Comparison of the Human Acellular Vessel (HAV) With ePTFE Grafts as Conduits for Hemodialysis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Comparison of the Human Acellular Vessel (HAV) With ePTFE Grafts as Conduits for Hemodialysis (NCT02644941), a randomized phase 3 study. The primary outcome is Number of Participants With Loss of Secondary Patency.

2. Clinical Question

The central comparison is the number of participants with loss of secondary patency in the HAV and ePTFE groups. This endpoint concerns whether the access remained usable as part of the dialysis circuit, rather than whether it remained free from interventions. The registry defines abandonment as having no remaining segment of the study conduit incorporated into the vascular access circuit used for dialysis. If some portion continued to be used for dialysis, the conduit was not considered abandoned.

The comparison is between two conduit strategies, not between access and no access. The randomized allocation supports a group-level comparison, but the registry record does not report enough information to assess how randomization was implemented, how participants were followed, or whether the analysis accounted for differences after allocation. The posted outcome is a count at a specified follow-up time; it does not by itself describe when each event occurred or how many interventions preceded it.

3. Trial Design

NCT02644941 is a phase 3, randomized, parallel-group study. The registry lists no masking, so the study is described as open-label. Its stated purpose was to compare HAV with ePTFE grafts when used for hemodialysis access. The listed enrollment is 355, and the record status is completed. The study start is recorded as 2016-05-24, with primary completion in 2019-05.

The HAV arm used a tissue-engineered vascular conduit described as 6mm in diameter. The ePTFE arm used one of two commercially available comparators, Bard Impra® or Gore PROPATEN®. The record does not report how the choice between those two ePTFE products was made, whether it was balanced across sites, or whether participants or clinicians could choose the product.

The posted primary outcome is the number of participants with loss of secondary patency at 12 months post-implantation. The registry also lists secondary outcomes addressing loss of primary patency, conduit abandonment, and conduit access-related infections. The posted secondary outcomes include measures at different follow-up times and use different measurement scales, so they do not all answer the same statistical question.

The registry lists 36 outcome measures, while the posted results include 29 secondary outcomes. It lists no analyses. The sample-size justification, randomization method, intended analysis populations, handling of missing outcome data, and original statistical analysis plan are not reported in the registry record. The posted planning illustrations are based on observed effects and are not evidence about the assumptions used to design the trial.

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.

18 months

Reasons for not completing this period:

24 months

60 months

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 Number of Participants With Loss of Secondary Patency, measured over 12 months post-implantation.

The primary endpoint is the number of participants with loss of secondary patency at 12 months post-implantation. The registry describes secondary patency as the interval from access placement until access abandonment, with the access considered patent whether or not interventions were needed. Abandonment means that no remaining segment of the study conduit is incorporated into the vascular access circuit used for dialysis; continued use of any portion means it is not considered abandoned.

This endpoint is used to describe whether a conduit remains part of the access circuit over follow-up, while allowing for interventions to maintain or restore patency. It therefore captures a broader aspect of access durability than an outcome that counts only uninterrupted patency. At the same time, a participant count at a follow-up time does not show the timing or number of interventions, the length of time each conduit remained usable, or the event history leading to abandonment. Those details are not reported in the primary result.

The posted result gives the number of participants with the endpoint in each arm. It is not a time-to-event estimate, and the registry does not report an adjusted primary analysis or additional detail about the primary endpoint population.

7. Results Posted in the Registry

• ePTFE: 19.1% (34/178) versus 16.4% (29/177) on control; risk difference 2.7 percentage points (95% CI -5.2 to 10.7), risk ratio 1.17 (0.74–1.83); unadjusted two-proportion z-test p = 0.503.

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.

Number of Participants With Loss of Primary Patency

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • ePTFE: 43.8% (78/178) versus 66.7% (118/177) on control; risk difference -22.8 percentage points (95% CI -32.9 to -12.8), risk ratio 0.66 (0.54–0.80); unadjusted two-proportion z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the proportion with the event is statistically lower for ePTFE than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Study Conduit Abandonment

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • ePTFE: 24.7% (44/178) versus 32.2% (57/177) on control; risk difference -7.5 percentage points (95% CI -16.8 to 1.9), risk ratio 0.77 (0.55–1.07); unadjusted two-proportion z-test p = 0.118.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between ePTFE and the control. The interval gives the range of effects that remain compatible with the data.

Rate of Adjudicated Study Conduit Access Related Infections

• Endpoint type: Event rate: events per unit of follow-up, compared as a rate ratio.
• Test: Poisson rate ratio, based on the estimated number of events and follow-up time.
• Result:
  • ePTFE: 4.54 versus 0.93 (Events per 100 Person-Years) on control; rate ratio 4.88 (95% CI 1.49–15.97, approximate, Poisson model); p ≈ 0.009.
• Interpretation:
  • The 95% confidence interval excludes no difference (a ratio of 1), so the event rate is statistically higher for ePTFE than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The secondary outcomes broaden the assessment beyond the primary measure of loss of secondary patency. They include loss of primary patency, conduit abandonment, and access-related infection outcomes. Together, these address different features of access performance: whether patency is maintained without the broader allowance for interventions, whether the conduit remains in use, and how often access-related infections occur relative to time at risk.

The pattern is not uniform across outcome types. The binary outcomes do not all point to the same degree of separation between groups, while the infection-rate comparison gives a more distinct contrast in the posted unadjusted analysis. This variation is a reason to avoid treating any one secondary result as a substitute for the primary endpoint. The outcomes measure different things, use different time frames, and have different statistical scales.

Secondary findings can help describe the broader clinical and statistical picture, but they generally carry less weight than a prespecified primary comparison when there are many outcomes. With numerous opportunities to compare groups, some apparently notable findings can arise by chance. The registry lists many outcome measures and does not report a multiplicity adjustment or a hierarchy for interpreting secondary outcomes. The unadjusted p-values should therefore be viewed as exploratory signals rather than definitive evidence.

These outcomes also do not explain why an individual conduit had an event or how interventions affected subsequent patency. The posted summaries do not provide participant-level sequences or adjusted comparisons. Interpretation should remain focused on the definitions and follow-up time attached to each endpoint, while recognizing that the registry record does not describe a unified analysis plan for integrating the secondary results with the primary finding.

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

• Number of Participants With Loss of Primary Patency
• Number of Participants With Loss of Primary Patency
• Number of Participants With Loss of Primary Patency
• Number of Participants With Loss of Primary Patency
• Study Conduit Abandonment
• Study Conduit Abandonment
• Rate of Adjudicated Study Conduit Access Related Infections
• Access-related Infections

9. Statistical Interpretation

10. Statistical Methods Explained

What does the risk difference represent?

For a binary outcome, such as whether a participant had loss of secondary patency, a risk difference compares the proportion with the event in one arm against the proportion in the other. The posted contrast uses ePTFE relative to HAV. A value above zero indicates a higher observed event proportion in ePTFE; a value below zero indicates a lower observed event proportion in ePTFE. Zero represents no difference in the observed proportions. The primary risk difference is 0.027.

The proportions used in the primary comparison are 0.164 for HAV and 0.191 for ePTFE. Their observed counts are 29 of 177 and 34 of 178, respectively. The risk difference is useful because it expresses the contrast in absolute rather than relative terms. The confidence interval around that contrast reflects uncertainty from the available group data; it is not a range containing a specified share of individual participant outcomes.

How should the relative measures be read?

A risk ratio compares the event proportions as a ratio, while an odds ratio compares the odds of the event. Both are relative measures, and their numerical values are not interchangeable with the risk difference. The posted primary risk ratio is 1.166, with a confidence interval from 0.744 to 1.828. The odds ratio is 1.205, with a confidence interval from 0.698 to 2.08. Each interval includes the value representing no relative difference. These measures are also unadjusted recalculations from the posted summaries.

What does the p-value add?

The primary unadjusted p-value is 0.503. A p-value assesses how inconsistent the observed data are with a specified null model, given the test assumptions. It does not measure the size or importance of an effect, and it is not the probability that the null hypothesis is true. The record does not report a detailed test specification, covariate adjustment, or a multiplicity procedure for the primary comparison. The p-value should therefore be considered alongside the effect estimate and its confidence interval rather than as a stand-alone verdict.

Why distinguish counts from rates?

The primary outcome and several secondary outcomes are binary participant counts: each participant is classified according to whether an event occurred during the stated follow-up. A rate outcome instead relates events to time at risk. The adjudicated access-related infection outcome is reported as events per 100 person-years, and its comparison is expressed as a rate ratio. A rate can reflect recurrent events and unequal time at risk in a way a simple participant count cannot.

For the infection rate, the posted HAV and ePTFE values are 0.93 and 4.54 events per 100 person-years. The posted rate ratio for ePTFE relative to HAV is 4.882, with a confidence interval from 1.492 to 15.97 and an unadjusted p-value of 0.009. The record identifies a Poisson approach for this calculation. In general, Poisson methods model event counts relative to exposure time. Over-dispersion matters when the observed variability is greater than the model expects: it can make conventional uncertainty estimates too narrow if not handled appropriately. The registry record does not report a check for over-dispersion or an alternative model.

What is and is not documented about analysis?

The registry lists no analyses. It does not report whether the primary comparison was prespecified in an analysis plan, whether stratification or adjustment was planned, how missing outcome information was handled, or which analysis population was intended. It also does not report a detailed account of censoring or follow-up completeness. These omissions limit assessment of the analysis beyond the posted summary comparisons.

General statistical practice distinguishes an intention-to-treat analysis, which retains participants according to randomized assignment, from analyses based on treatment received or on a defined evaluable population. The population used for the posted results is not reported in the registry record. It is therefore not possible to determine from these results alone whether all randomized participants were included in each endpoint comparison or how deviations from assigned treatment were handled.

The number of endpoint outcomes and the number of analysis entries are not the same thing. An outcome may have a posted result without a corresponding reported analysis description. For this record, analysis details should not be inferred from the presence of outcome counts or calculated comparisons.

11. Confidence Intervals and Precision

The primary risk difference is 0.027, with a 95% confidence interval from -0.052 to 0.107. The interval includes zero, so the data are compatible with no difference in event proportions as well as with differences in either direction. Its width signals that the posted primary comparison does not pin down the contrast precisely. The record does not provide a prespecified threshold for deciding what range of differences would be clinically important.

A confidence interval describes uncertainty about an estimated group contrast under the statistical method used. It does not mean that the true effect has a 95% probability of lying within the observed interval. It also does not describe the range of outcomes expected for individual participants. The interval should be interpreted as a measure of precision for the estimate, subject to the analysis assumptions and the completeness and quality of the posted data.

The relative primary estimates are also uncertain. The risk ratio confidence interval, 0.744 to 1.828, includes the no-relative-difference value. The odds ratio confidence interval, 0.698 to 2.08, does as well. Because both are unadjusted recalculations from posted summary statistics, they should not be mistaken for model-adjusted estimates.

Precision is not the same as clinical importance. A narrow interval can still include effects that matter to patients, while a wide interval can leave several interpretations plausible. The registry does not report a clinical margin or a formal equivalence or non-inferiority framework. The primary result therefore supports cautious interpretation of the observed contrast, not a claim that the groups are equivalent or that a difference of a particular size has been ruled out.

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 sample-size display is a planning illustration based on the observed effect, not a record of the trial’s original design calculation. For these outcomes, the figures are participants per arm. The registry’s general planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect to detect is set to the stated fraction of the observed effect. The original trial’s sample-size assumptions are not reported in the registry record.

The 80% power column gives the illustrative number of participants per arm for a design with an 80% chance of detecting the stated effect under those planning assumptions, if that effect were the true one. The 90% power column uses a higher chance of detection and consequently requires more participants for a given effect scenario. These are design quantities, not a measure of the probability that the observed result is true. This is not observed power.

Each row represents planning for a different fraction of the observed effect. Planning for a smaller effect requires more participants because smaller differences are harder to distinguish from random variation. The sample-size curve is read in the same way: it illustrates how the planning requirement changes as the effect assumption changes. The figures are not a recommendation for a future study and should not be read as the actual enrollment target used in this trial.

The registry’s convention is that time-to-event planning displays give total numbers of events, while other displays give participants per arm. The posted outcomes discussed for this trial use participant counts or an infection rate rather than a time-to-event planning display, so the planning figures are participants per arm.

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, p₀ and p₁ are the control and treatment proportions, and p̄ is their average.

Worked calculation for this trial

1. Control proportion p₀ = 0.164; treatment proportion p₁ = 0.191; average p̄ = 0.177.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.5403 = 1.0589.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.5399 = 0.4544.
4. n = (1.0589 + 0.4544)² / (0.0272)² = 3,102.5, rounded up to 3,103 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
p0 <- 0.163841807909605                          # control proportion
p1 <- 0.191011235955056                          # treatment proportion
n_per_arm <- function(power, frac = 1) {
  q1 <- p0 + (p1 - p0) * frac               # smaller effect = fraction of the observed difference
  pbar <- (p0 + q1) / 2
  z_b <- qnorm(power)
  ceiling(round((z_a * sqrt(2 * pbar * (1 - pbar)) + z_b * sqrt(p0 * (1 - p0) + q1 * (1 - q1)))^2 / (q1 - p0)^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 (unrounded n per arm)
cat("power.prop.test:", round(power.prop.test(p1 = p0, p2 = p1, power = 0.80)$n, 1), "\n")

# Simulation: how often does the z-test reject at the 80%-power sample size?
set.seed(2644941)
n    <- n_per_arm(0.80)
reps <- 20000
x0 <- rbinom(reps, n, p0); x1 <- rbinom(reps, n, p1)
ph <- (x0 + x1) / (2 * n)
z  <- ((x1 - x0) / n) / sqrt(ph * (1 - ph) * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(z) > z_a, na.rm = TRUE), reps))

Output from running the code

100% of observed effect: n per arm = 3,103 (80% power), 4,153 (90% power)
 75% of observed effect: n per arm = 5,434 (80% power), 7,273 (90% power)
 50% of observed effect: n per arm = 12,037 (80% power), 16,114 (90% power)
power.prop.test: 3102.5 
Simulated power at n = 3,103 per arm: 0.802 (20000 replicates)

The simulation draws many pairs of event counts at the planned sample size and counts how often the two-proportion z-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

The registry lists 36 outcome measures and posts 29 secondary outcomes, but it lists no analyses. The record does not report how the primary and secondary outcomes were prioritized for statistical interpretation, whether a testing hierarchy was set in advance, or whether the family of comparisons was considered when interpreting p-values. It also does not report a multiplicity adjustment.

Multiplicity arises when several outcomes or comparisons are examined. Even if each individual test is conducted at a conventional significance level, making many tests can increase the chance of at least one apparently unusual result under a setting where no effects exist. Adjustments or a prespecified hierarchy can help manage that issue, but the record does not say whether any such approach was used outside the posted figures. The secondary p-values should consequently be read as unadjusted, and positive findings warrant caution.

Missing-data handling is also not reported in the registry record. The outcome counts are accompanied by arm denominators, but the record does not explain whether those denominators represent all randomized participants, participants with available outcome data, or another analysis population. It does not describe how missing assessments, withdrawal, loss to follow-up, or death before outcome assessment were handled. No assumptions for missing outcomes or sensitivity analyses are reported.

The registry does not report the original statistical analysis plan, the intended analysis populations, or whether analyses were adjusted for baseline characteristics or other factors. General methods for handling missingness and multiplicity depend on the study question and assumptions; they cannot be reconstructed from group-level counts alone. These omissions do not invalidate the posted summaries, but they constrain how confidently readers can assess whether the reported comparisons follow a prespecified plan and how robust the findings are to alternative analysis choices.

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 1.4% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: vascular access site thrombosis (45.8%), vascular stenosis (29.9%), pneumonia (10.1%), vascular access site infection (10.1%), vascular access site pseudoaneurysm (9.6%).

The adverse-event summary reports participants affected by serious adverse events and other adverse events in each group, along with deaths. In the HAV group, 157 participants are listed as affected by serious adverse events and 176 by other adverse events; deaths are listed as 46. In the ePTFE group, the corresponding figures are 146, 176, and 39. These are descriptive group counts, not estimates of a causal treatment effect.

The registry lists vascular access site thrombosis at 45.8% and vascular stenosis at 29.9% among the most frequently listed serious terms, followed by pneumonia and vascular access site infection at 10.1% each, vascular access site pseudoaneurysm at 9.6%, and sepsis at 7.3%. The denominator used for these percentages is not reported in the registry record, so they should not be interpreted as percentages of all randomized participants without further information.

Serious-event counts and deaths are important context but do not, on their own, establish whether an event was caused by a conduit or whether the groups differed in risk. The record does not provide event timing, severity detail beyond the listed serious-event classification, or an adjusted safety comparison.

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

The primary result describes the observed number of participants with loss of secondary patency at 12 months post-implantation in each randomized group. The unadjusted estimate is close to zero on the risk-difference scale, but its confidence interval is wide enough to include differences in either direction. The result therefore does not provide a precise estimate of the contrast between HAV and ePTFE on this endpoint.

It does not establish equivalence. Showing equivalence requires a prespecified margin and an analysis designed to assess whether the confidence interval lies within that margin. Neither is reported in the registry record. Likewise, the result does not establish non-inferiority, because the record does not report a non-inferiority margin or a corresponding analysis.

The primary endpoint allows interventions while access remains patent, so it should not be interpreted as a measure of uninterrupted function or freedom from procedures. The posted count does not report the duration of patency, the number or type of interventions, the timing of loss, or participant-level experience. The secondary outcomes add other perspectives but are not interchangeable with the primary endpoint and are reported without a documented multiplicity plan.

The findings also do not support a treatment recommendation. They are registry-level group summaries from a specific randomized comparison among patients needing hemodialysis access. The record does not report detailed baseline characteristics, follow-up completeness, the analysis population, or the methods used to handle missing data. Those gaps limit assessment of how representative the observed groups are and how sensitive the estimates may be to analysis choices.

The appropriate interpretation is therefore bounded: the posted primary comparison does not show a clear difference, but its uncertainty means it also cannot rule out potentially relevant differences in either direction. The study’s other posted outcomes and safety counts can inform a broader description, while requiring caution about unadjusted secondary comparisons and missing analysis detail.

17. Why This Trial Matters Statistically

This trial is statistically informative because it compares two conduit approaches using randomized allocation and reports outcomes that reflect different aspects of hemodialysis access. The primary endpoint makes an important distinction: continued secondary patency can include access that required interventions, while loss of secondary patency is tied to abandonment of the access circuit. That definition affects what the outcome means and what it can capture.

The result also illustrates why an estimate should be read together with its confidence interval. The primary risk difference is 0.027, but its interval extends across zero and includes effects in either direction. A point estimate alone can sound more definite than the data justify. The interval makes the uncertainty visible, while the p-value does not establish equivalence or tell readers whether any possible difference is clinically important.

The secondary outcomes show the value and challenge of examining several dimensions of access performance. Patency, abandonment, and infection rates are related, but they answer different questions and use different scales. A notable unadjusted secondary comparison should not automatically outweigh the primary result, especially when the record does not report a multiplicity strategy or a hierarchy for secondary outcomes.

Finally, the planning illustrations distinguish retrospective planning calculations from the trial’s actual design rationale. They show how assumptions about the effect to detect influence sample-size requirements, but they do not establish the original design assumptions or provide observed power. Together, these points make the record a useful example of separating endpoint definitions, effect estimates, uncertainty, secondary findings, and design information rather than reducing interpretation to a single p-value.

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.

The registry record leaves several trial-specific questions unanswered. It does not report baseline characteristics, site-level details, eligibility criteria beyond the broad clinical context, or the process used to choose between the two commercial ePTFE products. Without those details, readers cannot assess the balance and comparability of participant characteristics or the consistency of the comparator implementation.

Although allocation is listed as randomized, the method of sequence generation and allocation concealment is not reported. Masking is listed as none; the record does not explain whether outcome adjudication was blinded, even though one secondary outcome refers to adjudicated infections. The randomization unit and any stratification factors are also not reported.

The registry posts outcome counts and comparisons but does not describe follow-up completeness, missing outcomes, treatment deviations, or the analysis population. It does not report adjusted primary analyses or a detailed statistical analysis plan. These limits matter because group-level summaries cannot show whether missingness, censoring, or post-randomization events influenced the comparisons.

The primary endpoint is a count at a fixed follow-up time, and the registry does not provide the timing of loss of patency or intervention histories. The infection outcome uses a rate, but the record does not describe a check for over-dispersion or other model diagnostics. The denominator for the serious-event term percentages is also not reported.

Finally, the record does not report a multiplicity approach for the many outcomes, a clinical threshold for the primary contrast, or the assumptions used in the original sample-size calculation. These omissions limit confidence in interpreting secondary p-values and in judging whether the study was designed to resolve a particular clinically important difference.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Comparison of the Human Acellular Vessel (HAV) With ePTFE Grafts as Conduits for Hemodialysis — NCT02644941.
• Registry record last updated 2026-08-19; status last verified 2026-07.
• Results first posted 2025-03-30.
• 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

NCT02644941 is a completed, phase 3, randomized, open-label, parallel-group comparison of HAV and ePTFE grafts as conduits for hemodialysis. The listed enrollment is 355. The study began on 2016-05-24, with primary completion in 2019-05.

The primary outcome is the number of participants with loss of secondary patency at 12 months post-implantation. The posted unadjusted comparison is imprecise: its risk-difference confidence interval includes zero, and the record does not report an equivalence or non-inferiority framework. Secondary outcomes address patency, abandonment, and infection, while safety summaries list adverse-event counts and deaths. Interpretation is limited by absent analysis-plan, missing-data, and multiplicity details in the registry record.