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 DelIVery for Pulmonary Arterial Hypertension (PAH) & Continued Support Study (NCT01321073), a na na study. The primary outcome is Rate of Catheter-related Complications Per 1000 Patient Days.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01321073 |
| Phase | NA |
| Condition | Pulmonary Arterial Hypertension |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 64 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Medtronic Cardiac Rhythm and Heart Failure |
| Results posted | Yes |
2. Clinical Question
Population
People with pulmonary arterial hypertension enrolled for implantation of the Model 10642 Implantable Intravascular Catheter. The arm description says all enrolled subjects were intended to receive the catheter with the SynchroMed II Implantable Infusion System to deliver Remodulin Injection. The endpoint population is described as all days of follow-up for implanted patients.
Intervention
The intervention is the Model 10642 Implantable Intravascular Catheter, used with the SynchroMed II Implantable Infusion System to deliver Remodulin (treprostinil) Injection. The study purpose is to evaluate safety in this use.
Comparator
There is no concurrent comparator group in this single-group study. Allocation is recorded as NA. The results therefore do not provide a like-for-like comparison with another device, treatment, or usual care.
Primary question
What is the rate of catheter-related complications per 1000 patient-days from implantation through 2 years? A complication is defined as an adverse event requiring invasive intervention; catheter-related complications are counted, and pneumothoraxes are also included in the endpoint.
3. Trial Design
DelIVery for Pulmonary Arterial Hypertension (PAH) is a single-group clinical study of the Medtronic Model 10642 Implantable Intravascular Catheter. The catheter is used in combination with the SynchroMed II Implantable Infusion System (Model 8637) to deliver Remodulin Injection. The study condition is pulmonary arterial hypertension, and its stated purpose is to evaluate the safety of that device system in this use.
The registry lists enrollment as 64 and the study phase as NA. Allocation is also recorded as NA, and masking is listed as none. The arm description states that all subjects were enrolled for implantation of the catheter-system combination. This is not a randomized comparison: there is no separate control arm against which the observed experience can be directly compared.
The registry lists the study start as 2011-06 and primary completion as 2013-06. Its status is active, not recruiting. These record entries describe the administrative status and timeline; they do not, by themselves, establish how long any individual was followed or whether follow-up was complete.
The brief summary also explains a change in the study’s context. As of June 2021, approval of the Implantable System for Remodulin was no longer being pursued, and development and commercialization efforts had been halted. The protocol was amended to allow continued support for approximately 30 subjects still implanted with the PIVoT system. The registry record does not provide further details about how that ongoing support was implemented or how it relates to the primary endpoint analysis.
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 | DelIVery for Pulmonary Arterial Hypertension Single Arm |
|---|---|
| STARTED | 64 |
| COMPLETED | 57 |
| NOT COMPLETED | 7 |
Reasons for not completing this period:
| Reason | DelIVery for Pulmonary Arterial Hypertension Single Arm |
|---|---|
| Did not attempt implant | 4 |
| Death | 3 |
Analysis population for the primary outcome, as defined in the registry: All days of follow-up for implanted patients
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.
Population: All patients attempting implant
| Characteristic | Unit | DelIVery for Pulmonary Arterial Hypertension Single Arm |
|---|---|---|
| Participants analysed | 60 | |
| Age, Continuous | years | 50.1 (SD 13.5) |
| Sex: Female, Male: Female | Participants | 48 |
| Sex: Female, Male: Male | Participants | 12 |
| Race/Ethnicity, Customized: Asian | Participants | 2 |
| Race/Ethnicity, Customized: Black or African American | Participants | 3 |
| Race/Ethnicity, Customized: Hispanic or Latino | Participants | 8 |
| Race/Ethnicity, Customized: White or Caucasian | Participants | 47 |
| Region of Enrollment: United States | Participants | 60 |
6. Primary Endpoint
The registry lists the primary outcome as Rate of Catheter-related Complications Per 1000 Patient Days, measured over Implant to 2 years.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | complications per 1000 patient-days |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the rate of catheter-related complications per 1000 patient-days, with a timeframe from implantation to 2 years. A complication is defined as an adverse event that required an invasive intervention. The endpoint counts complications related to the implanted catheter and also includes pneumothoraxes.
This is an exposure-adjusted rate rather than a simple proportion of people with at least one complication. Patient-days represent time under observation while implanted; using time at risk as the denominator can describe how frequently events occur over accumulated follow-up, including when participants contribute different lengths of observation. That is a general feature of rate endpoints, not a statement about the follow-up distribution in this study.
The registry describes the endpoint population as all days of follow-up for implanted patients. The record does not include the numerical primary endpoint result, the event count used in its calculation, the total patient-days, or a confidence interval. Consequently, the endpoint definition can be interpreted, but the rate’s magnitude and precision cannot be assessed from the registry record.
Including pneumothoraxes as part of the endpoint is an explicit feature of the stated definition. The record does not give a separate endpoint result for those events, so their contribution to the overall rate is not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes a safety-focused, single-group study and specifies a catheter-complication rate as its primary endpoint. It does not report the numerical value of that rate. Without the event total and the accumulated patient-days, it is not possible to describe the observed rate or its precision. No confidence interval or other uncertainty measure for the primary endpoint is reported in the registry record.
The endpoint is expressed per 1000 patient-days and covers follow-up from implantation to 2 years. Such a rate uses time under observation as its exposure denominator; it is not interchangeable with the proportion of participants who experienced at least one event. As a general statistical point, the interpretation of an exposure-adjusted rate depends on the event definition, how follow-up time is accumulated, and whether event recurrence is counted. The registry provides the event definition but does not report the rate’s component counts or details of event recurrence handling.
The single-group design means the recorded experience has no concurrent control group. It can describe the observed experience under the study’s conditions if outcome results are available, but it cannot isolate a treatment or device effect from differences in patient characteristics, care, follow-up, or other influences through a randomized comparison. There is no basis in this record for a comparative estimate.
The adverse-event entries are separate from the unavailable primary endpoint result. The registry lists serious adverse event fields of 60 at risk and 29 affected, and other adverse event fields of 60 at risk and 57 affected; it also lists 3 deaths. These entries should be read as safety-record information, not as the catheter-complication rate. The registry also gives percentages for selected serious-event terms, but does not state the denominator or provide a term-specific event count alongside each percentage.
Accordingly, the posted results support describing the study design, endpoint definition, and listed safety entries. They do not support a conclusion about the size or precision of the primary complication rate, a comparison against another approach, or a causal claim. The absence of a reported endpoint value is an information gap in the registry record, not evidence that the rate was zero or that no complications occurred.
9. Statistical Methods Explained
The primary outcome is a count-based rate: catheter-related complications are counted over patient-days of follow-up. In general, a rate places an event count over accumulated time at risk. This can be useful when participants contribute different amounts of observed time, because the denominator reflects exposure rather than treating every participant as if observed for an identical period. Here, the registry specifies the unit as complications per 1000 patient-days and the timeframe as implantation to 2 years. It does not report the event count, patient-day total, or numerical rate.
What does a rate describe?
A rate describes event occurrence relative to accumulated observation time. It is distinct from a risk or proportion, which describes the share of a defined group experiencing an event over a specified period. A participant can contribute follow-up time without experiencing a complication; a participant with more than one event may contribute multiple events if the analysis counts recurrences. The registry record does not say whether recurrent complications were counted separately or how the time at risk was handled after a complication.
Patient-days are the stated denominator unit, but the record does not provide the total amount of follow-up contributing to the endpoint. Nor does it explain censoring, loss to follow-up, or the handling of time after device removal, death, or an endpoint event. These details matter because rate estimates depend on which observation time is included and which events qualify. The endpoint definition does clarify that an adverse event must require invasive intervention, must be related to the implanted catheter, and that pneumothoraxes are included.
Why does uncertainty matter?
An estimate from observed events is subject to sampling uncertainty. A confidence interval is a general way to communicate that uncertainty: it gives a range of values compatible with the data under the method’s assumptions. A narrow interval indicates greater precision than a wide interval, but the interval itself does not establish that the study design was unbiased or that the endpoint was completely ascertained. No confidence interval for the primary endpoint is reported in the registry record, so its precision cannot be evaluated from this record.
For count data, a simple model may assume that event counts vary according to a particular probability distribution. In general, over-dispersion means the observed variability is greater than that assumed by a basic count model. If present and ignored, standard errors can be too small and confidence intervals can be too narrow. This is a general methodological consideration, not a statement that over-dispersion was assessed or found in this study. The registry record does not report the statistical model, variance assumptions, or any adjustment for over-dispersion.
What does the study design allow?
The study is listed as single-group, with no masking and allocation recorded as NA. The endpoint rate is therefore not a randomized contrast between groups. A single-group rate can characterize observed events relative to observed time, but by itself it does not estimate how the same participants would have fared under a different device or treatment. Differences in follow-up, participant characteristics, and other factors cannot be separated from device experience through a concurrent randomized comparison in this design.
The registry record does not report a statistical analysis plan, a model used to estimate the primary rate, a confidence-interval method, or a hypothesis test for that outcome. It also does not report an adjusted estimate. No recalculated estimate is available from the posted summary information, and there is no sponsor analysis of the primary endpoint included for comparison.
How should the planning illustration be read?
The planning assumptions describe an illustration based on an observed effect, not the study’s own design. They specify a two-sided significance level of 0.05, equal allocation between two hypothetical arms, and a normal approximation; the effect to detect is described as a stated fraction of the observed effect. For time-to-event illustrations, the stated output is a total event count; other illustrations are expressed as participants per arm. These are planning concepts, not observed trial findings and not observed power.
The study itself is single-group, so the hypothetical equal-allocation comparison does not describe its enrollment or actual design. The registry record does not report the calculated planning values or the observed primary endpoint effect needed to interpret such an illustration. It also does not report the protocol’s sample-size justification. A planning illustration cannot fill in those missing design details or be treated as evidence that the study had a particular probability of detecting an effect.
10. Multiplicity, Missing Data and Analysis Populations
The registry record identifies one primary outcome measure and one analysis. It does not report whether additional outcome analyses were planned, whether any interim analyses took place, or how multiple outcomes or repeated analyses were handled. The number of listed measures alone does not establish the full analysis plan or whether multiplicity adjustments were considered.
Missing-data procedures and analysis populations are not described in the registry record. The primary endpoint population is described as all days of follow-up for implanted patients, but the record does not explain which participants contributed to the analysis, how incomplete follow-up was handled, or whether any participants were excluded. It also does not report missingness by outcome, reasons for missing data, censoring rules, or sensitivity analyses.
These omissions limit interpretation of the endpoint independently of its missing numerical result. For a rate, incomplete observation can affect both the event count and the patient-time denominator. General statistical practice is to describe how both are assembled and to examine whether missing follow-up could influence the estimate. The registry record does not provide those details, so no specific missing-data approach or analysis population should be inferred.
The record also does not report a statistical analysis plan or a prespecified method for the primary endpoint. Whether estimates were adjusted, how uncertainty was calculated, and whether any subgroup analyses were performed 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 |
|---|---|---|---|
| Single Arm | 29 | 60 | 48.3% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Single Arm | 3 of 60 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Single Arm | 57 of 60 |
Most frequent serious adverse event terms
| Event term | Organ system | Single Arm |
|---|---|---|
| Immediate post-injection reaction | General disorders | 3 of 60 |
| Atrial fibrillation | Cardiac disorders | 2 of 60 |
| Device dislocation | General disorders | 2 of 60 |
| Fluid overload | Metabolism and nutrition disorders | 2 of 60 |
| Pneumothorax | Respiratory, thoracic and mediastinal disorders | 2 of 60 |
| Anaemia | Blood and lymphatic system disorders | 1 of 60 |
| Autoimmune thrombocytopenia | Blood and lymphatic system disorders | 1 of 60 |
| Angina unstable | Cardiac disorders | 1 of 60 |
| Atrial flutter | Cardiac disorders | 1 of 60 |
| Cardiac failure | Cardiac disorders | 1 of 60 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Single Arm |
|---|---|---|
| Implant site pain | General disorders | 51 of 60 |
| Upper respiratory tract infection | Infections and infestations | 17 of 60 |
| Nausea | Gastrointestinal disorders | 11 of 60 |
| Implant site bruising | General disorders | 10 of 60 |
| Dyspnoea | Respiratory, thoracic and mediastinal disorders | 10 of 60 |
| Injection site reaction | General disorders | 9 of 60 |
| Hypotension | Vascular disorders | 9 of 60 |
| Headache | Nervous system disorders | 8 of 60 |
| Pulmonary arterial hypertension | Respiratory, thoracic and mediastinal disorders | 8 of 60 |
| Pain in extremity | Musculoskeletal and connective tissue disorders | 7 of 60 |
Serious events with the highest arm-level rate: immediate post-injection reaction (5.0%), atrial fibrillation (3.3%), device dislocation (3.3%), fluid overload (3.3%), pneumothorax (3.3%).
The registry lists a single-arm safety group with 60 at risk and 29 affected for serious adverse events, and 60 at risk and 57 affected for other adverse events. It lists 3 deaths. These are registry safety entries and should not be treated as the primary catheter-complication rate: the endpoint is defined by invasive intervention, catheter relationship, and inclusion of pneumothoraxes, while the listed adverse-event fields are not presented as that endpoint’s calculation.
The registry gives these serious-event terms and percentages: Immediate post-injection reaction, 5.0%; Atrial fibrillation, 3.3%; Device dislocation, 3.3%; Fluid overload, 3.3%; Pneumothorax, 3.3%; and Anaemia, 1.7%. The denominator for these percentages and term-specific event counts are not reported in the registry record. The listed percentages therefore should not be converted into counts or assumed to use the same denominator as the at-risk and affected fields.
These figures describe recorded safety information; they do not establish that an event was caused by the device or treatment. The registry record does not provide further details about event timing, duration, relatedness assessment, or overlap among people experiencing different events.
12. What the Result Does, and Does Not, Mean
The DelIVery study addresses a defined safety question: the rate of specified catheter-related complications per 1000 patient-days from implantation to 2 years. It uses a single-group design and identifies the catheter used with the SynchroMed II implantable infusion system to deliver Remodulin. The registry record supplies the endpoint definition, but not the numerical endpoint result or its uncertainty.
That distinction is central. The design and endpoint describe what the study set out to assess; they do not reveal the observed rate. Without the numerical result, event count, patient-days, and a measure of precision, the magnitude and reliability of the primary endpoint estimate cannot be evaluated. The missing result should not be interpreted as a rate of zero, as absence of complications, or as evidence in favor of or against the device system.
Because there is no concurrent comparator, the study also does not provide a randomized estimate of how outcomes differ between this system and another option. A single-group safety record may describe observed events in the enrolled group, but it cannot by itself establish what would have happened to the same participants under a different approach. The registry does not provide a basis for a causal comparison.
The safety entries offer additional descriptive information, including the reported serious adverse event fields, other adverse event fields, selected terms and percentages, and deaths. They are not interchangeable with the primary endpoint, and the record does not provide enough detail to infer event attribution or the denominators behind the term percentages.
Thus, the record supports a careful account of the study’s purpose, design, endpoint definition, status, and listed safety information. It does not support a quantitative conclusion about the primary complication rate, a comparative conclusion, or an inference about the effect of the system. Those limits reflect what is and is not reported in the registry record.
13. Why This Trial Matters Statistically
This study illustrates why an endpoint’s definition and denominator matter. The primary outcome is not simply the number of participants who experienced a complication: it is a complication rate per 1000 patient-days. The event definition includes a requirement for invasive intervention, a relationship to the implanted catheter, and an explicit inclusion of pneumothoraxes. Each element shapes what the rate represents and what events it can include.
It also shows the limits of interpreting a single-group safety study. The study has no concurrent control group, so the observed experience cannot be directly contrasted with a randomized comparator. This is a design constraint, not a defect that can be resolved by statistical adjustment alone. Any description of the study must distinguish safety monitoring in one group from a comparative estimate.
The record’s context is also relevant to how the study is understood. It states that approval was no longer being pursued and development and commercialization efforts had been halted as of June 2021. The protocol was amended to allow continued support for approximately 30 subjects still implanted with the PIVoT system. The record does not explain how those activities relate to the primary endpoint result, which is not numerically reported.
Finally, the record demonstrates the difference between an endpoint specification and an endpoint finding. A precise definition makes the intended measurement understandable, but a result and an uncertainty measure are needed to assess its magnitude and precision. The listed safety entries add context but cannot substitute for the missing primary rate.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The most important limitation for interpreting the primary outcome is that its numerical result is not reported in the registry record. The record also omits the event count, accumulated patient-days, and confidence interval. Without these, the rate’s magnitude and precision cannot be assessed.
The single-group design has no concurrent control arm. It therefore cannot provide a randomized comparison with another device or treatment. The record lists allocation as NA and masking as none; it does not describe any method that would address the lack of a comparator.
Several details needed to understand the endpoint analysis are not reported in the registry record. These include the statistical model, uncertainty method, recurrence handling, censoring rules, treatment of time after an event or device removal, and handling of incomplete follow-up. The analysis population is described in terms of follow-up days for implanted patients, but eligibility and inclusion details for the reported analysis are not given.
The adverse-event information has its own interpretive limits. The record lists affected and at-risk counts and selected serious-event terms with percentages, but does not state the denominators for those percentages or provide term-specific counts. It also does not report details about timing, relatedness, or overlap among events. The registry entries should therefore be read descriptively and not as a complete account of event attribution.
Finally, the registry does not report the protocol’s sample-size justification, statistical analysis plan, interim-analysis approach, or missing-data methods. The planning assumptions described for an illustration are not evidence of the trial’s own design choices. These omissions limit assessment of both the analysis and the completeness of the reported record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: DelIVery for Pulmonary Arterial Hypertension (PAH) & Continued Support Study — NCT01321073.
- Registry record last updated 2026-01-26; status last verified 2025-12.
- Results first posted 2018-05-04.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
The DelIVery for PAH study is a single-group, unmasked device study in pulmonary arterial hypertension. It evaluates the Model 10642 Implantable Intravascular Catheter used with the SynchroMed II Implantable Infusion System to deliver Remodulin Injection. Enrollment is listed as 64; phase and allocation are recorded as NA.
The primary outcome is catheter-related complications per 1000 patient-days from implantation to 2 years. Complications require invasive intervention, and pneumothoraxes are included. The registry record does not report a numerical result or confidence interval for this endpoint.
The record lists the study start as 2011-06, primary completion as 2013-06, and status as active, not recruiting. It also lists safety fields of 60 at risk and 29 affected for serious adverse events, 60 at risk and 57 affected for other adverse events, and 3 deaths. These safety entries do not replace the unreported primary endpoint result.