in the Registry

• Indigo: mean -0.52 versus -0.24 on control; difference -0.28 (95% CI -0.43 to -0.13), standardized effect d = -0.72; z-test p = <0.001.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Functional Outcome Assessment With the 6-minute Walk Test

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Indigo: mean 478.70 versus 368.00 on control; difference 110.70 (95% CI 40.02 to 181.38), standardized effect d = 0.77; z-test p = 0.002.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Indigo than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Functional Outcome Assessment With the Modified Medical Research Council Dyspnea Scale

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Indigo: mean 0.40 versus 0.60 on control; difference -0.20 (95% CI -0.61 to 0.21), standardized effect d = -0.21; z-test p = 0.336.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Indigo and the control. The interval gives the range of effects that remain compatible with the data.

Quality of Life Assessment With the Pulmonary Embolism Quality of Life Questionnaire

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Indigo: mean 15.80 versus 21.70 on control; difference -5.90 (95% CI -14.88 to 3.08), standardized effect d = -0.28; z-test p = 0.198.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Indigo and the control. The interval gives the range of effects that remain compatible with the data.

The posted secondary results span functional capacity, dyspnea, and quality of life, alongside listed outcomes for adverse events and other assessments. Across the three secondary continuous outcomes with numerical comparisons, the evidence is not uniform: the 6-minute walk result has an interval excluding zero, while the dyspnea and pulmonary embolism quality-of-life intervals include zero. This range of findings is compatible with outcome-specific differences in effect, precision, or both; the measures address different aspects of recovery and cannot be read as repeated measures of the same thing.

The primary result concerns an imaging measure at 48 hours. Secondary measures assessed through 90 days address later function and quality of life. They therefore complement, rather than duplicate, the primary endpoint. A group difference in the imaging outcome does not establish that every functional or quality-of-life outcome will show a corresponding difference. Conversely, a secondary result cannot by itself confirm or overturn the primary imaging comparison.

The registry lists 11 posted secondary outcomes, but numerical summaries are not reported in the registry record for every listed measure. The record also reports no formal analyses for the secondary outcomes. The secondary estimates that are posted are unadjusted. General statistical explanation: when many outcomes are considered, isolated small p-values can arise by chance, so prespecified analysis and multiplicity control affect how strongly such results should be interpreted. The registry record does not report a multiplicity procedure or a prespecified hierarchy.

For these reasons, secondary results are useful for describing the broader pattern and identifying questions for further study, but they carry less confirmatory weight than a primary outcome tested under a prespecified analysis plan. The registry record does not report enough analysis detail to establish that the secondary comparisons were prespecified, adjusted, or intended as confirmatory. They should be considered alongside the primary estimate, the intervals, the safety summaries, and the limitations in outcome reporting.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Major Adverse Events
• Functional Outcome Assessment With the 6-minute Walk Test
• Functional Outcome Assessment With the New York Heart Association Classification
• Functional Outcome Assessment With the Post Venous Thromboembolism Functional Status Scale
• Functional Outcome Assessment With the Modified Medical Research Council Dyspnea Scale
• Functional Outcome Assessment With the Borg Scale
• Quality of Life Assessment With the Pulmonary Embolism Quality of Life Questionnaire
• Quality of Life Assessment With the EQ-5D-5L Questionnaire

9. Statistical Interpretation

10. Statistical Methods Explained

General statistical explanation: a continuous outcome is often summarized by its mean and standard deviation. The mean describes the group’s average observed value, while the standard deviation describes how spread out individual values are around that average. Neither number shows the full distribution, and neither implies that every participant experienced a value close to the mean.

For the primary endpoint, the registry reports mean changes and standard deviations for both groups. The posted comparison is a mean difference, calculated as the Indigo group mean minus the anticoagulation group mean. Its value is -0.28. Since the outcome is a change score and negative values represent a reduction in RV/LV ratio, the negative contrast indicates a greater average reduction in the Indigo group in these summaries. The comparison is unadjusted and recalculated from posted summary statistics. The registry record does not report an adjusted estimate or a formal analysis model for the primary result.

What does the comparison interval describe?

General statistical explanation: a confidence interval expresses uncertainty about an estimated quantity under the assumptions of the method used to construct it. For a mean difference, an interval that excludes zero is consistent with a nonzero difference under that method. An interval that includes zero is compatible with a range of possibilities that includes no difference. An interval is not a guarantee that the true value lies within its endpoints, and it does not describe the spread of individual outcomes. The registry record does not state the confidence level for the posted intervals, so a confidence level is not assigned.

The primary comparison interval excludes zero. The unadjusted p-value is <0.001. General statistical explanation: a p-value measures how unusual data at least as incompatible with a null hypothesis would be if that hypothesis and the test assumptions held. It is not the probability that a treatment effect is real, and it does not measure effect size or clinical importance. Because the posted p-value is unadjusted, it does not account for testing several endpoints.

Why do group sizes and variability matter?

General statistical explanation: an estimated mean difference is more precise when the measurements are less variable and when there is more information in the groups. The standard error reflects uncertainty in an estimated mean; the registry summaries list standard errors for each group. Standard deviations instead describe variability among individual measurements. These quantities answer related but different questions. The primary group standard deviations are 0.4 and 0.37, while the listed standard errors are 0.056 and 0.055.

The primary outcome summaries list 52 participants for anticoagulation and 46 for Indigo. These counts differ by group and should be read as the outcome-specific counts associated with the posted summaries, not as proof of the analysis population or of the reason for any difference. The registry record does not report why those counts differ from the enrollment figure, how missing measurements were handled, or which analysis population was used.

What does randomization contribute?

General statistical explanation: random allocation is intended to make treatment assignment independent of measured and unmeasured participant characteristics on average. It supports a causal comparison when trial conduct, follow-up, and analysis preserve the benefits of assignment. Randomization does not ensure that groups are identical in every realized sample, and it cannot resolve biases caused by missing outcome data, deviations from assigned treatment, or outcome assessment. The registry identifies randomized allocation but does not report enough analysis detail to assess those issues fully.

The trial is unmasked. General statistical explanation: lack of masking may matter when expectations can affect care, participant reporting, adherence, or outcome assessment. The primary endpoint is assessed by computed tomography pulmonary angiography, but the registry record does not describe whether image readers were masked or how measurements were standardized. Those details are not reported in the registry record.

Why are the secondary comparisons more tentative?

General statistical explanation: when multiple outcomes are tested, the chance of obtaining at least one apparently unusual result can increase, even if no underlying differences exist. A prespecified testing hierarchy or multiplicity adjustment can address this issue. The registry record does not report a multiplicity strategy. The posted secondary p-values are unadjusted, so they should be interpreted as exploratory evidence rather than as a set of confirmatory tests. The record also lists no formal analyses for the secondary outcomes.

Continuous secondary measures are summarized with group means and standard deviations, with mean differences and intervals in the posted comparisons. The 6-minute walk test measures distance walked in meters; the dyspnea and quality-of-life instruments use their own scales. Direction and magnitude have to be interpreted according to each outcome’s definition. A change on one scale cannot be directly equated with a change on another.

General statistical explanation: over-dispersion is a concern when count data vary more than a chosen model expects. It is not a method used for these continuous mean comparisons, and the registry record does not describe a count model for the posted outcomes. The safety summaries are event counts, but a formal event-rate analysis is not reported in the registry record. This distinction matters because descriptive counts and model-based estimates are not the same kind of evidence.

11. Confidence Intervals and Precision

Precision concerns how narrowly an estimate is determined by the observed data and the method used. The primary mean difference is -0.28, with a comparison interval from -0.432 to -0.128 in the registry-derived statistics. That interval lies entirely below zero, indicating that the posted comparison is not compatible with a zero difference across the interval’s range. The unadjusted p-value is <0.001. The registry record does not state the confidence level for the interval, so its level is not specified.

The interval does not indicate the range of individual changes. Individual measurements can vary around each group mean, as reflected by the standard deviations of 0.4 and 0.37. Nor does the interval identify the probability that a particular effect is true. It describes uncertainty in the group-level mean difference under the calculation’s assumptions.

For the 6-minute walk test, the estimated mean difference is 110.7 meters, with an interval from 40.02 to 181.4 and an unadjusted p-value of 0.002. In contrast, the interval for the modified Medical Research Council Dyspnea Scale, from -0.607 to 0.207, includes zero, as does the interval for the Pulmonary Embolism Quality of Life Questionnaire, from -14.88 to 3.084. Those intervals convey less certainty about the direction of the corresponding mean differences.

General statistical explanation: interval width depends on variability, the amount of information, and the method used. A narrow interval can still surround an effect whose clinical importance is unclear, while a wide interval can leave several interpretations plausible. The registry record does not report a clinical threshold for meaningful change in the primary measure. Precision should therefore be considered separately from clinical importance and from the broader safety picture.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are expressed as participants per arm for 80% power and participants per arm for 90% power. They are not total participants across both groups, and they are not total event counts. The assumptions listed for these illustrations are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. Each planning scenario uses a stated fraction of the observed effect as the effect to detect.

For the primary endpoint, planning for 100% of the observed effect gives 30 participants per arm for 80% power and 40 participants per arm for 90% power. Planning for 75% of the observed effect gives 54 participants per arm for 80% power and 72 participants per arm for 90% power. Planning for 50% of the observed effect gives 120 participants per arm for 80% power and 160 participants per arm for 90% power.

In plain language, 80% power describes the chance of detecting the assumed effect under the planning assumptions if that effect is present; 90% power describes a higher chance under the same conditions. The calculation is conditional on the assumed effect, variability, allocation, and testing approach. A smaller effect is harder to distinguish from random variation, so the planning figures require more participants as the assumed effect becomes smaller.

These figures are planning illustrations based on the observed effect, not observed power and not the trial’s original design justification. The registry record does not report the original sample-size assumptions or explain whether the completed trial was designed around the same effect, variance, allocation, or analysis method used for this illustration. The values are therefore best read as hypothetical design requirements under the listed assumptions, rather than as a retrospective judgment about the trial’s adequacy.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = -0.280; pooled standard deviation σ = 0.386.
2. n = 2 × (1.96 + 0.842)² × 0.386² / -0.280² = 29.9, rounded up to 30 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- -0.28                      # observed difference in means
sigma <- 0.386227750168214                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(5684796)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 30 (80% power), 40 (90% power)
 75% of observed effect: n per arm = 54 (80% power), 72 (90% power)
 50% of observed effect: n per arm = 120 (80% power), 160 (90% power)
power.t.test: 30.9 
Simulated power at n = 30 per arm: 0.790 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when a study evaluates several outcomes or performs several comparisons. General statistical explanation: without a plan for handling multiple tests, the chance of at least one apparently unusual result can increase. Approaches such as a testing hierarchy or an adjustment to significance thresholds can help preserve the intended error rate. The registry record does not report a multiplicity strategy, a testing hierarchy, or whether secondary outcomes were treated as confirmatory or exploratory. The posted secondary p-values are unadjusted and should be interpreted with that limitation in mind.

The record lists 12 outcome measures and 11 posted secondary outcomes, while the number of reported analyses is listed as zero. Numerical results are available for the primary outcome and for three secondary continuous outcomes in the statistical summaries, but formal analysis descriptions are not reported in the registry record. The record does not state which outcomes were included in a prespecified analysis plan, whether all planned outcomes were reported, or whether any analyses were changed after the trial began.

Missing outcome data can affect group comparisons if the people with measurements differ systematically from those without measurements. General statistical explanation: a group mean based only on observed outcomes may not represent the full randomized group when missingness is related to outcome or treatment assignment. The registry record does not report missing-data methods, reasons for missing measurements, imputation procedures, or sensitivity analyses. The outcome-specific participant counts differ across measures, but the record does not explain why.

The registry also does not report the analysis population, such as whether participants were analyzed according to randomized assignment or according to treatment received. Nor does it describe protocol deviations or treatment discontinuations. These omissions limit assessment of how closely the posted summaries reflect the randomized comparison and how robust the results are to missing data or analysis choices. The record does not report interim analyses or stopping rules; those details are not reported in the registry record.

15. 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.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: hemoptysis (2.1%), cardiac arrest (2.1%), left radial artery bleed (2.1%), new acute bilateral le dvt and edema (2.1%), adenocarcinoma of the gastroesophageal junction (2.1%).

The safety summaries list serious adverse events in 14 of 53 participants at risk in the anticoagulation group and 11 of 47 at risk in the Indigo group. Other adverse events are listed for 5 of 53 and 8 of 47, respectively. Deaths are recorded as 1 in the anticoagulation group and 4 in the Indigo group. These are descriptive counts, not adjusted comparisons, and the registry record does not provide a formal statistical analysis of the safety outcomes.

The listed serious adverse event terms each have a reported frequency of 2.1%: hemoptysis, cardiac arrest, left radial artery bleed, new acute bilateral LE DVT and edema, adenocarcinoma of the gastroesophageal junction, and anaphylactic shock. The registry record does not provide further detail about timing, severity grading, relationship to treatment, or whether events could be counted in more than one category. These details are not reported in the registry record.

Counts alone do not establish whether an event was caused by treatment or whether the groups differ reliably in risk. The denominators and event ascertainment matter, and small counts can be imprecise. Safety should be interpreted alongside the randomized design and the available follow-up, while recognizing that the registry record does not report a formal comparative safety analysis.

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

The primary posted result shows different average changes in RV/LV ratio between the randomized groups at 48 hours. The Indigo group’s mean change was -0.52, compared with -0.24 for anticoagulation alone; the unadjusted mean difference was -0.28. The interval excludes zero and the unadjusted p-value is <0.001. Because negative changes indicate a reduction in the ratio, the observed group averages favor a larger reduction in the Indigo group on this imaging measure.

This finding is limited to a particular endpoint, assessment method, and timeframe. It does not establish that every participant had a reduction, or that the magnitude of the group-average contrast is clinically important. The registry record does not report a threshold for a meaningful change in RV/LV ratio. It also does not provide a formal adjusted primary analysis, detailed missing-data methods, or a confidence level for the posted interval.

The primary measure is not a complete summary of treatment outcomes. The record also includes functional, quality-of-life, and safety outcomes. Their posted results do not all provide the same degree of statistical precision, and the secondary p-values are unadjusted. Serious adverse event and death counts are descriptive, without a formal comparative safety analysis in the registry record. The primary result therefore should not be interpreted as resolving the balance of all potential benefits and harms.

The randomized design supports comparison of assigned strategies, but interpretation also depends on trial conduct, outcome availability, analysis methods, and the extent to which the registry’s posted summaries reflect prespecified procedures. Several of those details are not reported in the registry record. The most defensible reading is that the posted summaries indicate a difference in average short-term imaging change, while broader conclusions about safety, function, quality of life, and longer-term outcomes remain limited by the information reported.

17. Why This Trial Matters Statistically

This trial illustrates why statistical interpretation should separate the size of an estimate from its precision and from its clinical importance. The primary mean difference is -0.28, and its interval excludes zero, indicating a comparatively clear group contrast under the unadjusted calculation. That does not establish how important the difference is for patients, because the registry record does not report a threshold for a meaningful change in RV/LV ratio.

The trial also highlights the value of looking beyond a single endpoint. The primary measure is an imaging change at 48 hours, whereas secondary assessments address function and quality of life through 90 days. Their results are not uniform in precision, and the safety summaries include serious events and deaths. These outcomes provide different kinds of information and should not be collapsed into one claim based on the primary p-value.

Statistically, the record makes the distinction between observed summaries and formal analysis important. Group means and unadjusted comparisons can be informative, but they do not reveal whether a prespecified model, missing-data strategy, or multiplicity plan was used. The registry record does not report those details. Transparent reporting of those methods would help readers judge how strongly to rely on each comparison and whether secondary findings are confirmatory or exploratory.

The planning illustrations also show how sample-size requirements depend on the effect a future study aims to detect. Smaller assumed effects require more participants under the stated assumptions. These planning figures are not a substitute for the trial’s original design rationale, which is not reported in the registry record. Overall, the statistical importance of STORM-PE lies in the combination of a randomized design, a measurable primary contrast, several complementary outcomes, and reporting gaps that constrain interpretation.

18. 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 limitations specific to this trial are visible in the registry record. The trial is unmasked, and the record does not say whether imaging readers or other outcome assessors were masked. The primary endpoint uses computed tomography pulmonary angiography, but the record does not describe image-reading procedures or measurement standardization. These details matter when interpreting an imaging-based outcome.

The primary comparison is an unadjusted recalculation from posted group summaries; a formal primary analysis is not reported in the registry record. The record does not state the confidence level for the posted intervals, identify the analysis population, or describe how missing outcomes were handled. Outcome-specific participant counts vary, and the reasons for those differences are not reported.

Although secondary outcomes cover function, dyspnea, and quality of life, numerical summaries are not reported in the registry record for every listed measure. No formal secondary analyses or multiplicity procedures are reported. The secondary estimates and p-values therefore have limited confirmatory interpretation, especially when considered across several outcomes.

Safety information is reported as counts, with no formal comparative analysis in the registry record. The record does not describe event timing, treatment relationship, or detailed ascertainment. It also does not report the original sample-size justification, interim-analysis plans, or the statistical analysis plan. These limitations do not negate the posted group summaries, but they constrain assessment of robustness, generalizability, and the full balance of outcomes.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Comparison of Two Pulmonary Embolism Treatments — NCT05684796.
• Registry record last updated 2026-08-18; status last verified 2026-07.
• Results first posted 2026-08-18.
• 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.

22. Record Summary

STORM-PE (NCT05684796) is a completed, prospective, multicenter, randomized, unmasked, parallel-group trial sponsored by Penumbra Inc. It compares anticoagulation alone with anticoagulation plus mechanical aspiration thrombectomy using the Indigo Aspiration System in intermediate-high risk acute pulmonary embolism. The registry lists enrollment as 100, a start date of 2023-11-27, and a primary completion date of 2025-06-12.

The primary endpoint is change in RV/LV ratio at 48 hours. The posted group means are -0.24 for anticoagulation and -0.52 for Indigo, with an unadjusted mean difference of -0.28 and an unadjusted p-value of <0.001. Secondary outcomes include functional and quality-of-life assessments, while safety summaries list serious adverse events, other adverse events, and deaths. The registry record does not report a formal analysis plan, multiplicity strategy, or missing-data methods.